Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path. | Date | Thu, 02 May 2013 14:00:05 +0200 |
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On Wednesday, May 01, 2013 09:53:30 PM Konrad Rzeszutek Wilk wrote: > The git commite7a5cd063c7b4c58417f674821d63f5eb6747e37 > ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path > is not needed.") assumes that for the hibernate path the booting > kernel and the resuming kernel MUST be the same. That is certainly > the case for a 32-bit kernel (see check_image_kernel and > CONFIG_ARCH_HIBERNATION_HEADER config option). > > However for 64-bit kernels it is OK to have a different kernel > version (and size of the image) of the booting and resuming kernels. > Hence the above mentioned git commit introduces an regression. > > This patch fixes it by introducing a 'struct desc_ptr gdt_desc' > back in the 'struct saved_context'. However instead of having in the > 'save_processor_state' and 'restore_processor_state' the > store/load_gdt calls, we are only saving the GDT in the > save_processor_state. > > For the restore path the lgdt operation is done in > hibernate_asm_[32|64].S in the 'restore_registers' path. > > The apt reader of this description will recognize that only 64-bit > kernels need this treatment, not 32-bit. This patch adds the logic > in the 32-bit path to be more similar to 64-bit so that in the future > the unification process can take advantage of this. > > Suggested-by: "H. Peter Anvin" <hpa@zytor.com> > CC: "Rafael J. Wysocki" <rjw@sisk.pl> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> --- > arch/x86/include/asm/suspend_32.h | 1 + > arch/x86/include/asm/suspend_64.h | 2 ++ > arch/x86/kernel/asm-offsets_32.c | 3 +++ > arch/x86/kernel/asm-offsets_64.c | 1 + > arch/x86/power/cpu.c | 15 ++++++++++----- > arch/x86/power/hibernate_asm_32.S | 4 ++++ > arch/x86/power/hibernate_asm_64.S | 3 +++ > 7 files changed, 24 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h > index f6064b7..552d6c9 100644 > --- a/arch/x86/include/asm/suspend_32.h > +++ b/arch/x86/include/asm/suspend_32.h > @@ -15,6 +15,7 @@ struct saved_context { > unsigned long cr0, cr2, cr3, cr4; > u64 misc_enable; > bool misc_enable_saved; > + struct desc_ptr gdt_desc; > struct desc_ptr idt; > u16 ldt; > u16 tss; > diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h > index 97b84e0..bc62328 100644 > --- a/arch/x86/include/asm/suspend_64.h > +++ b/arch/x86/include/asm/suspend_64.h > @@ -25,6 +25,8 @@ struct saved_context { > u64 misc_enable; > bool misc_enable_saved; > unsigned long efer; > + u16 gdt_pad; /* Unused */ > + struct desc_ptr gdt_desc; > u16 idt_pad; > u16 idt_limit; > unsigned long idt_base; > diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c > index 85d98ab..0ef4bba 100644 > --- a/arch/x86/kernel/asm-offsets_32.c > +++ b/arch/x86/kernel/asm-offsets_32.c > @@ -60,6 +60,9 @@ void foo(void) > OFFSET(IA32_RT_SIGFRAME_sigcontext, rt_sigframe, uc.uc_mcontext); > BLANK(); > > + OFFSET(saved_context_gdt_desc, saved_context, gdt_desc); > + BLANK(); > + > /* Offset from the sysenter stack to tss.sp0 */ > DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) - > sizeof(struct tss_struct)); > diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c > index 1b4754f..e7c798b 100644 > --- a/arch/x86/kernel/asm-offsets_64.c > +++ b/arch/x86/kernel/asm-offsets_64.c > @@ -73,6 +73,7 @@ int main(void) > ENTRY(cr3); > ENTRY(cr4); > ENTRY(cr8); > + ENTRY(gdt_desc); > BLANK(); > #undef ENTRY > > diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c > index 6d6e907..1cf5b30 100644 > --- a/arch/x86/power/cpu.c > +++ b/arch/x86/power/cpu.c > @@ -25,16 +25,12 @@ > #include <asm/cpu.h> > > #ifdef CONFIG_X86_32 > -static struct saved_context saved_context; > - > unsigned long saved_context_ebx; > unsigned long saved_context_esp, saved_context_ebp; > unsigned long saved_context_esi, saved_context_edi; > unsigned long saved_context_eflags; > -#else > -/* CONFIG_X86_64 */ > -struct saved_context saved_context; > #endif > +struct saved_context saved_context; > > /** > * __save_processor_state - save CPU registers before creating a > @@ -67,6 +63,15 @@ static void __save_processor_state(struct saved_context *ctxt) > /* CONFIG_X86_64 */ > store_idt((struct desc_ptr *)&ctxt->idt_limit); > #endif > + /* > + * We save it here, but restore it only in the hibernate case. > + * For ACPI S3 resume, this is loaded via 'early_gdt_desc' in 64-bit > + * mode in "secondary_startup_64". In 32-bit mode it is done via > + * 'pmode_gdt' in wakeup_start. > + */ > + ctxt->gdt_desc.size = GDT_SIZE - 1; > + ctxt->gdt_desc.address = (unsigned long)get_cpu_gdt_table(smp_processor_id()); > + > store_tr(ctxt->tr); > > /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */ > diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S > index ad47dae..1d0fa0e 100644 > --- a/arch/x86/power/hibernate_asm_32.S > +++ b/arch/x86/power/hibernate_asm_32.S > @@ -75,6 +75,10 @@ done: > pushl saved_context_eflags > popfl > > + /* Saved in save_processor_state. */ > + movl $saved_context, %eax > + lgdt saved_context_gdt_desc(%eax) > + > xorl %eax, %eax > > ret > diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S > index 9356547..3c4469a 100644 > --- a/arch/x86/power/hibernate_asm_64.S > +++ b/arch/x86/power/hibernate_asm_64.S > @@ -139,6 +139,9 @@ ENTRY(restore_registers) > pushq pt_regs_flags(%rax) > popfq > > + /* Saved in save_processor_state. */ > + lgdt saved_context_gdt_desc(%rax) > + > xorq %rax, %rax > > /* tell the hibernation core that we've just restored the memory */ > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.
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