[PATCH 4.9 012/101] x86/power/64: Use char arrays for asm function names

From: Greg Kroah-Hartman
Date: Thu Dec 06 2018 - 09:44:21 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Kees Cook <keescook@xxxxxxxxxxxx>

commit c0944883c97c0ddc71da67cc731590a7c878a1a2 upstream.

This switches the hibernate_64.S function names into character arrays
to match other areas of the kernel where this is done (e.g., linker
scripts). Specifically this fixes a compile-time error noticed by the
future CONFIG_FORTIFY_SOURCE routines that complained about PAGE_SIZE
being copied out of the "single byte" core_restore_code variable.

Additionally drops the "acpi_save_state_mem" exern which does not
appear to be used anywhere else in the kernel.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/include/asm/suspend_64.h | 5 ++---
arch/x86/power/hibernate_64.c | 6 +++---
2 files changed, 5 insertions(+), 6 deletions(-)

--- a/arch/x86/include/asm/suspend_64.h
+++ b/arch/x86/include/asm/suspend_64.h
@@ -42,8 +42,7 @@ struct saved_context {
set_debugreg((thread)->debugreg##register, register)

/* routines for saving/restoring kernel state */
-extern int acpi_save_state_mem(void);
-extern char core_restore_code;
-extern char restore_registers;
+extern char core_restore_code[];
+extern char restore_registers[];

#endif /* _ASM_X86_SUSPEND_64_H */
--- a/arch/x86/power/hibernate_64.c
+++ b/arch/x86/power/hibernate_64.c
@@ -126,7 +126,7 @@ static int relocate_restore_code(void)
if (!relocated_restore_code)
return -ENOMEM;

- memcpy((void *)relocated_restore_code, &core_restore_code, PAGE_SIZE);
+ 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);
@@ -197,8 +197,8 @@ int arch_hibernation_header_save(void *a

if (max_size < sizeof(struct restore_data_record))
return -EOVERFLOW;
- rdr->jump_address = (unsigned long)&restore_registers;
- rdr->jump_address_phys = __pa_symbol(&restore_registers);
+ 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;