Matt Fleming b1994304fc x86, efi: Add dedicated EFI stub entry point ... The method used to work out whether we were booted by EFI firmware or via a boot loader is broken. Because efi_main() is always executed when booting from a boot loader we will dereference invalid pointers either on the stack (CONFIG_X86_32) or contained in %rdx (CONFIG_X86_64) when searching for an EFI System Table signature. Instead of dereferencing these invalid system table pointers, add a new entry point that is only used when booting from EFI firmware, when we know the pointer arguments will be valid. With this change legacy boot loaders will no longer execute efi_main(), but will instead skip EFI stub initialisation completely. [ hpa: Marking this for urgent/stable since it is a regression when the option is enabled; without the option the patch has no effect ] Signed-off-by: Matt Fleming <matt.hfleming@intel.com> Link: http://lkml.kernel.org/r/1334584744.26997.14.camel@mfleming-mobl1.ger.corp.intel.com Reported-by: Jordan Justen <jordan.l.justen@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: <stable@vger.kernel.org> v3.3		2012-04-16 11:41:44 -07:00
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.gitignore	i386: move boot	2007-10-11 11:16:41 +02:00
build.c	x86, efi: Add dedicated EFI stub entry point	2012-04-16 11:41:44 -07:00