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authorJosh Boyer <jwboyer@gmail.com>2013-03-06 20:23:30 -0800
committerH. Peter Anvin <hpa@zytor.com>2013-03-06 20:23:30 -0800
commit2e604c0f19dcdd433b3863ffc3da9bc0787ca765 (patch)
treecc1280c896e0db70cf53dda68f5b8c29651cbad6
parent98e7a989979b185f49e86ddaed2ad6890299d9f0 (diff)
downloadlinaro-lsk-2e604c0f19dcdd433b3863ffc3da9bc0787ca765.tar.gz
x86: Don't clear efi_info even if the sentinel hits
When boot_params->sentinel is set, all we really know is that some undefined set of fields in struct boot_params contain garbage. In the particular case of efi_info, however, there is a private magic for that substructure, so it is generally safe to leave it even if the bootloader is broken. kexec (for which we did the initial analysis) did not initialize this field, but of course all the EFI bootloaders do, and most EFI bootloaders are broken in this respect (and should be fixed.) Reported-by: Robin Holt <holt@sgi.com> Link: http://lkml.kernel.org/r/CA%2B5PVA51-FT14p4CRYKbicykugVb=PiaEycdQ57CK2km_OQuRQ@mail.gmail.com Tested-by: Josh Boyer <jwboyer@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--arch/x86/include/asm/bootparam_utils.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
index 5b5e9cb774b..ff808ef4fdb 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -14,13 +14,15 @@
* analysis of kexec-tools; if other broken bootloaders initialize a
* different set of fields we will need to figure out how to disambiguate.
*
+ * Note: efi_info is commonly left uninitialized, but that field has a
+ * private magic, so it is better to leave it unchanged.
*/
static void sanitize_boot_params(struct boot_params *boot_params)
{
if (boot_params->sentinel) {
/*fields in boot_params are not valid, clear them */
memset(&boot_params->olpc_ofw_header, 0,
- (char *)&boot_params->alt_mem_k -
+ (char *)&boot_params->efi_info -
(char *)&boot_params->olpc_ofw_header);
memset(&boot_params->kbd_status, 0,
(char *)&boot_params->hdr -