From de41984003ed2315dbb7d58168cc3e72e15b075c Mon Sep 17 00:00:00 2001 From: Jon Medhurst Date: Tue, 14 Jun 2011 13:08:04 +0100 Subject: [PATCH] ARM: kprobes: Make kprobes framework work on Thumb-2 kernels Fix up kprobes framework so that it builds and correctly interworks on Thumb-2 kernels. Signed-off-by: Jon Medhurst Acked-by: Nicolas Pitre --- arch/arm/kernel/kprobes.c | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c index 3ba5f8d0d82..0e47d3d6742 100644 --- a/arch/arm/kernel/kprobes.c +++ b/arch/arm/kernel/kprobes.c @@ -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"); } -- 2.39.5