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Diffstat (limited to 'arch/x86/ia32/ia32entry.S')
-rw-r--r--arch/x86/ia32/ia32entry.S18
1 files changed, 17 insertions, 1 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 4299eb05023c..711de084ab57 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -151,6 +151,16 @@ ENTRY(ia32_sysenter_target)
1: movl (%rbp),%ebp
_ASM_EXTABLE(1b,ia32_badarg)
ASM_CLAC
+
+ /*
+ * Sysenter doesn't filter flags, so we need to clear NT
+ * ourselves. To save a few cycles, we can check whether
+ * NT was set instead of doing an unconditional popfq.
+ */
+ testl $X86_EFLAGS_NT,EFLAGS(%rsp) /* saved EFLAGS match cpu */
+ jnz sysenter_fix_flags
+sysenter_flags_fixed:
+
orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
CFI_REMEMBER_STATE
@@ -184,6 +194,8 @@ sysexit_from_sys_call:
TRACE_IRQS_ON
ENABLE_INTERRUPTS_SYSEXIT32
+ CFI_RESTORE_STATE
+
#ifdef CONFIG_AUDITSYSCALL
.macro auditsys_entry_common
movl %esi,%r9d /* 6th arg: 4th syscall arg */
@@ -226,7 +238,6 @@ sysexit_from_sys_call:
.endm
sysenter_auditsys:
- CFI_RESTORE_STATE
auditsys_entry_common
movl %ebp,%r9d /* reload 6th syscall arg */
jmp sysenter_dispatch
@@ -235,6 +246,11 @@ sysexit_audit:
auditsys_exit sysexit_from_sys_call
#endif
+sysenter_fix_flags:
+ pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
+ popfq_cfi
+ jmp sysenter_flags_fixed
+
sysenter_tracesys:
#ifdef CONFIG_AUDITSYSCALL
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)