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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: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2016-08-03 01:19:26 +02:00
parent 4ce827b4cc
commit c226fab474
2 changed files with 9 additions and 11 deletions
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18
arch/x86/power/hibernate_64.c
View File

@ -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;
}

2
arch/x86/power/hibernate_asm_64.S
View File

@ -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