x86/entry/traps: Refactor preemption and interrupt flag handling
Make the preemption and interrupt flag handling more readable by
removing preempt_conditional_sti() and preempt_conditional_cli()
helpers and using preempt_disable() and
preempt_enable_no_resched() instead.
Rename contitional_sti() and conditional_cli() to the more
understandable cond_local_irq_enable() and
cond_local_irq_disable() respectively, while at it.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
[ Boris: massage text. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1453750913-4781-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ade185a..410e8e2 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -83,32 +83,18 @@
DECLARE_BITMAP(used_vectors, NR_VECTORS);
EXPORT_SYMBOL_GPL(used_vectors);
-static inline void conditional_sti(struct pt_regs *regs)
+static inline void cond_local_irq_enable(struct pt_regs *regs)
{
if (regs->flags & X86_EFLAGS_IF)
local_irq_enable();
}
-static inline void preempt_conditional_sti(struct pt_regs *regs)
-{
- preempt_count_inc();
- if (regs->flags & X86_EFLAGS_IF)
- local_irq_enable();
-}
-
-static inline void conditional_cli(struct pt_regs *regs)
+static inline void cond_local_irq_disable(struct pt_regs *regs)
{
if (regs->flags & X86_EFLAGS_IF)
local_irq_disable();
}
-static inline void preempt_conditional_cli(struct pt_regs *regs)
-{
- if (regs->flags & X86_EFLAGS_IF)
- local_irq_disable();
- preempt_count_dec();
-}
-
void ist_enter(struct pt_regs *regs)
{
if (user_mode(regs)) {
@@ -286,7 +272,7 @@
if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
NOTIFY_STOP) {
- conditional_sti(regs);
+ cond_local_irq_enable(regs);
do_trap(trapnr, signr, str, regs, error_code,
fill_trap_info(regs, signr, trapnr, &info));
}
@@ -368,7 +354,7 @@
if (notify_die(DIE_TRAP, "bounds", regs, error_code,
X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
return;
- conditional_sti(regs);
+ cond_local_irq_enable(regs);
if (!user_mode(regs))
die("bounds", regs, error_code);
@@ -443,7 +429,7 @@
struct task_struct *tsk;
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
- conditional_sti(regs);
+ cond_local_irq_enable(regs);
if (v8086_mode(regs)) {
local_irq_enable();
@@ -517,9 +503,11 @@
* as we may switch to the interrupt stack.
*/
debug_stack_usage_inc();
- preempt_conditional_sti(regs);
+ preempt_disable();
+ cond_local_irq_enable(regs);
do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
- preempt_conditional_cli(regs);
+ cond_local_irq_disable(regs);
+ preempt_enable_no_resched();
debug_stack_usage_dec();
exit:
ist_exit(regs);
@@ -648,12 +636,14 @@
debug_stack_usage_inc();
/* It's safe to allow irq's after DR6 has been saved */
- preempt_conditional_sti(regs);
+ preempt_disable();
+ cond_local_irq_enable(regs);
if (v8086_mode(regs)) {
handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
X86_TRAP_DB);
- preempt_conditional_cli(regs);
+ cond_local_irq_disable(regs);
+ preempt_enable_no_resched();
debug_stack_usage_dec();
goto exit;
}
@@ -673,7 +663,8 @@
si_code = get_si_code(tsk->thread.debugreg6);
if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
send_sigtrap(tsk, regs, error_code, si_code);
- preempt_conditional_cli(regs);
+ cond_local_irq_disable(regs);
+ preempt_enable_no_resched();
debug_stack_usage_dec();
exit:
@@ -696,7 +687,7 @@
if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
return;
- conditional_sti(regs);
+ cond_local_irq_enable(regs);
if (!user_mode(regs)) {
if (!fixup_exception(regs)) {
@@ -743,7 +734,7 @@
dotraplinkage void
do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
{
- conditional_sti(regs);
+ cond_local_irq_enable(regs);
}
dotraplinkage void
@@ -756,7 +747,7 @@
if (read_cr0() & X86_CR0_EM) {
struct math_emu_info info = { };
- conditional_sti(regs);
+ cond_local_irq_enable(regs);
info.regs = regs;
math_emulate(&info);
@@ -765,7 +756,7 @@
#endif
fpu__restore(¤t->thread.fpu); /* interrupts still off */
#ifdef CONFIG_X86_32
- conditional_sti(regs);
+ cond_local_irq_enable(regs);
#endif
}
NOKPROBE_SYMBOL(do_device_not_available);