1 files changed, 28 insertions, 90 deletions

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index ec138e538c44..1433f6b4607d 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -40,10 +40,10 @@ static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)
 
 #ifdef CONFIG_CONTEXT_TRACKING
 /* Called on entry from user mode with IRQs off. */
-__visible void enter_from_user_mode(void)
+__visible inline void enter_from_user_mode(void)
 {
 	CT_WARN_ON(ct_state() != CONTEXT_USER);
-	user_exit();
+	user_exit_irqoff();
 }
 #else
 static inline void enter_from_user_mode(void) {}
@@ -64,22 +64,16 @@ static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
 }
 
 /*
- * We can return 0 to resume the syscall or anything else to go to phase
- * 2.  If we resume the syscall, we need to put something appropriate in
- * regs->orig_ax.
- *
- * NB: We don't have full pt_regs here, but regs->orig_ax and regs->ax
- * are fully functional.
- *
- * For phase 2's benefit, our return value is:
- * 0:			resume the syscall
- * 1:			go to phase 2; no seccomp phase 2 needed
- * anything else:	go to phase 2; pass return value to seccomp
+ * Returns the syscall nr to run (which should match regs->orig_ax) or -1
+ * to skip the syscall.
  */
-unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
+static long syscall_trace_enter(struct pt_regs *regs)
 {
+	u32 arch = in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
+
 	struct thread_info *ti = pt_regs_to_thread_info(regs);
 	unsigned long ret = 0;
+	bool emulated = false;
 	u32 work;
 
 	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
@@ -87,11 +81,19 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
 
 	work = ACCESS_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;
 
+	if (unlikely(work & _TIF_SYSCALL_EMU))
+		emulated = true;
+
+	if ((emulated || (work & _TIF_SYSCALL_TRACE)) &&
+	    tracehook_report_syscall_entry(regs))
+		return -1L;
+
+	if (emulated)
+		return -1L;
+
 #ifdef CONFIG_SECCOMP
 	/*
-	 * Do seccomp first -- it should minimize exposure of other
-	 * code, and keeping seccomp fast is probably more valuable
-	 * than the rest of this.
+	 * Do seccomp after ptrace, to catch any tracer changes.
 	 */
 	if (work & _TIF_SECCOMP) {
 		struct seccomp_data sd;
@@ -118,69 +120,12 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
 			sd.args[5] = regs->bp;
 		}
 
-		BUILD_BUG_ON(SECCOMP_PHASE1_OK != 0);
-		BUILD_BUG_ON(SECCOMP_PHASE1_SKIP != 1);
-
-		ret = seccomp_phase1(&sd);
-		if (ret == SECCOMP_PHASE1_SKIP) {
-			regs->orig_ax = -1;
-			ret = 0;
-		} else if (ret != SECCOMP_PHASE1_OK) {
-			return ret;  /* Go directly to phase 2 */
-		}
-
-		work &= ~_TIF_SECCOMP;
-	}
-#endif
-
-	/* Do our best to finish without phase 2. */
-	if (work == 0)
-		return ret;  /* seccomp and/or nohz only (ret == 0 here) */
-
-#ifdef CONFIG_AUDITSYSCALL
-	if (work == _TIF_SYSCALL_AUDIT) {
-		/*
-		 * If there is no more work to be done except auditing,
-		 * then audit in phase 1.  Phase 2 always audits, so, if
-		 * we audit here, then we can't go on to phase 2.
-		 */
-		do_audit_syscall_entry(regs, arch);
-		return 0;
-	}
-#endif
-
-	return 1;  /* Something is enabled that we can't handle in phase 1 */
-}
-
-/* Returns the syscall nr to run (which should match regs->orig_ax). */
-long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
-				unsigned long phase1_result)
-{
-	struct thread_info *ti = pt_regs_to_thread_info(regs);
-	long ret = 0;
-	u32 work = ACCESS_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;
-
-	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
-		BUG_ON(regs != task_pt_regs(current));
-
-#ifdef CONFIG_SECCOMP
-	/*
-	 * Call seccomp_phase2 before running the other hooks so that
-	 * they can see any changes made by a seccomp tracer.
-	 */
-	if (phase1_result > 1 && seccomp_phase2(phase1_result)) {
-		/* seccomp failures shouldn't expose any additional code. */
-		return -1;
+		ret = __secure_computing(&sd);
+		if (ret == -1)
+			return ret;
 	}
 #endif
 
-	if (unlikely(work & _TIF_SYSCALL_EMU))
-		ret = -1L;
-
-	if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) &&
-	    tracehook_report_syscall_entry(regs))
-		ret = -1L;
-
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 		trace_sys_enter(regs, regs->orig_ax);
 
@@ -189,17 +134,6 @@ long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
 	return ret ?: regs->orig_ax;
 }
 
-long syscall_trace_enter(struct pt_regs *regs)
-{
-	u32 arch = in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
-	unsigned long phase1_result = syscall_trace_enter_phase1(regs, arch);
-
-	if (phase1_result == 0)
-		return regs->orig_ax;
-	else
-		return syscall_trace_enter_phase2(regs, arch, phase1_result);
-}
-
 #define EXIT_TO_USERMODE_LOOP_FLAGS				\
 	(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE |	\
 	 _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY)
@@ -270,11 +204,15 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
 	 * handling, because syscall restart has a fixup for compat
 	 * syscalls.  The fixup is exercised by the ptrace_syscall_32
 	 * selftest.
+	 *
+	 * We also need to clear TS_REGS_POKED_I386: the 32-bit tracer
+	 * special case only applies after poking regs and before the
+	 * very next return to user mode.
 	 */
-	ti->status &= ~TS_COMPAT;
+	ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
 #endif
 
-	user_enter();
+	user_enter_irqoff();
 }
 
 #define SYSCALL_EXIT_WORK_FLAGS				\