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From: tip-bot for Alexander Kuleshov <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: dave.hansen@linux.intel.com, tony.luck@intel.com, bp@alien8.de,
	wangnan0@huawei.com, bp@suse.de, peterz@infradead.org,
	kuleshovmail@gmail.com, torvalds@linux-foundation.org,
	tglx@linutronix.de, luto@kernel.org, hpa@zytor.com,
	mingo@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip:x86/asm] x86/entry/traps: Refactor preemption and interrupt flag handling
Date: Mon, 1 Feb 2016 03:39:38 -0800	[thread overview]
Message-ID: <tip-d99e1bd175f4291ddb6e62b22bb5bdbe3976389a@git.kernel.org> (raw)
In-Reply-To: <1453750913-4781-2-git-send-email-bp@alien8.de>

Commit-ID:  d99e1bd175f4291ddb6e62b22bb5bdbe3976389a
Gitweb:     http://git.kernel.org/tip/d99e1bd175f4291ddb6e62b22bb5bdbe3976389a
Author:     Alexander Kuleshov <kuleshovmail@gmail.com>
AuthorDate: Mon, 25 Jan 2016 20:41:46 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 1 Feb 2016 10:45:14 +0100

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>
---
 arch/x86/kernel/traps.c | 47 +++++++++++++++++++----------------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

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
@@ -83,30 +83,16 @@ gate_desc idt_table[NR_VECTORS] __page_aligned_bss;
 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)
-{
-	if (regs->flags & X86_EFLAGS_IF)
-		local_irq_disable();
-}
-
-static inline void preempt_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();
-	preempt_count_dec();
 }
 
 void ist_enter(struct pt_regs *regs)
@@ -286,7 +272,7 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
 
 	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 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 	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 @@ do_general_protection(struct pt_regs *regs, long error_code)
 	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 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 	 * 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 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 	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 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 	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 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 
 	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 @@ do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 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 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 	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 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 #endif
 	fpu__restore(&current->thread.fpu); /* interrupts still off */
 #ifdef CONFIG_X86_32
-	conditional_sti(regs);
+	cond_local_irq_enable(regs);
 #endif
 }
 NOKPROBE_SYMBOL(do_device_not_available);

  reply	other threads:[~2016-02-01 11:40 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-25 19:41 [PATCH 0/8] tip-queue 2016-01-25 Borislav Petkov
2016-01-25 19:41 ` [PATCH 1/8] x86/traps.c: Refactor preemption and interrupt flag handling Borislav Petkov
2016-02-01 11:39   ` tip-bot for Alexander Kuleshov [this message]
2016-01-25 19:41 ` [PATCH 2/8] x86/cpufeature: Use enum cpuid_leafs instead of magic numbers Borislav Petkov
2016-02-01 11:40   ` [tip:x86/cpu] " tip-bot for Huaitong Han
2016-01-25 19:41 ` [PATCH 3/8] x86/mce: Fix order of AMD MCE init function call Borislav Petkov
2016-02-01 11:40   ` [tip:ras/core] " tip-bot for Aravind Gopalakrishnan
2016-01-25 19:41 ` [PATCH 4/8] x86/mce/AMD: Do not perform shared bank check for future processors Borislav Petkov
2016-02-01 11:40   ` [tip:ras/core] " tip-bot for Aravind Gopalakrishnan
2016-01-25 19:41 ` [PATCH 5/8] x86/mce/AMD: Reduce number of blocks scanned per bank Borislav Petkov
2016-02-01 11:41   ` [tip:ras/core] " tip-bot for Aravind Gopalakrishnan
2016-01-25 19:41 ` [PATCH 6/8] x86/mce/AMD: Fix LVT offset configuration for thresholding Borislav Petkov
2016-02-01 11:41   ` [tip:ras/core] " tip-bot for Aravind Gopalakrishnan
2016-01-25 19:41 ` [PATCH 7/8] x86/mce/AMD: Carve out threshold block preparation Borislav Petkov
2016-02-01 11:41   ` [tip:ras/core] " tip-bot for Borislav Petkov
2016-01-25 19:41 ` [PATCH 8/8] x86/mce/AMD: Set MCAX Enable bit Borislav Petkov
2016-02-01 11:42   ` [tip:ras/core] " tip-bot for Aravind Gopalakrishnan

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