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author | Kevin | 2014-11-15 09:58:27 +0800 |
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committer | Kevin | 2014-11-15 09:58:27 +0800 |
commit | 392e8802486cb573b916e746010e141a75f507e6 (patch) | |
tree | 50029aca02c81f087b90336e670b44e510782330 /ANDROID_3.4.5/arch/x86/boot/compressed/head_32.S | |
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init android origin source code
Diffstat (limited to 'ANDROID_3.4.5/arch/x86/boot/compressed/head_32.S')
-rw-r--r-- | ANDROID_3.4.5/arch/x86/boot/compressed/head_32.S | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/ANDROID_3.4.5/arch/x86/boot/compressed/head_32.S b/ANDROID_3.4.5/arch/x86/boot/compressed/head_32.S new file mode 100644 index 00000000..c85e3ac9 --- /dev/null +++ b/ANDROID_3.4.5/arch/x86/boot/compressed/head_32.S @@ -0,0 +1,225 @@ +/* + * linux/boot/head.S + * + * Copyright (C) 1991, 1992, 1993 Linus Torvalds + */ + +/* + * head.S contains the 32-bit startup code. + * + * NOTE!!! Startup happens at absolute address 0x00001000, which is also where + * the page directory will exist. The startup code will be overwritten by + * the page directory. [According to comments etc elsewhere on a compressed + * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC] + * + * Page 0 is deliberately kept safe, since System Management Mode code in + * laptops may need to access the BIOS data stored there. This is also + * useful for future device drivers that either access the BIOS via VM86 + * mode. + */ + +/* + * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 + */ + .text + +#include <linux/init.h> +#include <linux/linkage.h> +#include <asm/segment.h> +#include <asm/page_types.h> +#include <asm/boot.h> +#include <asm/asm-offsets.h> + + __HEAD +ENTRY(startup_32) +#ifdef CONFIG_EFI_STUB + jmp preferred_addr + + .balign 0x10 + /* + * We don't need the return address, so set up the stack so + * efi_main() can find its arugments. + */ + add $0x4, %esp + + call efi_main + cmpl $0, %eax + movl %eax, %esi + jne 2f +1: + /* EFI init failed, so hang. */ + hlt + jmp 1b +2: + call 3f +3: + popl %eax + subl $3b, %eax + subl BP_pref_address(%esi), %eax + add BP_code32_start(%esi), %eax + leal preferred_addr(%eax), %eax + jmp *%eax + +preferred_addr: +#endif + cld + /* + * Test KEEP_SEGMENTS flag to see if the bootloader is asking + * us to not reload segments + */ + testb $(1<<6), BP_loadflags(%esi) + jnz 1f + + cli + movl $__BOOT_DS, %eax + movl %eax, %ds + movl %eax, %es + movl %eax, %fs + movl %eax, %gs + movl %eax, %ss +1: + +/* + * Calculate the delta between where we were compiled to run + * at and where we were actually loaded at. This can only be done + * with a short local call on x86. Nothing else will tell us what + * address we are running at. The reserved chunk of the real-mode + * data at 0x1e4 (defined as a scratch field) are used as the stack + * for this calculation. Only 4 bytes are needed. + */ + leal (BP_scratch+4)(%esi), %esp + call 1f +1: popl %ebp + subl $1b, %ebp + +/* + * %ebp contains the address we are loaded at by the boot loader and %ebx + * contains the address where we should move the kernel image temporarily + * for safe in-place decompression. + */ + +#ifdef CONFIG_RELOCATABLE + movl %ebp, %ebx + movl BP_kernel_alignment(%esi), %eax + decl %eax + addl %eax, %ebx + notl %eax + andl %eax, %ebx +#else + movl $LOAD_PHYSICAL_ADDR, %ebx +#endif + + /* Target address to relocate to for decompression */ + addl $z_extract_offset, %ebx + + /* Set up the stack */ + leal boot_stack_end(%ebx), %esp + + /* Zero EFLAGS */ + pushl $0 + popfl + +/* + * Copy the compressed kernel to the end of our buffer + * where decompression in place becomes safe. + */ + pushl %esi + leal (_bss-4)(%ebp), %esi + leal (_bss-4)(%ebx), %edi + movl $(_bss - startup_32), %ecx + shrl $2, %ecx + std + rep movsl + cld + popl %esi + +/* + * Jump to the relocated address. + */ + leal relocated(%ebx), %eax + jmp *%eax +ENDPROC(startup_32) + + .text +relocated: + +/* + * Clear BSS (stack is currently empty) + */ + xorl %eax, %eax + leal _bss(%ebx), %edi + leal _ebss(%ebx), %ecx + subl %edi, %ecx + shrl $2, %ecx + rep stosl + +/* + * Adjust our own GOT + */ + leal _got(%ebx), %edx + leal _egot(%ebx), %ecx +1: + cmpl %ecx, %edx + jae 2f + addl %ebx, (%edx) + addl $4, %edx + jmp 1b +2: + +/* + * Do the decompression, and jump to the new kernel.. + */ + leal z_extract_offset_negative(%ebx), %ebp + /* push arguments for decompress_kernel: */ + pushl %ebp /* output address */ + pushl $z_input_len /* input_len */ + leal input_data(%ebx), %eax + pushl %eax /* input_data */ + leal boot_heap(%ebx), %eax + pushl %eax /* heap area */ + pushl %esi /* real mode pointer */ + call decompress_kernel + addl $20, %esp + +#if CONFIG_RELOCATABLE +/* + * Find the address of the relocations. + */ + leal z_output_len(%ebp), %edi + +/* + * Calculate the delta between where vmlinux was compiled to run + * and where it was actually loaded. + */ + movl %ebp, %ebx + subl $LOAD_PHYSICAL_ADDR, %ebx + jz 2f /* Nothing to be done if loaded at compiled addr. */ +/* + * Process relocations. + */ + +1: subl $4, %edi + movl (%edi), %ecx + testl %ecx, %ecx + jz 2f + addl %ebx, -__PAGE_OFFSET(%ebx, %ecx) + jmp 1b +2: +#endif + +/* + * Jump to the decompressed kernel. + */ + xorl %ebx, %ebx + jmp *%ebp + +/* + * Stack and heap for uncompression + */ + .bss + .balign 4 +boot_heap: + .fill BOOT_HEAP_SIZE, 1, 0 +boot_stack: + .fill BOOT_STACK_SIZE, 1, 0 +boot_stack_end: |