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Date: Thu, 19 Sep 2019 17:03:17 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: x86@...nel.org, Peter Zijlstra <peterz@...radead.org>,
Andy Lutomirski <luto@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Marc Zyngier <maz@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
linux-arch@...r.kernel.org
Subject: [RFC patch 03/15] x86/entry: Use generic syscall entry function
Replace the syscall entry work handling with the generic version, Provide
the necessary helper inlines to handle the real architecture specific
parts, e.g. audit and seccomp invocations.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
arch/x86/Kconfig | 1
arch/x86/entry/common.c | 108 +++---------------------------------
arch/x86/include/asm/entry-common.h | 59 +++++++++++++++++++
arch/x86/include/asm/thread_info.h | 5 -
4 files changed, 70 insertions(+), 103 deletions(-)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -110,6 +110,7 @@ config X86
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES
select GENERIC_EARLY_IOREMAP
+ select GENERIC_ENTRY
select GENERIC_FIND_FIRST_BIT
select GENERIC_IOMAP
select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -10,13 +10,13 @@
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
+#include <linux/entry-common.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/tracehook.h>
#include <linux/audit.h>
-#include <linux/seccomp.h>
#include <linux/signal.h>
#include <linux/export.h>
#include <linux/context_tracking.h>
@@ -34,7 +34,6 @@
#include <asm/fpu/api.h>
#include <asm/nospec-branch.h>
-#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
#ifdef CONFIG_CONTEXT_TRACKING
@@ -48,86 +47,6 @@
static inline void enter_from_user_mode(void) {}
#endif
-static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
-{
-#ifdef CONFIG_X86_64
- if (arch == AUDIT_ARCH_X86_64) {
- audit_syscall_entry(regs->orig_ax, regs->di,
- regs->si, regs->dx, regs->r10);
- } else
-#endif
- {
- audit_syscall_entry(regs->orig_ax, regs->bx,
- regs->cx, regs->dx, regs->si);
- }
-}
-
-/*
- * Returns the syscall nr to run (which should match regs->orig_ax) or -1
- * to skip the syscall.
- */
-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 = current_thread_info();
- unsigned long ret = 0;
- u32 work;
-
- if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
- BUG_ON(regs != task_pt_regs(current));
-
- work = READ_ONCE(ti->flags);
-
- if (work & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU)) {
- ret = tracehook_report_syscall_entry(regs);
- if (ret || (work & _TIF_SYSCALL_EMU))
- return -1L;
- }
-
-#ifdef CONFIG_SECCOMP
- /*
- * Do seccomp after ptrace, to catch any tracer changes.
- */
- if (work & _TIF_SECCOMP) {
- struct seccomp_data sd;
-
- sd.arch = arch;
- sd.nr = regs->orig_ax;
- sd.instruction_pointer = regs->ip;
-#ifdef CONFIG_X86_64
- if (arch == AUDIT_ARCH_X86_64) {
- sd.args[0] = regs->di;
- sd.args[1] = regs->si;
- sd.args[2] = regs->dx;
- sd.args[3] = regs->r10;
- sd.args[4] = regs->r8;
- sd.args[5] = regs->r9;
- } else
-#endif
- {
- sd.args[0] = regs->bx;
- sd.args[1] = regs->cx;
- sd.args[2] = regs->dx;
- sd.args[3] = regs->si;
- sd.args[4] = regs->di;
- sd.args[5] = regs->bp;
- }
-
- ret = __secure_computing(&sd);
- if (ret == -1)
- return ret;
- }
-#endif
-
- if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
- trace_sys_enter(regs, regs->orig_ax);
-
- do_audit_syscall_entry(regs, arch);
-
- return ret ?: regs->orig_ax;
-}
-
#define EXIT_TO_USERMODE_LOOP_FLAGS \
(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
_TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY | _TIF_PATCH_PENDING)
@@ -277,13 +196,10 @@ static void syscall_slow_exit_work(struc
#ifdef CONFIG_X86_64
__visible void do_syscall_64(unsigned long nr, struct pt_regs *regs)
{
- struct thread_info *ti;
-
enter_from_user_mode();
local_irq_enable();
- ti = current_thread_info();
- if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY)
- nr = syscall_trace_enter(regs);
+
+ nr = syscall_enter_from_usermode(regs, nr);
if (likely(nr < NR_syscalls)) {
nr = array_index_nospec(nr, NR_syscalls);
@@ -310,22 +226,18 @@ static void syscall_slow_exit_work(struc
*/
static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
{
- struct thread_info *ti = current_thread_info();
unsigned int nr = (unsigned int)regs->orig_ax;
#ifdef CONFIG_IA32_EMULATION
- ti->status |= TS_COMPAT;
+ current_thread_info()->status |= TS_COMPAT;
#endif
- if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
- /*
- * Subtlety here: if ptrace pokes something larger than
- * 2^32-1 into orig_ax, this truncates it. This may or
- * may not be necessary, but it matches the old asm
- * behavior.
- */
- nr = syscall_trace_enter(regs);
- }
+ /*
+ * Subtlety here: if ptrace pokes something larger than 2^32-1 into
+ * orig_ax, this truncates it. This may or may not be necessary,
+ * but it matches the old asm behavior.
+ */
+ nr = syscall_enter_from_usermode(regs, nr);
if (likely(nr < IA32_NR_syscalls)) {
nr = array_index_nospec(nr, IA32_NR_syscalls);
--- /dev/null
+++ b/arch/x86/include/asm/entry-common.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_X86_ENTRY_COMMON_H
+#define _ASM_X86_ENTRY_COMMON_H
+
+#include <linux/seccomp.h>
+#include <linux/audit.h>
+
+static inline long arch_syscall_enter_seccomp(struct pt_regs *regs)
+{
+#ifdef CONFIG_SECCOMP
+ u32 arch = in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
+ struct seccomp_data sd;
+
+ sd.arch = arch;
+ sd.nr = regs->orig_ax;
+ sd.instruction_pointer = regs->ip;
+
+#ifdef CONFIG_X86_64
+ if (arch == AUDIT_ARCH_X86_64) {
+ sd.args[0] = regs->di;
+ sd.args[1] = regs->si;
+ sd.args[2] = regs->dx;
+ sd.args[3] = regs->r10;
+ sd.args[4] = regs->r8;
+ sd.args[5] = regs->r9;
+ } else
+#endif
+ {
+ sd.args[0] = regs->bx;
+ sd.args[1] = regs->cx;
+ sd.args[2] = regs->dx;
+ sd.args[3] = regs->si;
+ sd.args[4] = regs->di;
+ sd.args[5] = regs->bp;
+ }
+
+ return __secure_computing(&sd);
+#else
+ return 0;
+#endif
+}
+#define arch_syscall_enter_seccomp arch_syscall_enter_seccomp
+
+static inline void arch_syscall_enter_audit(struct pt_regs *regs)
+{
+#ifdef CONFIG_X86_64
+ if (in_ia32_syscall()) {
+ audit_syscall_entry(regs->orig_ax, regs->di,
+ regs->si, regs->dx, regs->r10);
+ } else
+#endif
+ {
+ audit_syscall_entry(regs->orig_ax, regs->bx,
+ regs->cx, regs->dx, regs->si);
+ }
+}
+#define arch_syscall_enter_audit arch_syscall_enter_audit
+
+#endif
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -133,11 +133,6 @@ struct thread_info {
#define _TIF_X32 (1 << TIF_X32)
#define _TIF_FSCHECK (1 << TIF_FSCHECK)
-/* Work to do before invoking the actual syscall. */
-#define _TIF_WORK_SYSCALL_ENTRY \
- (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \
- _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT)
-
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW_BASE \
(_TIF_IO_BITMAP|_TIF_NOCPUID|_TIF_NOTSC|_TIF_BLOCKSTEP| \
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