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" <hpa@zytor.com> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1367459610-9656-2-git-send-email-konrad.wilk@oracle.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
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5a148af669
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@ -15,6 +15,7 @@ struct saved_context {
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unsigned long cr0, cr2, cr3, cr4;
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u64 misc_enable;
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bool misc_enable_saved;
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struct desc_ptr gdt_desc;
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struct desc_ptr idt;
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u16 ldt;
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u16 tss;
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@ -25,6 +25,8 @@ struct saved_context {
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u64 misc_enable;
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bool misc_enable_saved;
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unsigned long efer;
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u16 gdt_pad; /* Unused */
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struct desc_ptr gdt_desc;
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u16 idt_pad;
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u16 idt_limit;
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unsigned long idt_base;
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@ -60,6 +60,9 @@ void foo(void)
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OFFSET(IA32_RT_SIGFRAME_sigcontext, rt_sigframe, uc.uc_mcontext);
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BLANK();
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OFFSET(saved_context_gdt_desc, saved_context, gdt_desc);
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BLANK();
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/* Offset from the sysenter stack to tss.sp0 */
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DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) -
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sizeof(struct tss_struct));
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@ -73,6 +73,7 @@ int main(void)
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ENTRY(cr3);
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ENTRY(cr4);
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ENTRY(cr8);
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ENTRY(gdt_desc);
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BLANK();
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#undef ENTRY
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@ -25,16 +25,12 @@
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#include <asm/cpu.h>
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#ifdef CONFIG_X86_32
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static struct saved_context saved_context;
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unsigned long saved_context_ebx;
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unsigned long saved_context_esp, saved_context_ebp;
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unsigned long saved_context_esi, saved_context_edi;
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unsigned long saved_context_eflags;
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#else
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/* CONFIG_X86_64 */
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struct saved_context saved_context;
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#endif
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struct saved_context saved_context;
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/**
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* __save_processor_state - save CPU registers before creating a
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@ -67,6 +63,15 @@ static void __save_processor_state(struct saved_context *ctxt)
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/* CONFIG_X86_64 */
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store_idt((struct desc_ptr *)&ctxt->idt_limit);
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#endif
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/*
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* We save it here, but restore it only in the hibernate case.
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* For ACPI S3 resume, this is loaded via 'early_gdt_desc' in 64-bit
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* mode in "secondary_startup_64". In 32-bit mode it is done via
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* 'pmode_gdt' in wakeup_start.
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*/
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ctxt->gdt_desc.size = GDT_SIZE - 1;
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ctxt->gdt_desc.address = (unsigned long)get_cpu_gdt_table(smp_processor_id());
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store_tr(ctxt->tr);
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/* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
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@ -75,6 +75,10 @@ done:
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pushl saved_context_eflags
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popfl
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/* Saved in save_processor_state. */
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movl $saved_context, %eax
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lgdt saved_context_gdt_desc(%eax)
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xorl %eax, %eax
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ret
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@ -139,6 +139,9 @@ ENTRY(restore_registers)
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pushq pt_regs_flags(%rax)
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popfq
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/* Saved in save_processor_state. */
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lgdt saved_context_gdt_desc(%rax)
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xorq %rax, %rax
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/* tell the hibernation core that we've just restored the memory */
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