[PATCH urgent 2/3] x86/power/32: Move SYSENTER MSR restoration to fix_processor_context()

From: Andy Lutomirski
Date: Thu Dec 14 2017 - 16:19:26 EST


x86_64 restores system call MSRs in fix_processor_context(), and
x86_32 restored them along with segment registers. The 64-bit
variant makes more sense, so move the 32-bit code to match the
64-bit code.

Tested-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
arch/x86/power/cpu.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 472bc8c8212b..033c61e6891b 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -174,6 +174,9 @@ static void fix_processor_context(void)
write_gdt_entry(desc, GDT_ENTRY_TSS, &tss, DESC_TSS);

syscall_init(); /* This sets MSR_*STAR and related */
+#else
+ if (boot_cpu_has(X86_FEATURE_SEP))
+ enable_sep_cpu();
#endif
load_TR_desc(); /* This does ltr */
load_mm_ldt(current->active_mm); /* This does lldt */
@@ -237,12 +240,6 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
loadsegment(fs, ctxt->fs);
loadsegment(gs, ctxt->gs);
loadsegment(ss, ctxt->ss);
-
- /*
- * sysenter MSRs
- */
- if (boot_cpu_has(X86_FEATURE_SEP))
- enable_sep_cpu();
#else
/* CONFIG_X86_64 */
asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
--
2.13.6