From: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>
Date: Tue, 7 Feb 2012 21:31:14 +0000 (+0100)
Subject: 	* grub-core/lib/i386/relocator16.S: Revert moving A20 code into PM
X-Git-Tag: 2.00~685
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=215c90cb822c1704d3b529b300a0835c4e026cd6;p=thirdparty%2Fgrub.git

	* grub-core/lib/i386/relocator16.S: Revert moving A20 code into PM
	part. Instead setup the correct stack in RM.
	* grub-core/lib/i386/relocator.c (grub_relocator16_boot): Reserve place
	for stack.
	* include/grub/i386/relocator_private.h: New file.
---

diff --git a/ChangeLog b/ChangeLog
index 313d135aa..ede7f8e1e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2012-02-07  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/lib/i386/relocator16.S: Revert moving A20 code into PM
+	part. Instead setup the correct stack in RM.
+	* grub-core/lib/i386/relocator.c (grub_relocator16_boot): Reserve place
+	for stack.
+	* include/grub/i386/relocator_private.h: New file.
+
 2012-02-05  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/commands/minicmd.c (GRUB_MOD_INIT): Add missing SIZE
diff --git a/grub-core/lib/i386/relocator.c b/grub-core/lib/i386/relocator.c
index 1f0aa0dd1..ac7d4ca4c 100644
--- a/grub-core/lib/i386/relocator.c
+++ b/grub-core/lib/i386/relocator.c
@@ -25,6 +25,7 @@
 
 #include <grub/i386/relocator.h>
 #include <grub/relocator_private.h>
+#include <grub/cpu/relocator_private.h>
 
 extern grub_uint8_t grub_relocator_forward_start;
 extern grub_uint8_t grub_relocator_forward_end;
@@ -200,8 +201,10 @@ grub_relocator16_boot (struct grub_relocator *rel,
 
   /* Put it higher than the byte it checks for A20 check.  */
   err = grub_relocator_alloc_chunk_align (rel, &ch, 0x8010,
-					  0xa0000 - RELOCATOR_SIZEOF (16),
-					  RELOCATOR_SIZEOF (16), 16,
+					  0xa0000 - RELOCATOR_SIZEOF (16)
+					  - GRUB_RELOCATOR16_STACK_SIZE,
+					  RELOCATOR_SIZEOF (16)
+					  + GRUB_RELOCATOR16_STACK_SIZE, 16,
 					  GRUB_RELOCATOR_PREFERENCE_NONE);
   if (err)
     return err;
diff --git a/grub-core/lib/i386/relocator16.S b/grub-core/lib/i386/relocator16.S
index 8500c2f94..d6c5fe5f8 100644
--- a/grub-core/lib/i386/relocator16.S
+++ b/grub-core/lib/i386/relocator16.S
@@ -26,6 +26,8 @@
 
 #define PSEUDO_REAL_DSEG 0x20
 
+#include <grub/cpu/relocator_private.h>
+
 #include "relocator_common.S"
 	
 	.p2align	4	/* force 16-byte alignment */
@@ -63,6 +65,37 @@ 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)
@@ -70,10 +103,9 @@ VARIABLE(grub_relocator16_keep_a20_enabled)
 	test	%ax, %ax
 	jnz	LOCAL(gate_a20_done)
 
-	/* first of all, test if already in a good state */
-	call	LOCAL(gate_a20_check_state)
-	testb	%al, %al
-	jz	LOCAL(gate_a20_done)
+	movw    %cs, %ax
+	movw    %ax, %ss 
+	leaw    EXT_C(grub_relocator16_end) + GRUB_RELOCATOR16_STACK_SIZE, %sp
 
 	/* second, try a BIOS call */
 	movw	$0x2400, %ax
@@ -101,14 +133,6 @@ LOCAL(gate_a20_check_state):
 	/* iterate the checking for a while */
 	movw	$100, %cx
 1:
-	call	3f
-	testb	%al, %al
-	jz	2f
-	loop	1b
-2:
-	ret
-
-3:
 	xorw    %ax, %ax
 	movw    %ax, %ds
 	decw    %ax
@@ -137,41 +161,15 @@ LOCAL(gate_a20_check_state):
 	subb	%dh, %al
 	xorb	$1, %al
 	/* restore the original */
-	movb	%dl, %es:(%di)
+	movb	%dl, %ds:(%si)
+
+	testb	%al, %al
+	jz	LOCAL(gate_a20_done)
+	loop	1b
+2:
 	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
 	 */
diff --git a/include/grub/i386/relocator_private.h b/include/grub/i386/relocator_private.h
new file mode 100644
index 000000000..b7c96a664
--- /dev/null
+++ b/include/grub/i386/relocator_private.h
@@ -0,0 +1 @@
+#define GRUB_RELOCATOR16_STACK_SIZE 4096