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* grub-core/lib/i386/relocator16.S (grub_relocator16_start): Move switch

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to real mode down to execute A20-related code in protected mode as
	intended.
This commit is contained in:
Vladimir 'phcoder' Serbinenko 2012-02-05 10:12:18 +01:00
parent eb6e664936
commit a51dab1328
2 changed files with 37 additions and 31 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
2012-02-05 Vladimir Serbinenko <phcoder@gmail.com>
* grub-core/lib/i386/relocator16.S (grub_relocator16_start): Move switch
to real mode down to execute A20-related code in protected mode as
intended.
2012-02-05 Grégoire Sutre <gregoire.sutre@gmail.com>
* grub-core/disk/diskfilter.c (grub_diskfilter_make_raid): Return

62
grub-core/lib/i386/relocator16.S
View file

@ -63,37 +63,6 @@ VARIABLE(grub_relocator16_start)
andl $(~GRUB_MEMORY_CPU_CR4_PAE_ON), %eax
movl %eax, %cr4
/* Update other registers. */
movl $PSEUDO_REAL_DSEG, %eax
movl %eax, %ds
movl %eax, %es
movl %eax, %fs
movl %eax, %gs
movl %eax, %ss
movl %esi, %eax
shrl $4, %eax
movw %ax, (LOCAL (segment) - LOCAL (base)) (%esi, 1)
/* jump to a 16 bit segment */
ljmp $PSEUDO_REAL_CSEG, $(LOCAL (cont2) - LOCAL(base))
LOCAL(cont2):
.code16
/* clear the PE bit of CR0 */
movl %cr0, %eax
andl $(~GRUB_MEMORY_CPU_CR0_PE_ON), %eax
movl %eax, %cr0
/* flush prefetch queue, reload %cs */
/* ljmp */
.byte 0xea
.word LOCAL(cont3)-LOCAL(base)
LOCAL(segment):
.word 0
LOCAL(cont3):
/* movw imm16, %ax. */
.byte 0xb8
VARIABLE(grub_relocator16_keep_a20_enabled)
@ -172,6 +141,37 @@ LOCAL(gate_a20_check_state):
ret
LOCAL(gate_a20_done):
/* Update other registers. */
movl $PSEUDO_REAL_DSEG, %eax
movl %eax, %ds
movl %eax, %es
movl %eax, %fs
movl %eax, %gs
movl %eax, %ss
movl %esi, %eax
shrl $4, %eax
movw %ax, (LOCAL (segment) - LOCAL (base)) (%esi, 1)
/* jump to a 16 bit segment */
ljmp $PSEUDO_REAL_CSEG, $(LOCAL (cont2) - LOCAL(base))
LOCAL(cont2):
.code16
/* clear the PE bit of CR0 */
movl %cr0, %eax
andl $(~GRUB_MEMORY_CPU_CR0_PE_ON), %eax
movl %eax, %cr0
/* flush prefetch queue, reload %cs */
/* ljmp */
.byte 0xea
.word LOCAL(cont3)-LOCAL(base)
LOCAL(segment):
.word 0
LOCAL(cont3):
/* we are in real mode now
* set up the real mode segment registers : DS, SS, ES
*/