The generic syscall syscall_exit_work() has the following content: | audit_syscall_exit(regs) | trace_sys_exit(regs, ...) | ptrace_report_syscall_exit(regs, step) The generic syscall syscall_exit_to_user_mode_work() has the following form: | unsigned long work = READ_ONCE(current_thread_info()->syscall_work) | rseq_syscall() | if (unlikely(work & SYSCALL_WORK_EXIT)) | syscall_exit_work(regs, work) In preparation for moving arm64 over to the generic entry code, rework el0_svc_common() as below: - Rename syscall_trace_exit() to syscall_exit_work(). - Add syscall_exit_to_user_mode_prepare() function to replace the combination of read_thread_flags() and syscall_exit_work(), also move the syscall exit check logic into it. Move has_syscall_work() helper into asm/syscall.h for reuse. - As currently rseq_syscall() is always called and itself is controlled by the CONFIG_DEBUG_RSEQ macro, so the CONFIG_DEBUG_RSEQ check is removed. Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/syscall.h | 7 ++++++- arch/arm64/kernel/ptrace.c | 14 +++++++++++--- arch/arm64/kernel/syscall.c | 20 +------------------- 3 files changed, 18 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h index d69f590a989b..6225981fbbdb 100644 --- a/arch/arm64/include/asm/syscall.h +++ b/arch/arm64/include/asm/syscall.h @@ -114,7 +114,12 @@ static inline int syscall_get_arch(struct task_struct *task) return AUDIT_ARCH_AARCH64; } +static inline bool has_syscall_work(unsigned long flags) +{ + return unlikely(flags & _TIF_SYSCALL_WORK); +} + int syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long flags); -void syscall_trace_exit(struct pt_regs *regs, unsigned long flags); +void syscall_exit_to_user_mode_prepare(struct pt_regs *regs); #endif /* __ASM_SYSCALL_H */ diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index dfdd886dc0a9..233a7688ac94 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -2409,10 +2409,8 @@ int syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long flags) return syscall; } -void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) +static void syscall_exit_work(struct pt_regs *regs, unsigned long flags) { - rseq_syscall(regs); - audit_syscall_exit(regs); if (flags & _TIF_SYSCALL_TRACEPOINT) @@ -2422,6 +2420,16 @@ void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) report_syscall_exit(regs); } +void syscall_exit_to_user_mode_prepare(struct pt_regs *regs) +{ + unsigned long flags = read_thread_flags(); + + rseq_syscall(regs); + + if (has_syscall_work(flags) || flags & _TIF_SINGLESTEP) + syscall_exit_work(regs, flags); +} + /* * SPSR_ELx bits which are always architecturally RES0 per ARM DDI 0487D.a. * We permit userspace to set SSBS (AArch64 bit 12, AArch32 bit 23) which is diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index ec31f82d2e9f..65021d0f49e1 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -65,11 +65,6 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, choose_random_kstack_offset(get_random_u16()); } -static inline bool has_syscall_work(unsigned long flags) -{ - return unlikely(flags & _TIF_SYSCALL_WORK); -} - static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, const syscall_fn_t syscall_table[]) { @@ -130,21 +125,8 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, } invoke_syscall(regs, scno, sc_nr, syscall_table); - - /* - * The tracing status may have changed under our feet, so we have to - * check again. However, if we were tracing entry, then we always trace - * exit regardless, as the old entry assembly did. - */ - if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) { - flags = read_thread_flags(); - if (!has_syscall_work(flags) && !(flags & _TIF_SINGLESTEP)) - return; - } - trace_exit: - flags = read_thread_flags(); - syscall_trace_exit(regs, flags); + syscall_exit_to_user_mode_prepare(regs); } void do_el0_svc(struct pt_regs *regs) -- 2.34.1