The patch titled
x86_64: display more intutive error message if kernel is not 2MB aligned
has been added to the -mm tree. Its filename is
x86_64-display-more-intutive-error-message-if-kernel-is-not-2mb-aligned.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: x86_64: display more intutive error message if kernel is not 2MB aligned
From: Vivek Goyal <vgoyal@xxxxxxxxxx>
o x86_64 kernel needs to be compiled for 2MB aligned addresses. Currently
we are using BUILD_BUG_ON() to warn the user if he has not done so. But
looks like folks are not finding message very intutive and don't open
the respective c file to find problem source. (Bug 8439)
arch/x86_64/kernel/head64.c: In function 'x86_64_start_kernel':
arch/x86_64/kernel/head64.c:70: error: size of array 'type name' is negative
o Using preprocessor directive #error to print a better message if
CONFIG_PHYSICAL_START is not aligned to 2MB boundary.
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86_64/kernel/head64.c | 7 -------
include/asm-x86_64/page.h | 9 +++++++++
2 files changed, 9 insertions(+), 7 deletions(-)
diff -puN arch/x86_64/kernel/head64.c~x86_64-display-more-intutive-error-message-if-kernel-is-not-2mb-aligned arch/x86_64/kernel/head64.c
--- a/arch/x86_64/kernel/head64.c~x86_64-display-more-intutive-error-message-if-kernel-is-not-2mb-aligned
+++ a/arch/x86_64/kernel/head64.c
@@ -62,13 +62,6 @@ void __init x86_64_start_kernel(char * r
{
int i;
- /*
- * Make sure kernel is aligned to 2MB address. Catching it at compile
- * time is better. Change your config file and compile the kernel
- * for a 2MB aligned address (CONFIG_PHYSICAL_START)
- */
- BUILD_BUG_ON(CONFIG_PHYSICAL_START & (__KERNEL_ALIGN - 1));
-
/* clear bss before set_intr_gate with early_idt_handler */
clear_bss();
diff -puN include/asm-x86_64/page.h~x86_64-display-more-intutive-error-message-if-kernel-is-not-2mb-aligned include/asm-x86_64/page.h
--- a/include/asm-x86_64/page.h~x86_64-display-more-intutive-error-message-if-kernel-is-not-2mb-aligned
+++ a/include/asm-x86_64/page.h
@@ -80,6 +80,15 @@ extern unsigned long phys_base;
#define __PHYSICAL_START CONFIG_PHYSICAL_START
#define __KERNEL_ALIGN 0x200000
+/*
+ * Make sure kernel is aligned to 2MB address. Catching it at compile
+ * time is better. Change your config file and compile the kernel
+ * for a 2MB aligned address (CONFIG_PHYSICAL_START)
+ */
+#if (CONFIG_PHYSICAL_START % __KERNEL_ALIGN) != 0
+#error "CONFIG_PHYSICAL_START must be a multiple of 2MB"
+#endif
+
#define __START_KERNEL (__START_KERNEL_map + __PHYSICAL_START)
#define __START_KERNEL_map _AC(0xffffffff80000000, UL)
#define __PAGE_OFFSET _AC(0xffff810000000000, UL)
_
Patches currently in -mm which might be from vgoyal@xxxxxxxxxx are
origin.patch
kdump-kexec-calculate-note-size-at-compile-time.patch
fix-i-oat-for-kexec.patch
x86_64-display-more-intutive-error-message-if-kernel-is-not-2mb-aligned.patch
remove-hardcoding-of-hard_smp_processor_id-on-up.patch
use-the-apic-to-determine-the-hardware-processor-id-i386.patch
use-the-apic-to-determine-the-hardware-processor-id-x86_64.patch
always-ask-the-hardware-to-obtain-hardware-processor-id-ia64.patch
-
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