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OpenCloudOS-Kernel
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x86, boot: stylistic cleanups for boot/compressed/head_64.S 

Clean up style issues in arch/x86/boot/compressed/head_64.S.  This
file had a lot fewer style issues than its 32-bit cousin, but the ones
it has are worth fixing, especially since it makes the two files more
similar.

[ Impact: cleanup, no object code change ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin 2009-05-08 15:59:13 -07:00
parent 5f64ec64e7
commit b40d68d5b5
1 changed files with 31 additions and 21 deletions
arch/x86/boot/compressed
head_64.S

52
arch/x86/boot/compressed/head_64.S
View File

@ -21,8 +21,8 @@
/* /*
* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
*/ */
.code32 .code32
.text .text
#include <linux/linkage.h> #include <linux/linkage.h>
#include <asm/segment.h> #include <asm/segment.h>
@ -33,12 +33,14 @@
#include <asm/processor-flags.h> #include <asm/processor-flags.h>
#include <asm/asm-offsets.h> #include <asm/asm-offsets.h>
.section ".text.head" .section ".text.head"
.code32 .code32
ENTRY(startup_32) ENTRY(startup_32)
cld 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) testb $(1<<6), BP_loadflags(%esi)
jnz 1f jnz 1f
@ -49,7 +51,8 @@ ENTRY(startup_32)
movl %eax, %ss movl %eax, %ss
1: 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 * 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 * 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 * address we are running at. The reserved chunk of the real-mode
@ -70,10 +73,11 @@ ENTRY(startup_32)
testl %eax, %eax testl %eax, %eax
jnz no_longmode 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. * 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 * contains the address where we should move the kernel image temporarily
* for safe in-place decompression. * for safe in-place decompression.
*/ */
@ -114,7 +118,7 @@ ENTRY(startup_32)
/* /*
* Build early 4G boot pagetable * Build early 4G boot pagetable
*/ */
/* Initialize Page tables to 0*/ /* Initialize Page tables to 0 */
leal pgtable(%ebx), %edi leal pgtable(%ebx), %edi
xorl %eax, %eax xorl %eax, %eax
movl $((4096*6)/4), %ecx movl $((4096*6)/4), %ecx
@ -155,7 +159,8 @@ ENTRY(startup_32)
btsl $_EFER_LME, %eax btsl $_EFER_LME, %eax
wrmsr 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 * 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 * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1
@ -184,7 +189,8 @@ no_longmode:
#include "../../kernel/verify_cpu_64.S" #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 * address so I can export it in an ELF header. Bootloaders
* should look at the ELF header to find this address, as * should look at the ELF header to find this address, as
* it may change in the future. * it may change in the future.
@ -192,7 +198,8 @@ no_longmode:
.code64 .code64
.org 0x200 .org 0x200
ENTRY(startup_64) 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 * 64bit bootloader. If we come here from a bootloader we depend on
* an identity mapped page table being provied that maps our * an identity mapped page table being provied that maps our
* entire text+data+bss and hopefully all of memory. * entire text+data+bss and hopefully all of memory.
@ -209,7 +216,8 @@ ENTRY(startup_64)
movl $0x20, %eax movl $0x20, %eax
ltr %ax 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 * we were loaded at aligned to a 2M boundary. %rbp contains the
* decompressed kernel start address. * decompressed kernel start address.
* *
@ -241,7 +249,8 @@ ENTRY(startup_64)
addq $(32768 + 18 + 4095), %rbx addq $(32768 + 18 + 4095), %rbx
andq $~4095, %rbx andq $~4095, %rbx
/* Copy the compressed kernel to the end of our buffer /*
* Copy the compressed kernel to the end of our buffer
* where decompression in place becomes safe. * where decompression in place becomes safe.
*/ */
leaq _end_before_pgt(%rip), %r8 leaq _end_before_pgt(%rip), %r8
@ -260,7 +269,7 @@ ENTRY(startup_64)
leaq relocated(%rbx), %rax leaq relocated(%rbx), %rax
jmp *%rax jmp *%rax
.section ".text" .text
relocated: relocated:
/* /*
@ -271,8 +280,7 @@ relocated:
leaq _end_before_pgt(%rbx), %rcx leaq _end_before_pgt(%rbx), %rcx
subq %rdi, %rcx subq %rdi, %rcx
cld cld
rep rep stosb
stosb
/* Setup the stack */ /* Setup the stack */
leaq boot_stack_end(%rip), %rsp leaq boot_stack_end(%rip), %rsp
@ -311,9 +319,11 @@ gdt:
.quad 0x0000000000000000 /* TS continued */ .quad 0x0000000000000000 /* TS continued */
gdt_end: gdt_end:
.bss /*
/* Stack and heap for uncompression */ * Stack and heap for uncompression
.balign 4 */
.bss
.balign 4
boot_heap: boot_heap:
.fill BOOT_HEAP_SIZE, 1, 0 .fill BOOT_HEAP_SIZE, 1, 0
boot_stack: boot_stack: