diff options
| author | H. Peter Anvin <hpa@zytor.com> | 2009-05-08 17:42:16 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-05-08 17:46:34 -0700 |
| commit | 02a884c0fe7ec8459d00d34b7d4101af21fc4a86 (patch) | |
| tree | 164783f84130482e52290af03d96ff8e887f8605 /arch/x86/boot/compressed/head_64.S | |
| parent | 36d3793c947f1ef7ba3d24eeeddc1be41adc5ab4 (diff) | |
x86, boot: determine compressed code offset at compile time
Determine the compressed code offset (from the kernel runtime address)
at compile time. This allows some minor optimizations in
arch/x86/boot/compressed/head_*.S, but more importantly it makes this
value available to the build process, which will enable a future patch
to export the necessary linear memory footprint into the bzImage
header.
[ Impact: cleanup, future patch enabling ]
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 41 |
1 files changed, 13 insertions, 28 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 723c72dfd7b..2b9f2510507 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -90,16 +90,8 @@ ENTRY(startup_32) movl $CONFIG_PHYSICAL_START, %ebx #endif - /* Replace the compressed data size with the uncompressed size */ - subl input_len(%ebp), %ebx - movl output_len(%ebp), %eax - addl %eax, %ebx - /* Add 8 bytes for every 32K input block */ - shrl $12, %eax - addl %eax, %ebx - /* Add 32K + 18 bytes of extra slack and align on a 4K boundary */ - addl $(32768 + 18 + 4095), %ebx - andl $~4095, %ebx + /* Target address to relocate to for decompression */ + addl $z_extract_offset, %ebx /* * Prepare for entering 64 bit mode @@ -224,6 +216,9 @@ ENTRY(startup_64) * If it is a relocatable kernel then decompress and run the kernel * from load address aligned to 2MB addr, otherwise decompress and * run the kernel from CONFIG_PHYSICAL_START + * + * We cannot rely on the calculation done in 32-bit mode, since we + * may have been invoked via the 64-bit entry point. */ /* Start with the delta to where the kernel will run at. */ @@ -237,17 +232,8 @@ ENTRY(startup_64) movq %rbp, %rbx #endif - /* Replace the compressed data size with the uncompressed size */ - movl input_len(%rip), %eax - subq %rax, %rbx - movl output_len(%rip), %eax - addq %rax, %rbx - /* Add 8 bytes for every 32K input block */ - shrq $12, %rax - addq %rax, %rbx - /* Add 32K + 18 bytes of extra slack and align on a 4K boundary */ - addq $(32768 + 18 + 4095), %rbx - andq $~4095, %rbx + /* Target address to relocate to for decompression */ + leaq z_extract_offset(%rbp), %rbx /* Set up the stack */ leaq boot_stack_end(%rbx), %rsp @@ -292,13 +278,12 @@ relocated: /* * Do the decompression, and jump to the new kernel.. */ - pushq %rsi # Save the real mode argument - movq %rsi, %rdi # real mode address - 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 - movq %rbp, %r8 # output + pushq %rsi /* Save the real mode argument */ + movq %rsi, %rdi /* real mode address */ + leaq boot_heap(%rip), %rsi /* malloc area for uncompression */ + leaq input_data(%rip), %rdx /* input_data */ + movl $z_input_len, %ecx /* input_len */ + movq %rbp, %r8 /* output target address */ call decompress_kernel popq %rsi |