From d75cd22fdd5f7d203fb60014d426942df33dd9a6 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 25 Jun 2008 00:19:26 -0400 Subject: x86/paravirt: split sysret and sysexit Don't conflate sysret and sysexit; they're different instructions with different semantics, and may be in use at the same time (at least within the same kernel, depending on whether its an Intel or AMD system). sysexit - just return to userspace, does no register restoration of any kind; must explicitly atomically enable interrupts. sysret - reloads flags from r11, so no need to explicitly enable interrupts on 64-bit, responsible for restoring usermode %gs Signed-off-by: Jeremy Fitzhardinge Cc: xen-devel Cc: Stephen Tweedie Cc: Eduardo Habkost Cc: Mark McLoughlin Signed-off-by: Ingo Molnar --- arch/x86/kernel/entry_32.S | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/x86/kernel/entry_32.S') diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 159a1c76d2b..53393c306e1 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -58,7 +58,7 @@ * for paravirtualization. The following will never clobber any registers: * INTERRUPT_RETURN (aka. "iret") * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax") - * ENABLE_INTERRUPTS_SYSCALL_RET (aka "sti; sysexit"). + * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit"). * * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY). @@ -349,7 +349,7 @@ sysenter_past_esp: xorl %ebp,%ebp TRACE_IRQS_ON 1: mov PT_FS(%esp), %fs - ENABLE_INTERRUPTS_SYSCALL_RET + ENABLE_INTERRUPTS_SYSEXIT CFI_ENDPROC .pushsection .fixup,"ax" 2: movl $0,PT_FS(%esp) @@ -874,10 +874,10 @@ ENTRY(native_iret) .previous END(native_iret) -ENTRY(native_irq_enable_syscall_ret) +ENTRY(native_irq_enable_sysexit) sti sysexit -END(native_irq_enable_syscall_ret) +END(native_irq_enable_sysexit) #endif KPROBE_ENTRY(int3) -- cgit v1.2.3