In preparation for being able to decompress into a buffer starting at a different address than startup_32, save the calculated output address instead of recalculating it later. We now keep track of three addresses: %edx: startup_32 as we were loaded by bootloader %ebx: new location of compressed kernel %ebp: start of decompression buffer Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx> --- arch/x86/boot/compressed/head_32.S | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index 46bbe7ab4adf..894182500606 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -75,11 +75,11 @@ SYM_FUNC_START(startup_32) */ leal (BP_scratch+4)(%esi), %esp call 1f -1: popl %ebp - subl $1b, %ebp +1: popl %edx + subl $1b, %edx /* Load new GDT */ - leal gdt(%ebp), %eax + leal gdt(%edx), %eax movl %eax, 2(%eax) lgdt (%eax) @@ -92,13 +92,14 @@ SYM_FUNC_START(startup_32) movl %eax, %ss /* - * %ebp contains the address we are loaded at by the boot loader and %ebx + * %edx 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. + * for safe in-place decompression. %ebp contains the address that the kernel + * will be decompressed to. */ #ifdef CONFIG_RELOCATABLE - movl %ebp, %ebx + movl %edx, %ebx movl BP_kernel_alignment(%esi), %eax decl %eax addl %eax, %ebx @@ -110,10 +111,10 @@ SYM_FUNC_START(startup_32) movl $LOAD_PHYSICAL_ADDR, %ebx 1: + movl %ebx, %ebp // Save the output address for later /* Target address to relocate to for decompression */ - movl BP_init_size(%esi), %eax - subl $_end, %eax - addl %eax, %ebx + addl BP_init_size(%esi), %ebx + subl $_end, %ebx /* Set up the stack */ leal boot_stack_end(%ebx), %esp @@ -127,7 +128,7 @@ SYM_FUNC_START(startup_32) * where decompression in place becomes safe. */ pushl %esi - leal (_bss-4)(%ebp), %esi + leal (_bss-4)(%edx), %esi leal (_bss-4)(%ebx), %edi movl $(_bss - startup_32), %ecx shrl $2, %ecx @@ -196,9 +197,7 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) /* push arguments for extract_kernel: */ pushl $z_output_len /* decompressed length, end of relocs */ - leal _end(%ebx), %eax - subl BP_init_size(%esi), %eax - pushl %eax /* output address */ + pushl %ebp /* output address */ pushl $z_input_len /* input_len */ leal input_data(%ebx), %eax -- 2.24.1
