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authorJeremy Fitzhardinge <jeremy@goop.org>2008-06-25 04:19:30 (GMT)
committerIngo Molnar <mingo@elte.hu>2008-07-08 11:15:56 (GMT)
commita00394f81f419beb6fb9f7023bd4d15913dc625d (patch)
tree0faef5a52c4244173a3669bc646ef12bb79d6bc6 /include/asm-x86/irqflags.h
parent6680415481c7bd38967cf7488787f509f17ba307 (diff)
downloadlinux-a00394f81f419beb6fb9f7023bd4d15913dc625d.tar.xz
x86, 64-bit: swapgs pvop with a user-stack can never be called
It's never safe to call a swapgs pvop when the user stack is current - it must be inline replaced. Rather than making a call, the SWAPGS_UNSAFE_STACK pvop always just puts "swapgs" as a placeholder, which must either be replaced inline or trap'n'emulated (somehow). Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: xen-devel <xen-devel@lists.xensource.com> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-x86/irqflags.h')
-rw-r--r--include/asm-x86/irqflags.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/asm-x86/irqflags.h b/include/asm-x86/irqflags.h
index ea9bd26..d17e1f6 100644
--- a/include/asm-x86/irqflags.h
+++ b/include/asm-x86/irqflags.h
@@ -111,6 +111,7 @@ static inline unsigned long __raw_local_irq_save(void)
#define DISABLE_INTERRUPTS(x) cli
#ifdef CONFIG_X86_64
+#define SWAPGS_UNSAFE_STACK swapgs
#define INTERRUPT_RETURN iretq
#define USERGS_SYSRET64 \
swapgs; \
@@ -185,7 +186,6 @@ static inline void trace_hardirqs_fixup(void)
* Either way, this is a good way to document that we don't
* have a reliable stack. x86_64 only.
*/
-#define SWAPGS_UNSAFE_STACK swapgs
#define ARCH_TRACE_IRQS_ON call trace_hardirqs_on_thunk
#define ARCH_TRACE_IRQS_OFF call trace_hardirqs_off_thunk
#define ARCH_LOCKDEP_SYS_EXIT call lockdep_sys_exit_thunk