[tip:x86/urgent] x86-32: Make sure the stack is set up before we use it
From: tip-bot for H. Peter Anvin
Date: Fri Feb 04 2011 - 19:34:34 EST
Commit-ID: 990957d4076354d449921b598cc8de28764cf7ed
Gitweb: http://git.kernel.org/tip/990957d4076354d449921b598cc8de28764cf7ed
Author: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 4 Feb 2011 16:14:11 -0800
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Fri, 4 Feb 2011 16:27:21 -0800
x86-32: Make sure the stack is set up before we use it
Since checkin ebba638ae723d8a8fc2f7abce5ec18b688b791d7 we call
verify_cpu even in 32-bit mode. Unfortunately, calling a function
means using the stack, and the stack pointer was not initialized in
the 32-bit setup code! This code initializes the stack pointer, and
simplifies the interface slightly since it is easier to rely on just a
pointer value rather than a descriptor; we need to have different
values for the segment register anyway.
This retains start_stack as a virtual address, even though a physical
address would be more convenient for 32 bits; the 64-bit code wants
the other way around...
Reported-by: Matthieu Castet <castet.matthieu@xxxxxxx>
LKML-Reference: <4D41E86D.8060205@xxxxxxx>
Cc: Kees Cook <kees.cook@xxxxxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/smp.h | 5 +----
arch/x86/kernel/acpi/sleep.c | 2 +-
arch/x86/kernel/head_32.S | 20 ++++++++++++--------
arch/x86/kernel/head_64.S | 1 -
arch/x86/kernel/smpboot.c | 4 ++--
5 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 4c2f63c..1f46951 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -40,10 +40,7 @@ DECLARE_EARLY_PER_CPU(u16, x86_cpu_to_apicid);
DECLARE_EARLY_PER_CPU(u16, x86_bios_cpu_apicid);
/* Static state in head.S used to set up a CPU */
-extern struct {
- void *sp;
- unsigned short ss;
-} stack_start;
+extern unsigned long stack_start; /* Initial stack pointer address */
struct smp_ops {
void (*smp_prepare_boot_cpu)(void);
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 69fd72a..4d9ebba 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -100,7 +100,7 @@ int acpi_save_state_mem(void)
#else /* CONFIG_64BIT */
header->trampoline_segment = setup_trampoline() >> 4;
#ifdef CONFIG_SMP
- stack_start.sp = temp_stack + sizeof(temp_stack);
+ stack_start = (unsigned long)temp_stack + sizeof(temp_stack);
early_gdt_descr.address =
(unsigned long)get_cpu_gdt_table(smp_processor_id());
initial_gs = per_cpu_offset(smp_processor_id());
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index fc293dc..10a6381 100644
--- 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
@@ -475,7 +480,6 @@ is386: movl $2,%ecx # set MP
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 +674,15 @@ 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"
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 239046b..1ee8493 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -264,7 +264,6 @@ ENTRY(secondary_startup_64)
ENTRY(stack_start)
.quad init_thread_union+THREAD_SIZE-8
- .word 0
__FINITDATA
bad_address:
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 0cbe8c0..03273b6 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -638,7 +638,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
* target processor state.
*/
startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
- (unsigned long)stack_start.sp);
+ stack_start);
/*
* Run STARTUP IPI loop.
@@ -785,7 +785,7 @@ do_rest:
#endif
early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
initial_code = (unsigned long)start_secondary;
- stack_start.sp = (void *) c_idle.idle->thread.sp;
+ stack_start = c_idle.idle->thread.sp;
/* start_ip had better be page-aligned! */
start_ip = setup_trampoline();
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/