x86: cleanup boot-heap usage
The kernel decompressor wrapper uses memory located beyond the
end of the image. This might lead to hard to debug problems,
but even if it can be proven to be safe, it is at the very
least unclean. I don't see any advantages either, unless you
count it not being zeroed out as an advantage. This patch
moves the boot-heap area to the bss segment.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index e8657b9..7a212a6 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -28,6 +28,7 @@
#include <asm/segment.h>
#include <asm/pgtable.h>
#include <asm/page.h>
+#include <asm/boot.h>
#include <asm/msr.h>
#include <asm/asm-offsets.h>
@@ -62,7 +63,7 @@
subl $1b, %ebp
/* setup a stack and make sure cpu supports long mode. */
- movl $user_stack_end, %eax
+ movl $boot_stack_end, %eax
addl %ebp, %eax
movl %eax, %esp
@@ -274,7 +275,7 @@
stosb
/* Setup the stack */
- leaq user_stack_end(%rip), %rsp
+ leaq boot_stack_end(%rip), %rsp
/* zero EFLAGS after setting rsp */
pushq $0
@@ -285,7 +286,7 @@
*/
pushq %rsi # Save the real mode argument
movq %rsi, %rdi # real mode address
- leaq _heap(%rip), %rsi # _heap
+ 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
@@ -310,9 +311,12 @@
.quad 0x0080890000000000 /* TS descriptor */
.quad 0x0000000000000000 /* TS continued */
gdt_end:
- .bss
-/* Stack for uncompression */
- .balign 4
-user_stack:
- .fill 4096,4,0
-user_stack_end:
+
+.bss
+/* Stack and heap for uncompression */
+.balign 4
+boot_heap:
+ .fill BOOT_HEAP_SIZE, 1, 0
+boot_stack:
+ .fill BOOT_STACK_SIZE, 1, 0
+boot_stack_end: