/*
* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
*/
-.code32
-.text
+ .code32
+ .text
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/processor-flags.h>
#include <asm/asm-offsets.h>
-.section ".text.head"
+ .section ".text.head"
.code32
ENTRY(startup_32)
cld
- /* test KEEP_SEGMENTS flag to see if the bootloader is asking
- * us to not reload segments */
+ /*
+ * Test KEEP_SEGMENTS flag to see if the bootloader is asking
+ * us to not reload segments
+ */
testb $(1<<6), BP_loadflags(%esi)
jnz 1f
movl %eax, %ss
1:
-/* Calculate the delta between where we were compiled to run
+/*
+ * 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 (0x1e4+4)(%esi), %esp
+ leal (BP_scratch+4)(%esi), %esp
call 1f
1: popl %ebp
subl $1b, %ebp
testl %eax, %eax
jnz no_longmode
-/* Compute the delta between where we were compiled to run at
+/*
+ * Compute the delta between where we were compiled to run at
* and where the code will actually run at.
- */
-/* %ebp contains the address we are loaded at by the boot loader and %ebx
+ *
+ * %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.
*/
/*
* Build early 4G boot pagetable
*/
- /* Initialize Page tables to 0*/
+ /* Initialize Page tables to 0 */
leal pgtable(%ebx), %edi
xorl %eax, %eax
movl $((4096*6)/4), %ecx
btsl $_EFER_LME, %eax
wrmsr
- /* Setup for the jump to 64bit mode
+ /*
+ * Setup for the jump to 64bit mode
*
* When the jump is performend we will be in long mode but
* in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1
#include "../../kernel/verify_cpu_64.S"
- /* Be careful here startup_64 needs to be at a predictable
+ /*
+ * Be careful here startup_64 needs to be at a predictable
* address so I can export it in an ELF header. Bootloaders
* should look at the ELF header to find this address, as
* it may change in the future.
.code64
.org 0x200
ENTRY(startup_64)
- /* We come here either from startup_32 or directly from a
+ /*
+ * We come here either from startup_32 or directly from a
* 64bit bootloader. If we come here from a bootloader we depend on
* an identity mapped page table being provied that maps our
* entire text+data+bss and hopefully all of memory.
movl $0x20, %eax
ltr %ax
- /* Compute the decompressed kernel start address. It is where
+ /*
+ * Compute the decompressed kernel start address. It is where
* we were loaded at aligned to a 2M boundary. %rbp contains the
* decompressed kernel start address.
*
addq $(32768 + 18 + 4095), %rbx
andq $~4095, %rbx
-/* Copy the compressed kernel to the end of our buffer
+ /* Set up the stack */
+ leaq boot_stack_end(%rbx), %rsp
+
+ /* Zero EFLAGS */
+ pushq $0
+ popfq
+
+/*
+ * Copy the compressed kernel to the end of our buffer
* where decompression in place becomes safe.
*/
- leaq _end_before_pgt(%rip), %r8
- leaq _end_before_pgt(%rbx), %r9
- movq $_end_before_pgt /* - $startup_32 */, %rcx
-1: subq $8, %r8
- subq $8, %r9
- movq 0(%r8), %rax
- movq %rax, 0(%r9)
- subq $8, %rcx
- jnz 1b
+ pushq %rsi
+ leaq (_bss-8)(%rip), %rsi
+ leaq (_bss-8)(%rbx), %rdi
+ movq $_bss /* - $startup_32 */, %rcx
+ shrq $3, %rcx
+ std
+ rep movsq
+ cld
+ popq %rsi
/*
* Jump to the relocated address.
leaq relocated(%rbx), %rax
jmp *%rax
-.section ".text"
+ .text
relocated:
/*
- * Clear BSS
+ * Clear BSS (stack is currently empty)
*/
- xorq %rax, %rax
- leaq _edata(%rbx), %rdi
- leaq _end_before_pgt(%rbx), %rcx
+ xorl %eax, %eax
+ leaq _bss(%rip), %rdi
+ leaq _ebss(%rip), %rcx
subq %rdi, %rcx
- cld
- rep
- stosb
-
- /* Setup the stack */
- leaq boot_stack_end(%rip), %rsp
-
- /* zero EFLAGS after setting rsp */
- pushq $0
- popfq
+ shrq $3, %rcx
+ rep stosq
/*
* Do the decompression, and jump to the new kernel..
.quad 0x0000000000000000 /* TS continued */
gdt_end:
-.bss
-/* Stack and heap for uncompression */
-.balign 4
+/*
+ * 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:
+
+/*
+ * Space for page tables (not in .bss so not zeroed)
+ */
+ .section ".pgtable","a",@nobits
+ .balign 4096
+pgtable:
+ .fill 6*4096, 1, 0
git.openpandora.org / pandora-kernel.git / blobdiff