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authorMatt Fleming <matt.fleming@intel.com>2014-06-07 12:26:20 +0100
committerH. Peter Anvin <hpa@zytor.com>2014-06-07 09:31:00 -0700
commit745c51673e289acf4d9ffc2835524de73ef923fd (patch)
tree16ac951fdd60f740cf138f57e3eb18968f2952c5
parent177875423eb01179738f6badcbb9eef4be789a0e (diff)
x86/boot: EFI_MIXED should not prohibit loading above 4G
commit 7d453eee36ae ("x86/efi: Wire up CONFIG_EFI_MIXED") introduced a regression for the functionality to load kernels above 4G. The relevant (incorrect) reasoning behind this change can be seen in the commit message, "The xloadflags field in the bzImage header is also updated to reflect that the kernel supports both entry points by setting both of XLF_EFI_HANDOVER_32 and XLF_EFI_HANDOVER_64 when CONFIG_EFI_MIXED=y. XLF_CAN_BE_LOADED_ABOVE_4G is disabled so that the kernel text is guaranteed to be addressable with 32-bits." This is obviously bogus since 32-bit EFI loaders will never place the kernel above the 4G mark. So this restriction is entirely unnecessary. But things are worse than that - since we want to encourage people to always compile with CONFIG_EFI_MIXED=y so that their kernels work out of the box for both 32-bit and 64-bit firmware, commit 7d453eee36ae effectively disables XLF_CAN_BE_LOADED_ABOVE_4G completely. Remove the overzealous and superfluous restriction and restore the XLF_CAN_BE_LOADED_ABOVE_4G functionality. Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Link: http://lkml.kernel.org/r/1402140380-15377-1-git-send-email-matt@console-pimps.org Signed-off-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--arch/x86/boot/header.S3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 0ca9a5c362b..84c223479e3 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -375,8 +375,7 @@ xloadflags:
# define XLF0 0
#endif
-#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_X86_64) && \
- !defined(CONFIG_EFI_MIXED)
+#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_X86_64)
/* kernel/boot_param/ramdisk could be loaded above 4g */
# define XLF1 XLF_CAN_BE_LOADED_ABOVE_4G
#else