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efiboot: Don't access old stack after copying a kernel. 

It's possible that the old stack is overwritten by the kernel.
This commit is contained in:
nonaka 2017-02-24 12:24:25 +00:00
parent ede9d3bf43
commit 8f1f7d8414
1 changed files with 18 additions and 17 deletions
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35
sys/arch/i386/stand/efiboot/bootia32/startprog32.S
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@ -1,4 +1,4 @@
/* $NetBSD: startprog32.S,v 1.1 2017/02/21 10:53:37 nonaka Exp $ */
/* $NetBSD: startprog32.S,v 1.2 2017/02/24 12:24:25 nonaka Exp $ */
/* NetBSD: startprog.S,v 1.4 2016/12/04 08:21:08 maxv Exp */
/*
@ -91,6 +91,9 @@ start:
cli
movl 8(%ebp), %ebx /* %ebx: entry address */
movl 36(%ebp), %edx /* %edx: loaded start address */
/* Prepare a new stack */
movl 20(%ebp), %eax /* stack */
subl $4, %eax
@ -108,12 +111,12 @@ start:
rep
movsl /* copy %ds:(%esi) -> %es:(%edi) */
cld
mov %edi, %edx /* %edx: new stack pointer */
mov %edi, %esp /* set new stack pointer */
/* Copy kernel */
movl 24(%esp), %edi /* dest */
movl 28(%esp), %esi /* src */
movl 32(%esp), %ecx /* size */
movl 24(%ebp), %edi /* dest */
movl 28(%ebp), %esi /* src */
movl 32(%ebp), %ecx /* size */
#if defined(NO_OVERLAP)
movl %ecx, %eax
#else
@ -179,20 +182,17 @@ start:
.Lcopy_done:
cld /* LynxOS depends on it */
movl 8(%ebp), %esi /* %esi: entry address */
movl 36(%ebp), %edi /* %edi: loaded start address */
/* Prepare jump address */
lea (start32a - start)(%edi), %eax
movl %eax, (start32r - start)(%edi)
lea (start32a - start)(%edx), %eax
movl %eax, (start32r - start)(%edx)
/* Setup GDT */
lea (gdt - start)(%edi), %eax
movl %eax, (gdtrr - start)(%edi)
lgdt (gdtr - start)(%edi)
lea (gdt - start)(%edx), %eax
movl %eax, (gdtrr - start)(%edx)
lgdt (gdtr - start)(%edx)
/* Jump to set %cs */
ljmp *(start32r - start)(%edi)
ljmp *(start32r - start)(%edx)
.align 4
start32a:
@ -203,7 +203,8 @@ start32a:
movw %ax, %gs
movw %ax, %ss
movl %edx, %esp
/* Already set new stack pointer */
movl %esp, %ebp
/* Disable Paging in CR0 */
movl %cr0, %eax
@ -220,8 +221,8 @@ start32a:
.align 4
start32b:
xor %eax, %eax
movl %esi, (start32r - start)(%edi)
ljmp *(start32r - start)(%edi)
movl %ebx, (start32r - start)(%edx)
ljmp *(start32r - start)(%edx)
.align 16
start32r: