x86: Fix boot protocol KEEP_SEGMENTS check.

The kernel only ever supports 1 version of the boot protocol
so there is no need to check the boot protocol revision to
see if a feature is supported.

Both x86 and x86_64 support the same boot protocol so we need
to implement the KEEP_SEGMENTS on x86_64 as well.  It isn't
just paravirt bootloaders that could use this functionality.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@suse.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 7e50bda565b4..d1b6ed98774e 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -15,12 +15,16 @@
 #include <asm/segment.h>
 #include <asm/thread_info.h>
 #include <asm/ia32.h>
+#include <asm/bootparam.h>
 
 #define DEFINE(sym, val) \
         asm volatile("\n->" #sym " %0 " #val : : "i" (val))
 
 #define BLANK() asm volatile("\n->" : : )
 
+#define OFFSET(sym, str, mem) \
+        DEFINE(sym, offsetof(struct str, mem))
+
 #define __NO_STUBS 1
 #undef __SYSCALL
 #undef _ASM_X86_64_UNISTD_H_
@@ -109,5 +113,11 @@ int main(void)
         DEFINE(crypto_tfm_ctx_offset, offsetof(struct crypto_tfm, __crt_ctx));
         BLANK();
         DEFINE(__NR_syscall_max, sizeof(syscalls) - 1);
+
+        BLANK();
+        OFFSET(BP_scratch, boot_params, scratch);
+        OFFSET(BP_loadflags, boot_params, hdr.loadflags);
+        OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch);
+        OFFSET(BP_version, boot_params, hdr.version);
         return 0;
 }