Commit c09230f3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents ac904ae6 7fe39a21

arch/x86/power/hibernate_64.c

+85 −12
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <asm/mtrr.h>

#include <asm/sections.h>

#include <asm/suspend.h>

#include <asm/tlbflush.h>



/* Defined in hibernate_asm_64.S */

extern asmlinkage __visible int restore_image(void);
@@ -28,6 +29,7 @@ extern asmlinkage __visible int restore_image(void); 
 * kernel's text (this value is passed in the image header).

 */

unsigned long restore_jump_address __visible;

unsigned long jump_address_phys;



/*

 * Value of the cr3 register from before the hibernation (this value is passed
@@ -37,7 +39,43 @@ unsigned long restore_cr3 __visible; 


pgd_t *temp_level4_pgt __visible;



void *relocated_restore_code __visible;

unsigned long relocated_restore_code __visible;



static int set_up_temporary_text_mapping(void)

{

	pmd_t *pmd;

	pud_t *pud;



	/*

	 * The new mapping only has to cover the page containing the image

	 * kernel's entry point (jump_address_phys), because the switch over to

	 * it is carried out by relocated code running from a page allocated

	 * specifically for this purpose and covered by the identity mapping, so

	 * the temporary kernel text mapping is only needed for the final jump.

	 * Moreover, in that mapping the virtual address of the image kernel's

	 * entry point must be the same as its virtual address in the image

	 * kernel (restore_jump_address), so the image kernel's

	 * restore_registers() code doesn't find itself in a different area of

	 * the virtual address space after switching over to the original page

	 * tables used by the image kernel.

	 */

	pud = (pud_t *)get_safe_page(GFP_ATOMIC);

	if (!pud)

		return -ENOMEM;



	pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);

	if (!pmd)

		return -ENOMEM;



	set_pmd(pmd + pmd_index(restore_jump_address),

		__pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));

	set_pud(pud + pud_index(restore_jump_address),

		__pud(__pa(pmd) | _KERNPG_TABLE));

	set_pgd(temp_level4_pgt + pgd_index(restore_jump_address),

		__pgd(__pa(pud) | _KERNPG_TABLE));



	return 0;

}



static void *alloc_pgt_page(void *context)

{
@@ -59,9 +97,10 @@ static int set_up_temporary_mappings(void) 
	if (!temp_level4_pgt)

		return -ENOMEM;



	/* It is safe to reuse the original kernel mapping */

	set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),

		init_level4_pgt[pgd_index(__START_KERNEL_map)]);

	/* Prepare a temporary mapping for the kernel text */

	result = set_up_temporary_text_mapping();

	if (result)

		return result;



	/* Set up the direct mapping from scratch */

	for (i = 0; i < nr_pfn_mapped; i++) {
@@ -78,19 +117,50 @@ static int set_up_temporary_mappings(void) 
	return 0;

}



static int relocate_restore_code(void)

{

	pgd_t *pgd;

	pud_t *pud;



	relocated_restore_code = get_safe_page(GFP_ATOMIC);

	if (!relocated_restore_code)

		return -ENOMEM;



	memcpy((void *)relocated_restore_code, &core_restore_code, PAGE_SIZE);



	/* Make the page containing the relocated code executable */

	pgd = (pgd_t *)__va(read_cr3()) + pgd_index(relocated_restore_code);

	pud = pud_offset(pgd, relocated_restore_code);

	if (pud_large(*pud)) {

		set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));

	} else {

		pmd_t *pmd = pmd_offset(pud, relocated_restore_code);



		if (pmd_large(*pmd)) {

			set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));

		} else {

			pte_t *pte = pte_offset_kernel(pmd, relocated_restore_code);



			set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));

		}

	}

	__flush_tlb_all();



	return 0;

}



int swsusp_arch_resume(void)

{

	int error;



	/* We have got enough memory and from now on we cannot recover */

	if ((error = set_up_temporary_mappings()))

	error = set_up_temporary_mappings();

	if (error)

		return error;



	relocated_restore_code = (void *)get_safe_page(GFP_ATOMIC);

	if (!relocated_restore_code)

		return -ENOMEM;

	memcpy(relocated_restore_code, &core_restore_code,

	       &restore_registers - &core_restore_code);

	error = relocate_restore_code();

	if (error)

		return error;



	restore_image();

	return 0;
@@ -109,11 +179,12 @@ int pfn_is_nosave(unsigned long pfn) 


struct restore_data_record {

	unsigned long jump_address;

	unsigned long jump_address_phys;

	unsigned long cr3;

	unsigned long magic;

};



#define RESTORE_MAGIC	0x0123456789ABCDEFUL

#define RESTORE_MAGIC	0x123456789ABCDEF0UL



/**

 *	arch_hibernation_header_save - populate the architecture specific part
@@ -126,7 +197,8 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size) 


	if (max_size < sizeof(struct restore_data_record))

		return -EOVERFLOW;

	rdr->jump_address = restore_jump_address;

	rdr->jump_address = (unsigned long)&restore_registers;

	rdr->jump_address_phys = __pa_symbol(&restore_registers);

	rdr->cr3 = restore_cr3;

	rdr->magic = RESTORE_MAGIC;

	return 0;
@@ -142,6 +214,7 @@ int arch_hibernation_header_restore(void *addr) 
	struct restore_data_record *rdr = addr;



	restore_jump_address = rdr->jump_address;

	jump_address_phys = rdr->jump_address_phys;

	restore_cr3 = rdr->cr3;

	return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL;

}

arch/x86/power/hibernate_asm_64.S

+24 −31
Original line number Diff line number Diff line
@@ -44,9 +44,6 @@ ENTRY(swsusp_arch_suspend) 
	pushfq

	popq	pt_regs_flags(%rax)



	/* save the address of restore_registers */

	movq	$restore_registers, %rax

	movq	%rax, restore_jump_address(%rip)

	/* save cr3 */

	movq	%cr3, %rax

	movq	%rax, restore_cr3(%rip)
@@ -57,31 +54,34 @@ ENTRY(swsusp_arch_suspend) 
ENDPROC(swsusp_arch_suspend)



ENTRY(restore_image)

	/* switch to temporary page tables */

	movq	$__PAGE_OFFSET, %rdx

	movq	temp_level4_pgt(%rip), %rax

	subq	%rdx, %rax

	movq	%rax, %cr3

	/* Flush TLB */

	movq	mmu_cr4_features(%rip), %rax

	movq	%rax, %rdx

	andq	$~(X86_CR4_PGE), %rdx

	movq	%rdx, %cr4;  # turn off PGE

	movq	%cr3, %rcx;  # flush TLB

	movq	%rcx, %cr3;

	movq	%rax, %cr4;  # turn PGE back on



	/* prepare to jump to the image kernel */

	movq	restore_jump_address(%rip), %rax

	movq	restore_cr3(%rip), %rbx

	movq	restore_jump_address(%rip), %r8

	movq	restore_cr3(%rip), %r9



	/* prepare to switch to temporary page tables */

	movq	temp_level4_pgt(%rip), %rax

	movq	mmu_cr4_features(%rip), %rbx



	/* prepare to copy image data to their original locations */

	movq	restore_pblist(%rip), %rdx



	/* jump to relocated restore code */

	movq	relocated_restore_code(%rip), %rcx

	jmpq	*%rcx



	/* code below has been relocated to a safe page */

ENTRY(core_restore_code)

	/* switch to temporary page tables */

	movq	$__PAGE_OFFSET, %rcx

	subq	%rcx, %rax

	movq	%rax, %cr3

	/* flush TLB */

	movq	%rbx, %rcx

	andq	$~(X86_CR4_PGE), %rcx

	movq	%rcx, %cr4;  # turn off PGE

	movq	%cr3, %rcx;  # flush TLB

	movq	%rcx, %cr3;

	movq	%rbx, %cr4;  # turn PGE back on

.Lloop:

	testq	%rdx, %rdx

	jz	.Ldone
@@ -96,24 +96,17 @@ ENTRY(core_restore_code) 
	/* progress to the next pbe */

	movq	pbe_next(%rdx), %rdx

	jmp	.Lloop



.Ldone:

	/* jump to the restore_registers address from the image header */

	jmpq	*%rax

	/*

	 * NOTE: This assumes that the boot kernel's text mapping covers the

	 * image kernel's page containing restore_registers and the address of

	 * this page is the same as in the image kernel's text mapping (it

	 * should always be true, because the text mapping is linear, starting

	 * from 0, and is supposed to cover the entire kernel text for every

	 * kernel).

	 *

	 * code below belongs to the image kernel

	 */

	jmpq	*%r8



	 /* code below belongs to the image kernel */

	.align PAGE_SIZE

ENTRY(restore_registers)

	FRAME_BEGIN

	/* go back to the original page tables */

	movq    %rbx, %cr3

	movq    %r9, %cr3



	/* Flush TLB, including "global" things (vmalloc) */

	movq	mmu_cr4_features(%rip), %rax

drivers/cpuidle/cpuidle.c

+4 −8
Original line number Diff line number Diff line
@@ -173,7 +173,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, 


	struct cpuidle_state *target_state = &drv->states[index];

	bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);

	u64 time_start, time_end;

	ktime_t time_start, time_end;

	s64 diff;



	/*
@@ -195,13 +195,13 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, 
	sched_idle_set_state(target_state);



	trace_cpu_idle_rcuidle(index, dev->cpu);

	time_start = local_clock();

	time_start = ns_to_ktime(local_clock());



	stop_critical_timings();

	entered_state = target_state->enter(dev, drv, index);

	start_critical_timings();



	time_end = local_clock();

	time_end = ns_to_ktime(local_clock());

	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);



	/* The cpu is no longer idle or about to enter idle. */
@@ -217,11 +217,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, 
	if (!cpuidle_state_is_coupled(drv, index))

		local_irq_enable();



	/*

	 * local_clock() returns the time in nanosecond, let's shift

	 * by 10 (divide by 1024) to have microsecond based time.

	 */

	diff = (time_end - time_start) >> 10;

	diff = ktime_us_delta(time_end, time_start);

	if (diff > INT_MAX)

		diff = INT_MAX;

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