| Message ID | 1367459610-9656-2-git-send-email-konrad.wilk@oracle.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
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 */ >
Hi! > 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. Ok. > 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. So the on-disk format changed and we need to bump the version number somewhere? I guess we should add big fat warning to the affected structures. Pavel
On Thu, May 02, 2013 at 02:34:38PM +0200, Pavel Machek wrote: > Hi! > > > 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. > > Ok. > > > 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. > > So the on-disk format changed and we need to bump the version number > somewhere? Fortunatly not. The patch (7a5cd063c7b4c58417f674821d63f5eb6747e37) that just just landed in Linus a couple of days ago did change it a bit (as the 'saved_context' struct shrunk), but this patch brings it back to what it was before. But I don't know if the 'saved_context' structure is actually somewhere specifically mentioned as 'on-disk' or in the kernel. Looking at the code, I think the on-disk structure you are referring to is the 'struct restore_data_record' (please correct me if I am incorrect) which has not been affected by any of these patches. > > I guess we should add big fat warning to the affected structures. We certainly can. I can prep a patch to that affect on Friday or Monday. > > Pavel > > -- > (english) http://www.livejournal.com/~pavelmachek > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 */
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> --- 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(-)