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authorH. Peter Anvin <hpa@zytor.com>2009-05-08 16:27:41 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-05-08 17:18:47 -0700
commit0a137736704ef9af719409933b3c33e138461786 (patch)
treeb6ca7c13de5db34de9eda7bfa7549121f4c6a855
parent5b11f1cee5797b38d16b94d8745b12b6727a8373 (diff)
x86, boot: set up the decompression stack as early as possible
Set up the decompression stack as soon as we know where it needs to go. That way we have a full-service stack as soon as possible, rather than relying on the BP_scratch field. Note that the stack does need to be empty during bss zeroing (or else the stack needs to be moved out of the bss segment, which is also an option.) [ Impact: cleanup, minor paranoia ] Signed-off-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--arch/x86/boot/compressed/head_32.S10
-rw-r--r--arch/x86/boot/compressed/head_64.S16
2 files changed, 12 insertions, 14 deletions
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 59425e157df..d7245cf8026 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -88,6 +88,9 @@ ENTRY(startup_32)
addl $4095, %ebx
andl $~4095, %ebx
+ /* Set up the stack */
+ leal boot_stack_end(%ebx), %esp
+
/*
* Copy the compressed kernel to the end of our buffer
* where decompression in place becomes safe.
@@ -122,7 +125,7 @@ ENDPROC(startup_32)
relocated:
/*
- * Clear BSS
+ * Clear BSS (stack is currently empty)
*/
xorl %eax, %eax
leal _bss(%ebx), %edi
@@ -132,11 +135,6 @@ relocated:
rep stosb
/*
- * Setup the stack for the decompressor
- */
- leal boot_stack_end(%ebx), %esp
-
-/*
* Do the decompression, and jump to the new kernel..
*/
movl output_len(%ebx), %eax
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 5bc9052615b..a0b18426069 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -249,6 +249,13 @@ ENTRY(startup_64)
addq $(32768 + 18 + 4095), %rbx
andq $~4095, %rbx
+ /* 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.
@@ -273,7 +280,7 @@ ENTRY(startup_64)
relocated:
/*
- * Clear BSS
+ * Clear BSS (stack is currently empty)
*/
xorq %rax, %rax
leaq _bss(%rbx), %rdi
@@ -282,13 +289,6 @@ relocated:
cld
rep stosb
- /* Setup the stack */
- leaq boot_stack_end(%rip), %rsp
-
- /* zero EFLAGS after setting rsp */
- pushq $0
- popfq
-
/*
* Do the decompression, and jump to the new kernel..
*/