redonkable/alistair23-linux
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[PATCH] x86_64: Don't schedule on exception stack on preemptive kernels

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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: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2006-05-15 18:19:47 +02:00 committed by Linus Torvalds
parent fad7906d16
commit 40e59a6166
1 changed files with 17 additions and 4 deletions
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21
arch/x86_64/kernel/traps.c
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@ -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