Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
x86, reboot: Fix relocations in reboot_32.S
The use of base for %ebx in this file is arbitrary, *except* that we
also use it to compute the real-mode segment. Therefore, make it so
that r_base really is the true address to which %ebx points.
This resolves kernel bugzilla 33302.
Reported-and-tested-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-08os5wi3yq1no0y4i5m4z7he@git.kernel.org
+6
-6
arch/x86/kernel/reboot_32.S
+6
-6
arch/x86/kernel/reboot_32.S
···
21
/* Get our own relocated address */
22
call 1f
23
1: popl %ebx
24
-
subl $1b, %ebx
25
26
/* Compute the equivalent real-mode segment */
27
movl %ebx, %ecx
28
shrl $4, %ecx
29
30
/* Patch post-real-mode segment jump */
31
-
movw dispatch_table(%ebx,%eax,2),%ax
32
-
movw %ax, 101f(%ebx)
33
-
movw %cx, 102f(%ebx)
34
35
/* Set up the IDT for real mode. */
36
-
lidtl machine_real_restart_idt(%ebx)
37
38
/*
39
* Set up a GDT from which we can load segment descriptors for real
40
* mode. The GDT is not used in real mode; it is just needed here to
41
* prepare the descriptors.
42
*/
43
-
lgdtl machine_real_restart_gdt(%ebx)
44
45
/*
46
* Load the data segment registers with 16-bit compatible values
···
21
/* Get our own relocated address */
22
call 1f
23
1: popl %ebx
24
+
subl $(1b - r_base), %ebx
25
26
/* Compute the equivalent real-mode segment */
27
movl %ebx, %ecx
28
shrl $4, %ecx
29
30
/* Patch post-real-mode segment jump */
31
+
movw (dispatch_table - r_base)(%ebx,%eax,2),%ax
32
+
movw %ax, (101f - r_base)(%ebx)
33
+
movw %cx, (102f - r_base)(%ebx)
34
35
/* Set up the IDT for real mode. */
36
+
lidtl (machine_real_restart_idt - r_base)(%ebx)
37
38
/*
39
* Set up a GDT from which we can load segment descriptors for real
40
* mode. The GDT is not used in real mode; it is just needed here to
41
* prepare the descriptors.
42
*/
43
+
lgdtl (machine_real_restart_gdt - r_base)(%ebx)
44
45
/*
46
* Load the data segment registers with 16-bit compatible values