* [RFC] Fix restore from hibernate with different kernel versions.
@ 2013-05-02 1:53 Konrad Rzeszutek Wilk
2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk
0 siblings, 1 reply; 5+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-05-02 1:53 UTC (permalink / raw)
To: linux-kernel, linux-pm, rjw, pavel, tglx, mingo, hpa, x86
This patch is intended for v3.10 and it should be considered RFC as I had
only tested it under QEMU and not real hardware (that to be done on Friday).
The patch addresses a shortcomming of the git commite
7a5cd063c7b4c58417f674821d63f5eb6747e37 ("x86-64, gdt: Store/load GDT for
ACPI S3 or hibernate/resume path is not needed.") where its assumption
about restoring a kernel was incorrect. Specifically it assumed that a resumed
kernel MUST be the same as the one booted. That is only true for 32-bit
kernels but not for 64-bit.
And as such it introduces a regression which the attached patch is
fixing.
The patch goes further and also lays the groundwork to make this work under
a 32-bit kernel - even though it is not neccessary. This is done to unify
the 32 and 64-bit code and make it easier in the future to unify the
respective code closer.
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(-)
Konrad Rzeszutek Wilk (1):
x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path.
2013-05-02 1:53 [RFC] Fix restore from hibernate with different kernel versions Konrad Rzeszutek Wilk
@ 2013-05-02 1:53 ` Konrad Rzeszutek Wilk
2013-05-02 12:00 ` Rafael J. Wysocki
2013-05-02 12:34 ` Pavel Machek
0 siblings, 2 replies; 5+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-05-02 1:53 UTC (permalink / raw)
To: linux-kernel, linux-pm, rjw, pavel, tglx, mingo, hpa, x86
Cc: Konrad Rzeszutek Wilk
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(-)
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 */
--
1.8.1.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path.
2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk
@ 2013-05-02 12:00 ` Rafael J. Wysocki
2013-05-02 12:34 ` Pavel Machek
1 sibling, 0 replies; 5+ messages in thread
From: Rafael J. Wysocki @ 2013-05-02 12:00 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: linux-kernel, linux-pm, pavel, tglx, mingo, hpa, x86
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.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path.
2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk
2013-05-02 12:00 ` Rafael J. Wysocki
@ 2013-05-02 12:34 ` Pavel Machek
2013-05-02 12:50 ` Konrad Rzeszutek Wilk
1 sibling, 1 reply; 5+ messages in thread
From: Pavel Machek @ 2013-05-02 12:34 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk; +Cc: linux-kernel, linux-pm, rjw, tglx, mingo, hpa, x86
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
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path.
2013-05-02 12:34 ` Pavel Machek
@ 2013-05-02 12:50 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 5+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-05-02 12:50 UTC (permalink / raw)
To: Pavel Machek; +Cc: linux-kernel, linux-pm, rjw, tglx, mingo, hpa, x86
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
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-05-02 12:50 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2013-05-02 1:53 [RFC] Fix restore from hibernate with different kernel versions Konrad Rzeszutek Wilk
2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk
2013-05-02 12:00 ` Rafael J. Wysocki
2013-05-02 12:34 ` Pavel Machek
2013-05-02 12:50 ` Konrad Rzeszutek Wilk
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