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Linux/kernel/trace/trace_events_filter.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * trace_events_filter - generic event filtering
  4  *
  5  * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
  6  */
  7 
  8 #include <linux/module.h>
  9 #include <linux/ctype.h>
 10 #include <linux/mutex.h>
 11 #include <linux/perf_event.h>
 12 #include <linux/slab.h>
 13 
 14 #include "trace.h"
 15 #include "trace_output.h"
 16 
 17 #define DEFAULT_SYS_FILTER_MESSAGE                                      \
 18         "### global filter ###\n"                                       \
 19         "# Use this to set filters for multiple events.\n"              \
 20         "# Only events with the given fields will be affected.\n"       \
 21         "# If no events are modified, an error message will be displayed here"
 22 
 23 /* Due to token parsing '<=' must be before '<' and '>=' must be before '>' */
 24 #define OPS                                     \
 25         C( OP_GLOB,     "~"  ),                 \
 26         C( OP_NE,       "!=" ),                 \
 27         C( OP_EQ,       "==" ),                 \
 28         C( OP_LE,       "<=" ),                 \
 29         C( OP_LT,       "<"  ),                 \
 30         C( OP_GE,       ">=" ),                 \
 31         C( OP_GT,       ">"  ),                 \
 32         C( OP_BAND,     "&"  ),                 \
 33         C( OP_MAX,      NULL )
 34 
 35 #undef C
 36 #define C(a, b) a
 37 
 38 enum filter_op_ids { OPS };
 39 
 40 #undef C
 41 #define C(a, b) b
 42 
 43 static const char * ops[] = { OPS };
 44 
 45 /*
 46  * pred functions are OP_LE, OP_LT, OP_GE, OP_GT, and OP_BAND
 47  * pred_funcs_##type below must match the order of them above.
 48  */
 49 #define PRED_FUNC_START                 OP_LE
 50 #define PRED_FUNC_MAX                   (OP_BAND - PRED_FUNC_START)
 51 
 52 #define ERRORS                                                          \
 53         C(NONE,                 "No error"),                            \
 54         C(INVALID_OP,           "Invalid operator"),                    \
 55         C(TOO_MANY_OPEN,        "Too many '('"),                        \
 56         C(TOO_MANY_CLOSE,       "Too few '('"),                         \
 57         C(MISSING_QUOTE,        "Missing matching quote"),              \
 58         C(OPERAND_TOO_LONG,     "Operand too long"),                    \
 59         C(EXPECT_STRING,        "Expecting string field"),              \
 60         C(EXPECT_DIGIT,         "Expecting numeric field"),             \
 61         C(ILLEGAL_FIELD_OP,     "Illegal operation for field type"),    \
 62         C(FIELD_NOT_FOUND,      "Field not found"),                     \
 63         C(ILLEGAL_INTVAL,       "Illegal integer value"),               \
 64         C(BAD_SUBSYS_FILTER,    "Couldn't find or set field in one of a subsystem's events"), \
 65         C(TOO_MANY_PREDS,       "Too many terms in predicate expression"), \
 66         C(INVALID_FILTER,       "Meaningless filter expression"),       \
 67         C(IP_FIELD_ONLY,        "Only 'ip' field is supported for function trace"), \
 68         C(INVALID_VALUE,        "Invalid value (did you forget quotes)?"), \
 69         C(ERRNO,                "Error"),                               \
 70         C(NO_FILTER,            "No filter found")
 71 
 72 #undef C
 73 #define C(a, b)         FILT_ERR_##a
 74 
 75 enum { ERRORS };
 76 
 77 #undef C
 78 #define C(a, b)         b
 79 
 80 static const char *err_text[] = { ERRORS };
 81 
 82 /* Called after a '!' character but "!=" and "!~" are not "not"s */
 83 static bool is_not(const char *str)
 84 {
 85         switch (str[1]) {
 86         case '=':
 87         case '~':
 88                 return false;
 89         }
 90         return true;
 91 }
 92 
 93 /**
 94  * prog_entry - a singe entry in the filter program
 95  * @target:          Index to jump to on a branch (actually one minus the index)
 96  * @when_to_branch:  The value of the result of the predicate to do a branch
 97  * @pred:            The predicate to execute.
 98  */
 99 struct prog_entry {
100         int                     target;
101         int                     when_to_branch;
102         struct filter_pred      *pred;
103 };
104 
105 /**
106  * update_preds- assign a program entry a label target
107  * @prog: The program array
108  * @N: The index of the current entry in @prog
109  * @when_to_branch: What to assign a program entry for its branch condition
110  *
111  * The program entry at @N has a target that points to the index of a program
112  * entry that can have its target and when_to_branch fields updated.
113  * Update the current program entry denoted by index @N target field to be
114  * that of the updated entry. This will denote the entry to update if
115  * we are processing an "||" after an "&&"
116  */
117 static void update_preds(struct prog_entry *prog, int N, int invert)
118 {
119         int t, s;
120 
121         t = prog[N].target;
122         s = prog[t].target;
123         prog[t].when_to_branch = invert;
124         prog[t].target = N;
125         prog[N].target = s;
126 }
127 
128 struct filter_parse_error {
129         int lasterr;
130         int lasterr_pos;
131 };
132 
133 static void parse_error(struct filter_parse_error *pe, int err, int pos)
134 {
135         pe->lasterr = err;
136         pe->lasterr_pos = pos;
137 }
138 
139 typedef int (*parse_pred_fn)(const char *str, void *data, int pos,
140                              struct filter_parse_error *pe,
141                              struct filter_pred **pred);
142 
143 enum {
144         INVERT          = 1,
145         PROCESS_AND     = 2,
146         PROCESS_OR      = 4,
147 };
148 
149 /*
150  * Without going into a formal proof, this explains the method that is used in
151  * parsing the logical expressions.
152  *
153  * For example, if we have: "a && !(!b || (c && g)) || d || e && !f"
154  * The first pass will convert it into the following program:
155  *
156  * n1: r=a;       l1: if (!r) goto l4;
157  * n2: r=b;       l2: if (!r) goto l4;
158  * n3: r=c; r=!r; l3: if (r) goto l4;
159  * n4: r=g; r=!r; l4: if (r) goto l5;
160  * n5: r=d;       l5: if (r) goto T
161  * n6: r=e;       l6: if (!r) goto l7;
162  * n7: r=f; r=!r; l7: if (!r) goto F
163  * T: return TRUE
164  * F: return FALSE
165  *
166  * To do this, we use a data structure to represent each of the above
167  * predicate and conditions that has:
168  *
169  *  predicate, when_to_branch, invert, target
170  *
171  * The "predicate" will hold the function to determine the result "r".
172  * The "when_to_branch" denotes what "r" should be if a branch is to be taken
173  * "&&" would contain "!r" or (0) and "||" would contain "r" or (1).
174  * The "invert" holds whether the value should be reversed before testing.
175  * The "target" contains the label "l#" to jump to.
176  *
177  * A stack is created to hold values when parentheses are used.
178  *
179  * To simplify the logic, the labels will start at 0 and not 1.
180  *
181  * The possible invert values are 1 and 0. The number of "!"s that are in scope
182  * before the predicate determines the invert value, if the number is odd then
183  * the invert value is 1 and 0 otherwise. This means the invert value only
184  * needs to be toggled when a new "!" is introduced compared to what is stored
185  * on the stack, where parentheses were used.
186  *
187  * The top of the stack and "invert" are initialized to zero.
188  *
189  * ** FIRST PASS **
190  *
191  * #1 A loop through all the tokens is done:
192  *
193  * #2 If the token is an "(", the stack is push, and the current stack value
194  *    gets the current invert value, and the loop continues to the next token.
195  *    The top of the stack saves the "invert" value to keep track of what
196  *    the current inversion is. As "!(a && !b || c)" would require all
197  *    predicates being affected separately by the "!" before the parentheses.
198  *    And that would end up being equivalent to "(!a || b) && !c"
199  *
200  * #3 If the token is an "!", the current "invert" value gets inverted, and
201  *    the loop continues. Note, if the next token is a predicate, then
202  *    this "invert" value is only valid for the current program entry,
203  *    and does not affect other predicates later on.
204  *
205  * The only other acceptable token is the predicate string.
206  *
207  * #4 A new entry into the program is added saving: the predicate and the
208  *    current value of "invert". The target is currently assigned to the
209  *    previous program index (this will not be its final value).
210  *
211  * #5 We now enter another loop and look at the next token. The only valid
212  *    tokens are ")", "&&", "||" or end of the input string "\0".
213  *
214  * #6 The invert variable is reset to the current value saved on the top of
215  *    the stack.
216  *
217  * #7 The top of the stack holds not only the current invert value, but also
218  *    if a "&&" or "||" needs to be processed. Note, the "&&" takes higher
219  *    precedence than "||". That is "a && b || c && d" is equivalent to
220  *    "(a && b) || (c && d)". Thus the first thing to do is to see if "&&" needs
221  *    to be processed. This is the case if an "&&" was the last token. If it was
222  *    then we call update_preds(). This takes the program, the current index in
223  *    the program, and the current value of "invert".  More will be described
224  *    below about this function.
225  *
226  * #8 If the next token is "&&" then we set a flag in the top of the stack
227  *    that denotes that "&&" needs to be processed, break out of this loop
228  *    and continue with the outer loop.
229  *
230  * #9 Otherwise, if a "||" needs to be processed then update_preds() is called.
231  *    This is called with the program, the current index in the program, but
232  *    this time with an inverted value of "invert" (that is !invert). This is
233  *    because the value taken will become the "when_to_branch" value of the
234  *    program.
235  *    Note, this is called when the next token is not an "&&". As stated before,
236  *    "&&" takes higher precedence, and "||" should not be processed yet if the
237  *    next logical operation is "&&".
238  *
239  * #10 If the next token is "||" then we set a flag in the top of the stack
240  *     that denotes that "||" needs to be processed, break out of this loop
241  *     and continue with the outer loop.
242  *
243  * #11 If this is the end of the input string "\0" then we break out of both
244  *     loops.
245  *
246  * #12 Otherwise, the next token is ")", where we pop the stack and continue
247  *     this inner loop.
248  *
249  * Now to discuss the update_pred() function, as that is key to the setting up
250  * of the program. Remember the "target" of the program is initialized to the
251  * previous index and not the "l" label. The target holds the index into the
252  * program that gets affected by the operand. Thus if we have something like
253  *  "a || b && c", when we process "a" the target will be "-1" (undefined).
254  * When we process "b", its target is "", which is the index of "a", as that's
255  * the predicate that is affected by "||". But because the next token after "b"
256  * is "&&" we don't call update_preds(). Instead continue to "c". As the
257  * next token after "c" is not "&&" but the end of input, we first process the
258  * "&&" by calling update_preds() for the "&&" then we process the "||" by
259  * callin updates_preds() with the values for processing "||".
260  *
261  * What does that mean? What update_preds() does is to first save the "target"
262  * of the program entry indexed by the current program entry's "target"
263  * (remember the "target" is initialized to previous program entry), and then
264  * sets that "target" to the current index which represents the label "l#".
265  * That entry's "when_to_branch" is set to the value passed in (the "invert"
266  * or "!invert"). Then it sets the current program entry's target to the saved
267  * "target" value (the old value of the program that had its "target" updated
268  * to the label).
269  *
270  * Looking back at "a || b && c", we have the following steps:
271  *  "a"  - prog[0] = { "a", X, -1 } // pred, when_to_branch, target
272  *  "||" - flag that we need to process "||"; continue outer loop
273  *  "b"  - prog[1] = { "b", X, 0 }
274  *  "&&" - flag that we need to process "&&"; continue outer loop
275  * (Notice we did not process "||")
276  *  "c"  - prog[2] = { "c", X, 1 }
277  *  update_preds(prog, 2, 0); // invert = 0 as we are processing "&&"
278  *    t = prog[2].target; // t = 1
279  *    s = prog[t].target; // s = 0
280  *    prog[t].target = 2; // Set target to "l2"
281  *    prog[t].when_to_branch = 0;
282  *    prog[2].target = s;
283  * update_preds(prog, 2, 1); // invert = 1 as we are now processing "||"
284  *    t = prog[2].target; // t = 0
285  *    s = prog[t].target; // s = -1
286  *    prog[t].target = 2; // Set target to "l2"
287  *    prog[t].when_to_branch = 1;
288  *    prog[2].target = s;
289  *
290  * #13 Which brings us to the final step of the first pass, which is to set
291  *     the last program entry's when_to_branch and target, which will be
292  *     when_to_branch = 0; target = N; ( the label after the program entry after
293  *     the last program entry processed above).
294  *
295  * If we denote "TRUE" to be the entry after the last program entry processed,
296  * and "FALSE" the program entry after that, we are now done with the first
297  * pass.
298  *
299  * Making the above "a || b && c" have a progam of:
300  *  prog[0] = { "a", 1, 2 }
301  *  prog[1] = { "b", 0, 2 }
302  *  prog[2] = { "c", 0, 3 }
303  *
304  * Which translates into:
305  * n0: r = a; l0: if (r) goto l2;
306  * n1: r = b; l1: if (!r) goto l2;
307  * n2: r = c; l2: if (!r) goto l3;  // Which is the same as "goto F;"
308  * T: return TRUE; l3:
309  * F: return FALSE
310  *
311  * Although, after the first pass, the program is correct, it is
312  * inefficient. The simple sample of "a || b && c" could be easily been
313  * converted into:
314  * n0: r = a; if (r) goto T
315  * n1: r = b; if (!r) goto F
316  * n2: r = c; if (!r) goto F
317  * T: return TRUE;
318  * F: return FALSE;
319  *
320  * The First Pass is over the input string. The next too passes are over
321  * the program itself.
322  *
323  * ** SECOND PASS **
324  *
325  * Which brings us to the second pass. If a jump to a label has the
326  * same condition as that label, it can instead jump to its target.
327  * The original example of "a && !(!b || (c && g)) || d || e && !f"
328  * where the first pass gives us:
329  *
330  * n1: r=a;       l1: if (!r) goto l4;
331  * n2: r=b;       l2: if (!r) goto l4;
332  * n3: r=c; r=!r; l3: if (r) goto l4;
333  * n4: r=g; r=!r; l4: if (r) goto l5;
334  * n5: r=d;       l5: if (r) goto T
335  * n6: r=e;       l6: if (!r) goto l7;
336  * n7: r=f; r=!r; l7: if (!r) goto F:
337  * T: return TRUE;
338  * F: return FALSE
339  *
340  * We can see that "l3: if (r) goto l4;" and at l4, we have "if (r) goto l5;".
341  * And "l5: if (r) goto T", we could optimize this by converting l3 and l4
342  * to go directly to T. To accomplish this, we start from the last
343  * entry in the program and work our way back. If the target of the entry
344  * has the same "when_to_branch" then we could use that entry's target.
345  * Doing this, the above would end up as:
346  *
347  * n1: r=a;       l1: if (!r) goto l4;
348  * n2: r=b;       l2: if (!r) goto l4;
349  * n3: r=c; r=!r; l3: if (r) goto T;
350  * n4: r=g; r=!r; l4: if (r) goto T;
351  * n5: r=d;       l5: if (r) goto T;
352  * n6: r=e;       l6: if (!r) goto F;
353  * n7: r=f; r=!r; l7: if (!r) goto F;
354  * T: return TRUE
355  * F: return FALSE
356  *
357  * In that same pass, if the "when_to_branch" doesn't match, we can simply
358  * go to the program entry after the label. That is, "l2: if (!r) goto l4;"
359  * where "l4: if (r) goto T;", then we can convert l2 to be:
360  * "l2: if (!r) goto n5;".
361  *
362  * This will have the second pass give us:
363  * n1: r=a;       l1: if (!r) goto n5;
364  * n2: r=b;       l2: if (!r) goto n5;
365  * n3: r=c; r=!r; l3: if (r) goto T;
366  * n4: r=g; r=!r; l4: if (r) goto T;
367  * n5: r=d;       l5: if (r) goto T
368  * n6: r=e;       l6: if (!r) goto F;
369  * n7: r=f; r=!r; l7: if (!r) goto F
370  * T: return TRUE
371  * F: return FALSE
372  *
373  * Notice, all the "l#" labels are no longer used, and they can now
374  * be discarded.
375  *
376  * ** THIRD PASS **
377  *
378  * For the third pass we deal with the inverts. As they simply just
379  * make the "when_to_branch" get inverted, a simple loop over the
380  * program to that does: "when_to_branch ^= invert;" will do the
381  * job, leaving us with:
382  * n1: r=a; if (!r) goto n5;
383  * n2: r=b; if (!r) goto n5;
384  * n3: r=c: if (!r) goto T;
385  * n4: r=g; if (!r) goto T;
386  * n5: r=d; if (r) goto T
387  * n6: r=e; if (!r) goto F;
388  * n7: r=f; if (r) goto F
389  * T: return TRUE
390  * F: return FALSE
391  *
392  * As "r = a; if (!r) goto n5;" is obviously the same as
393  * "if (!a) goto n5;" without doing anything we can interperate the
394  * program as:
395  * n1: if (!a) goto n5;
396  * n2: if (!b) goto n5;
397  * n3: if (!c) goto T;
398  * n4: if (!g) goto T;
399  * n5: if (d) goto T
400  * n6: if (!e) goto F;
401  * n7: if (f) goto F
402  * T: return TRUE
403  * F: return FALSE
404  *
405  * Since the inverts are discarded at the end, there's no reason to store
406  * them in the program array (and waste memory). A separate array to hold
407  * the inverts is used and freed at the end.
408  */
409 static struct prog_entry *
410 predicate_parse(const char *str, int nr_parens, int nr_preds,
411                 parse_pred_fn parse_pred, void *data,
412                 struct filter_parse_error *pe)
413 {
414         struct prog_entry *prog_stack;
415         struct prog_entry *prog;
416         const char *ptr = str;
417         char *inverts = NULL;
418         int *op_stack;
419         int *top;
420         int invert = 0;
421         int ret = -ENOMEM;
422         int len;
423         int N = 0;
424         int i;
425 
426         nr_preds += 2; /* For TRUE and FALSE */
427 
428         op_stack = kmalloc_array(nr_parens, sizeof(*op_stack), GFP_KERNEL);
429         if (!op_stack)
430                 return ERR_PTR(-ENOMEM);
431         prog_stack = kcalloc(nr_preds, sizeof(*prog_stack), GFP_KERNEL);
432         if (!prog_stack) {
433                 parse_error(pe, -ENOMEM, 0);
434                 goto out_free;
435         }
436         inverts = kmalloc_array(nr_preds, sizeof(*inverts), GFP_KERNEL);
437         if (!inverts) {
438                 parse_error(pe, -ENOMEM, 0);
439                 goto out_free;
440         }
441 
442         top = op_stack;
443         prog = prog_stack;
444         *top = 0;
445 
446         /* First pass */
447         while (*ptr) {                                          /* #1 */
448                 const char *next = ptr++;
449 
450                 if (isspace(*next))
451                         continue;
452 
453                 switch (*next) {
454                 case '(':                                       /* #2 */
455                         if (top - op_stack > nr_parens)
456                                 return ERR_PTR(-EINVAL);
457                         *(++top) = invert;
458                         continue;
459                 case '!':                                       /* #3 */
460                         if (!is_not(next))
461                                 break;
462                         invert = !invert;
463                         continue;
464                 }
465 
466                 if (N >= nr_preds) {
467                         parse_error(pe, FILT_ERR_TOO_MANY_PREDS, next - str);
468                         goto out_free;
469                 }
470 
471                 inverts[N] = invert;                            /* #4 */
472                 prog[N].target = N-1;
473 
474                 len = parse_pred(next, data, ptr - str, pe, &prog[N].pred);
475                 if (len < 0) {
476                         ret = len;
477                         goto out_free;
478                 }
479                 ptr = next + len;
480 
481                 N++;
482 
483                 ret = -1;
484                 while (1) {                                     /* #5 */
485                         next = ptr++;
486                         if (isspace(*next))
487                                 continue;
488 
489                         switch (*next) {
490                         case ')':
491                         case '\0':
492                                 break;
493                         case '&':
494                         case '|':
495                                 /* accepting only "&&" or "||" */
496                                 if (next[1] == next[0]) {
497                                         ptr++;
498                                         break;
499                                 }
500                                 /* fall through */
501                         default:
502                                 parse_error(pe, FILT_ERR_TOO_MANY_PREDS,
503                                             next - str);
504                                 goto out_free;
505                         }
506 
507                         invert = *top & INVERT;
508 
509                         if (*top & PROCESS_AND) {               /* #7 */
510                                 update_preds(prog, N - 1, invert);
511                                 *top &= ~PROCESS_AND;
512                         }
513                         if (*next == '&') {                     /* #8 */
514                                 *top |= PROCESS_AND;
515                                 break;
516                         }
517                         if (*top & PROCESS_OR) {                /* #9 */
518                                 update_preds(prog, N - 1, !invert);
519                                 *top &= ~PROCESS_OR;
520                         }
521                         if (*next == '|') {                     /* #10 */
522                                 *top |= PROCESS_OR;
523                                 break;
524                         }
525                         if (!*next)                             /* #11 */
526                                 goto out;
527 
528                         if (top == op_stack) {
529                                 ret = -1;
530                                 /* Too few '(' */
531                                 parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, ptr - str);
532                                 goto out_free;
533                         }
534                         top--;                                  /* #12 */
535                 }
536         }
537  out:
538         if (top != op_stack) {
539                 /* Too many '(' */
540                 parse_error(pe, FILT_ERR_TOO_MANY_OPEN, ptr - str);
541                 goto out_free;
542         }
543 
544         if (!N) {
545                 /* No program? */
546                 ret = -EINVAL;
547                 parse_error(pe, FILT_ERR_NO_FILTER, ptr - str);
548                 goto out_free;
549         }
550 
551         prog[N].pred = NULL;                                    /* #13 */
552         prog[N].target = 1;             /* TRUE */
553         prog[N+1].pred = NULL;
554         prog[N+1].target = 0;           /* FALSE */
555         prog[N-1].target = N;
556         prog[N-1].when_to_branch = false;
557 
558         /* Second Pass */
559         for (i = N-1 ; i--; ) {
560                 int target = prog[i].target;
561                 if (prog[i].when_to_branch == prog[target].when_to_branch)
562                         prog[i].target = prog[target].target;
563         }
564 
565         /* Third Pass */
566         for (i = 0; i < N; i++) {
567                 invert = inverts[i] ^ prog[i].when_to_branch;
568                 prog[i].when_to_branch = invert;
569                 /* Make sure the program always moves forward */
570                 if (WARN_ON(prog[i].target <= i)) {
571                         ret = -EINVAL;
572                         goto out_free;
573                 }
574         }
575 
576         kfree(op_stack);
577         kfree(inverts);
578         return prog;
579 out_free:
580         kfree(op_stack);
581         kfree(inverts);
582         if (prog_stack) {
583                 for (i = 0; prog_stack[i].pred; i++)
584                         kfree(prog_stack[i].pred);
585                 kfree(prog_stack);
586         }
587         return ERR_PTR(ret);
588 }
589 
590 #define DEFINE_COMPARISON_PRED(type)                                    \
591 static int filter_pred_LT_##type(struct filter_pred *pred, void *event) \
592 {                                                                       \
593         type *addr = (type *)(event + pred->offset);                    \
594         type val = (type)pred->val;                                     \
595         return *addr < val;                                             \
596 }                                                                       \
597 static int filter_pred_LE_##type(struct filter_pred *pred, void *event) \
598 {                                                                       \
599         type *addr = (type *)(event + pred->offset);                    \
600         type val = (type)pred->val;                                     \
601         return *addr <= val;                                            \
602 }                                                                       \
603 static int filter_pred_GT_##type(struct filter_pred *pred, void *event) \
604 {                                                                       \
605         type *addr = (type *)(event + pred->offset);                    \
606         type val = (type)pred->val;                                     \
607         return *addr > val;                                     \
608 }                                                                       \
609 static int filter_pred_GE_##type(struct filter_pred *pred, void *event) \
610 {                                                                       \
611         type *addr = (type *)(event + pred->offset);                    \
612         type val = (type)pred->val;                                     \
613         return *addr >= val;                                            \
614 }                                                                       \
615 static int filter_pred_BAND_##type(struct filter_pred *pred, void *event) \
616 {                                                                       \
617         type *addr = (type *)(event + pred->offset);                    \
618         type val = (type)pred->val;                                     \
619         return !!(*addr & val);                                         \
620 }                                                                       \
621 static const filter_pred_fn_t pred_funcs_##type[] = {                   \
622         filter_pred_LE_##type,                                          \
623         filter_pred_LT_##type,                                          \
624         filter_pred_GE_##type,                                          \
625         filter_pred_GT_##type,                                          \
626         filter_pred_BAND_##type,                                        \
627 };
628 
629 #define DEFINE_EQUALITY_PRED(size)                                      \
630 static int filter_pred_##size(struct filter_pred *pred, void *event)    \
631 {                                                                       \
632         u##size *addr = (u##size *)(event + pred->offset);              \
633         u##size val = (u##size)pred->val;                               \
634         int match;                                                      \
635                                                                         \
636         match = (val == *addr) ^ pred->not;                             \
637                                                                         \
638         return match;                                                   \
639 }
640 
641 DEFINE_COMPARISON_PRED(s64);
642 DEFINE_COMPARISON_PRED(u64);
643 DEFINE_COMPARISON_PRED(s32);
644 DEFINE_COMPARISON_PRED(u32);
645 DEFINE_COMPARISON_PRED(s16);
646 DEFINE_COMPARISON_PRED(u16);
647 DEFINE_COMPARISON_PRED(s8);
648 DEFINE_COMPARISON_PRED(u8);
649 
650 DEFINE_EQUALITY_PRED(64);
651 DEFINE_EQUALITY_PRED(32);
652 DEFINE_EQUALITY_PRED(16);
653 DEFINE_EQUALITY_PRED(8);
654 
655 /* Filter predicate for fixed sized arrays of characters */
656 static int filter_pred_string(struct filter_pred *pred, void *event)
657 {
658         char *addr = (char *)(event + pred->offset);
659         int cmp, match;
660 
661         cmp = pred->regex.match(addr, &pred->regex, pred->regex.field_len);
662 
663         match = cmp ^ pred->not;
664 
665         return match;
666 }
667 
668 /* Filter predicate for char * pointers */
669 static int filter_pred_pchar(struct filter_pred *pred, void *event)
670 {
671         char **addr = (char **)(event + pred->offset);
672         int cmp, match;
673         int len = strlen(*addr) + 1;    /* including tailing '\0' */
674 
675         cmp = pred->regex.match(*addr, &pred->regex, len);
676 
677         match = cmp ^ pred->not;
678 
679         return match;
680 }
681 
682 /*
683  * Filter predicate for dynamic sized arrays of characters.
684  * These are implemented through a list of strings at the end
685  * of the entry.
686  * Also each of these strings have a field in the entry which
687  * contains its offset from the beginning of the entry.
688  * We have then first to get this field, dereference it
689  * and add it to the address of the entry, and at last we have
690  * the address of the string.
691  */
692 static int filter_pred_strloc(struct filter_pred *pred, void *event)
693 {
694         u32 str_item = *(u32 *)(event + pred->offset);
695         int str_loc = str_item & 0xffff;
696         int str_len = str_item >> 16;
697         char *addr = (char *)(event + str_loc);
698         int cmp, match;
699 
700         cmp = pred->regex.match(addr, &pred->regex, str_len);
701 
702         match = cmp ^ pred->not;
703 
704         return match;
705 }
706 
707 /* Filter predicate for CPUs. */
708 static int filter_pred_cpu(struct filter_pred *pred, void *event)
709 {
710         int cpu, cmp;
711 
712         cpu = raw_smp_processor_id();
713         cmp = pred->val;
714 
715         switch (pred->op) {
716         case OP_EQ:
717                 return cpu == cmp;
718         case OP_NE:
719                 return cpu != cmp;
720         case OP_LT:
721                 return cpu < cmp;
722         case OP_LE:
723                 return cpu <= cmp;
724         case OP_GT:
725                 return cpu > cmp;
726         case OP_GE:
727                 return cpu >= cmp;
728         default:
729                 return 0;
730         }
731 }
732 
733 /* Filter predicate for COMM. */
734 static int filter_pred_comm(struct filter_pred *pred, void *event)
735 {
736         int cmp;
737 
738         cmp = pred->regex.match(current->comm, &pred->regex,
739                                 TASK_COMM_LEN);
740         return cmp ^ pred->not;
741 }
742 
743 static int filter_pred_none(struct filter_pred *pred, void *event)
744 {
745         return 0;
746 }
747 
748 /*
749  * regex_match_foo - Basic regex callbacks
750  *
751  * @str: the string to be searched
752  * @r:   the regex structure containing the pattern string
753  * @len: the length of the string to be searched (including '\0')
754  *
755  * Note:
756  * - @str might not be NULL-terminated if it's of type DYN_STRING
757  *   or STATIC_STRING, unless @len is zero.
758  */
759 
760 static int regex_match_full(char *str, struct regex *r, int len)
761 {
762         /* len of zero means str is dynamic and ends with '\0' */
763         if (!len)
764                 return strcmp(str, r->pattern) == 0;
765 
766         return strncmp(str, r->pattern, len) == 0;
767 }
768 
769 static int regex_match_front(char *str, struct regex *r, int len)
770 {
771         if (len && len < r->len)
772                 return 0;
773 
774         return strncmp(str, r->pattern, r->len) == 0;
775 }
776 
777 static int regex_match_middle(char *str, struct regex *r, int len)
778 {
779         if (!len)
780                 return strstr(str, r->pattern) != NULL;
781 
782         return strnstr(str, r->pattern, len) != NULL;
783 }
784 
785 static int regex_match_end(char *str, struct regex *r, int len)
786 {
787         int strlen = len - 1;
788 
789         if (strlen >= r->len &&
790             memcmp(str + strlen - r->len, r->pattern, r->len) == 0)
791                 return 1;
792         return 0;
793 }
794 
795 static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
796 {
797         if (glob_match(r->pattern, str))
798                 return 1;
799         return 0;
800 }
801 
802 /**
803  * filter_parse_regex - parse a basic regex
804  * @buff:   the raw regex
805  * @len:    length of the regex
806  * @search: will point to the beginning of the string to compare
807  * @not:    tell whether the match will have to be inverted
808  *
809  * This passes in a buffer containing a regex and this function will
810  * set search to point to the search part of the buffer and
811  * return the type of search it is (see enum above).
812  * This does modify buff.
813  *
814  * Returns enum type.
815  *  search returns the pointer to use for comparison.
816  *  not returns 1 if buff started with a '!'
817  *     0 otherwise.
818  */
819 enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
820 {
821         int type = MATCH_FULL;
822         int i;
823 
824         if (buff[0] == '!') {
825                 *not = 1;
826                 buff++;
827                 len--;
828         } else
829                 *not = 0;
830 
831         *search = buff;
832 
833         if (isdigit(buff[0]))
834                 return MATCH_INDEX;
835 
836         for (i = 0; i < len; i++) {
837                 if (buff[i] == '*') {
838                         if (!i) {
839                                 type = MATCH_END_ONLY;
840                         } else if (i == len - 1) {
841                                 if (type == MATCH_END_ONLY)
842                                         type = MATCH_MIDDLE_ONLY;
843                                 else
844                                         type = MATCH_FRONT_ONLY;
845                                 buff[i] = 0;
846                                 break;
847                         } else {        /* pattern continues, use full glob */
848                                 return MATCH_GLOB;
849                         }
850                 } else if (strchr("[?\\", buff[i])) {
851                         return MATCH_GLOB;
852                 }
853         }
854         if (buff[0] == '*')
855                 *search = buff + 1;
856 
857         return type;
858 }
859 
860 static void filter_build_regex(struct filter_pred *pred)
861 {
862         struct regex *r = &pred->regex;
863         char *search;
864         enum regex_type type = MATCH_FULL;
865 
866         if (pred->op == OP_GLOB) {
867                 type = filter_parse_regex(r->pattern, r->len, &search, &pred->not);
868                 r->len = strlen(search);
869                 memmove(r->pattern, search, r->len+1);
870         }
871 
872         switch (type) {
873         /* MATCH_INDEX should not happen, but if it does, match full */
874         case MATCH_INDEX:
875         case MATCH_FULL:
876                 r->match = regex_match_full;
877                 break;
878         case MATCH_FRONT_ONLY:
879                 r->match = regex_match_front;
880                 break;
881         case MATCH_MIDDLE_ONLY:
882                 r->match = regex_match_middle;
883                 break;
884         case MATCH_END_ONLY:
885                 r->match = regex_match_end;
886                 break;
887         case MATCH_GLOB:
888                 r->match = regex_match_glob;
889                 break;
890         }
891 }
892 
893 /* return 1 if event matches, 0 otherwise (discard) */
894 int filter_match_preds(struct event_filter *filter, void *rec)
895 {
896         struct prog_entry *prog;
897         int i;
898 
899         /* no filter is considered a match */
900         if (!filter)
901                 return 1;
902 
903         /* Protected by either SRCU(tracepoint_srcu) or preempt_disable */
904         prog = rcu_dereference_raw(filter->prog);
905         if (!prog)
906                 return 1;
907 
908         for (i = 0; prog[i].pred; i++) {
909                 struct filter_pred *pred = prog[i].pred;
910                 int match = pred->fn(pred, rec);
911                 if (match == prog[i].when_to_branch)
912                         i = prog[i].target;
913         }
914         return prog[i].target;
915 }
916 EXPORT_SYMBOL_GPL(filter_match_preds);
917 
918 static void remove_filter_string(struct event_filter *filter)
919 {
920         if (!filter)
921                 return;
922 
923         kfree(filter->filter_string);
924         filter->filter_string = NULL;
925 }
926 
927 static void append_filter_err(struct trace_array *tr,
928                               struct filter_parse_error *pe,
929                               struct event_filter *filter)
930 {
931         struct trace_seq *s;
932         int pos = pe->lasterr_pos;
933         char *buf;
934         int len;
935 
936         if (WARN_ON(!filter->filter_string))
937                 return;
938 
939         s = kmalloc(sizeof(*s), GFP_KERNEL);
940         if (!s)
941                 return;
942         trace_seq_init(s);
943 
944         len = strlen(filter->filter_string);
945         if (pos > len)
946                 pos = len;
947 
948         /* indexing is off by one */
949         if (pos)
950                 pos++;
951 
952         trace_seq_puts(s, filter->filter_string);
953         if (pe->lasterr > 0) {
954                 trace_seq_printf(s, "\n%*s", pos, "^");
955                 trace_seq_printf(s, "\nparse_error: %s\n", err_text[pe->lasterr]);
956                 tracing_log_err(tr, "event filter parse error",
957                                 filter->filter_string, err_text,
958                                 pe->lasterr, pe->lasterr_pos);
959         } else {
960                 trace_seq_printf(s, "\nError: (%d)\n", pe->lasterr);
961                 tracing_log_err(tr, "event filter parse error",
962                                 filter->filter_string, err_text,
963                                 FILT_ERR_ERRNO, 0);
964         }
965         trace_seq_putc(s, 0);
966         buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL);
967         if (buf) {
968                 kfree(filter->filter_string);
969                 filter->filter_string = buf;
970         }
971         kfree(s);
972 }
973 
974 static inline struct event_filter *event_filter(struct trace_event_file *file)
975 {
976         return file->filter;
977 }
978 
979 /* caller must hold event_mutex */
980 void print_event_filter(struct trace_event_file *file, struct trace_seq *s)
981 {
982         struct event_filter *filter = event_filter(file);
983 
984         if (filter && filter->filter_string)
985                 trace_seq_printf(s, "%s\n", filter->filter_string);
986         else
987                 trace_seq_puts(s, "none\n");
988 }
989 
990 void print_subsystem_event_filter(struct event_subsystem *system,
991                                   struct trace_seq *s)
992 {
993         struct event_filter *filter;
994 
995         mutex_lock(&event_mutex);
996         filter = system->filter;
997         if (filter && filter->filter_string)
998                 trace_seq_printf(s, "%s\n", filter->filter_string);
999         else
1000                 trace_seq_puts(s, DEFAULT_SYS_FILTER_MESSAGE "\n");
1001         mutex_unlock(&event_mutex);
1002 }
1003 
1004 static void free_prog(struct event_filter *filter)
1005 {
1006         struct prog_entry *prog;
1007         int i;
1008 
1009         prog = rcu_access_pointer(filter->prog);
1010         if (!prog)
1011                 return;
1012 
1013         for (i = 0; prog[i].pred; i++)
1014                 kfree(prog[i].pred);
1015         kfree(prog);
1016 }
1017 
1018 static void filter_disable(struct trace_event_file *file)
1019 {
1020         unsigned long old_flags = file->flags;
1021 
1022         file->flags &= ~EVENT_FILE_FL_FILTERED;
1023 
1024         if (old_flags != file->flags)
1025                 trace_buffered_event_disable();
1026 }
1027 
1028 static void __free_filter(struct event_filter *filter)
1029 {
1030         if (!filter)
1031                 return;
1032 
1033         free_prog(filter);
1034         kfree(filter->filter_string);
1035         kfree(filter);
1036 }
1037 
1038 void free_event_filter(struct event_filter *filter)
1039 {
1040         __free_filter(filter);
1041 }
1042 
1043 static inline void __remove_filter(struct trace_event_file *file)
1044 {
1045         filter_disable(file);
1046         remove_filter_string(file->filter);
1047 }
1048 
1049 static void filter_free_subsystem_preds(struct trace_subsystem_dir *dir,
1050                                         struct trace_array *tr)
1051 {
1052         struct trace_event_file *file;
1053 
1054         list_for_each_entry(file, &tr->events, list) {
1055                 if (file->system != dir)
1056                         continue;
1057                 __remove_filter(file);
1058         }
1059 }
1060 
1061 static inline void __free_subsystem_filter(struct trace_event_file *file)
1062 {
1063         __free_filter(file->filter);
1064         file->filter = NULL;
1065 }
1066 
1067 static void filter_free_subsystem_filters(struct trace_subsystem_dir *dir,
1068                                           struct trace_array *tr)
1069 {
1070         struct trace_event_file *file;
1071 
1072         list_for_each_entry(file, &tr->events, list) {
1073                 if (file->system != dir)
1074                         continue;
1075                 __free_subsystem_filter(file);
1076         }
1077 }
1078 
1079 int filter_assign_type(const char *type)
1080 {
1081         if (strstr(type, "__data_loc") && strstr(type, "char"))
1082                 return FILTER_DYN_STRING;
1083 
1084         if (strchr(type, '[') && strstr(type, "char"))
1085                 return FILTER_STATIC_STRING;
1086 
1087         return FILTER_OTHER;
1088 }
1089 
1090 static filter_pred_fn_t select_comparison_fn(enum filter_op_ids op,
1091                                             int field_size, int field_is_signed)
1092 {
1093         filter_pred_fn_t fn = NULL;
1094         int pred_func_index = -1;
1095 
1096         switch (op) {
1097         case OP_EQ:
1098         case OP_NE:
1099                 break;
1100         default:
1101                 if (WARN_ON_ONCE(op < PRED_FUNC_START))
1102                         return NULL;
1103                 pred_func_index = op - PRED_FUNC_START;
1104                 if (WARN_ON_ONCE(pred_func_index > PRED_FUNC_MAX))
1105                         return NULL;
1106         }
1107 
1108         switch (field_size) {
1109         case 8:
1110                 if (pred_func_index < 0)
1111                         fn = filter_pred_64;
1112                 else if (field_is_signed)
1113                         fn = pred_funcs_s64[pred_func_index];
1114                 else
1115                         fn = pred_funcs_u64[pred_func_index];
1116                 break;
1117         case 4:
1118                 if (pred_func_index < 0)
1119                         fn = filter_pred_32;
1120                 else if (field_is_signed)
1121                         fn = pred_funcs_s32[pred_func_index];
1122                 else
1123                         fn = pred_funcs_u32[pred_func_index];
1124                 break;
1125         case 2:
1126                 if (pred_func_index < 0)
1127                         fn = filter_pred_16;
1128                 else if (field_is_signed)
1129                         fn = pred_funcs_s16[pred_func_index];
1130                 else
1131                         fn = pred_funcs_u16[pred_func_index];
1132                 break;
1133         case 1:
1134                 if (pred_func_index < 0)
1135                         fn = filter_pred_8;
1136                 else if (field_is_signed)
1137                         fn = pred_funcs_s8[pred_func_index];
1138                 else
1139                         fn = pred_funcs_u8[pred_func_index];
1140                 break;
1141         }
1142 
1143         return fn;
1144 }
1145 
1146 /* Called when a predicate is encountered by predicate_parse() */
1147 static int parse_pred(const char *str, void *data,
1148                       int pos, struct filter_parse_error *pe,
1149                       struct filter_pred **pred_ptr)
1150 {
1151         struct trace_event_call *call = data;
1152         struct ftrace_event_field *field;
1153         struct filter_pred *pred = NULL;
1154         char num_buf[24];       /* Big enough to hold an address */
1155         char *field_name;
1156         char q;
1157         u64 val;
1158         int len;
1159         int ret;
1160         int op;
1161         int s;
1162         int i = 0;
1163 
1164         /* First find the field to associate to */
1165         while (isspace(str[i]))
1166                 i++;
1167         s = i;
1168 
1169         while (isalnum(str[i]) || str[i] == '_')
1170                 i++;
1171 
1172         len = i - s;
1173 
1174         if (!len)
1175                 return -1;
1176 
1177         field_name = kmemdup_nul(str + s, len, GFP_KERNEL);
1178         if (!field_name)
1179                 return -ENOMEM;
1180 
1181         /* Make sure that the field exists */
1182 
1183         field = trace_find_event_field(call, field_name);
1184         kfree(field_name);
1185         if (!field) {
1186                 parse_error(pe, FILT_ERR_FIELD_NOT_FOUND, pos + i);
1187                 return -EINVAL;
1188         }
1189 
1190         while (isspace(str[i]))
1191                 i++;
1192 
1193         /* Make sure this op is supported */
1194         for (op = 0; ops[op]; op++) {
1195                 /* This is why '<=' must come before '<' in ops[] */
1196                 if (strncmp(str + i, ops[op], strlen(ops[op])) == 0)
1197                         break;
1198         }
1199 
1200         if (!ops[op]) {
1201                 parse_error(pe, FILT_ERR_INVALID_OP, pos + i);
1202                 goto err_free;
1203         }
1204 
1205         i += strlen(ops[op]);
1206 
1207         while (isspace(str[i]))
1208                 i++;
1209 
1210         s = i;
1211 
1212         pred = kzalloc(sizeof(*pred), GFP_KERNEL);
1213         if (!pred)
1214                 return -ENOMEM;
1215 
1216         pred->field = field;
1217         pred->offset = field->offset;
1218         pred->op = op;
1219 
1220         if (ftrace_event_is_function(call)) {
1221                 /*
1222                  * Perf does things different with function events.
1223                  * It only allows an "ip" field, and expects a string.
1224                  * But the string does not need to be surrounded by quotes.
1225                  * If it is a string, the assigned function as a nop,
1226                  * (perf doesn't use it) and grab everything.
1227                  */
1228                 if (strcmp(field->name, "ip") != 0) {
1229                         parse_error(pe, FILT_ERR_IP_FIELD_ONLY, pos + i);
1230                         goto err_free;
1231                 }
1232                 pred->fn = filter_pred_none;
1233 
1234                 /*
1235                  * Quotes are not required, but if they exist then we need
1236                  * to read them till we hit a matching one.
1237                  */
1238                 if (str[i] == '\'' || str[i] == '"')
1239                         q = str[i];
1240                 else
1241                         q = 0;
1242 
1243                 for (i++; str[i]; i++) {
1244                         if (q && str[i] == q)
1245                                 break;
1246                         if (!q && (str[i] == ')' || str[i] == '&' ||
1247                                    str[i] == '|'))
1248                                 break;
1249                 }
1250                 /* Skip quotes */
1251                 if (q)
1252                         s++;
1253                 len = i - s;
1254                 if (len >= MAX_FILTER_STR_VAL) {
1255                         parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
1256                         goto err_free;
1257                 }
1258 
1259                 pred->regex.len = len;
1260                 strncpy(pred->regex.pattern, str + s, len);
1261                 pred->regex.pattern[len] = 0;
1262 
1263         /* This is either a string, or an integer */
1264         } else if (str[i] == '\'' || str[i] == '"') {
1265                 char q = str[i];
1266 
1267                 /* Make sure the op is OK for strings */
1268                 switch (op) {
1269                 case OP_NE:
1270                         pred->not = 1;
1271                         /* Fall through */
1272                 case OP_GLOB:
1273                 case OP_EQ:
1274                         break;
1275                 default:
1276                         parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
1277                         goto err_free;
1278                 }
1279 
1280                 /* Make sure the field is OK for strings */
1281                 if (!is_string_field(field)) {
1282                         parse_error(pe, FILT_ERR_EXPECT_DIGIT, pos + i);
1283                         goto err_free;
1284                 }
1285 
1286                 for (i++; str[i]; i++) {
1287                         if (str[i] == q)
1288                                 break;
1289                 }
1290                 if (!str[i]) {
1291                         parse_error(pe, FILT_ERR_MISSING_QUOTE, pos + i);
1292                         goto err_free;
1293                 }
1294 
1295                 /* Skip quotes */
1296                 s++;
1297                 len = i - s;
1298                 if (len >= MAX_FILTER_STR_VAL) {
1299                         parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
1300                         goto err_free;
1301                 }
1302 
1303                 pred->regex.len = len;
1304                 strncpy(pred->regex.pattern, str + s, len);
1305                 pred->regex.pattern[len] = 0;
1306 
1307                 filter_build_regex(pred);
1308 
1309                 if (field->filter_type == FILTER_COMM) {
1310                         pred->fn = filter_pred_comm;
1311 
1312                 } else if (field->filter_type == FILTER_STATIC_STRING) {
1313                         pred->fn = filter_pred_string;
1314                         pred->regex.field_len = field->size;
1315 
1316                 } else if (field->filter_type == FILTER_DYN_STRING)
1317                         pred->fn = filter_pred_strloc;
1318                 else
1319                         pred->fn = filter_pred_pchar;
1320                 /* go past the last quote */
1321                 i++;
1322 
1323         } else if (isdigit(str[i]) || str[i] == '-') {
1324 
1325                 /* Make sure the field is not a string */
1326                 if (is_string_field(field)) {
1327                         parse_error(pe, FILT_ERR_EXPECT_STRING, pos + i);
1328                         goto err_free;
1329                 }
1330 
1331                 if (op == OP_GLOB) {
1332                         parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
1333                         goto err_free;
1334                 }
1335 
1336                 if (str[i] == '-')
1337                         i++;
1338 
1339                 /* We allow 0xDEADBEEF */
1340                 while (isalnum(str[i]))
1341                         i++;
1342 
1343                 len = i - s;
1344                 /* 0xfeedfacedeadbeef is 18 chars max */
1345                 if (len >= sizeof(num_buf)) {
1346                         parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
1347                         goto err_free;
1348                 }
1349 
1350                 strncpy(num_buf, str + s, len);
1351                 num_buf[len] = 0;
1352 
1353                 /* Make sure it is a value */
1354                 if (field->is_signed)
1355                         ret = kstrtoll(num_buf, 0, &val);
1356                 else
1357                         ret = kstrtoull(num_buf, 0, &val);
1358                 if (ret) {
1359                         parse_error(pe, FILT_ERR_ILLEGAL_INTVAL, pos + s);
1360                         goto err_free;
1361                 }
1362 
1363                 pred->val = val;
1364 
1365                 if (field->filter_type == FILTER_CPU)
1366                         pred->fn = filter_pred_cpu;
1367                 else {
1368                         pred->fn = select_comparison_fn(pred->op, field->size,
1369                                                         field->is_signed);
1370                         if (pred->op == OP_NE)
1371                                 pred->not = 1;
1372                 }
1373 
1374         } else {
1375                 parse_error(pe, FILT_ERR_INVALID_VALUE, pos + i);
1376                 goto err_free;
1377         }
1378 
1379         *pred_ptr = pred;
1380         return i;
1381 
1382 err_free:
1383         kfree(pred);
1384         return -EINVAL;
1385 }
1386 
1387 enum {
1388         TOO_MANY_CLOSE          = -1,
1389         TOO_MANY_OPEN           = -2,
1390         MISSING_QUOTE           = -3,
1391 };
1392 
1393 /*
1394  * Read the filter string once to calculate the number of predicates
1395  * as well as how deep the parentheses go.
1396  *
1397  * Returns:
1398  *   0 - everything is fine (err is undefined)
1399  *  -1 - too many ')'
1400  *  -2 - too many '('
1401  *  -3 - No matching quote
1402  */
1403 static int calc_stack(const char *str, int *parens, int *preds, int *err)
1404 {
1405         bool is_pred = false;
1406         int nr_preds = 0;
1407         int open = 1; /* Count the expression as "(E)" */
1408         int last_quote = 0;
1409         int max_open = 1;
1410         int quote = 0;
1411         int i;
1412 
1413         *err = 0;
1414 
1415         for (i = 0; str[i]; i++) {
1416                 if (isspace(str[i]))
1417                         continue;
1418                 if (quote) {
1419                         if (str[i] == quote)
1420                                quote = 0;
1421                         continue;
1422                 }
1423 
1424                 switch (str[i]) {
1425                 case '\'':
1426                 case '"':
1427                         quote = str[i];
1428                         last_quote = i;
1429                         break;
1430                 case '|':
1431                 case '&':
1432                         if (str[i+1] != str[i])
1433                                 break;
1434                         is_pred = false;
1435                         continue;
1436                 case '(':
1437                         is_pred = false;
1438                         open++;
1439                         if (open > max_open)
1440                                 max_open = open;
1441                         continue;
1442                 case ')':
1443                         is_pred = false;
1444                         if (open == 1) {
1445                                 *err = i;
1446                                 return TOO_MANY_CLOSE;
1447                         }
1448                         open--;
1449                         continue;
1450                 }
1451                 if (!is_pred) {
1452                         nr_preds++;
1453                         is_pred = true;
1454                 }
1455         }
1456 
1457         if (quote) {
1458                 *err = last_quote;
1459                 return MISSING_QUOTE;
1460         }
1461 
1462         if (open != 1) {
1463                 int level = open;
1464 
1465                 /* find the bad open */
1466                 for (i--; i; i--) {
1467                         if (quote) {
1468                                 if (str[i] == quote)
1469                                         quote = 0;
1470                                 continue;
1471                         }
1472                         switch (str[i]) {
1473                         case '(':
1474                                 if (level == open) {
1475                                         *err = i;
1476                                         return TOO_MANY_OPEN;
1477                                 }
1478                                 level--;
1479                                 break;
1480                         case ')':
1481                                 level++;
1482                                 break;
1483                         case '\'':
1484                         case '"':
1485                                 quote = str[i];
1486                                 break;
1487                         }
1488                 }
1489                 /* First character is the '(' with missing ')' */
1490                 *err = 0;
1491                 return TOO_MANY_OPEN;
1492         }
1493 
1494         /* Set the size of the required stacks */
1495         *parens = max_open;
1496         *preds = nr_preds;
1497         return 0;
1498 }
1499 
1500 static int process_preds(struct trace_event_call *call,
1501                          const char *filter_string,
1502                          struct event_filter *filter,
1503                          struct filter_parse_error *pe)
1504 {
1505         struct prog_entry *prog;
1506         int nr_parens;
1507         int nr_preds;
1508         int index;
1509         int ret;
1510 
1511         ret = calc_stack(filter_string, &nr_parens, &nr_preds, &index);
1512         if (ret < 0) {
1513                 switch (ret) {
1514                 case MISSING_QUOTE:
1515                         parse_error(pe, FILT_ERR_MISSING_QUOTE, index);
1516                         break;
1517                 case TOO_MANY_OPEN:
1518                         parse_error(pe, FILT_ERR_TOO_MANY_OPEN, index);
1519                         break;
1520                 default:
1521                         parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, index);
1522                 }
1523                 return ret;
1524         }
1525 
1526         if (!nr_preds)
1527                 return -EINVAL;
1528 
1529         prog = predicate_parse(filter_string, nr_parens, nr_preds,
1530                                parse_pred, call, pe);
1531         if (IS_ERR(prog))
1532                 return PTR_ERR(prog);
1533 
1534         rcu_assign_pointer(filter->prog, prog);
1535         return 0;
1536 }
1537 
1538 static inline void event_set_filtered_flag(struct trace_event_file *file)
1539 {
1540         unsigned long old_flags = file->flags;
1541 
1542         file->flags |= EVENT_FILE_FL_FILTERED;
1543 
1544         if (old_flags != file->flags)
1545                 trace_buffered_event_enable();
1546 }
1547 
1548 static inline void event_set_filter(struct trace_event_file *file,
1549                                     struct event_filter *filter)
1550 {
1551         rcu_assign_pointer(file->filter, filter);
1552 }
1553 
1554 static inline void event_clear_filter(struct trace_event_file *file)
1555 {
1556         RCU_INIT_POINTER(file->filter, NULL);
1557 }
1558 
1559 static inline void
1560 event_set_no_set_filter_flag(struct trace_event_file *file)
1561 {
1562         file->flags |= EVENT_FILE_FL_NO_SET_FILTER;
1563 }
1564 
1565 static inline void
1566 event_clear_no_set_filter_flag(struct trace_event_file *file)
1567 {
1568         file->flags &= ~EVENT_FILE_FL_NO_SET_FILTER;
1569 }
1570 
1571 static inline bool
1572 event_no_set_filter_flag(struct trace_event_file *file)
1573 {
1574         if (file->flags & EVENT_FILE_FL_NO_SET_FILTER)
1575                 return true;
1576 
1577         return false;
1578 }
1579 
1580 struct filter_list {
1581         struct list_head        list;
1582         struct event_filter     *filter;
1583 };
1584 
1585 static int process_system_preds(struct trace_subsystem_dir *dir,
1586                                 struct trace_array *tr,
1587                                 struct filter_parse_error *pe,
1588                                 char *filter_string)
1589 {
1590         struct trace_event_file *file;
1591         struct filter_list *filter_item;
1592         struct event_filter *filter = NULL;
1593         struct filter_list *tmp;
1594         LIST_HEAD(filter_list);
1595         bool fail = true;
1596         int err;
1597 
1598         list_for_each_entry(file, &tr->events, list) {
1599 
1600                 if (file->system != dir)
1601                         continue;
1602 
1603                 filter = kzalloc(sizeof(*filter), GFP_KERNEL);
1604                 if (!filter)
1605                         goto fail_mem;
1606 
1607                 filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
1608                 if (!filter->filter_string)
1609                         goto fail_mem;
1610 
1611                 err = process_preds(file->event_call, filter_string, filter, pe);
1612                 if (err) {
1613                         filter_disable(file);
1614                         parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1615                         append_filter_err(tr, pe, filter);
1616                 } else
1617                         event_set_filtered_flag(file);
1618 
1619 
1620                 filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
1621                 if (!filter_item)
1622                         goto fail_mem;
1623 
1624                 list_add_tail(&filter_item->list, &filter_list);
1625                 /*
1626                  * Regardless of if this returned an error, we still
1627                  * replace the filter for the call.
1628                  */
1629                 filter_item->filter = event_filter(file);
1630                 event_set_filter(file, filter);
1631                 filter = NULL;
1632 
1633                 fail = false;
1634         }
1635 
1636         if (fail)
1637                 goto fail;
1638 
1639         /*
1640          * The calls can still be using the old filters.
1641          * Do a synchronize_rcu() and to ensure all calls are
1642          * done with them before we free them.
1643          */
1644         tracepoint_synchronize_unregister();
1645         list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1646                 __free_filter(filter_item->filter);
1647                 list_del(&filter_item->list);
1648                 kfree(filter_item);
1649         }
1650         return 0;
1651  fail:
1652         /* No call succeeded */
1653         list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1654                 list_del(&filter_item->list);
1655                 kfree(filter_item);
1656         }
1657         parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1658         return -EINVAL;
1659  fail_mem:
1660         kfree(filter);
1661         /* If any call succeeded, we still need to sync */
1662         if (!fail)
1663                 tracepoint_synchronize_unregister();
1664         list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1665                 __free_filter(filter_item->filter);
1666                 list_del(&filter_item->list);
1667                 kfree(filter_item);
1668         }
1669         return -ENOMEM;
1670 }
1671 
1672 static int create_filter_start(char *filter_string, bool set_str,
1673                                struct filter_parse_error **pse,
1674                                struct event_filter **filterp)
1675 {
1676         struct event_filter *filter;
1677         struct filter_parse_error *pe = NULL;
1678         int err = 0;
1679 
1680         if (WARN_ON_ONCE(*pse || *filterp))
1681                 return -EINVAL;
1682 
1683         filter = kzalloc(sizeof(*filter), GFP_KERNEL);
1684         if (filter && set_str) {
1685                 filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
1686                 if (!filter->filter_string)
1687                         err = -ENOMEM;
1688         }
1689 
1690         pe = kzalloc(sizeof(*pe), GFP_KERNEL);
1691 
1692         if (!filter || !pe || err) {
1693                 kfree(pe);
1694                 __free_filter(filter);
1695                 return -ENOMEM;
1696         }
1697 
1698         /* we're committed to creating a new filter */
1699         *filterp = filter;
1700         *pse = pe;
1701 
1702         return 0;
1703 }
1704 
1705 static void create_filter_finish(struct filter_parse_error *pe)
1706 {
1707         kfree(pe);
1708 }
1709 
1710 /**
1711  * create_filter - create a filter for a trace_event_call
1712  * @call: trace_event_call to create a filter for
1713  * @filter_str: filter string
1714  * @set_str: remember @filter_str and enable detailed error in filter
1715  * @filterp: out param for created filter (always updated on return)
1716  *           Must be a pointer that references a NULL pointer.
1717  *
1718  * Creates a filter for @call with @filter_str.  If @set_str is %true,
1719  * @filter_str is copied and recorded in the new filter.
1720  *
1721  * On success, returns 0 and *@filterp points to the new filter.  On
1722  * failure, returns -errno and *@filterp may point to %NULL or to a new
1723  * filter.  In the latter case, the returned filter contains error
1724  * information if @set_str is %true and the caller is responsible for
1725  * freeing it.
1726  */
1727 static int create_filter(struct trace_array *tr,
1728                          struct trace_event_call *call,
1729                          char *filter_string, bool set_str,
1730                          struct event_filter **filterp)
1731 {
1732         struct filter_parse_error *pe = NULL;
1733         int err;
1734 
1735         /* filterp must point to NULL */
1736         if (WARN_ON(*filterp))
1737                 *filterp = NULL;
1738 
1739         err = create_filter_start(filter_string, set_str, &pe, filterp);
1740         if (err)
1741                 return err;
1742 
1743         err = process_preds(call, filter_string, *filterp, pe);
1744         if (err && set_str)
1745                 append_filter_err(tr, pe, *filterp);
1746         create_filter_finish(pe);
1747 
1748         return err;
1749 }
1750 
1751 int create_event_filter(struct trace_array *tr,
1752                         struct trace_event_call *call,
1753                         char *filter_str, bool set_str,
1754                         struct event_filter **filterp)
1755 {
1756         return create_filter(tr, call, filter_str, set_str, filterp);
1757 }
1758 
1759 /**
1760  * create_system_filter - create a filter for an event_subsystem
1761  * @system: event_subsystem to create a filter for
1762  * @filter_str: filter string
1763  * @filterp: out param for created filter (always updated on return)
1764  *
1765  * Identical to create_filter() except that it creates a subsystem filter
1766  * and always remembers @filter_str.
1767  */
1768 static int create_system_filter(struct trace_subsystem_dir *dir,
1769                                 struct trace_array *tr,
1770                                 char *filter_str, struct event_filter **filterp)
1771 {
1772         struct filter_parse_error *pe = NULL;
1773         int err;
1774 
1775         err = create_filter_start(filter_str, true, &pe, filterp);
1776         if (!err) {
1777                 err = process_system_preds(dir, tr, pe, filter_str);
1778                 if (!err) {
1779                         /* System filters just show a default message */
1780                         kfree((*filterp)->filter_string);
1781                         (*filterp)->filter_string = NULL;
1782                 } else {
1783                         append_filter_err(tr, pe, *filterp);
1784                 }
1785         }
1786         create_filter_finish(pe);
1787 
1788         return err;
1789 }
1790 
1791 /* caller must hold event_mutex */
1792 int apply_event_filter(struct trace_event_file *file, char *filter_string)
1793 {
1794         struct trace_event_call *call = file->event_call;
1795         struct event_filter *filter = NULL;
1796         int err;
1797 
1798         if (!strcmp(strstrip(filter_string), "")) {
1799                 filter_disable(file);
1800                 filter = event_filter(file);
1801 
1802                 if (!filter)
1803                         return 0;
1804 
1805                 event_clear_filter(file);
1806 
1807                 /* Make sure the filter is not being used */
1808                 tracepoint_synchronize_unregister();
1809                 __free_filter(filter);
1810 
1811                 return 0;
1812         }
1813 
1814         err = create_filter(file->tr, call, filter_string, true, &filter);
1815 
1816         /*
1817          * Always swap the call filter with the new filter
1818          * even if there was an error. If there was an error
1819          * in the filter, we disable the filter and show the error
1820          * string
1821          */
1822         if (filter) {
1823                 struct event_filter *tmp;
1824 
1825                 tmp = event_filter(file);
1826                 if (!err)
1827                         event_set_filtered_flag(file);
1828                 else
1829                         filter_disable(file);
1830 
1831                 event_set_filter(file, filter);
1832 
1833                 if (tmp) {
1834                         /* Make sure the call is done with the filter */
1835                         tracepoint_synchronize_unregister();
1836                         __free_filter(tmp);
1837                 }
1838         }
1839 
1840         return err;
1841 }
1842 
1843 int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
1844                                  char *filter_string)
1845 {
1846         struct event_subsystem *system = dir->subsystem;
1847         struct trace_array *tr = dir->tr;
1848         struct event_filter *filter = NULL;
1849         int err = 0;
1850 
1851         mutex_lock(&event_mutex);
1852 
1853         /* Make sure the system still has events */
1854         if (!dir->nr_events) {
1855                 err = -ENODEV;
1856                 goto out_unlock;
1857         }
1858 
1859         if (!strcmp(strstrip(filter_string), "")) {
1860                 filter_free_subsystem_preds(dir, tr);
1861                 remove_filter_string(system->filter);
1862                 filter = system->filter;
1863                 system->filter = NULL;
1864                 /* Ensure all filters are no longer used */
1865                 tracepoint_synchronize_unregister();
1866                 filter_free_subsystem_filters(dir, tr);
1867                 __free_filter(filter);
1868                 goto out_unlock;
1869         }
1870 
1871         err = create_system_filter(dir, tr, filter_string, &filter);
1872         if (filter) {
1873                 /*
1874                  * No event actually uses the system filter
1875                  * we can free it without synchronize_rcu().
1876                  */
1877                 __free_filter(system->filter);
1878                 system->filter = filter;
1879         }
1880 out_unlock:
1881         mutex_unlock(&event_mutex);
1882 
1883         return err;
1884 }
1885 
1886 #ifdef CONFIG_PERF_EVENTS
1887 
1888 void ftrace_profile_free_filter(struct perf_event *event)
1889 {
1890         struct event_filter *filter = event->filter;
1891 
1892         event->filter = NULL;
1893         __free_filter(filter);
1894 }
1895 
1896 struct function_filter_data {
1897         struct ftrace_ops *ops;
1898         int first_filter;
1899         int first_notrace;
1900 };
1901 
1902 #ifdef CONFIG_FUNCTION_TRACER
1903 static char **
1904 ftrace_function_filter_re(char *buf, int len, int *count)
1905 {
1906         char *str, **re;
1907 
1908         str = kstrndup(buf, len, GFP_KERNEL);
1909         if (!str)
1910                 return NULL;
1911 
1912         /*
1913          * The argv_split function takes white space
1914          * as a separator, so convert ',' into spaces.
1915          */
1916         strreplace(str, ',', ' ');
1917 
1918         re = argv_split(GFP_KERNEL, str, count);
1919         kfree(str);
1920         return re;
1921 }
1922 
1923 static int ftrace_function_set_regexp(struct ftrace_ops *ops, int filter,
1924                                       int reset, char *re, int len)
1925 {
1926         int ret;
1927 
1928         if (filter)
1929                 ret = ftrace_set_filter(ops, re, len, reset);
1930         else
1931                 ret = ftrace_set_notrace(ops, re, len, reset);
1932 
1933         return ret;
1934 }
1935 
1936 static int __ftrace_function_set_filter(int filter, char *buf, int len,
1937                                         struct function_filter_data *data)
1938 {
1939         int i, re_cnt, ret = -EINVAL;
1940         int *reset;
1941         char **re;
1942 
1943         reset = filter ? &data->first_filter : &data->first_notrace;
1944 
1945         /*
1946          * The 'ip' field could have multiple filters set, separated
1947          * either by space or comma. We first cut the filter and apply
1948          * all pieces separatelly.
1949          */
1950         re = ftrace_function_filter_re(buf, len, &re_cnt);
1951         if (!re)
1952                 return -EINVAL;
1953 
1954         for (i = 0; i < re_cnt; i++) {
1955                 ret = ftrace_function_set_regexp(data->ops, filter, *reset,
1956                                                  re[i], strlen(re[i]));
1957                 if (ret)
1958                         break;
1959 
1960                 if (*reset)
1961                         *reset = 0;
1962         }
1963 
1964         argv_free(re);
1965         return ret;
1966 }
1967 
1968 static int ftrace_function_check_pred(struct filter_pred *pred)
1969 {
1970         struct ftrace_event_field *field = pred->field;
1971 
1972         /*
1973          * Check the predicate for function trace, verify:
1974          *  - only '==' and '!=' is used
1975          *  - the 'ip' field is used
1976          */
1977         if ((pred->op != OP_EQ) && (pred->op != OP_NE))
1978                 return -EINVAL;
1979 
1980         if (strcmp(field->name, "ip"))
1981                 return -EINVAL;
1982 
1983         return 0;
1984 }
1985 
1986 static int ftrace_function_set_filter_pred(struct filter_pred *pred,
1987                                            struct function_filter_data *data)
1988 {
1989         int ret;
1990 
1991         /* Checking the node is valid for function trace. */
1992         ret = ftrace_function_check_pred(pred);
1993         if (ret)
1994                 return ret;
1995 
1996         return __ftrace_function_set_filter(pred->op == OP_EQ,
1997                                             pred->regex.pattern,
1998                                             pred->regex.len,
1999                                             data);
2000 }
2001 
2002 static bool is_or(struct prog_entry *prog, int i)
2003 {
2004         int target;
2005 
2006         /*
2007          * Only "||" is allowed for function events, thus,
2008          * all true branches should jump to true, and any
2009          * false branch should jump to false.
2010          */
2011         target = prog[i].target + 1;
2012         /* True and false have NULL preds (all prog entries should jump to one */
2013         if (prog[target].pred)
2014                 return false;
2015 
2016         /* prog[target].target is 1 for TRUE, 0 for FALSE */
2017         return prog[i].when_to_branch == prog[target].target;
2018 }
2019 
2020 static int ftrace_function_set_filter(struct perf_event *event,
2021                                       struct event_filter *filter)
2022 {
2023         struct prog_entry *prog = rcu_dereference_protected(filter->prog,
2024                                                 lockdep_is_held(&event_mutex));
2025         struct function_filter_data data = {
2026                 .first_filter  = 1,
2027                 .first_notrace = 1,
2028                 .ops           = &event->ftrace_ops,
2029         };
2030         int i;
2031 
2032         for (i = 0; prog[i].pred; i++) {
2033                 struct filter_pred *pred = prog[i].pred;
2034 
2035                 if (!is_or(prog, i))
2036                         return -EINVAL;
2037 
2038                 if (ftrace_function_set_filter_pred(pred, &data) < 0)
2039                         return -EINVAL;
2040         }
2041         return 0;
2042 }
2043 #else
2044 static int ftrace_function_set_filter(struct perf_event *event,
2045                                       struct event_filter *filter)
2046 {
2047         return -ENODEV;
2048 }
2049 #endif /* CONFIG_FUNCTION_TRACER */
2050 
2051 int ftrace_profile_set_filter(struct perf_event *event, int event_id,
2052                               char *filter_str)
2053 {
2054         int err;
2055         struct event_filter *filter = NULL;
2056         struct trace_event_call *call;
2057 
2058         mutex_lock(&event_mutex);
2059 
2060         call = event->tp_event;
2061 
2062         err = -EINVAL;
2063         if (!call)
2064                 goto out_unlock;
2065 
2066         err = -EEXIST;
2067         if (event->filter)
2068                 goto out_unlock;
2069 
2070         err = create_filter(NULL, call, filter_str, false, &filter);
2071         if (err)
2072                 goto free_filter;
2073 
2074         if (ftrace_event_is_function(call))
2075                 err = ftrace_function_set_filter(event, filter);
2076         else
2077                 event->filter = filter;
2078 
2079 free_filter:
2080         if (err || ftrace_event_is_function(call))
2081                 __free_filter(filter);
2082 
2083 out_unlock:
2084         mutex_unlock(&event_mutex);
2085 
2086         return err;
2087 }
2088 
2089 #endif /* CONFIG_PERF_EVENTS */
2090 
2091 #ifdef CONFIG_FTRACE_STARTUP_TEST
2092 
2093 #include <linux/types.h>
2094 #include <linux/tracepoint.h>
2095 
2096 #define CREATE_TRACE_POINTS
2097 #include "trace_events_filter_test.h"
2098 
2099 #define DATA_REC(m, va, vb, vc, vd, ve, vf, vg, vh, nvisit) \
2100 { \
2101         .filter = FILTER, \
2102         .rec    = { .a = va, .b = vb, .c = vc, .d = vd, \
2103                     .e = ve, .f = vf, .g = vg, .h = vh }, \
2104         .match  = m, \
2105         .not_visited = nvisit, \
2106 }
2107 #define YES 1
2108 #define NO  0
2109 
2110 static struct test_filter_data_t {
2111         char *filter;
2112         struct trace_event_raw_ftrace_test_filter rec;
2113         int match;
2114         char *not_visited;
2115 } test_filter_data[] = {
2116 #define FILTER "a == 1 && b == 1 && c == 1 && d == 1 && " \
2117                "e == 1 && f == 1 && g == 1 && h == 1"
2118         DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, ""),
2119         DATA_REC(NO,  0, 1, 1, 1, 1, 1, 1, 1, "bcdefgh"),
2120         DATA_REC(NO,  1, 1, 1, 1, 1, 1, 1, 0, ""),
2121 #undef FILTER
2122 #define FILTER "a == 1 || b == 1 || c == 1 || d == 1 || " \
2123                "e == 1 || f == 1 || g == 1 || h == 1"
2124         DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 0, ""),
2125         DATA_REC(YES, 0, 0, 0, 0, 0, 0, 0, 1, ""),
2126         DATA_REC(YES, 1, 0, 0, 0, 0, 0, 0, 0, "bcdefgh"),
2127 #undef FILTER
2128 #define FILTER "(a == 1 || b == 1) && (c == 1 || d == 1) && " \
2129                "(e == 1 || f == 1) && (g == 1 || h == 1)"
2130         DATA_REC(NO,  0, 0, 1, 1, 1, 1, 1, 1, "dfh"),
2131         DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2132         DATA_REC(YES, 1, 0, 1, 0, 0, 1, 0, 1, "bd"),
2133         DATA_REC(NO,  1, 0, 1, 0, 0, 1, 0, 0, "bd"),
2134 #undef FILTER
2135 #define FILTER "(a == 1 && b == 1) || (c == 1 && d == 1) || " \
2136                "(e == 1 && f == 1) || (g == 1 && h == 1)"
2137         DATA_REC(YES, 1, 0, 1, 1, 1, 1, 1, 1, "efgh"),
2138         DATA_REC(YES, 0, 0, 0, 0, 0, 0, 1, 1, ""),
2139         DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 1, ""),
2140 #undef FILTER
2141 #define FILTER "(a == 1 && b == 1) && (c == 1 && d == 1) && " \
2142                "(e == 1 && f == 1) || (g == 1 && h == 1)"
2143         DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 0, "gh"),
2144         DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 1, ""),
2145         DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, ""),
2146 #undef FILTER
2147 #define FILTER "((a == 1 || b == 1) || (c == 1 || d == 1) || " \
2148                "(e == 1 || f == 1)) && (g == 1 || h == 1)"
2149         DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 1, "bcdef"),
2150         DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 0, ""),
2151         DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, "h"),
2152 #undef FILTER
2153 #define FILTER "((((((((a == 1) && (b == 1)) || (c == 1)) && (d == 1)) || " \
2154                "(e == 1)) && (f == 1)) || (g == 1)) && (h == 1))"
2155         DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "ceg"),
2156         DATA_REC(NO,  0, 1, 0, 1, 0, 1, 0, 1, ""),
2157         DATA_REC(NO,  1, 0, 1, 0, 1, 0, 1, 0, ""),
2158 #undef FILTER
2159 #define FILTER "((((((((a == 1) || (b == 1)) && (c == 1)) || (d == 1)) && " \
2160                "(e == 1)) || (f == 1)) && (g == 1)) || (h == 1))"
2161         DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "bdfh"),
2162         DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2163         DATA_REC(YES, 1, 0, 1, 0, 1, 0, 1, 0, "bdfh"),
2164 };
2165 
2166 #undef DATA_REC
2167 #undef FILTER
2168 #undef YES
2169 #undef NO
2170 
2171 #define DATA_CNT ARRAY_SIZE(test_filter_data)
2172 
2173 static int test_pred_visited;
2174 
2175 static int test_pred_visited_fn(struct filter_pred *pred, void *event)
2176 {
2177         struct ftrace_event_field *field = pred->field;
2178 
2179         test_pred_visited = 1;
2180         printk(KERN_INFO "\npred visited %s\n", field->name);
2181         return 1;
2182 }
2183 
2184 static void update_pred_fn(struct event_filter *filter, char *fields)
2185 {
2186         struct prog_entry *prog = rcu_dereference_protected(filter->prog,
2187                                                 lockdep_is_held(&event_mutex));
2188         int i;
2189 
2190         for (i = 0; prog[i].pred; i++) {
2191                 struct filter_pred *pred = prog[i].pred;
2192                 struct ftrace_event_field *field = pred->field;
2193 
2194                 WARN_ON_ONCE(!pred->fn);
2195 
2196                 if (!field) {
2197                         WARN_ONCE(1, "all leafs should have field defined %d", i);
2198                         continue;
2199                 }
2200 
2201                 if (!strchr(fields, *field->name))
2202                         continue;
2203 
2204                 pred->fn = test_pred_visited_fn;
2205         }
2206 }
2207 
2208 static __init int ftrace_test_event_filter(void)
2209 {
2210         int i;
2211 
2212         printk(KERN_INFO "Testing ftrace filter: ");
2213 
2214         for (i = 0; i < DATA_CNT; i++) {
2215                 struct event_filter *filter = NULL;
2216                 struct test_filter_data_t *d = &test_filter_data[i];
2217                 int err;
2218 
2219                 err = create_filter(NULL, &event_ftrace_test_filter,
2220                                     d->filter, false, &filter);
2221                 if (err) {
2222                         printk(KERN_INFO
2223                                "Failed to get filter for '%s', err %d\n",
2224                                d->filter, err);
2225                         __free_filter(filter);
2226                         break;
2227                 }
2228 
2229                 /* Needed to dereference filter->prog */
2230                 mutex_lock(&event_mutex);
2231                 /*
2232                  * The preemption disabling is not really needed for self
2233                  * tests, but the rcu dereference will complain without it.
2234                  */
2235                 preempt_disable();
2236                 if (*d->not_visited)
2237                         update_pred_fn(filter, d->not_visited);
2238 
2239                 test_pred_visited = 0;
2240                 err = filter_match_preds(filter, &d->rec);
2241                 preempt_enable();
2242 
2243                 mutex_unlock(&event_mutex);
2244 
2245                 __free_filter(filter);
2246 
2247                 if (test_pred_visited) {
2248                         printk(KERN_INFO
2249                                "Failed, unwanted pred visited for filter %s\n",
2250                                d->filter);
2251                         break;
2252                 }
2253 
2254                 if (err != d->match) {
2255                         printk(KERN_INFO
2256                                "Failed to match filter '%s', expected %d\n",
2257                                d->filter, d->match);
2258                         break;
2259                 }
2260         }
2261 
2262         if (i == DATA_CNT)
2263                 printk(KERN_CONT "OK\n");
2264 
2265         return 0;
2266 }
2267 
2268 late_initcall(ftrace_test_event_filter);
2269 
2270 #endif /* CONFIG_FTRACE_STARTUP_TEST */
2271 

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