[patch V2 13/17] x86/entry: Use generic syscall exit functionality

Thomas Gleixner
2019-10-23T12:32:24Z

Replace the x86 variant with the generic version.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/common.c | 44 ------------------------------------
arch/x86/include/asm/entry-common.h | 2 +
2 files changed, 3 insertions(+), 43 deletions(-)

--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -142,55 +142,13 @@ static void exit_to_usermode_loop(struct
trace_hardirqs_on();
}

-#define SYSCALL_EXIT_WORK_FLAGS \
- (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
- _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT)
-
-static void syscall_slow_exit_work(struct pt_regs *regs, u32 cached_flags)
-{
- bool step;
-
- audit_syscall_exit(regs);
-
- if (cached_flags & _TIF_SYSCALL_TRACEPOINT)
- trace_sys_exit(regs, regs->ax);
-
- /*
- * If TIF_SYSCALL_EMU is set, we only get here because of
- * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
- * We already reported this syscall instruction in
- * syscall_trace_enter().
- */
- step = unlikely(
- (cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU))
- == _TIF_SINGLESTEP);
- if (step || cached_flags & _TIF_SYSCALL_TRACE)
- tracehook_report_syscall_exit(regs, step);
-}
-
/*
* Called with IRQs on and fully valid regs. Returns with IRQs off in a
* state such that we can immediately switch to user mode.
*/
__visible inline void syscall_return_slowpath(struct pt_regs *regs)
{
- struct thread_info *ti = current_thread_info();
- u32 cached_flags = READ_ONCE(ti->flags);
-
- CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
-
- if (IS_ENABLED(CONFIG_PROVE_LOCKING) &&
- WARN(irqs_disabled(), "syscall %ld left IRQs disabled", regs->orig_ax))
- local_irq_enable();
-
- rseq_syscall(regs);
-
- /*
- * First do one-time work. If these work items are enabled, we
- * want to run them exactly once per syscall exit with IRQs on.
- */
- if (unlikely(cached_flags & SYSCALL_EXIT_WORK_FLAGS))
- syscall_slow_exit_work(regs, cached_flags);
+ syscall_exit_to_usermode(regs, regs->orig_ax, regs->ax);

local_irq_disable();
prepare_exit_to_usermode(regs);
--- a/arch/x86/include/asm/entry-common.h
+++ b/arch/x86/include/asm/entry-common.h
@@ -5,6 +5,8 @@
#include <linux/seccomp.h>
#include <linux/audit.h>

+#define ARCH_SYSCALL_EXIT_WORK (_TIF_SINGLESTEP)
+
static inline long arch_syscall_enter_seccomp(struct pt_regs *regs)
{
#ifdef CONFIG_SECCOMP