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x86/entry: Provide idtentry_enter/exit_user()

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As there are exceptions which already handle entry from user mode and from
kernel mode separately, providing explicit user entry/exit handling callbacks
makes sense and makes the code easier to understand.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202117.289548561@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-05-21 22:05:18 +02:00
parent 3eeec38584
commit 9f9781b60d
2 changed files with 34 additions and 0 deletions
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31
arch/x86/entry/common.c
View File

@ -658,3 +658,34 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit)
rcu_irq_exit();
}
}
/**
* idtentry_enter_user - Handle state tracking on idtentry from user mode
* @regs: Pointer to pt_regs of interrupted context
*
* Invokes enter_from_user_mode() to establish the proper context for
* NOHZ_FULL. Otherwise scheduling on exit would not be possible.
*/
void noinstr idtentry_enter_user(struct pt_regs *regs)
{
enter_from_user_mode();
}
/**
* idtentry_exit_user - Handle return from exception to user mode
* @regs: Pointer to pt_regs (exception entry regs)
*
* Runs the necessary preemption and work checks and returns to the caller
* with interrupts disabled and no further work pending.
*
* This is the last action before returning to the low level ASM code which
* just needs to return to the appropriate context.
*
* Counterpart to idtentry_enter_user().
*/
void noinstr idtentry_exit_user(struct pt_regs *regs)
{
lockdep_assert_irqs_disabled();
prepare_exit_to_usermode(regs);
}

3
arch/x86/include/asm/idtentry.h
View File

@ -7,6 +7,9 @@
#ifndef __ASSEMBLY__
void idtentry_enter_user(struct pt_regs *regs);
void idtentry_exit_user(struct pt_regs *regs);
bool idtentry_enter_cond_rcu(struct pt_regs *regs, bool cond_rcu);
void idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit);