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entry: Move exit to usermode functions to header file 

To allow inlining, move exit_to_user_mode() to
entry-common.h.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20231218074520.1998026-2-svens@linux.ibm.com
This commit is contained in:
Sven Schnelle 2023-12-18 08:45:18 +01:00 committed by Thomas Gleixner
parent 98b1cc82c4
commit d680194719
2 changed files with 61 additions and 44 deletions
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53
include/linux/entry-common.h
View File

@ -7,6 +7,10 @@
#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 <asm/entry-common.h>
@ -258,6 +262,43 @@ 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
*
@ -276,7 +317,17 @@ 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

52
kernel/entry/common.c
View File

@ -123,29 +123,16 @@ noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
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 +177,6 @@ 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
@ -295,7 +261,7 @@ __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)
@ -308,7 +274,7 @@ 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)