x86-32: Make sure the stack is set up before we use it

[mv-sheeva.git] / arch / x86 / kernel / head_32.S

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index fc293dc8dc355bd2bd0f50493edc407a0c3822ab..767d6c43de372297daffc57ef3960d5b3c2a97ac 100644 (file)
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -85,6 +85,8 @@ RESERVE_BRK(pagetables, INIT_MAP_SIZE)
  */
 __HEAD
 ENTRY(startup_32)
+       movl pa(stack_start),%ecx
+       
        /* test KEEP_SEGMENTS flag to see if the bootloader is asking
                us to not reload segments */
        testb $(1<<6), BP_loadflags(%esi)
@@ -99,7 +101,9 @@ ENTRY(startup_32)
        movl %eax,%es
        movl %eax,%fs
        movl %eax,%gs
+       movl %eax,%ss
 2:
+       leal -__PAGE_OFFSET(%ecx),%esp
 
 /*
  * Clear BSS first so that there are no surprises...
@@ -145,8 +149,6 @@ ENTRY(startup_32)
  * _brk_end is set up to point to the first "safe" location.
  * Mappings are created both at virtual address 0 (identity mapping)
  * and PAGE_OFFSET for up to _end.
- *
- * Note that the stack is not yet set up!
  */
 #ifdef CONFIG_X86_PAE
 
@@ -282,6 +284,9 @@ ENTRY(startup_32_smp)
        movl %eax,%es
        movl %eax,%fs
        movl %eax,%gs
+       movl pa(stack_start),%ecx
+       movl %eax,%ss
+       leal -__PAGE_OFFSET(%ecx),%esp
 #endif /* CONFIG_SMP */
 default_entry:
 
@@ -347,8 +352,8 @@ default_entry:
        movl %eax,%cr0          /* ..and set paging (PG) bit */
        ljmp $__BOOT_CS,$1f     /* Clear prefetch and normalize %eip */
 1:
-       /* Set up the stack pointer */
-       lss stack_start,%esp
+       /* Shift the stack pointer to a virtual address */
+       addl $__PAGE_OFFSET, %esp
 
 /*
  * Initialize eflags.  Some BIOS's leave bits like NT set.  This would
@@ -360,9 +365,7 @@ default_entry:
 
 #ifdef CONFIG_SMP
        cmpb $0, ready
-       jz  1f                          /* Initial CPU cleans BSS */
-       jmp checkCPUtype
-1:
+       jnz checkCPUtype
 #endif /* CONFIG_SMP */
 
 /*
@@ -470,14 +473,7 @@ is386:     movl $2,%ecx            # set MP
 
        cld                     # gcc2 wants the direction flag cleared at all times
        pushl $0                # fake return address for unwinder
-#ifdef CONFIG_SMP
-       movb ready, %cl
        movb $1, ready
-       cmpb $0,%cl             # the first CPU calls start_kernel
-       je   1f
-       movl (stack_start), %esp
-1:
-#endif /* CONFIG_SMP */
        jmp *(initial_code)
 
 /*
@@ -670,15 +666,15 @@ ENTRY(initial_page_table)
 #endif
 
 .data
+.balign 4
 ENTRY(stack_start)
        .long init_thread_union+THREAD_SIZE
-       .long __BOOT_DS
-
-ready: .byte 0
 
 early_recursion_flag:
        .long 0
 
+ready: .byte 0
+
 int_msg:
        .asciz "Unknown interrupt or fault at: %p %p %p\n"