From 2e604c0f19dcdd433b3863ffc3da9bc0787ca765 Mon Sep 17 00:00:00 2001 From: Josh Boyer Date: Wed, 6 Mar 2013 20:23:30 -0800 Subject: [PATCH] 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 Link: http://lkml.kernel.org/r/CA%2B5PVA51-FT14p4CRYKbicykugVb=PiaEycdQ57CK2km_OQuRQ@mail.gmail.com Tested-by: Josh Boyer Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/bootparam_utils.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h index 5b5e9cb774b5..ff808ef4fdb4 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 - -- 2.20.1