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authorBernhard Walle <bwalle@suse.de>2007-05-02 19:27:10 +0200
committerAndi Kleen <andi@basil.nowhere.org>2007-05-02 19:27:10 +0200
commit8f9aeca7a081d81c4c9862be1e04f15b5ab5461f (patch)
tree49b802b90aca5b170aba5734ef99344a90426b01 /arch/x86_64
parent79e030114a8d97a1dcd593ab84fb986f8c91c536 (diff)
[PATCH] x86: add command line length to boot protocol
Because the command line is increased to 2048 characters after 2.6.21, it's not possible for boot loaders and userspace tools to determine the length of the command line the kernel can understand. The benefit of knowing the length is that users can be warned if the command line size is too long which prevents surprise if things don't work after bootup. This patch updates the boot protocol to contain a field called "cmdline_size" that contain the length of the command line (excluding the terminating zero). The patch also adds missing fields (of protocol version 2.05) to the x86_64 setup code. Signed-off-by: Bernhard Walle <bwalle@suse.de> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Alon Bar-Lev <alon.barlev@gmail.com> Acked-by: H. Peter Anvin <hpa@zytor.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/boot/setup.S7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86_64/boot/setup.S b/arch/x86_64/boot/setup.S
index 816d04faa2b..4f8851000d7 100644
--- a/arch/x86_64/boot/setup.S
+++ b/arch/x86_64/boot/setup.S
@@ -51,6 +51,7 @@
#include <asm/boot.h>
#include <asm/e820.h>
#include <asm/page.h>
+#include <asm/setup.h>
/* Signature words to ensure LILO loaded us right */
#define SIG1 0xAA55
@@ -80,7 +81,7 @@ start:
# This is the setup header, and it must start at %cs:2 (old 0x9020:2)
.ascii "HdrS" # header signature
- .word 0x0205 # header version number (>= 0x0105)
+ .word 0x0206 # header version number (>= 0x0105)
# or else old loadlin-1.5 will fail)
realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
start_sys_seg: .word SYSSEG
@@ -165,6 +166,10 @@ relocatable_kernel: .byte 0
pad2: .byte 0
pad3: .word 0
+cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
+ #added with boot protocol
+ #version 2.06
+
trampoline: call start_of_setup
.align 16
# The offset at this point is 0x240