From 8f9aeca7a081d81c4c9862be1e04f15b5ab5461f Mon Sep 17 00:00:00 2001 From: Bernhard Walle Date: Wed, 2 May 2007 19:27:10 +0200 Subject: [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 Signed-off-by: Andi Kleen Cc: Alon Bar-Lev Acked-by: H. Peter Anvin Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/x86_64/boot/setup.S | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/x86_64/boot') diff --git a/arch/x86_64/boot/setup.S b/arch/x86_64/boot/setup.S index 816d04f..4f88510 100644 --- a/arch/x86_64/boot/setup.S +++ b/arch/x86_64/boot/setup.S @@ -51,6 +51,7 @@ #include #include #include +#include /* 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 -- cgit v1.1