diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2008-03-24 16:43:21 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-17 17:41:29 +0200 |
| commit | d93c870bad38e8daaaf9f7e900a13431f24becbb (patch) | |
| tree | 9fa51e506bf6cddf362b25dfb2048941c8f24e1e /arch | |
| parent | 687c80540975709844699d9a96070e2cf3bad39d (diff) | |
x86: only enable interrupts when kernel state has been set up
The sysenter path tries to enable interrupts immediately. Unfortunately
this doesn't work in a paravirt environment, because not enough kernel
state has been set up at that point (namely, pointing %fs to the kernel
percpu data segment). To fix this, defer ENABLE_INTERRUPTS until after
the kernel state has been set up.
Unfortunately this means that we're running with interrupts disabled
for a while without calling the IRQ tracing code, but that can't be
called without setting up %fs either.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 4b87c32b639..a664d5726d8 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -291,10 +291,10 @@ ENTRY(ia32_sysenter_target) movl TSS_sysenter_sp0(%esp),%esp sysenter_past_esp: /* - * No need to follow this irqs on/off section: the syscall - * disabled irqs and here we enable it straight after entry: + * Interrupts are disabled here, but we can't trace it until + * enough kernel state to call TRACE_IRQS_OFF can be called - but + * we immediately enable interrupts at that point anyway. */ - ENABLE_INTERRUPTS(CLBR_NONE) pushl $(__USER_DS) CFI_ADJUST_CFA_OFFSET 4 /*CFI_REL_OFFSET ss, 0*/ @@ -302,6 +302,7 @@ sysenter_past_esp: CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET esp, 0 pushfl + orl $X86_EFLAGS_IF, (%esp) CFI_ADJUST_CFA_OFFSET 4 pushl $(__USER_CS) CFI_ADJUST_CFA_OFFSET 4 @@ -315,6 +316,11 @@ sysenter_past_esp: CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET eip, 0 + pushl %eax + CFI_ADJUST_CFA_OFFSET 4 + SAVE_ALL + ENABLE_INTERRUPTS(CLBR_NONE) + /* * Load the potential sixth argument from user stack. * Careful about security. @@ -322,14 +328,12 @@ sysenter_past_esp: cmpl $__PAGE_OFFSET-3,%ebp jae syscall_fault 1: movl (%ebp),%ebp + movl %ebp,PT_EBP(%esp) .section __ex_table,"a" .align 4 .long 1b,syscall_fault .previous - pushl %eax - CFI_ADJUST_CFA_OFFSET 4 - SAVE_ALL GET_THREAD_INFO(%ebp) /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */ @@ -543,9 +547,6 @@ END(syscall_exit_work) RING0_INT_FRAME # can't unwind into user space anyway syscall_fault: - pushl %eax # save orig_eax - CFI_ADJUST_CFA_OFFSET 4 - SAVE_ALL GET_THREAD_INFO(%ebp) movl $-EFAULT,PT_EAX(%esp) jmp resume_userspace |