From 600482c13d3d3612d71f39d8aaec47f63aafa801 Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Wed, 17 Feb 2010 10:44:22 +0000 Subject: [PATCH] Blackfin: fix single stepping over system calls On Blackfin systems, the hardware single step exception triggers before the system call exception, so we need to save this info to process it later on. Otherwise, single stepping in userspace misses a few insns right after the system call. This is based a bit on the SuperH code added in commit 4b505db9c4c72dbd. Reported-by: Roland McGrath Signed-off-by: Mike Frysinger --- arch/blackfin/include/asm/thread_info.h | 2 ++ arch/blackfin/kernel/ptrace.c | 11 +++++++++-- arch/blackfin/kernel/signal.c | 3 ++- arch/blackfin/mach-common/entry.S | 2 ++ 4 files changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/blackfin/include/asm/thread_info.h b/arch/blackfin/include/asm/thread_info.h index 0149c92..e9a5614 100644 --- a/arch/blackfin/include/asm/thread_info.h +++ b/arch/blackfin/include/asm/thread_info.h @@ -103,6 +103,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_FREEZE 6 /* is freezing for suspend */ #define TIF_IRQ_SYNC 7 /* sync pipeline stage */ #define TIF_NOTIFY_RESUME 8 /* callback before returning to user */ +#define TIF_SINGLESTEP 9 /* as above, but as bit values */ #define _TIF_SYSCALL_TRACE (1<syscfg |= SYSCFG_SSSTEP; + + set_tsk_thread_flag(child, TIF_SINGLESTEP); } void user_disable_single_step(struct task_struct *child) { struct pt_regs *regs = task_pt_regs(child); regs->syscfg &= ~SYSCFG_SSSTEP; + + clear_tsk_thread_flag(child, TIF_SINGLESTEP); } long arch_ptrace(struct task_struct *child, long request, long addr, long data) @@ -401,6 +405,9 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs) asmlinkage void syscall_trace_leave(struct pt_regs *regs) { - if (test_thread_flag(TIF_SYSCALL_TRACE)) - tracehook_report_syscall_exit(regs, 0); + int step; + + step = test_thread_flag(TIF_SINGLESTEP); + if (step || test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, step); } diff --git a/arch/blackfin/kernel/signal.c b/arch/blackfin/kernel/signal.c index e60990c..28d6f28 100644 --- a/arch/blackfin/kernel/signal.c +++ b/arch/blackfin/kernel/signal.c @@ -306,7 +306,8 @@ asmlinkage void do_signal(struct pt_regs *regs) if (test_thread_flag(TIF_RESTORE_SIGMASK)) clear_thread_flag(TIF_RESTORE_SIGMASK); - tracehook_signal_handler(signr, &info, &ka, regs, 1); + tracehook_signal_handler(signr, &info, &ka, regs, + test_thread_flag(TIF_SINGLESTEP)); } return; diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S index 0df5b83..0a9e458 100644 --- a/arch/blackfin/mach-common/entry.S +++ b/arch/blackfin/mach-common/entry.S @@ -642,6 +642,8 @@ ENTRY(_system_call) r7 = [p2+TI_FLAGS]; CC = BITTST(r7,TIF_SYSCALL_TRACE); if CC JUMP _sys_trace; + CC = BITTST(r7,TIF_SINGLESTEP); + if CC JUMP _sys_trace; /* Execute the appropriate system call */ -- 1.8.2.3