Commit fa95d7dc authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/idtentry: Switch to conditional RCU handling 



Switch all idtentry_enter/exit() users over to the new conditional RCU
handling scheme and make the user mode entries in #DB, #INT3 and #MCE use
the user mode idtentry functions.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202117.382387286@linutronix.de
parent 9f9781b6

arch/x86/include/asm/idtentry.h

+6 −4
Original line number Diff line number Diff line
@@ -61,11 +61,12 @@ static __always_inline void __##func(struct pt_regs *regs); \ 
									\

__visible noinstr void func(struct pt_regs *regs)			\

{									\

	idtentry_enter(regs);						\

	bool rcu_exit = idtentry_enter_cond_rcu(regs);			\

									\

	instrumentation_begin();					\

	__##func (regs);						\

	instrumentation_end();						\

	idtentry_exit(regs);						\

	idtentry_exit_cond_rcu(regs, rcu_exit);				\

}									\

									\

static __always_inline void __##func(struct pt_regs *regs)
@@ -107,11 +108,12 @@ static __always_inline void __##func(struct pt_regs *regs, \ 
__visible noinstr void func(struct pt_regs *regs,			\

			    unsigned long error_code)			\

{									\

	idtentry_enter(regs);						\

	bool rcu_exit = idtentry_enter_cond_rcu(regs);			\

									\

	instrumentation_begin();					\

	__##func (regs, error_code);					\

	instrumentation_end();						\

	idtentry_exit(regs);						\

	idtentry_exit_cond_rcu(regs, rcu_exit);				\

}									\

									\

static __always_inline void __##func(struct pt_regs *regs,		\

arch/x86/kernel/cpu/mce/core.c

+2 −2
Original line number Diff line number Diff line
@@ -1929,11 +1929,11 @@ static __always_inline void exc_machine_check_kernel(struct pt_regs *regs) 


static __always_inline void exc_machine_check_user(struct pt_regs *regs)

{

	idtentry_enter(regs);

	idtentry_enter_user(regs);

	instrumentation_begin();

	machine_check_vector(regs);

	instrumentation_end();

	idtentry_exit(regs);

	idtentry_exit_user(regs);

}



#ifdef CONFIG_X86_64

arch/x86/kernel/traps.c

+5 −5
Original line number Diff line number Diff line
@@ -619,18 +619,18 @@ DEFINE_IDTENTRY_RAW(exc_int3) 
		return;



	/*

	 * idtentry_enter() uses static_branch_{,un}likely() and therefore

	 * idtentry_enter_user() uses static_branch_{,un}likely() and therefore

	 * can trigger INT3, hence poke_int3_handler() must be done

	 * before. If the entry came from kernel mode, then use nmi_enter()

	 * because the INT3 could have been hit in any context including

	 * NMI.

	 */

	if (user_mode(regs)) {

		idtentry_enter(regs);

		idtentry_enter_user(regs);

		instrumentation_begin();

		do_int3_user(regs);

		instrumentation_end();

		idtentry_exit(regs);

		idtentry_exit_user(regs);

	} else {

		nmi_enter();

		instrumentation_begin();
@@ -877,7 +877,7 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, 
static __always_inline void exc_debug_user(struct pt_regs *regs,

					   unsigned long dr6)

{

	idtentry_enter(regs);

	idtentry_enter_user(regs);

	clear_thread_flag(TIF_BLOCKSTEP);



	/*
@@ -886,7 +886,7 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, 
	 * User wants a sigtrap for that.

	 */

	handle_debug(regs, dr6, !dr6);

	idtentry_exit(regs);

	idtentry_exit_user(regs);

}



#ifdef CONFIG_X86_64

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