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Commit c226fab4 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
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x86/power/64: Do not refer to __PAGE_OFFSET from assembly code 



When CONFIG_RANDOMIZE_MEMORY is set on x86-64, __PAGE_OFFSET becomes
a variable and using it as a symbol in the image memory restoration
assembly code under core_restore_code is not correct any more.

To avoid that problem, modify set_up_temporary_mappings() to compute
the physical address of the temporary page tables and store it in
temp_level4_pgt, so that the value of that variable is ready to be
written into CR3.  Then, the assembly code doesn't have to worry
about converting that value into a physical address and things work
regardless of whether or not CONFIG_RANDOMIZE_MEMORY is set.

Reported-and-tested-by: default avatarThomas Garnier <thgarnie@google.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 4ce827b4

arch/x86/power/hibernate_64.c

+9 −9
Original line number Diff line number Diff line
@@ -37,11 +37,11 @@ unsigned long jump_address_phys; 
 */

unsigned long restore_cr3 __visible;



pgd_t *temp_level4_pgt __visible;

unsigned long temp_level4_pgt __visible;



unsigned long relocated_restore_code __visible;



static int set_up_temporary_text_mapping(void)

static int set_up_temporary_text_mapping(pgd_t *pgd)

{

	pmd_t *pmd;

	pud_t *pud;
@@ -71,7 +71,7 @@ static int set_up_temporary_text_mapping(void) 
		__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),

	set_pgd(pgd + pgd_index(restore_jump_address),

		__pgd(__pa(pud) | _KERNPG_TABLE));



	return 0;
@@ -90,15 +90,16 @@ static int set_up_temporary_mappings(void) 
		.kernel_mapping = true,

	};

	unsigned long mstart, mend;

	pgd_t *pgd;

	int result;

	int i;



	temp_level4_pgt = (pgd_t *)get_safe_page(GFP_ATOMIC);

	if (!temp_level4_pgt)

	pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);

	if (!pgd)

		return -ENOMEM;



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

	result = set_up_temporary_text_mapping();

	result = set_up_temporary_text_mapping(pgd);

	if (result)

		return result;
@@ -107,13 +108,12 @@ static int set_up_temporary_mappings(void) 
		mstart = pfn_mapped[i].start << PAGE_SHIFT;

		mend   = pfn_mapped[i].end << PAGE_SHIFT;



		result = kernel_ident_mapping_init(&info, temp_level4_pgt,

						   mstart, mend);



		result = kernel_ident_mapping_init(&info, pgd, mstart, mend);

		if (result)

			return result;

	}



	temp_level4_pgt = (unsigned long)pgd - __PAGE_OFFSET;

	return 0;

}

arch/x86/power/hibernate_asm_64.S

+0 −2
Original line number Diff line number Diff line
@@ -72,8 +72,6 @@ ENTRY(restore_image) 
	/* 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