From cc456c4e7cac3837a86aaa7ca3cb9f488d44d196 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Wed, 1 May 2013 21:53:30 -0400 Subject: x86, gdt, hibernate: Store/load GDT for hibernate path. 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. [ hpa: this also reverts an inadvertent on-disk format change ] Suggested-by: "H. Peter Anvin" Acked-by: "Rafael J. Wysocki" Signed-off-by: Konrad Rzeszutek Wilk Link: http://lkml.kernel.org/r/1367459610-9656-2-git-send-email-konrad.wilk@oracle.com Signed-off-by: H. Peter Anvin --- arch/x86/power/cpu.c | 15 ++++++++++----- arch/x86/power/hibernate_asm_32.S | 4 ++++ arch/x86/power/hibernate_asm_64.S | 3 +++ 3 files changed, 17 insertions(+), 5 deletions(-) (limited to 'arch/x86/power') diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 6d6e907cee46..1cf5b300305e 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -25,16 +25,12 @@ #include #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 ad47daeafa4e..1d0fa0e24070 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 9356547d8c01..3c4469a7a929 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 */ -- cgit