From 7c53976404e2f906c60b69cc5793add87ee49c6a Mon Sep 17 00:00:00 2001 From: Alexander van Heukelum Date: Tue, 8 Apr 2008 12:54:30 +0200 Subject: [PATCH] x86: cleanup boot-heap usage The kernel decompressor wrapper uses memory located beyond the end of the image. This might lead to hard to debug problems, but even if it can be proven to be safe, it is at the very least unclean. I don't see any advantages either, unless you count it not being zeroed out as an advantage. This patch moves the boot-heap area to the bss segment. Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/boot/compressed/head_32.S | 15 +++++++++------ arch/x86/boot/compressed/head_64.S | 22 +++++++++++++--------- arch/x86/boot/compressed/misc.c | 8 +------- include/asm-x86/boot.h | 8 ++++++++ 4 files changed, 31 insertions(+), 22 deletions(-) diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index 036e635f18..ba7736cf2e 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -130,7 +130,7 @@ relocated: /* * Setup the stack for the decompressor */ - leal stack_end(%ebx), %esp + leal boot_stack_end(%ebx), %esp /* * Do the decompression, and jump to the new kernel.. @@ -142,8 +142,8 @@ relocated: pushl %eax # input_len leal input_data(%ebx), %eax pushl %eax # input_data - leal _end(%ebx), %eax - pushl %eax # end of the image as third argument + leal boot_heap(%ebx), %eax + pushl %eax # heap area as third argument pushl %esi # real mode pointer as second arg call decompress_kernel addl $20, %esp @@ -181,7 +181,10 @@ relocated: jmp *%ebp .bss +/* Stack and heap for uncompression */ .balign 4 -stack: - .fill 4096, 1, 0 -stack_end: +boot_heap: + .fill BOOT_HEAP_SIZE, 1, 0 +boot_stack: + .fill BOOT_STACK_SIZE, 1, 0 +boot_stack_end: diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index e8657b98c9..7a212a62db 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -62,7 +63,7 @@ startup_32: subl $1b, %ebp /* setup a stack and make sure cpu supports long mode. */ - movl $user_stack_end, %eax + movl $boot_stack_end, %eax addl %ebp, %eax movl %eax, %esp @@ -274,7 +275,7 @@ relocated: stosb /* Setup the stack */ - leaq user_stack_end(%rip), %rsp + leaq boot_stack_end(%rip), %rsp /* zero EFLAGS after setting rsp */ pushq $0 @@ -285,7 +286,7 @@ relocated: */ pushq %rsi # Save the real mode argument movq %rsi, %rdi # real mode address - leaq _heap(%rip), %rsi # _heap + leaq boot_heap(%rip), %rsi # malloc area for uncompression leaq input_data(%rip), %rdx # input_data movl input_len(%rip), %eax movq %rax, %rcx # input_len @@ -310,9 +311,12 @@ gdt: .quad 0x0080890000000000 /* TS descriptor */ .quad 0x0000000000000000 /* TS continued */ gdt_end: - .bss -/* Stack for uncompression */ - .balign 4 -user_stack: - .fill 4096,4,0 -user_stack_end: + +.bss +/* Stack and heap for uncompression */ +.balign 4 +boot_heap: + .fill BOOT_HEAP_SIZE, 1, 0 +boot_stack: + .fill BOOT_STACK_SIZE, 1, 0 +boot_stack_end: diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index dad4e699f5..90456cee47 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -217,12 +217,6 @@ static void putstr(const char *); static memptr free_mem_ptr; static memptr free_mem_end_ptr; -#ifdef CONFIG_X86_64 -#define HEAP_SIZE 0x7000 -#else -#define HEAP_SIZE 0x4000 -#endif - static char *vidmem; static int vidport; static int lines, cols; @@ -449,7 +443,7 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap, window = output; /* Output buffer (Normally at 1M) */ free_mem_ptr = heap; /* Heap */ - free_mem_end_ptr = heap + HEAP_SIZE; + free_mem_end_ptr = heap + BOOT_HEAP_SIZE; inbuf = input_data; /* Input buffer */ insize = input_len; inptr = 0; diff --git a/include/asm-x86/boot.h b/include/asm-x86/boot.h index ed8affbf96..2faed7ecb0 100644 --- a/include/asm-x86/boot.h +++ b/include/asm-x86/boot.h @@ -17,4 +17,12 @@ + (CONFIG_PHYSICAL_ALIGN - 1)) \ & ~(CONFIG_PHYSICAL_ALIGN - 1)) +#ifdef CONFIG_X86_64 +#define BOOT_HEAP_SIZE 0x7000 +#define BOOT_STACK_SIZE 0x4000 +#else +#define BOOT_HEAP_SIZE 0x4000 +#define BOOT_STACK_SIZE 0x1000 +#endif + #endif /* _ASM_BOOT_H */ -- 2.39.5