~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/powerpc/kernel/uprobes.c

Version: ~ [ linux-5.1-rc2 ] ~ [ linux-5.0.4 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.31 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.108 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.165 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.177 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.137 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * User-space Probes (UProbes) for powerpc
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License as published by
  6  * the Free Software Foundation; either version 2 of the License, or
  7  * (at your option) any later version.
  8  *
  9  * This program is distributed in the hope that it will be useful,
 10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12  * GNU General Public License for more details.
 13  *
 14  * You should have received a copy of the GNU General Public License
 15  * along with this program; if not, write to the Free Software
 16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 17  *
 18  * Copyright IBM Corporation, 2007-2012
 19  *
 20  * Adapted from the x86 port by Ananth N Mavinakayanahalli <ananth@in.ibm.com>
 21  */
 22 #include <linux/kernel.h>
 23 #include <linux/sched.h>
 24 #include <linux/ptrace.h>
 25 #include <linux/uprobes.h>
 26 #include <linux/uaccess.h>
 27 #include <linux/kdebug.h>
 28 
 29 #include <asm/sstep.h>
 30 
 31 #define UPROBE_TRAP_NR  UINT_MAX
 32 
 33 /**
 34  * is_trap_insn - check if the instruction is a trap variant
 35  * @insn: instruction to be checked.
 36  * Returns true if @insn is a trap variant.
 37  */
 38 bool is_trap_insn(uprobe_opcode_t *insn)
 39 {
 40         return (is_trap(*insn));
 41 }
 42 
 43 /**
 44  * arch_uprobe_analyze_insn
 45  * @mm: the probed address space.
 46  * @arch_uprobe: the probepoint information.
 47  * @addr: vaddr to probe.
 48  * Return 0 on success or a -ve number on error.
 49  */
 50 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe,
 51                 struct mm_struct *mm, unsigned long addr)
 52 {
 53         if (addr & 0x03)
 54                 return -EINVAL;
 55 
 56         return 0;
 57 }
 58 
 59 /*
 60  * arch_uprobe_pre_xol - prepare to execute out of line.
 61  * @auprobe: the probepoint information.
 62  * @regs: reflects the saved user state of current task.
 63  */
 64 int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 65 {
 66         struct arch_uprobe_task *autask = &current->utask->autask;
 67 
 68         autask->saved_trap_nr = current->thread.trap_nr;
 69         current->thread.trap_nr = UPROBE_TRAP_NR;
 70         regs->nip = current->utask->xol_vaddr;
 71 
 72         user_enable_single_step(current);
 73         return 0;
 74 }
 75 
 76 /**
 77  * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs
 78  * @regs: Reflects the saved state of the task after it has hit a breakpoint
 79  * instruction.
 80  * Return the address of the breakpoint instruction.
 81  */
 82 unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
 83 {
 84         return instruction_pointer(regs);
 85 }
 86 
 87 /*
 88  * If xol insn itself traps and generates a signal (SIGILL/SIGSEGV/etc),
 89  * then detect the case where a singlestepped instruction jumps back to its
 90  * own address. It is assumed that anything like do_page_fault/do_trap/etc
 91  * sets thread.trap_nr != UINT_MAX.
 92  *
 93  * arch_uprobe_pre_xol/arch_uprobe_post_xol save/restore thread.trap_nr,
 94  * arch_uprobe_xol_was_trapped() simply checks that ->trap_nr is not equal to
 95  * UPROBE_TRAP_NR == UINT_MAX set by arch_uprobe_pre_xol().
 96  */
 97 bool arch_uprobe_xol_was_trapped(struct task_struct *t)
 98 {
 99         if (t->thread.trap_nr != UPROBE_TRAP_NR)
100                 return true;
101 
102         return false;
103 }
104 
105 /*
106  * Called after single-stepping. To avoid the SMP problems that can
107  * occur when we temporarily put back the original opcode to
108  * single-step, we single-stepped a copy of the instruction.
109  *
110  * This function prepares to resume execution after the single-step.
111  */
112 int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
113 {
114         struct uprobe_task *utask = current->utask;
115 
116         WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
117 
118         current->thread.trap_nr = utask->autask.saved_trap_nr;
119 
120         /*
121          * On powerpc, except for loads and stores, most instructions
122          * including ones that alter code flow (branches, calls, returns)
123          * are emulated in the kernel. We get here only if the emulation
124          * support doesn't exist and have to fix-up the next instruction
125          * to be executed.
126          */
127         regs->nip = utask->vaddr + MAX_UINSN_BYTES;
128 
129         user_disable_single_step(current);
130         return 0;
131 }
132 
133 /* callback routine for handling exceptions. */
134 int arch_uprobe_exception_notify(struct notifier_block *self,
135                                 unsigned long val, void *data)
136 {
137         struct die_args *args = data;
138         struct pt_regs *regs = args->regs;
139 
140         /* regs == NULL is a kernel bug */
141         if (WARN_ON(!regs))
142                 return NOTIFY_DONE;
143 
144         /* We are only interested in userspace traps */
145         if (!user_mode(regs))
146                 return NOTIFY_DONE;
147 
148         switch (val) {
149         case DIE_BPT:
150                 if (uprobe_pre_sstep_notifier(regs))
151                         return NOTIFY_STOP;
152                 break;
153         case DIE_SSTEP:
154                 if (uprobe_post_sstep_notifier(regs))
155                         return NOTIFY_STOP;
156         default:
157                 break;
158         }
159         return NOTIFY_DONE;
160 }
161 
162 /*
163  * This function gets called when XOL instruction either gets trapped or
164  * the thread has a fatal signal, so reset the instruction pointer to its
165  * probed address.
166  */
167 void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
168 {
169         struct uprobe_task *utask = current->utask;
170 
171         current->thread.trap_nr = utask->autask.saved_trap_nr;
172         instruction_pointer_set(regs, utask->vaddr);
173 
174         user_disable_single_step(current);
175 }
176 
177 /*
178  * See if the instruction can be emulated.
179  * Returns true if instruction was emulated, false otherwise.
180  */
181 bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
182 {
183         int ret;
184 
185         /*
186          * emulate_step() returns 1 if the insn was successfully emulated.
187          * For all other cases, we need to single-step in hardware.
188          */
189         ret = emulate_step(regs, auprobe->insn);
190         if (ret > 0)
191                 return true;
192 
193         return false;
194 }
195 
196 unsigned long
197 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs)
198 {
199         unsigned long orig_ret_vaddr;
200 
201         orig_ret_vaddr = regs->link;
202 
203         /* Replace the return addr with trampoline addr */
204         regs->link = trampoline_vaddr;
205 
206         return orig_ret_vaddr;
207 }
208 
209 bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
210                                 struct pt_regs *regs)
211 {
212         if (ctx == RP_CHECK_CHAIN_CALL)
213                 return regs->gpr[1] <= ret->stack;
214         else
215                 return regs->gpr[1] < ret->stack;
216 }
217 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp