summaryrefslogtreecommitdiffstats
path: root/arch/x86/entry/entry_64.S
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--arch/x86/entry/entry_64.S11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 9953d966d..c2383c288 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -223,6 +223,7 @@ syscall_return_via_sysret:
SYM_INNER_LABEL(entry_SYSRETQ_unsafe_stack, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
swapgs
+ CLEAR_CPU_BUFFERS
sysretq
SYM_INNER_LABEL(entry_SYSRETQ_end, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
@@ -656,6 +657,7 @@ SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL)
/* Restore RDI. */
popq %rdi
swapgs
+ CLEAR_CPU_BUFFERS
jmp .Lnative_iret
@@ -767,6 +769,8 @@ native_irq_return_ldt:
*/
popq %rax /* Restore user RAX */
+ CLEAR_CPU_BUFFERS
+
/*
* RSP now points to an ordinary IRET frame, except that the page
* is read-only and RSP[31:16] are preloaded with the userspace
@@ -1494,6 +1498,12 @@ nmi_restore:
movq $0, 5*8(%rsp) /* clear "NMI executing" */
/*
+ * Skip CLEAR_CPU_BUFFERS here, since it only helps in rare cases like
+ * NMI in kernel after user state is restored. For an unprivileged user
+ * these conditions are hard to meet.
+ */
+
+ /*
* iretq reads the "iret" frame and exits the NMI stack in a
* single instruction. We are returning to kernel mode, so this
* cannot result in a fault. Similarly, we don't need to worry
@@ -1511,6 +1521,7 @@ SYM_CODE_START(ignore_sysret)
UNWIND_HINT_EMPTY
ENDBR
mov $-ENOSYS, %eax
+ CLEAR_CPU_BUFFERS
sysretl
SYM_CODE_END(ignore_sysret)
#endif