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>
diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c
index f2b5e6a..f0b5f2d 100644
--- a/arch/x86/power/hibernate_64.c
+++ b/arch/x86/power/hibernate_64.c
@@ -37,11 +37,11 @@
*/
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 @@
__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 @@
.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 @@
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;
}
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
index 8eee0e9..ce8da3a 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -72,8 +72,6 @@
/* 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