summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2024-01-09 05:37:13 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2024-01-09 05:37:13 +0300
commitcdc202281a5d5e2c4bbbbf78bbd68f035a49421a (patch)
treeb4b4134c0b9df4b387616a3513f285a7346b3e3d
parentab9517fa9aab71e312c7acc6fefefe080db3c972 (diff)
parent221a164035fd8b554a44bd7c4bf8e7715a497561 (diff)
downloadlinux-cdc202281a5d5e2c4bbbbf78bbd68f035a49421a.tar.xz
Merge tag 'core-entry-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull generic syscall updates from Ingo Molnar: "Move various entry functions from kernel/entry/common.c to a header file, and always-inline them, to improve syscall entry performance on s390 by ~11%" * tag 'core-entry-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: entry: Move syscall_enter_from_user_mode() to header file entry: Move enter_from_user_mode() to header file entry: Move exit to usermode functions to header file
-rw-r--r--include/linux/entry-common.h95
-rw-r--r--kernel/entry/common.c108
2 files changed, 103 insertions, 100 deletions
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index d95ab85f96ba..b0fb775a600d 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -7,6 +7,11 @@
#include <linux/syscalls.h>
#include <linux/seccomp.h>
#include <linux/sched.h>
+#include <linux/context_tracking.h>
+#include <linux/livepatch.h>
+#include <linux/resume_user_mode.h>
+#include <linux/tick.h>
+#include <linux/kmsan.h>
#include <asm/entry-common.h>
@@ -98,7 +103,19 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) {}
* done between establishing state and enabling interrupts. The caller must
* enable interrupts before invoking syscall_enter_from_user_mode_work().
*/
-void enter_from_user_mode(struct pt_regs *regs);
+static __always_inline void enter_from_user_mode(struct pt_regs *regs)
+{
+ arch_enter_from_user_mode(regs);
+ lockdep_hardirqs_off(CALLER_ADDR0);
+
+ CT_WARN_ON(__ct_state() != CONTEXT_USER);
+ user_exit_irqoff();
+
+ instrumentation_begin();
+ kmsan_unpoison_entry_regs(regs);
+ trace_hardirqs_off_finish();
+ instrumentation_end();
+}
/**
* syscall_enter_from_user_mode_prepare - Establish state and enable interrupts
@@ -117,6 +134,9 @@ void enter_from_user_mode(struct pt_regs *regs);
*/
void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
+long syscall_trace_enter(struct pt_regs *regs, long syscall,
+ unsigned long work);
+
/**
* syscall_enter_from_user_mode_work - Check and handle work before invoking
* a syscall
@@ -140,7 +160,15 @@ void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
* ptrace_report_syscall_entry(), __secure_computing(), trace_sys_enter()
* 2) Invocation of audit_syscall_entry()
*/
-long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
+static __always_inline long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
+{
+ unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
+
+ if (work & SYSCALL_WORK_ENTER)
+ syscall = syscall_trace_enter(regs, syscall, work);
+
+ return syscall;
+}
/**
* syscall_enter_from_user_mode - Establish state and check and handle work
@@ -159,7 +187,19 @@ long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
* Returns: The original or a modified syscall number. See
* syscall_enter_from_user_mode_work() for further explanation.
*/
-long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall);
+static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
+{
+ long ret;
+
+ enter_from_user_mode(regs);
+
+ instrumentation_begin();
+ local_irq_enable();
+ ret = syscall_enter_from_user_mode_work(regs, syscall);
+ instrumentation_end();
+
+ return ret;
+}
/**
* local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable()
@@ -259,6 +299,43 @@ static __always_inline void arch_exit_to_user_mode(void) { }
void arch_do_signal_or_restart(struct pt_regs *regs);
/**
+ * exit_to_user_mode_loop - do any pending work before leaving to user space
+ */
+unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
+ unsigned long ti_work);
+
+/**
+ * exit_to_user_mode_prepare - call exit_to_user_mode_loop() if required
+ * @regs: Pointer to pt_regs on entry stack
+ *
+ * 1) check that interrupts are disabled
+ * 2) call tick_nohz_user_enter_prepare()
+ * 3) call exit_to_user_mode_loop() if any flags from
+ * EXIT_TO_USER_MODE_WORK are set
+ * 4) check that interrupts are still disabled
+ */
+static __always_inline void exit_to_user_mode_prepare(struct pt_regs *regs)
+{
+ unsigned long ti_work;
+
+ lockdep_assert_irqs_disabled();
+
+ /* Flush pending rcuog wakeup before the last need_resched() check */
+ tick_nohz_user_enter_prepare();
+
+ ti_work = read_thread_flags();
+ if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
+ ti_work = exit_to_user_mode_loop(regs, ti_work);
+
+ arch_exit_to_user_mode_prepare(regs, ti_work);
+
+ /* Ensure that kernel state is sane for a return to userspace */
+ kmap_assert_nomap();
+ lockdep_assert_irqs_disabled();
+ lockdep_sys_exit();
+}
+
+/**
* exit_to_user_mode - Fixup state when exiting to user mode
*
* Syscall/interrupt exit enables interrupts, but the kernel state is
@@ -276,7 +353,17 @@ void arch_do_signal_or_restart(struct pt_regs *regs);
* non-instrumentable.
* The caller has to invoke syscall_exit_to_user_mode_work() before this.
*/
-void exit_to_user_mode(void);
+static __always_inline void exit_to_user_mode(void)
+{
+ instrumentation_begin();
+ trace_hardirqs_on_prepare();
+ lockdep_hardirqs_on_prepare();
+ instrumentation_end();
+
+ user_enter_irqoff();
+ arch_exit_to_user_mode();
+ lockdep_hardirqs_on(CALLER_ADDR0);
+}
/**
* syscall_exit_to_user_mode_work - Handle work before returning to user mode
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index d7ee4bc3f2ba..88cb3c88aaa5 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -15,26 +15,6 @@
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
-/* See comment for enter_from_user_mode() in entry-common.h */
-static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
-{
- arch_enter_from_user_mode(regs);
- lockdep_hardirqs_off(CALLER_ADDR0);
-
- CT_WARN_ON(__ct_state() != CONTEXT_USER);
- user_exit_irqoff();
-
- instrumentation_begin();
- kmsan_unpoison_entry_regs(regs);
- trace_hardirqs_off_finish();
- instrumentation_end();
-}
-
-void noinstr enter_from_user_mode(struct pt_regs *regs)
-{
- __enter_from_user_mode(regs);
-}
-
static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
{
if (unlikely(audit_context())) {
@@ -45,7 +25,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
}
}
-static long syscall_trace_enter(struct pt_regs *regs, long syscall,
+long syscall_trace_enter(struct pt_regs *regs, long syscall,
unsigned long work)
{
long ret = 0;
@@ -85,67 +65,24 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,
return ret ? : syscall;
}
-static __always_inline long
-__syscall_enter_from_user_work(struct pt_regs *regs, long syscall)
-{
- unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
-
- if (work & SYSCALL_WORK_ENTER)
- syscall = syscall_trace_enter(regs, syscall, work);
-
- return syscall;
-}
-
-long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
-{
- return __syscall_enter_from_user_work(regs, syscall);
-}
-
-noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
-{
- long ret;
-
- __enter_from_user_mode(regs);
-
- instrumentation_begin();
- local_irq_enable();
- ret = __syscall_enter_from_user_work(regs, syscall);
- instrumentation_end();
-
- return ret;
-}
-
noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
{
- __enter_from_user_mode(regs);
+ enter_from_user_mode(regs);
instrumentation_begin();
local_irq_enable();
instrumentation_end();
}
-/* See comment for exit_to_user_mode() in entry-common.h */
-static __always_inline void __exit_to_user_mode(void)
-{
- instrumentation_begin();
- trace_hardirqs_on_prepare();
- lockdep_hardirqs_on_prepare();
- instrumentation_end();
-
- user_enter_irqoff();
- arch_exit_to_user_mode();
- lockdep_hardirqs_on(CALLER_ADDR0);
-}
-
-void noinstr exit_to_user_mode(void)
-{
- __exit_to_user_mode();
-}
-
/* Workaround to allow gradual conversion of architecture code */
void __weak arch_do_signal_or_restart(struct pt_regs *regs) { }
-static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
- unsigned long ti_work)
+/**
+ * exit_to_user_mode_loop - do any pending work before leaving to user space
+ * @regs: Pointer to pt_regs on entry stack
+ * @ti_work: TIF work flags as read by the caller
+ */
+__always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
+ unsigned long ti_work)
{
/*
* Before returning to user space ensure that all pending work
@@ -190,27 +127,6 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
return ti_work;
}
-static void exit_to_user_mode_prepare(struct pt_regs *regs)
-{
- unsigned long ti_work;
-
- lockdep_assert_irqs_disabled();
-
- /* Flush pending rcuog wakeup before the last need_resched() check */
- tick_nohz_user_enter_prepare();
-
- ti_work = read_thread_flags();
- if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
- ti_work = exit_to_user_mode_loop(regs, ti_work);
-
- arch_exit_to_user_mode_prepare(regs, ti_work);
-
- /* Ensure that kernel state is sane for a return to userspace */
- kmap_assert_nomap();
- lockdep_assert_irqs_disabled();
- lockdep_sys_exit();
-}
-
/*
* If SYSCALL_EMU is set, then the only reason to report is when
* SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP). This syscall
@@ -295,12 +211,12 @@ __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
instrumentation_begin();
__syscall_exit_to_user_mode_work(regs);
instrumentation_end();
- __exit_to_user_mode();
+ exit_to_user_mode();
}
noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
{
- __enter_from_user_mode(regs);
+ enter_from_user_mode(regs);
}
noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
@@ -308,7 +224,7 @@ noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
instrumentation_begin();
exit_to_user_mode_prepare(regs);
instrumentation_end();
- __exit_to_user_mode();
+ exit_to_user_mode();
}
noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)