From: Vivek Goyal Date: Thu, 7 Dec 2006 01:14:04 +0000 (+0100) Subject: [PATCH] i386: extend bzImage protocol for relocatable protected mode kernel X-Git-Tag: v2.6.20-rc1~145^2^2~8^2~107 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=be274eeaf20b4c7155242645d5e2c48b023e609b;p=linux-2.6 [PATCH] i386: extend bzImage protocol for relocatable protected mode kernel Extend bzImage protocol to enable bootloaders to load a completely relocatable bzImage. Now protected mode component of kernel is also relocatable and a boot-loader can load the protected mode component at a differnt physical address than 1MB. (If kernel was built with CONFIG_RELOCATABLE) Kexec can make use of it to load this kernel at a different physical address to capture kernel crash dumps. Signed-off-by: Vivek Goyal Signed-off-by: Andi Kleen Cc: Andi Kleen Signed-off-by: Andrew Morton --- diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt index c51314b1a4..cb28254f15 100644 --- a/Documentation/i386/boot.txt +++ b/Documentation/i386/boot.txt @@ -35,6 +35,8 @@ Protocol 2.03: (Kernel 2.4.18-pre1) Explicitly makes the highest possible initrd address available to the bootloader. Protocol 2.04: (Kernel 2.6.14) Extend the syssize field to four bytes. +Protocol 2.05: (Kernel 2.6.20) Make protected mode kernel relocatable. + Introduce relocatable_kernel and kernel_alignment fields. **** MEMORY LAYOUT @@ -129,6 +131,8 @@ Offset Proto Name Meaning 0226/2 N/A pad1 Unused 0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line 022C/4 2.03+ initrd_addr_max Highest legal initrd address +0230/4 2.04+ kernel_alignment Physical addr alignment required for kernel +0234/1 2.04+ relocatable_kernel Whether kernel is relocatable or not (1) For backwards compatibility, if the setup_sects field contains 0, the real value is 4. diff --git a/arch/i386/boot/setup.S b/arch/i386/boot/setup.S index 9aa8b05181..06edf1c662 100644 --- a/arch/i386/boot/setup.S +++ b/arch/i386/boot/setup.S @@ -81,7 +81,7 @@ start: # This is the setup header, and it must start at %cs:2 (old 0x9020:2) .ascii "HdrS" # header signature - .word 0x0204 # header version number (>= 0x0105) + .word 0x0205 # 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 @@ -160,6 +160,17 @@ ramdisk_max: .long (-__PAGE_OFFSET-(512 << 20)-1) & 0x7fffffff # The highest safe address for # the contents of an initrd +kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment + #required for protected mode + #kernel +#ifdef CONFIG_RELOCATABLE +relocatable_kernel: .byte 1 +#else +relocatable_kernel: .byte 0 +#endif +pad2: .byte 0 +pad3: .word 0 + trampoline: call start_of_setup .align 16 # The offset at this point is 0x240