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Power management fixes for v4.7-rc7
- Fix a recent performance regression on Power systems (powernv and pseries) introduced by a core cpuidle commit that decreased the precision of the last_residency conversion from nano- to microseconds, which should not matter in theory, but turned out to play not-so-well with the special "snooze" idle state on Power (Shreyas B Prabhu). - Fix a crash during resume from hibernation on x86-64 caused by possible corruption of the kernel text part of page tables in the last phase of image restoration exposed by a security-related change during the 4.3 development cycle (Rafael Wysocki). -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAABCAAGBQJXfuVmAAoJEILEb/54YlRx/TUQALIrIgVMtNpPhC0Mu0DQp+1y S2t/vWfLnMqfl1lzH/scDi4OC3cqEbEsYB5CUJPRysc1KB0fjJbW+BEuQuJyEhgf ac95mv1IU7DKiJ1Rp4qWvvBoovY3fjb1rhHMzvo9uh6HmKrSlWLL4PmnbGw/BaFL PgqEazsy/a9FgGT7VnvamVL6bGXgVMEf8VqoBeZFd0krH4qvBZHrS97OLqU685vT VW0IDZr0sI3u0pG9ropJ5b8ETtnyZ4lmTO5D4TzD9P8kZyjl2TBnSZ/ls/1YLh4N WdBZXbsfmFFt4jyDnOjilWOBA8R3IDteCDmG1l8XhK4Smbl7TRh2XVuRAHHEjG6b oMPHTeqIil3ExBS2gdzVEFNzYfHsyg3N9cXSochqnp3vboyZOiKaxIPCiVeBOZ+t bDPwtbovIly1aEnsJKUbHvBxJ4A9uPUqw99YbBtMK1VpQXZFg+s/0mBVNynkuu/k EUOuU6KcY6Br4JJPsqfb26NmARgLrrI+gTJbC3pFDHARtALnCbkkbmNZRRVRS3Zs 7CzGaYqgZ0ejMv/46jFPsHYKXU52AJ5HDhfXfELd8X3AvdhtmIszfqTkBgKx4gto fyTVzi2c6+RJJr5Jc07msYawaz86nEUjeXFsM59g6jC5dguSWnRxUuWV2zUM/ENb GDkzNdzif0t2DheJ4bKc =XL6s -----END PGP SIGNATURE----- Merge tag 'pm-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management fixes from Rafael Wysocki: "One fix for a recent cpuidle core change that, against all odds, introduced a functional regression on Power systems and the fix for the crash during resume from hibernation on x86-64 that has been in the works for the last few weeks (it actually was ready last week, but I wanted to allow the reporters to test if for some more time). Specifics: - Fix a recent performance regression on Power systems (powernv and pseries) introduced by a core cpuidle commit that decreased the precision of the last_residency conversion from nano- to microseconds, which should not matter in theory, but turned out to play not-so-well with the special "snooze" idle state on Power (Shreyas B Prabhu). - Fix a crash during resume from hibernation on x86-64 caused by possible corruption of the kernel text part of page tables in the last phase of image restoration exposed by a security-related change during the 4.3 development cycle (Rafael Wysocki)" * tag 'pm-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: cpuidle: Fix last_residency division x86/power/64: Fix kernel text mapping corruption during image restoration
This commit is contained in:
commit
c09230f308
@ -19,6 +19,7 @@
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#include <asm/mtrr.h>
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#include <asm/sections.h>
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#include <asm/suspend.h>
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#include <asm/tlbflush.h>
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/* Defined in hibernate_asm_64.S */
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extern asmlinkage __visible int restore_image(void);
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@ -28,6 +29,7 @@ extern asmlinkage __visible int restore_image(void);
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* kernel's text (this value is passed in the image header).
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*/
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unsigned long restore_jump_address __visible;
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unsigned long jump_address_phys;
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/*
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* Value of the cr3 register from before the hibernation (this value is passed
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@ -37,7 +39,43 @@ unsigned long restore_cr3 __visible;
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pgd_t *temp_level4_pgt __visible;
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void *relocated_restore_code __visible;
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unsigned long relocated_restore_code __visible;
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static int set_up_temporary_text_mapping(void)
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{
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pmd_t *pmd;
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pud_t *pud;
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/*
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* The new mapping only has to cover the page containing the image
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* kernel's entry point (jump_address_phys), because the switch over to
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* it is carried out by relocated code running from a page allocated
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* specifically for this purpose and covered by the identity mapping, so
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* the temporary kernel text mapping is only needed for the final jump.
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* Moreover, in that mapping the virtual address of the image kernel's
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* entry point must be the same as its virtual address in the image
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* kernel (restore_jump_address), so the image kernel's
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* restore_registers() code doesn't find itself in a different area of
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* the virtual address space after switching over to the original page
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* tables used by the image kernel.
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*/
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pud = (pud_t *)get_safe_page(GFP_ATOMIC);
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if (!pud)
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return -ENOMEM;
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pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
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if (!pmd)
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return -ENOMEM;
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set_pmd(pmd + pmd_index(restore_jump_address),
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__pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
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set_pud(pud + pud_index(restore_jump_address),
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__pud(__pa(pmd) | _KERNPG_TABLE));
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set_pgd(temp_level4_pgt + pgd_index(restore_jump_address),
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__pgd(__pa(pud) | _KERNPG_TABLE));
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return 0;
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}
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static void *alloc_pgt_page(void *context)
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{
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@ -59,9 +97,10 @@ static int set_up_temporary_mappings(void)
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if (!temp_level4_pgt)
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return -ENOMEM;
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/* It is safe to reuse the original kernel mapping */
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set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
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init_level4_pgt[pgd_index(__START_KERNEL_map)]);
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/* Prepare a temporary mapping for the kernel text */
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result = set_up_temporary_text_mapping();
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if (result)
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return result;
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/* Set up the direct mapping from scratch */
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for (i = 0; i < nr_pfn_mapped; i++) {
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@ -78,19 +117,50 @@ static int set_up_temporary_mappings(void)
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return 0;
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}
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static int relocate_restore_code(void)
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{
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pgd_t *pgd;
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pud_t *pud;
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relocated_restore_code = get_safe_page(GFP_ATOMIC);
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if (!relocated_restore_code)
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return -ENOMEM;
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memcpy((void *)relocated_restore_code, &core_restore_code, PAGE_SIZE);
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/* Make the page containing the relocated code executable */
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pgd = (pgd_t *)__va(read_cr3()) + pgd_index(relocated_restore_code);
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pud = pud_offset(pgd, relocated_restore_code);
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if (pud_large(*pud)) {
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set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
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} else {
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pmd_t *pmd = pmd_offset(pud, relocated_restore_code);
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if (pmd_large(*pmd)) {
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set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
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} else {
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pte_t *pte = pte_offset_kernel(pmd, relocated_restore_code);
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set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
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}
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}
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__flush_tlb_all();
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return 0;
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}
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int swsusp_arch_resume(void)
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{
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int error;
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/* We have got enough memory and from now on we cannot recover */
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if ((error = set_up_temporary_mappings()))
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error = set_up_temporary_mappings();
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if (error)
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return error;
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relocated_restore_code = (void *)get_safe_page(GFP_ATOMIC);
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if (!relocated_restore_code)
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return -ENOMEM;
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memcpy(relocated_restore_code, &core_restore_code,
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&restore_registers - &core_restore_code);
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error = relocate_restore_code();
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if (error)
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return error;
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restore_image();
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return 0;
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@ -109,11 +179,12 @@ int pfn_is_nosave(unsigned long pfn)
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struct restore_data_record {
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unsigned long jump_address;
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unsigned long jump_address_phys;
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unsigned long cr3;
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unsigned long magic;
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};
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#define RESTORE_MAGIC 0x0123456789ABCDEFUL
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#define RESTORE_MAGIC 0x123456789ABCDEF0UL
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/**
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* arch_hibernation_header_save - populate the architecture specific part
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@ -126,7 +197,8 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
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if (max_size < sizeof(struct restore_data_record))
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return -EOVERFLOW;
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rdr->jump_address = restore_jump_address;
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rdr->jump_address = (unsigned long)&restore_registers;
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rdr->jump_address_phys = __pa_symbol(&restore_registers);
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rdr->cr3 = restore_cr3;
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rdr->magic = RESTORE_MAGIC;
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return 0;
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@ -142,6 +214,7 @@ int arch_hibernation_header_restore(void *addr)
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struct restore_data_record *rdr = addr;
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restore_jump_address = rdr->jump_address;
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jump_address_phys = rdr->jump_address_phys;
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restore_cr3 = rdr->cr3;
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return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL;
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}
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@ -44,9 +44,6 @@ ENTRY(swsusp_arch_suspend)
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pushfq
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popq pt_regs_flags(%rax)
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/* save the address of restore_registers */
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movq $restore_registers, %rax
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movq %rax, restore_jump_address(%rip)
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/* save cr3 */
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movq %cr3, %rax
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movq %rax, restore_cr3(%rip)
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@ -57,31 +54,34 @@ ENTRY(swsusp_arch_suspend)
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ENDPROC(swsusp_arch_suspend)
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ENTRY(restore_image)
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/* switch to temporary page tables */
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movq $__PAGE_OFFSET, %rdx
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movq temp_level4_pgt(%rip), %rax
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subq %rdx, %rax
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movq %rax, %cr3
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/* Flush TLB */
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movq mmu_cr4_features(%rip), %rax
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movq %rax, %rdx
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andq $~(X86_CR4_PGE), %rdx
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movq %rdx, %cr4; # turn off PGE
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movq %cr3, %rcx; # flush TLB
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movq %rcx, %cr3;
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movq %rax, %cr4; # turn PGE back on
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/* prepare to jump to the image kernel */
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movq restore_jump_address(%rip), %rax
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movq restore_cr3(%rip), %rbx
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movq restore_jump_address(%rip), %r8
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movq restore_cr3(%rip), %r9
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/* prepare to switch to temporary page tables */
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movq temp_level4_pgt(%rip), %rax
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movq mmu_cr4_features(%rip), %rbx
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/* prepare to copy image data to their original locations */
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movq restore_pblist(%rip), %rdx
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/* jump to relocated restore code */
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movq relocated_restore_code(%rip), %rcx
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jmpq *%rcx
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/* code below has been relocated to a safe page */
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ENTRY(core_restore_code)
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/* switch to temporary page tables */
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movq $__PAGE_OFFSET, %rcx
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subq %rcx, %rax
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movq %rax, %cr3
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/* flush TLB */
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movq %rbx, %rcx
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andq $~(X86_CR4_PGE), %rcx
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movq %rcx, %cr4; # turn off PGE
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movq %cr3, %rcx; # flush TLB
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movq %rcx, %cr3;
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movq %rbx, %cr4; # turn PGE back on
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.Lloop:
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testq %rdx, %rdx
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jz .Ldone
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@ -96,24 +96,17 @@ ENTRY(core_restore_code)
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/* progress to the next pbe */
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movq pbe_next(%rdx), %rdx
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jmp .Lloop
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.Ldone:
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/* jump to the restore_registers address from the image header */
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jmpq *%rax
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/*
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* NOTE: This assumes that the boot kernel's text mapping covers the
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* image kernel's page containing restore_registers and the address of
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* this page is the same as in the image kernel's text mapping (it
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* should always be true, because the text mapping is linear, starting
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* from 0, and is supposed to cover the entire kernel text for every
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* kernel).
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*
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* code below belongs to the image kernel
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*/
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jmpq *%r8
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/* code below belongs to the image kernel */
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.align PAGE_SIZE
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ENTRY(restore_registers)
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FRAME_BEGIN
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/* go back to the original page tables */
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movq %rbx, %cr3
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movq %r9, %cr3
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/* Flush TLB, including "global" things (vmalloc) */
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movq mmu_cr4_features(%rip), %rax
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struct cpuidle_state *target_state = &drv->states[index];
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bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);
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u64 time_start, time_end;
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ktime_t time_start, time_end;
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s64 diff;
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/*
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@ -195,13 +195,13 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
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sched_idle_set_state(target_state);
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trace_cpu_idle_rcuidle(index, dev->cpu);
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time_start = local_clock();
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time_start = ns_to_ktime(local_clock());
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stop_critical_timings();
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entered_state = target_state->enter(dev, drv, index);
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start_critical_timings();
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time_end = local_clock();
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time_end = ns_to_ktime(local_clock());
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trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
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/* The cpu is no longer idle or about to enter idle. */
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@ -217,11 +217,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
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if (!cpuidle_state_is_coupled(drv, index))
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local_irq_enable();
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/*
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* local_clock() returns the time in nanosecond, let's shift
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* by 10 (divide by 1024) to have microsecond based time.
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*/
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diff = (time_end - time_start) >> 10;
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diff = ktime_us_delta(time_end, time_start);
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if (diff > INT_MAX)
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diff = INT_MAX;
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