From: Wang Nan <wangn...@huawei.com> Store breakpoint single step state into pstate to fix the recursion issue on ARM64.
Signed-off-by: Kaixu Xia <xiaka...@huawei.com> Signed-off-by: Hanjun Guo <hanjun....@linaro.org> --- arch/arm64/include/asm/debug-monitors.h | 9 ++++++ arch/arm64/include/uapi/asm/ptrace.h | 10 +++++++ arch/arm64/kernel/hw_breakpoint.c | 49 +++++++++++++++++++++++++++++++++ arch/arm64/kernel/signal.c | 2 ++ 4 files changed, 70 insertions(+) diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h index 279c85b5..b5902e8 100644 --- a/arch/arm64/include/asm/debug-monitors.h +++ b/arch/arm64/include/asm/debug-monitors.h @@ -132,11 +132,20 @@ int kernel_active_single_step(void); #ifdef CONFIG_HAVE_HW_BREAKPOINT int reinstall_suspended_bps(struct pt_regs *regs); +u64 signal_single_step_enable_bps(void); +void signal_reinstall_single_step(u64 pstate); #else static inline int reinstall_suspended_bps(struct pt_regs *regs) { return -ENODEV; } + +static inline u64 signal_single_step_enable_bps(void) +{ + return 0; +} + +static inline void signal_reinstall_single_step(u64 pstate) { } #endif int aarch32_break_handler(struct pt_regs *regs); diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index 208db3d..8dbfdac 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -52,6 +52,16 @@ #define PSR_N_BIT 0x80000000 /* + * pstat in pt_regs and user_pt_regs are 64 bits. The highest 32 bits + * of it can be used by kernel. One user of them is signal handler. + */ +#define PSR_LINUX_MASK 0xffffffff00000000UL +#define PSR_LINUX_HW_BP_SS 0x0000000100000000UL /* Single step and disable breakpoints */ +#define PSR_LINUX_HW_WP_SS 0x0000000200000000UL /* Single step and disable watchpoints */ + +#define PSR_LINUX_HW_SS (PSR_LINUX_HW_BP_SS | PSR_LINUX_HW_WP_SS) + +/* * Groups of PSR bits */ #define PSR_f 0xff000000 /* Flags */ diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index b45c95d..18fd3d3 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -954,3 +954,52 @@ int hw_breakpoint_exceptions_notify(struct notifier_block *unused, { return NOTIFY_DONE; } + +u64 signal_single_step_enable_bps(void) +{ + struct debug_info *debug_info = ¤t->thread.debug; + u64 retval = 0; + + if (likely(!debug_info->bps_disabled && !debug_info->wps_disabled)) + return 0; + + if (debug_info->bps_disabled) { + retval |= PSR_LINUX_HW_BP_SS; + toggle_bp_registers(AARCH64_DBG_REG_BCR, DBG_ACTIVE_EL0, 1); + debug_info->bps_disabled = 0; + } + + if (debug_info->wps_disabled) { + retval |= PSR_LINUX_HW_WP_SS; + toggle_bp_registers(AARCH64_DBG_REG_WCR, DBG_ACTIVE_EL0, 1); + debug_info->wps_disabled = 0; + } + + if (debug_info->suspended_step) + debug_info->suspended_step = 0; + else + user_disable_single_step(current); + return retval; +} + +void signal_reinstall_single_step(u64 pstate) +{ + struct debug_info *debug_info = ¤t->thread.debug; + + if (likely(!(pstate & PSR_LINUX_HW_SS))) + return; + + if (pstate & PSR_LINUX_HW_BP_SS) { + debug_info->bps_disabled = 1; + toggle_bp_registers(AARCH64_DBG_REG_BCR, DBG_ACTIVE_EL0, 0); + } + if (pstate & PSR_LINUX_HW_WP_SS) { + debug_info->wps_disabled = 1; + toggle_bp_registers(AARCH64_DBG_REG_WCR, DBG_ACTIVE_EL0, 0); + } + + if (test_thread_flag(TIF_SINGLESTEP)) + debug_info->suspended_step = 1; + else + user_enable_single_step(current); +} diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index e18c48c..6cb1e49 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -151,6 +151,7 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) if (restore_altstack(&frame->uc.uc_stack)) goto badframe; + signal_reinstall_single_step(regs->pstate); return regs->regs[0]; badframe: @@ -292,6 +293,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) int usig = ksig->sig; int ret; + regs->pstate |= signal_single_step_enable_bps(); /* * Set up the stack frame */ -- 1.8.5.2