On Wed, Nov 29, 2017 at 9:57 AM, Andy Lutomirski <[email protected]> wrote:
> On Tue, Nov 28, 2017 at 11:09 PM, Ingo Molnar <[email protected]> wrote:
>>
>> * Jarkko Nikula <[email protected]> wrote:
>>
>>> Hi
>>>
>>> Suspend-to-ram and resume stopped working on v4.15-rc1 and I bisected it to
>>> commit ca37e57bbe0c ("x86/entry/64: Add missing irqflags tracing to
>>> native_load_gs_index()").
>>>
Jarkko, can you try the attached patch? If it survives resume, can
you see if the log contains anything interesting?
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 78c61c8ecfa8..ca5d978b86a0 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -245,14 +245,17 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
asm volatile ("movw %0, %%es" :: "r" (ctxt->es));
asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs));
- load_gs_index(0xffff);
- WARN_ON(1);
- load_gs_index(ctxt->gs);
asm volatile ("movw %0, %%ss" :: "r" (ctxt->ss));
wrmsrl(MSR_FS_BASE, ctxt->fs_base);
wrmsrl(MSR_GS_BASE, ctxt->gs_base);
wrmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
+
+ /*
+ * load_gs_index() potentially calls normal C code (irqflag tracing),
+ * so it needs GSBASE restored first.
+ */
+ load_gs_index(ctxt->gs);
#endif
fix_processor_context();
