[PATCH] i386: Implement CONFIG_PHYSICAL_ALIGN

o Now CONFIG_PHYSICAL_START is being replaced with CONFIG_PHYSICAL_ALIGN.
  Hardcoding the kernel physical start value creates a problem in relocatable
  kernel context due to boot loader limitations. For ex, if somebody
  compiles a relocatable kernel to be run from address 4MB, but this kernel
  will run from location 1MB as grub loads the kernel at physical address
  1MB. Kernel thinks that I am a relocatable kernel and I should run from
  the address I have been loaded at. So somebody wanting to run kernel
  from 4MB alignment location (for improved performance regions) can't do
  that.

o Hence, Eric proposed that probably CONFIG_PHYSICAL_ALIGN will make
  more sense in relocatable kernel context. At run time kernel will move
  itself to a physical addr location which meets user specified alignment
  restrictions.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 5 insertions, 1 deletions

diff --git a/include/asm-i386/boot.h b/include/asm-i386/boot.h
index 96b228e6e79c..8ce79a6fa891 100644
--- a/include/asm-i386/boot.h
+++ b/include/asm-i386/boot.h
@@ -12,4 +12,8 @@
 #define EXTENDED_VGA    0xfffe          /* 80x50 mode */
 #define ASK_VGA         0xfffd          /* ask for it at bootup */
 
-#endif
+/* Physical address where kenrel should be loaded. */
+#define LOAD_PHYSICAL_ADDR ((0x100000 + CONFIG_PHYSICAL_ALIGN - 1) \
+                                & ~(CONFIG_PHYSICAL_ALIGN - 1))
+
+#endif /* _LINUX_BOOT_H */