Re: [PATCH] powerpc ptrace block-step
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2009-04-02 05:27:06
On Wed, 2009-04-01 at 14:59 -0700, Roland McGrath wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h index c9c678f..d7692b8 100644 --- a/arch/powerpc/include/asm/ptrace.h +++ b/arch/powerpc/include/asm/ptrace.h@@ -135,7 +135,9 @@ do { \ * These are defined as per linux/ptrace.h, which see. */ #define arch_has_single_step() (1) +#define arch_has_block_step() (1)
The patch only implements it for "server/classic" processors, not BookE, thus it should probably only advertise it for these :-) Though it wouldn't be too hard to implement it for BookE using DBCR0:BRT (Branch Taken debug event) though it might need some careful fixups such as the one we have for single step regarding hitting exception entry code. Cheers, Ben.
quoted hunk ↗ jump to hunk
extern void user_enable_single_step(struct task_struct *); +extern void user_enable_block_step(struct task_struct *); extern void user_disable_single_step(struct task_struct *); #endif /* __ASSEMBLY__ */@@ -288,4 +290,6 @@ extern void user_disable_single_step(struct task_struct *); #define PPC_PTRACE_PEEKUSR_3264 0x91 #define PPC_PTRACE_POKEUSR_3264 0x90 +#define PTRACE_SINGLEBLOCK 0x100 /* resume execution until next branch */ + #endif /* _ASM_POWERPC_PTRACE_H */diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index 3635be6..656fea2 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c@@ -707,12 +707,29 @@ void user_enable_single_step(struct task_struct *task) task->thread.dbcr0 |= DBCR0_IDM | DBCR0_IC; regs->msr |= MSR_DE; #else + regs->msr &= ~MSR_BE; regs->msr |= MSR_SE; #endif } set_tsk_thread_flag(task, TIF_SINGLESTEP); } +void user_enable_block_step(struct task_struct *task) +{ + struct pt_regs *regs = task->thread.regs; + + if (regs != NULL) { +#if defined(CONFIG_40x) || defined(CONFIG_BOOKE) + task->thread.dbcr0 = DBCR0_IDM | DBCR0_BT; + regs->msr |= MSR_DE; +#else + regs->msr &= ~MSR_SE; + regs->msr |= MSR_BE; +#endif + } + set_tsk_thread_flag(task, TIF_SINGLESTEP); +} + void user_disable_single_step(struct task_struct *task) { struct pt_regs *regs = task->thread.regs;@@ -729,7 +746,7 @@ void user_disable_single_step(struct task_struct *task) task->thread.dbcr0 &= ~(DBCR0_IC | DBCR0_IDM); regs->msr &= ~MSR_DE; #else - regs->msr &= ~MSR_SE; + regs->msr &= ~(MSR_SE | MSR_BE); #endif } clear_tsk_thread_flag(task, TIF_SINGLESTEP);