From f82796214a95b1ec00c2f121c1080d10f2b099a1 Mon Sep 17 00:00:00 2001 From: Kumar Gala Date: Thu, 26 Jun 2008 02:01:37 -0500 Subject: powerpc/booke: Add kprobes support for booke style processors This patch is based on work done by Madhvesh. R. Sulibhavi back in March 2007. We refactor some of the single step handling since it differs between "classic" and "booke" powerpc cores. Signed-off-by: Kumar Gala --- arch/powerpc/kernel/kprobes.c | 25 +++++++++++++++++++------ arch/powerpc/kernel/traps.c | 26 +++++++++++++++++--------- 2 files changed, 36 insertions(+), 15 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 74693d91731..4ba2af12545 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -34,6 +34,13 @@ #include #include #include +#include + +#ifdef CONFIG_BOOKE +#define MSR_SINGLESTEP (MSR_DE) +#else +#define MSR_SINGLESTEP (MSR_SE) +#endif DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); @@ -53,7 +60,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) ret = -EINVAL; } - /* insn must be on a special executable page on ppc64 */ + /* insn must be on a special executable page on ppc64. This is + * not explicitly required on ppc32 (right now), but it doesn't hurt */ if (!ret) { p->ainsn.insn = get_insn_slot(); if (!p->ainsn.insn) @@ -100,7 +108,11 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) * possible we'd get the single step reported for an exception handler * like Decrementer or External Interrupt */ regs->msr &= ~MSR_EE; - regs->msr |= MSR_SE; + regs->msr |= MSR_SINGLESTEP; +#ifdef CONFIG_BOOKE + regs->msr &= ~MSR_CE; + mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); +#endif /* * On powerpc we should single step on the original @@ -163,7 +175,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) kprobe_opcode_t insn = *p->ainsn.insn; if (kcb->kprobe_status == KPROBE_HIT_SS && is_trap(insn)) { - regs->msr &= ~MSR_SE; + /* Turn off 'trace' bits */ + regs->msr &= ~MSR_SINGLESTEP; regs->msr |= kcb->kprobe_saved_msr; goto no_kprobe; } @@ -404,10 +417,10 @@ out: /* * if somebody else is singlestepping across a probe point, msr - * will have SE set, in which case, continue the remaining processing + * will have DE/SE set, in which case, continue the remaining processing * of do_debug, as if this is not a probe hit. */ - if (regs->msr & MSR_SE) + if (regs->msr & MSR_SINGLESTEP) return 0; return 1; @@ -430,7 +443,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) * normal page fault. */ regs->nip = (unsigned long)cur->addr; - regs->msr &= ~MSR_SE; + regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */ regs->msr |= kcb->kprobe_saved_msr; if (kcb->kprobe_status == KPROBE_REENTER) restore_previous_kprobe(kcb); diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 4b5b7ff4f78..b463d48145a 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1030,21 +1030,29 @@ void SoftwareEmulation(struct pt_regs *regs) #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) -void DebugException(struct pt_regs *regs, unsigned long debug_status) +void __kprobes DebugException(struct pt_regs *regs, unsigned long debug_status) { if (debug_status & DBSR_IC) { /* instruction completion */ regs->msr &= ~MSR_DE; + + /* Disable instruction completion */ + mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC); + /* Clear the instruction completion event */ + mtspr(SPRN_DBSR, DBSR_IC); + + if (notify_die(DIE_SSTEP, "single_step", regs, 5, + 5, SIGTRAP) == NOTIFY_STOP) { + return; + } + + if (debugger_sstep(regs)) + return; + if (user_mode(regs)) { current->thread.dbcr0 &= ~DBCR0_IC; - } else { - /* Disable instruction completion */ - mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC); - /* Clear the instruction completion event */ - mtspr(SPRN_DBSR, DBSR_IC); - if (debugger_sstep(regs)) - return; } - _exception(SIGTRAP, regs, TRAP_TRACE, 0); + + _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip); } } #endif /* CONFIG_4xx || CONFIG_BOOKE */ -- cgit v1.2.3-70-g09d2