diff options
Diffstat (limited to 'arch/sh/kernel/ptrace_32.c')
-rw-r--r-- | arch/sh/kernel/ptrace_32.c | 70 |
1 files changed, 51 insertions, 19 deletions
diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c index be9b5dcb402..c625cdab76d 100644 --- a/arch/sh/kernel/ptrace_32.c +++ b/arch/sh/kernel/ptrace_32.c @@ -2,7 +2,7 @@ * SuperH process tracing * * Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka - * Copyright (C) 2002 - 2008 Paul Mundt + * Copyright (C) 2002 - 2009 Paul Mundt * * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp> * @@ -26,6 +26,7 @@ #include <linux/tracehook.h> #include <linux/elf.h> #include <linux/regset.h> +#include <linux/hw_breakpoint.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/system.h> @@ -63,33 +64,64 @@ static inline int put_stack_long(struct task_struct *task, int offset, return 0; } -void user_enable_single_step(struct task_struct *child) +void ptrace_triggered(struct perf_event *bp, int nmi, + struct perf_sample_data *data, struct pt_regs *regs) { - /* Next scheduling will set up UBC */ - if (child->thread.ubc_pc == 0) - ubc_usercnt += 1; + struct perf_event_attr attr; + + /* + * Disable the breakpoint request here since ptrace has defined a + * one-shot behaviour for breakpoint exceptions. + */ + attr = bp->attr; + attr.disabled = true; + modify_user_hw_breakpoint(bp, &attr); +} + +static int set_single_step(struct task_struct *tsk, unsigned long addr) +{ + struct thread_struct *thread = &tsk->thread; + struct perf_event *bp; + struct perf_event_attr attr; + + bp = thread->ptrace_bps[0]; + if (!bp) { + hw_breakpoint_init(&attr); + + attr.bp_addr = addr; + attr.bp_len = HW_BREAKPOINT_LEN_2; + attr.bp_type = HW_BREAKPOINT_R; + + bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk); + if (IS_ERR(bp)) + return PTR_ERR(bp); + + thread->ptrace_bps[0] = bp; + } else { + int err; + + attr = bp->attr; + attr.bp_addr = addr; + err = modify_user_hw_breakpoint(bp, &attr); + if (unlikely(err)) + return err; + } + + return 0; +} - child->thread.ubc_pc = get_stack_long(child, - offsetof(struct pt_regs, pc)); +void user_enable_single_step(struct task_struct *child) +{ + unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc)); set_tsk_thread_flag(child, TIF_SINGLESTEP); + + set_single_step(child, pc); } void user_disable_single_step(struct task_struct *child) { clear_tsk_thread_flag(child, TIF_SINGLESTEP); - - /* - * Ensure the UBC is not programmed at the next context switch. - * - * Normally this is not needed but there are sequences such as - * singlestep, signal delivery, and continue that leave the - * ubc_pc non-zero leading to spurious SIGTRAPs. - */ - if (child->thread.ubc_pc != 0) { - ubc_usercnt -= 1; - child->thread.ubc_pc = 0; - } } /* |