Subject: [PATCH] x86, boot: keep data from boot stage to kernel stage. Need to 1. move compressed kernel close the end of buffer instead of middle of it. 2. use BRK to extend init_size so no one from kernel bss and brk will touch the data region from boot/compressed/misc.c Signed-off-by: Yinghai Lu --- arch/x86/boot/compressed/head_32.S | 13 +++++++++++-- arch/x86/boot/compressed/head_64.S | 10 ++++++++-- arch/x86/boot/compressed/misc.c | 4 ++++ arch/x86/boot/compressed/mkpiggy.c | 3 --- arch/x86/include/asm/boot.h | 2 ++ arch/x86/kernel/asm-offsets.c | 1 + arch/x86/kernel/setup.c | 3 +++ 7 files changed, 29 insertions(+), 7 deletions(-) Index: linux-2.6/arch/x86/boot/compressed/head_64.S =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/head_64.S +++ linux-2.6/arch/x86/boot/compressed/head_64.S @@ -102,7 +102,10 @@ ENTRY(startup_32) 1: /* Target address to relocate to for decompression */ - addl $z_extract_offset, %ebx + movl BP_init_size(%esi), %eax + subl $_end, %eax + andl $(~(4096-1)), %eax + addl %eax, %ebx /* * Prepare for entering 64 bit mode @@ -330,7 +333,10 @@ preferred_addr: 1: /* Target address to relocate to for decompression */ - leaq z_extract_offset(%rbp), %rbx + movl BP_init_size(%rsi), %ebx + subl $_end, %ebx + andl $(~(4096-1)), %ebx + addq %rbp, %rbx /* Set up the stack */ leaq boot_stack_end(%rbx), %rsp Index: linux-2.6/arch/x86/kernel/asm-offsets.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/asm-offsets.c +++ linux-2.6/arch/x86/kernel/asm-offsets.c @@ -66,6 +66,7 @@ void common(void) { OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch); OFFSET(BP_version, boot_params, hdr.version); OFFSET(BP_kernel_alignment, boot_params, hdr.kernel_alignment); + OFFSET(BP_init_size, boot_params, hdr.init_size); OFFSET(BP_pref_address, boot_params, hdr.pref_address); OFFSET(BP_code32_start, boot_params, hdr.code32_start); Index: linux-2.6/arch/x86/kernel/setup.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/setup.c +++ linux-2.6/arch/x86/kernel/setup.c @@ -111,6 +111,7 @@ #include #include #include +#include /* * max_low_pfn_mapped: highest direct mapped pfn under 4GB @@ -144,6 +145,8 @@ int default_check_phys_apicid_present(in } #endif +RESERVE_BRK(addon_zo, BOOT_ADDON_ZO_SIZE); + struct boot_params boot_params; /* Index: linux-2.6/arch/x86/boot/compressed/head_32.S =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/head_32.S +++ linux-2.6/arch/x86/boot/compressed/head_32.S @@ -148,7 +148,10 @@ preferred_addr: 1: /* Target address to relocate to for decompression */ - addl $z_extract_offset, %ebx + movl BP_init_size(%esi), %eax + subl $_end, %eax + andl $(~(4096-1)), %eax + addl %eax, %ebx /* Set up the stack */ leal boot_stack_end(%ebx), %esp @@ -210,8 +213,14 @@ relocated: /* push arguments for decompress_kernel: */ pushl $z_run_size /* size of kernel with .bss and .brk */ pushl $z_output_len /* decompressed length, end of relocs */ - leal z_extract_offset_negative(%ebx), %ebp + + movl BP_init_size(%esi), %eax + subl $_end, %eax + andl $(~(4096-1)), %eax + movl %ebx, %ebp + subl %eax, %ebp pushl %ebp /* output address */ + pushl $z_input_len /* input_len */ leal input_data(%ebx), %eax pushl %eax /* input_data */ Index: linux-2.6/arch/x86/boot/compressed/mkpiggy.c =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/mkpiggy.c +++ linux-2.6/arch/x86/boot/compressed/mkpiggy.c @@ -85,9 +85,6 @@ int main(int argc, char *argv[]) printf("z_output_len = %lu\n", (unsigned long)olen); printf(".globl z_extract_offset\n"); printf("z_extract_offset = 0x%lx\n", offs); - /* z_extract_offset_negative allows simplification of head_32.S */ - printf(".globl z_extract_offset_negative\n"); - printf("z_extract_offset_negative = -0x%lx\n", offs); printf(".globl z_run_size\n"); printf("z_run_size = %lu\n", run_size); Index: linux-2.6/arch/x86/boot/compressed/misc.c =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/misc.c +++ linux-2.6/arch/x86/boot/compressed/misc.c @@ -366,6 +366,8 @@ static void parse_elf(void *output) free(phdrs); } +extern char _rodata[], _end[]; + asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap, unsigned char *input_data, unsigned long input_len, @@ -392,6 +394,8 @@ asmlinkage __visible void *decompress_ke console_init(); debug_putstr("early console in decompress_kernel\n"); + if (_end - _rodata > BOOT_ADDON_ZO_SIZE) + debug_putstr("BOOT_ADDON_ZO_SIZE too small\n"); free_mem_ptr = heap; /* Heap */ free_mem_end_ptr = heap + BOOT_HEAP_SIZE; Index: linux-2.6/arch/x86/include/asm/boot.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/boot.h +++ linux-2.6/arch/x86/include/asm/boot.h @@ -37,4 +37,6 @@ #define BOOT_STACK_SIZE 0x1000 #endif +#define BOOT_ADDON_ZO_SIZE 0x40000 + #endif /* _ASM_X86_BOOT_H */