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ARM: kprobes: Make kprobes framework work on Thumb-2 kernels

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Fix up kprobes framework so that it builds and correctly interworks on
Thumb-2 kernels.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
This commit is contained in:
Jon Medhurst 2011-06-14 13:08:04 +01:00 committed by Tixy
parent aea490299f
commit de41984003
1 changed files with 35 additions and 2 deletions
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37
arch/arm/kernel/kprobes.c
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@ -302,7 +302,11 @@ void __naked __kprobes kretprobe_trampoline(void)
"bl trampoline_handler \n\t"
"mov lr, r0 \n\t"
"ldmia sp!, {r0 - r11} \n\t"
#ifdef CONFIG_THUMB2_KERNEL
"bx lr \n\t"
#else
"mov pc, lr \n\t"
#endif
: : : "memory");
}
@ -380,11 +384,22 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
struct jprobe *jp = container_of(p, struct jprobe, kp);
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
long sp_addr = regs->ARM_sp;
long cpsr;
kcb->jprobe_saved_regs = *regs;
memcpy(kcb->jprobes_stack, (void *)sp_addr, MIN_STACK_SIZE(sp_addr));
regs->ARM_pc = (long)jp->entry;
regs->ARM_cpsr |= PSR_I_BIT;
cpsr = regs->ARM_cpsr | PSR_I_BIT;
#ifdef CONFIG_THUMB2_KERNEL
/* Set correct Thumb state in cpsr */
if (regs->ARM_pc & 1)
cpsr |= PSR_T_BIT;
else
cpsr &= ~PSR_T_BIT;
#endif
regs->ARM_cpsr = cpsr;
preempt_disable();
return 1;
}
@ -406,7 +421,12 @@ void __kprobes jprobe_return(void)
* This is to prevent any simulated instruction from writing
* over the regs when they are accessing the stack.
*/
#ifdef CONFIG_THUMB2_KERNEL
"sub r0, %0, %1 \n\t"
"mov sp, r0 \n\t"
#else
"sub sp, %0, %1 \n\t"
#endif
"ldr r0, ="__stringify(JPROBE_MAGIC_ADDR)"\n\t"
"str %0, [sp, %2] \n\t"
"str r0, [sp, %3] \n\t"
@ -417,15 +437,28 @@ void __kprobes jprobe_return(void)
* Return to the context saved by setjmp_pre_handler
* and restored by longjmp_break_handler.
*/
#ifdef CONFIG_THUMB2_KERNEL
"ldr lr, [sp, %2] \n\t" /* lr = saved sp */
"ldrd r0, r1, [sp, %5] \n\t" /* r0,r1 = saved lr,pc */
"ldr r2, [sp, %4] \n\t" /* r2 = saved psr */
"stmdb lr!, {r0, r1, r2} \n\t" /* push saved lr and */
/* rfe context */
"ldmia sp, {r0 - r12} \n\t"
"mov sp, lr \n\t"
"ldr lr, [sp], #4 \n\t"
"rfeia sp! \n\t"
#else
"ldr r0, [sp, %4] \n\t"
"msr cpsr_cxsf, r0 \n\t"
"ldmia sp, {r0 - pc} \n\t"
#endif
:
: "r" (kcb->jprobe_saved_regs.ARM_sp),
"I" (sizeof(struct pt_regs) * 2),
"J" (offsetof(struct pt_regs, ARM_sp)),
"J" (offsetof(struct pt_regs, ARM_pc)),
"J" (offsetof(struct pt_regs, ARM_cpsr))
"J" (offsetof(struct pt_regs, ARM_cpsr)),
"J" (offsetof(struct pt_regs, ARM_lr))
: "memory", "cc");
}