Kexec command line length

Fine, New patch attached.

This patch does 5 things:
1) moves command line out of the zero page (struct bootparam)

2) extends command line length to support 2K command lines

3) adds a check to ensure that command line length is reasonably sized for new
boot protocols

4) adds a check to ensure that command line length is reasonably sized for old
boot protocols

5) imports variables from latest struct setup_header in kernel bootparams.h

Incorporates simplified version checking for boot protocol and conservatively
warns if the kernels boot protocol is below version 2.06 which is guaranteed to
have 2K commandlines (even though some arches  may have that support in
older boot protocols)

Neil

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

 include/x86/x86-linux.h           |   20 ++++++++++++++------
 kexec/arch/i386/kexec-bzImage.c   |   11 +++++++++++
 kexec/arch/i386/x86-linux-setup.c |    3 ++-
 3 files changed, 27 insertions(+), 7 deletions(-)
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 11 insertions, 0 deletions

diff --git a/kexec/arch/i386/kexec-bzImage.c b/kexec/arch/i386/kexec-bzImage.c
index 8fde799..93e37a4 100644
--- a/kexec/arch/i386/kexec-bzImage.c
+++ b/kexec/arch/i386/kexec-bzImage.c
@@ -134,6 +134,17 @@ int do_bzImage_load(struct kexec_info *info,
 		return -1;
 	}
 
+	if (setup_header.protocol_version >= 0x0206) {
+		if (command_line_len > setup_header.cmdline_size) {
+			dbgprintf("Kernel command line too long for kernel!\n");
+			return -1;
+		}
+	} else {
+		if (command_line_len > 255) {
+			dbgprintf("WARNING: This kernel may only support 255 byte command lines\n");
+		}
+	}
+
 	if (setup_header.protocol_version >= 0x0205) {
 		relocatable_kernel = setup_header.relocatable_kernel;
 		dbgprintf("bzImage is relocatable\n");