[PATCH] acpi_wakeup.S: simplify logic

This simplifies logic in acpi_wakeup.S by putting code and data into
same segment. Plus it kills off-by-3 bug and uses constant instead of
hardcoded value.

diff --git a/arch/i386/kernel/acpi_wakeup.S b/arch/i386/kernel/acpi_wakeup.S
index 0f0a6c9ada43ca80a211023cd71f6601028595d0..169bac0b5db3162662e0bc44669b715c08404ee7 100644 (file)
--- a/arch/i386/kernel/acpi_wakeup.S
+++ b/arch/i386/kernel/acpi_wakeup.S
@@ -1,12 +1,21 @@
-
 .text
 #include <linux/linkage.h>
 #include <asm/segment.h>
+#include <asm/page.h>
 
-# Do we need to deal with A20?
+#
+# wakeup_code runs in real mode, and at unknown address (determined at run-time).
+# Therefore it must only use relative jumps/calls. 
+#
+# Do we need to deal with A20? It is okay: ACPI specs says A20 must be enabled
+#
+# If physical address of wakeup_code is 0x12345, BIOS should call us with
+# cs = 0x1234, eip = 0x05
+# 
 
 ALIGN
-wakeup_start:
+       .align  4096
+ENTRY(wakeup_start)
 wakeup_code:
        wakeup_code_start = .
        .code16
@@ -14,49 +23,70 @@ wakeup_code:
        movw    $0xb800, %ax
        movw    %ax,%fs
        movw    $0x0e00 + 'L', %fs:(0x10)
+
        cli
        cld
-         
+
        # setup data segment
        movw    %cs, %ax
-
-       addw    $(wakeup_data - wakeup_code) >> 4, %ax
-       movw    %ax, %ds
+       movw    %ax, %ds                                        # Make ds:0 point to wakeup_start
        movw    %ax, %ss
-       mov     $(wakeup_stack - wakeup_data), %sp              # Private stack is needed for ASUS board
-       movw    $0x0e00 + 'S', %fs:(0x12)       
+       mov     wakeup_stack - wakeup_code, %sp                 # Private stack is needed for ASUS board
+       movw    $0x0e00 + 'S', %fs:(0x12)
 
-       movl    real_magic - wakeup_data, %eax
+       pushl   $0                                              # Kill any dangerous flags
+       popfl
+
+       movl    real_magic - wakeup_code, %eax
        cmpl    $0x12345678, %eax
        jne     bogus_real_magic
 
-       mov     video_mode - wakeup_data, %ax
+#if 1
+       lcall   $0xc000,$3
+#endif
+#if 0
+       mov     video_mode - wakeup_code, %ax
        call    mode_set
+#endif
 
        # set up page table
-       movl    (real_save_cr3 - wakeup_data), %eax
+#if 1
+       movl    $swapper_pg_dir-__PAGE_OFFSET, %eax
+#else
+       movl    (real_save_cr3 - wakeup_data), %eax
+#endif
        movl    %eax, %cr3
 
        # make sure %cr4 is set correctly (features, etc)
-       movl    (real_save_cr4 - wakeup_data), %eax
+       movl    real_save_cr4 - wakeup_code, %eax
        movl    %eax, %cr4
        movw    $0xb800, %ax
        movw    %ax,%fs
        movw    $0x0e00 + 'i', %fs:(0x12)
-
+       
        # need a gdt
-       lgdt    real_save_gdt - wakeup_data
+       lgdt    real_save_gdt - wakeup_code
 
-       movl    (real_save_cr0 - wakeup_data), %eax
+       movl    real_save_cr0 - wakeup_code, %eax
        movl    %eax, %cr0
+       jmp 1f
+1:
        movw    $0x0e00 + 'n', %fs:(0x14)
 
-       movl    real_magic - wakeup_data, %eax
+       movl    real_magic - wakeup_code, %eax
        cmpl    $0x12345678, %eax
        jne     bogus_real_magic
 
        ljmpl   $__KERNEL_CS,$wakeup_pmode_return
 
+real_save_gdt: .word 0
+               .long 0
+real_save_cr0: .long 0
+real_save_cr3: .long 0
+real_save_cr4: .long 0
+real_magic:    .long 0
+video_mode:    .long 0
+
 bogus_real_magic:
        movw    $0x0e00 + 'B', %fs:(0x12)
        jmp bogus_real_magic
@@ -129,20 +159,12 @@ _setbad: jmp setbad
        .code32
        ALIGN
 
-.org   0x300
-wakeup_data:
-               .word 0
-real_save_gdt: .word 0
-               .long 0
-real_save_cr0: .long 0
-real_save_cr3: .long 0
-real_save_cr4: .long 0
-real_magic:    .long 0
-video_mode:    .long 0
 
-.org   0x500
+.org   0x2000
 wakeup_stack:
-wakeup_end:
+.org   0x3000
+ENTRY(wakeup_end)
+.org   0x4000
 
 wakeup_pmode_return:
        movl    $__KERNEL_DS, %eax
@@ -205,7 +227,6 @@ bogus_magic2:
        movw    $0x0e00 + '2', %ds:(0xb8018)
        jmp bogus_magic2
                
-
 ##
 # acpi_copy_wakeup_routine
 #
@@ -228,7 +249,7 @@ ENTRY(acpi_copy_wakeup_routine)
 
        movl    %eax, %edi
        leal    wakeup_start, %esi
-       movl    $(wakeup_end - wakeup_start) >> 2, %ecx
+       movl    $(wakeup_end - wakeup_start + 3) >> 2, %ecx
 
        rep ;  movsl
 
@@ -290,8 +311,8 @@ ENTRY(do_suspend_lowlevel)
        ret
        .p2align 4,,7
 .L1432:
-       movl $104,%eax
-       movw %eax, %ds
+       movl $__KERNEL_DS,%eax
+       movw %ax, %ds
        movl saved_context_esp, %esp
        movl saved_context_ebp, %ebp
        movl saved_context_eax, %eax
@@ -310,5 +331,4 @@ saved_gdt:  .long   0,0
 saved_idt:     .long   0,0
 saved_ldt:     .long   0
 saved_tss:     .long   0
-saved_cr0:     .long   0