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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>
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parent
bb56968a37
commit
d99e1bd175
1 changed files with 19 additions and 28 deletions
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@ -83,32 +83,18 @@ gate_desc idt_table[NR_VECTORS] __page_aligned_bss;
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DECLARE_BITMAP(used_vectors, NR_VECTORS);
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EXPORT_SYMBOL_GPL(used_vectors);
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static inline void conditional_sti(struct pt_regs *regs)
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static inline void cond_local_irq_enable(struct pt_regs *regs)
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{
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_enable();
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}
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static inline void preempt_conditional_sti(struct pt_regs *regs)
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{
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preempt_count_inc();
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_enable();
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}
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static inline void conditional_cli(struct pt_regs *regs)
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static inline void cond_local_irq_disable(struct pt_regs *regs)
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{
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_disable();
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}
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static inline void preempt_conditional_cli(struct pt_regs *regs)
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{
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_disable();
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preempt_count_dec();
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}
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void ist_enter(struct pt_regs *regs)
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{
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if (user_mode(regs)) {
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@ -286,7 +272,7 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
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if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
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NOTIFY_STOP) {
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conditional_sti(regs);
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cond_local_irq_enable(regs);
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do_trap(trapnr, signr, str, regs, error_code,
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fill_trap_info(regs, signr, trapnr, &info));
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}
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@ -368,7 +354,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
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if (notify_die(DIE_TRAP, "bounds", regs, error_code,
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X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
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return;
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conditional_sti(regs);
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cond_local_irq_enable(regs);
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if (!user_mode(regs))
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die("bounds", regs, error_code);
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@ -443,7 +429,7 @@ do_general_protection(struct pt_regs *regs, long error_code)
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struct task_struct *tsk;
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
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conditional_sti(regs);
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cond_local_irq_enable(regs);
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if (v8086_mode(regs)) {
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local_irq_enable();
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@ -517,9 +503,11 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
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* as we may switch to the interrupt stack.
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*/
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debug_stack_usage_inc();
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preempt_conditional_sti(regs);
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preempt_disable();
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cond_local_irq_enable(regs);
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do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
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preempt_conditional_cli(regs);
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cond_local_irq_disable(regs);
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preempt_enable_no_resched();
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debug_stack_usage_dec();
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exit:
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ist_exit(regs);
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@ -648,12 +636,14 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
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debug_stack_usage_inc();
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/* It's safe to allow irq's after DR6 has been saved */
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preempt_conditional_sti(regs);
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preempt_disable();
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cond_local_irq_enable(regs);
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if (v8086_mode(regs)) {
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handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
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X86_TRAP_DB);
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preempt_conditional_cli(regs);
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cond_local_irq_disable(regs);
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preempt_enable_no_resched();
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debug_stack_usage_dec();
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goto exit;
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}
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@ -673,7 +663,8 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
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si_code = get_si_code(tsk->thread.debugreg6);
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if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
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send_sigtrap(tsk, regs, error_code, si_code);
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preempt_conditional_cli(regs);
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cond_local_irq_disable(regs);
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preempt_enable_no_resched();
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debug_stack_usage_dec();
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exit:
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@ -696,7 +687,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
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if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
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return;
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conditional_sti(regs);
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cond_local_irq_enable(regs);
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if (!user_mode(regs)) {
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if (!fixup_exception(regs)) {
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@ -743,7 +734,7 @@ do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
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dotraplinkage void
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do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
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{
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conditional_sti(regs);
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cond_local_irq_enable(regs);
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}
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dotraplinkage void
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@ -756,7 +747,7 @@ do_device_not_available(struct pt_regs *regs, long error_code)
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if (read_cr0() & X86_CR0_EM) {
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struct math_emu_info info = { };
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conditional_sti(regs);
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cond_local_irq_enable(regs);
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info.regs = regs;
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math_emulate(&info);
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@ -765,7 +756,7 @@ do_device_not_available(struct pt_regs *regs, long error_code)
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#endif
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fpu__restore(¤t->thread.fpu); /* interrupts still off */
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#ifdef CONFIG_X86_32
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conditional_sti(regs);
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cond_local_irq_enable(regs);
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#endif
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}
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NOKPROBE_SYMBOL(do_device_not_available);
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