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authorDaniel Drake <dsd@laptop.org>2013-08-09 18:14:20 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-29 09:47:35 -0700
commit8a34139a0c0ab7ed616b3e50f061cac8bc1e0531 (patch)
tree45320691a59f42fcc931b6298c4e1f419bd892b6
parent2bee1e0f280b159ce8f9f01c2f5c9de410231a3b (diff)
x86: Don't clear olpc_ofw_header when sentinel is detected
commit d55e37bb0f51316e552376ddc0a3fff34ca7108b upstream. OpenFirmware wasn't quite following the protocol described in boot.txt and the kernel has detected this through use of the sentinel value in boot_params. OFW does zero out almost all of the stuff that it should do, but not the sentinel. This causes the kernel to clear olpc_ofw_header, which breaks x86 OLPC support. OpenFirmware has now been fixed. However, it would be nice if we could maintain Linux compatibility with old firmware versions. To do that, we just have to avoid zeroing out olpc_ofw_header. OFW does not write to any other parts of the header that are being zapped by the sentinel-detection code, and all users of olpc_ofw_header are somewhat protected through checking for the OLPC_OFW_SIG magic value before using it. So this should not cause any problems for anyone. Signed-off-by: Daniel Drake <dsd@laptop.org> Link: http://lkml.kernel.org/r/20130809221420.618E6FAB03@dev.laptop.org Acked-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/include/asm/bootparam_utils.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
index 653668d140f9..4a8cb8d7cbd5 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -35,9 +35,9 @@ static void sanitize_boot_params(struct boot_params *boot_params)
*/
if (boot_params->sentinel) {
/* fields in boot_params are left uninitialized, clear them */
- memset(&boot_params->olpc_ofw_header, 0,
+ memset(&boot_params->ext_ramdisk_image, 0,
(char *)&boot_params->efi_info -
- (char *)&boot_params->olpc_ofw_header);
+ (char *)&boot_params->ext_ramdisk_image);
memset(&boot_params->kbd_status, 0,
(char *)&boot_params->hdr -
(char *)&boot_params->kbd_status);