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Subject[tip: x86/entry] x86/idtentry: Switch to conditional RCU handling
The following commit has been merged into the x86/entry branch of tip:

Commit-ID: 77d7843297dfe3bbd997a46548c9cdd8047ecffe
Gitweb: https://git.kernel.org/tip/77d7843297dfe3bbd997a46548c9cdd8047ecffe
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 21 May 2020 22:05:19 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 26 May 2020 19:06:27 +02:00

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: 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/20200521202117.382387286@linutronix.de
---
arch/x86/include/asm/idtentry.h | 10 ++++++----
arch/x86/kernel/cpu/mce/core.c | 4 ++--
arch/x86/kernel/traps.c | 10 +++++-----
3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index b3aca72..0f974e5 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -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, \
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index a32a7e2..c47f004 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -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
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 9e5d81c..f28be3e 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -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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