Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 40e59a61 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[PATCH] x86_64: Don't schedule on exception stack on preemptive kernels 



Extends an earlier patch from John Blackwood to more exception handlers
that also run on the exception stacks.

Expand the use of preempt_conditional_{sti,cli} to all cases where
interrupts are to be re-enabled during exception handling while running
on an IST stack.

Based on original patch from Jan Beulich.

Cc: John Blackwood <john.blackwood@ccur.com>
Cc: jbeulich@novell.com
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fad7906d

arch/x86_64/kernel/traps.c

+17 −4
Original line number Diff line number Diff line
@@ -102,6 +102,8 @@ static inline void preempt_conditional_cli(struct pt_regs *regs) 
{

	if (regs->eflags & X86_EFLAGS_IF)

		local_irq_disable();

	/* Make sure to not schedule here because we could be running

	   on an exception stack. */

	preempt_enable_no_resched();

}
@@ -483,8 +485,6 @@ static void __kprobes do_trap(int trapnr, int signr, char *str, 
{

	struct task_struct *tsk = current;



	conditional_sti(regs);



	tsk->thread.error_code = error_code;

	tsk->thread.trap_no = trapnr;
@@ -521,6 +521,7 @@ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ 
	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \

							== NOTIFY_STOP) \

		return; \

	conditional_sti(regs);						\

	do_trap(trapnr, signr, str, regs, error_code, NULL); \

}
@@ -535,6 +536,7 @@ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ 
	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \

							== NOTIFY_STOP) \

		return; \

	conditional_sti(regs);						\

	do_trap(trapnr, signr, str, regs, error_code, &info); \

}
@@ -548,7 +550,17 @@ DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS) 
DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present)

DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)

DO_ERROR(18, SIGSEGV, "reserved", reserved)

DO_ERROR(12, SIGBUS,  "stack segment", stack_segment)



/* Runs on IST stack */

asmlinkage void do_stack_segment(struct pt_regs *regs, long error_code)

{

	if (notify_die(DIE_TRAP, "stack segment", regs, error_code,

			12, SIGBUS) == NOTIFY_STOP)

		return;

	preempt_conditional_sti(regs);

	do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);

	preempt_conditional_cli(regs);

}



asmlinkage void do_double_fault(struct pt_regs * regs, long error_code)

{
@@ -682,8 +694,9 @@ asmlinkage void __kprobes do_int3(struct pt_regs * regs, long error_code) 
	if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) {

		return;

	}

	preempt_conditional_sti(regs);

	do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);

	return;

	preempt_conditional_cli(regs);

}



/* Help handler running on IST stack to switch back to user stack