[RFC] [PATCH 10/16] x86_64: 64bit PIC ACPI wakeup

From: Vivek Goyal
Date: Mon Nov 13 2006 - 11:57:48 EST



- Killed lots of dead code
- Improve the cpu sanity checks to verify long mode
is enabled when we wake up.
- Removed the need for modifying any existing kernel page table.
- Moved wakeup_level4_pgt into the wakeup routine so we can
run the kernel above 4G.
- Increased the size of the wakeup routine to 8K.
- Renamed the variables to use the 64bit register names.
- Lots of misc cleanups to match trampoline.S

I don't have a configuration I can test this but it compiles cleanly
and it should work, the code is very similar to the SMP trampoline,
which I have tested. At least now the comments about still running in
low memory are actually correct.

Vivek has tested this patch for suspend to memory and it works fine.

Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---

arch/x86_64/kernel/acpi/sleep.c | 19 --
arch/x86_64/kernel/acpi/wakeup.S | 329 +++++++++++++++++----------------------
arch/x86_64/kernel/head.S | 9 -
include/asm-x86_64/suspend.h | 12 -
4 files changed, 153 insertions(+), 216 deletions(-)

diff -puN arch/x86_64/kernel/acpi/sleep.c~x86_64-64bit-PIC-ACPI-wakeup arch/x86_64/kernel/acpi/sleep.c
--- linux-2.6.19-rc5-reloc/arch/x86_64/kernel/acpi/sleep.c~x86_64-64bit-PIC-ACPI-wakeup 2006-11-09 22:59:48.000000000 -0500
+++ linux-2.6.19-rc5-reloc-root/arch/x86_64/kernel/acpi/sleep.c 2006-11-09 22:59:48.000000000 -0500
@@ -60,17 +60,6 @@ extern char wakeup_start, wakeup_end;

extern unsigned long FASTCALL(acpi_copy_wakeup_routine(unsigned long));

-static pgd_t low_ptr;
-
-static void init_low_mapping(void)
-{
- pgd_t *slot0 = pgd_offset(current->mm, 0UL);
- low_ptr = *slot0;
- set_pgd(slot0, *pgd_offset(current->mm, PAGE_OFFSET));
- WARN_ON(num_online_cpus() != 1);
- local_flush_tlb();
-}
-
/**
* acpi_save_state_mem - save kernel state
*
@@ -79,8 +68,6 @@ static void init_low_mapping(void)
*/
int acpi_save_state_mem(void)
{
- init_low_mapping();
-
memcpy((void *)acpi_wakeup_address, &wakeup_start,
&wakeup_end - &wakeup_start);
acpi_copy_wakeup_routine(acpi_wakeup_address);
@@ -93,8 +80,6 @@ int acpi_save_state_mem(void)
*/
void acpi_restore_state_mem(void)
{
- set_pgd(pgd_offset(current->mm, 0UL), low_ptr);
- local_flush_tlb();
}

/**
@@ -107,8 +92,8 @@ void acpi_restore_state_mem(void)
*/
void __init acpi_reserve_bootmem(void)
{
- acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE);
- if ((&wakeup_end - &wakeup_start) > PAGE_SIZE)
+ acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE*2);
+ if ((&wakeup_end - &wakeup_start) > (PAGE_SIZE*2))
printk(KERN_CRIT
"ACPI: Wakeup code way too big, will crash on attempt to suspend\n");
}
diff -puN arch/x86_64/kernel/acpi/wakeup.S~x86_64-64bit-PIC-ACPI-wakeup arch/x86_64/kernel/acpi/wakeup.S
--- linux-2.6.19-rc5-reloc/arch/x86_64/kernel/acpi/wakeup.S~x86_64-64bit-PIC-ACPI-wakeup 2006-11-09 22:59:48.000000000 -0500
+++ linux-2.6.19-rc5-reloc-root/arch/x86_64/kernel/acpi/wakeup.S 2006-11-09 22:59:48.000000000 -0500
@@ -1,6 +1,7 @@
.text
#include <linux/linkage.h>
#include <asm/segment.h>
+#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/msr.h>

@@ -15,7 +16,6 @@
# cs = 0x1234, eip = 0x05
#

-
ALIGN
.align 16
ENTRY(wakeup_start)
@@ -30,22 +30,25 @@ wakeup_code:
cld
# setup data segment
movw %cs, %ax
- movw %ax, %ds # Make ds:0 point to wakeup_start
+ movw %ax, %ds # Make ds:0 point to wakeup_start
movw %ax, %ss
- mov $(wakeup_stack - wakeup_code), %sp # Private stack is needed for ASUS board
+ # Private stack is needed for ASUS board
+ mov $(wakeup_stack - wakeup_code), %sp

- pushl $0 # Kill any dangerous flags
+ pushl $0 # Kill any dangerous flags
popfl

movl real_magic - wakeup_code, %eax
cmpl $0x12345678, %eax
jne bogus_real_magic

+ call verify_cpu # Verify the cpu supports long mode
+
testl $1, video_flags - wakeup_code
jz 1f
lcall $0xc000,$3
movw %cs, %ax
- movw %ax, %ds # Bios might have played with that
+ movw %ax, %ds # Bios might have played with that
movw %ax, %ss
1:

@@ -60,13 +63,17 @@ wakeup_code:
movw $0x0e00 + 'L', %fs:(0x10)

movb $0xa2, %al ; outb %al, $0x80
+
+ mov %ds, %ax # Find 32bit wakeup_code address
+ movzx %ax, %esi # (Convert %ds:gdt to a linear ptr)
+ shll $4, %esi
+
+ # Fixup the vectors
+ addl %esi, wakeup_32_vector - wakeup_code
+ addl %esi, wakeup_long64_vector - wakeup_code
+ addl %esi, gdt_48a + 2 - wakeup_code # Fixup the gdt pointer

- lidt %ds:idt_48a - wakeup_code
- xorl %eax, %eax
- movw %ds, %ax # (Convert %ds:gdt to a linear ptr)
- shll $4, %eax
- addl $(gdta - wakeup_code), %eax
- movl %eax, gdt_48a +2 - wakeup_code
+ lidtl %ds:idt_48a - wakeup_code
lgdtl %ds:gdt_48a - wakeup_code # load gdt with whatever is
# appropriate

@@ -75,85 +82,47 @@ wakeup_code:
jmp 1f
1:

- .byte 0x66, 0xea # prefix + jmpi-opcode
- .long wakeup_32 - __START_KERNEL_map
- .word __KERNEL_CS
+ ljmpl *(wakeup_32_vector - wakeup_code)
+
+ .balign 4
+wakeup_32_vector:
+ .long wakeup_32 - wakeup_code
+ .word __KERNEL32_CS, 0

.code32
wakeup_32:
# Running in this code, but at low address; paging is not yet turned on.
movb $0xa5, %al ; outb %al, $0x80

- /* Check if extended functions are implemented */
- movl $0x80000000, %eax
- cpuid
- cmpl $0x80000000, %eax
- jbe bogus_cpu
- wbinvd
- mov $0x80000001, %eax
- cpuid
- btl $29, %edx
- jnc bogus_cpu
- movl %edx,%edi
-
- movw $__KERNEL_DS, %ax
- movw %ax, %ds
- movw %ax, %es
- movw %ax, %fs
- movw %ax, %gs
-
- movw $__KERNEL_DS, %ax
- movw %ax, %ss
+ /* Initialize segments */
+ movl $__KERNEL_DS, %eax
+ movl %eax, %ds

- mov $(wakeup_stack - __START_KERNEL_map), %esp
- movl saved_magic - __START_KERNEL_map, %eax
- cmpl $0x9abcdef0, %eax
- jne bogus_32_magic
+ movw $0x0e00 + 'i', %ds:(0xb8012)
+ movb $0xa8, %al ; outb %al, $0x80;

/*
* Prepare for entering 64bits mode
*/

- /* Enable PAE mode and PGE */
+ /* Enable PAE */
xorl %eax, %eax
btsl $5, %eax
- btsl $7, %eax
movl %eax, %cr4

/* Setup early boot stage 4 level pagetables */
- movl $(wakeup_level4_pgt - __START_KERNEL_map), %eax
+ leal (wakeup_level4_pgt - wakeup_code)(%esi), %eax
movl %eax, %cr3

- /* Setup EFER (Extended Feature Enable Register) */
- movl $MSR_EFER, %ecx
- rdmsr
- /* Fool rdmsr and reset %eax to avoid dependences */
- xorl %eax, %eax
/* Enable Long Mode */
- btsl $_EFER_LME, %eax
- /* Enable System Call */
- btsl $_EFER_SCE, %eax
-
- /* No Execute supported? */
- btl $20,%edi
- jnc 1f
- btsl $_EFER_NX, %eax
-1:
-
- /* Make changes effective */
+ movl $MSR_EFER, %ecx
+ movl $(1 << _EFER_LME), %eax # Enable Long Mode
+ xorl %edx, %edx
wrmsr
- wbinvd

xorl %eax, %eax
btsl $31, %eax /* Enable paging and in turn activate Long Mode */
btsl $0, %eax /* Enable protected mode */
- btsl $1, %eax /* Enable MP */
- btsl $4, %eax /* Enable ET */
- btsl $5, %eax /* Enable NE */
- btsl $16, %eax /* Enable WP */
- btsl $18, %eax /* Enable AM */
-
- /* Make changes effective */
movl %eax, %cr0
/* At this point:
CR4.PAE must be 1
@@ -162,11 +131,6 @@ wakeup_32:
Next instruction must be a branch
This must be on identity-mapped page
*/
- jmp reach_compatibility_mode
-reach_compatibility_mode:
- movw $0x0e00 + 'i', %ds:(0xb8012)
- movb $0xa8, %al ; outb %al, $0x80;
-
/*
* At this point we're in long mode but in 32bit compatibility mode
* with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
@@ -174,20 +138,13 @@ reach_compatibility_mode:
* the new gdt/idt that has __KERNEL_CS with CS.L = 1.
*/

- movw $0x0e00 + 'n', %ds:(0xb8014)
- movb $0xa9, %al ; outb %al, $0x80
-
- /* Load new GDT with the 64bit segment using 32bit descriptor */
- movl $(pGDT32 - __START_KERNEL_map), %eax
- lgdt (%eax)
-
- movl $(wakeup_jumpvector - __START_KERNEL_map), %eax
/* Finally jump in 64bit mode */
- ljmp *(%eax)
+ ljmp *(wakeup_long64_vector - wakeup_code)(%esi)

-wakeup_jumpvector:
- .long wakeup_long64 - __START_KERNEL_map
- .word __KERNEL_CS
+ .balign 4
+wakeup_long64_vector:
+ .long wakeup_long64 - wakeup_code
+ .word __KERNEL_CS, 0

.code64

@@ -199,10 +156,18 @@ wakeup_long64:
* addresses where we're currently running on. We have to do that here
* because in 32bit we couldn't load a 64bit linear address.
*/
- lgdt cpu_gdt_descr - __START_KERNEL_map
+ lgdt cpu_gdt_descr
+
+ movw $0x0e00 + 'n', %ds:(0xb8014)
+ movb $0xa9, %al ; outb %al, $0x80
+
+ movq saved_magic, %rax
+ movq $0x123456789abcdef0, %rdx
+ cmpq %rdx, %rax
+ jne bogus_64_magic

movw $0x0e00 + 'u', %ds:(0xb8016)
-
+
nop
nop
movw $__KERNEL_DS, %ax
@@ -211,16 +176,16 @@ wakeup_long64:
movw %ax, %es
movw %ax, %fs
movw %ax, %gs
- movq saved_esp, %rsp
+ movq saved_rsp, %rsp

movw $0x0e00 + 'x', %ds:(0xb8018)
- movq saved_ebx, %rbx
- movq saved_edi, %rdi
- movq saved_esi, %rsi
- movq saved_ebp, %rbp
+ movq saved_rbx, %rbx
+ movq saved_rdi, %rdi
+ movq saved_rsi, %rsi
+ movq saved_rbp, %rbp

movw $0x0e00 + '!', %ds:(0xb801a)
- movq saved_eip, %rax
+ movq saved_rip, %rax
jmp *%rax

.code32
@@ -228,25 +193,10 @@ wakeup_long64:
.align 64
gdta:
.word 0, 0, 0, 0 # dummy
-
- .word 0, 0, 0, 0 # unused
-
- .word 0xFFFF # 4Gb - (0x100000*0x1000 = 4Gb)
- .word 0 # base address = 0
- .word 0x9B00 # code read/exec. ??? Why I need 0x9B00 (as opposed to 0x9A00 in order for this to work?)
- .word 0x00CF # granularity = 4096, 386
- # (+5th nibble of limit)
-
- .word 0xFFFF # 4Gb - (0x100000*0x1000 = 4Gb)
- .word 0 # base address = 0
- .word 0x9200 # data read/write
- .word 0x00CF # granularity = 4096, 386
- # (+5th nibble of limit)
-# this is 64bit descriptor for code
- .word 0xFFFF
- .word 0
- .word 0x9A00 # code read/exec
- .word 0x00AF # as above, but it is long mode and with D=0
+ /* ??? Why I need the accessed bit set in order for this to work? */
+ .quad 0x00cf9b000000ffff # __KERNEL32_CS
+ .quad 0x00af9b000000ffff # __KERNEL_CS
+ .quad 0x00cf93000000ffff # __KERNEL_DS

idt_48a:
.word 0 # idt limit = 0
@@ -255,30 +205,24 @@ idt_48a:
gdt_48a:
.word 0x8000 # gdt limit=2048,
# 256 GDT entries
- .word 0, 0 # gdt base (filled in later)
-
-
+ .long gdta - wakeup_code # gdt base (relocated in later)
+
+
real_save_gdt: .word 0
.quad 0
real_magic: .quad 0
video_mode: .quad 0
video_flags: .quad 0

+.code16
bogus_real_magic:
movb $0xba,%al ; outb %al,$0x80
jmp bogus_real_magic

-bogus_32_magic:
+.code64
+bogus_64_magic:
movb $0xb3,%al ; outb %al,$0x80
- jmp bogus_32_magic
-
-bogus_31_magic:
- movb $0xb1,%al ; outb %al,$0x80
- jmp bogus_31_magic
-
-bogus_cpu:
- movb $0xbc,%al ; outb %al,$0x80
- jmp bogus_cpu
+ jmp bogus_64_magic


/* This code uses an extended set of video mode numbers. These include:
@@ -301,6 +245,7 @@ bogus_cpu:
#define VIDEO_FIRST_V7 0x0900

# Setting of user mode (AX=mode ID) => CF=success
+.code16
mode_seta:
movw %ax, %bx
#if 0
@@ -346,14 +291,59 @@ check_vesaa:

_setbada: jmp setbada

- .code64
-bogus_magic:
- movw $0x0e00 + 'B', %ds:(0xb8018)
- jmp bogus_magic
-
-bogus_magic2:
- movw $0x0e00 + '2', %ds:(0xb8018)
- jmp bogus_magic2
+ .code16
+verify_cpu:
+ pushl $0 # Kill any dangerous flags
+ popfl
+
+ /* minimum CPUID flags for x86-64 */
+ /* see http://www.x86-64.org/lists/discuss/msg02971.html */
+#define REQUIRED_MASK1 ((1<<0)|(1<<3)|(1<<4)|(1<<5)|(1<<6)|(1<<8)|\
+ (1<<13)|(1<<15)|(1<<24)|(1<<25)|(1<<26))
+#define REQUIRED_MASK2 (1<<29)
+
+ pushfl # check for cpuid
+ popl %eax
+ movl %eax, %ebx
+ xorl $0x200000,%eax
+ pushl %eax
+ popfl
+ pushfl
+ popl %eax
+ pushl %ebx
+ popfl
+ cmpl %eax, %ebx
+ jz no_longmode
+
+ xorl %eax, %eax # See if cpuid 1 is implemented
+ cpuid
+ cmpl $0x1, %eax
+ jb no_longmode
+
+ movl $0x01, %eax # Does the cpu have what it takes?
+ cpuid
+ andl $REQUIRED_MASK1, %edx
+ xorl $REQUIRED_MASK1, %edx
+ jnz no_longmode
+
+ movl $0x80000000, %eax # See if extended cpuid is implemented
+ cpuid
+ cmpl $0x80000001, %eax
+ jb no_longmode
+
+ movl $0x80000001, %eax # Does the cpu have what it takes?
+ cpuid
+ andl $REQUIRED_MASK2, %edx
+ xorl $REQUIRED_MASK2, %edx
+ jnz no_longmode
+
+ ret # The cpu supports long mode
+
+no_longmode:
+ movb $0xbc,%al ; outb %al,$0x80
+ jmp no_longmode
+
+ ret


wakeup_stack_begin: # Stack grows down
@@ -361,7 +351,15 @@ wakeup_stack_begin: # Stack grows down
.org 0xff0
wakeup_stack: # Just below end of page

+.org 0x1000
+ENTRY(wakeup_level4_pgt)
+ .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+ .fill 510,8,0
+ /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
+ .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
+
ENTRY(wakeup_end)
+ .code64

##
# acpi_copy_wakeup_routine
@@ -378,23 +376,6 @@ ENTRY(acpi_copy_wakeup_routine)
pushq %rcx
pushq %rdx

- sgdt saved_gdt
- sidt saved_idt
- sldt saved_ldt
- str saved_tss
-
- movq %cr3, %rdx
- movq %rdx, saved_cr3
- movq %cr4, %rdx
- movq %rdx, saved_cr4
- movq %cr0, %rdx
- movq %rdx, saved_cr0
- sgdt real_save_gdt - wakeup_start (,%rdi)
- movl $MSR_EFER, %ecx
- rdmsr
- movl %eax, saved_efer
- movl %edx, saved_efer2
-
movl saved_video_mode, %edx
movl %edx, video_mode - wakeup_start (,%rdi)
movl acpi_video_flags, %edx
@@ -403,18 +384,11 @@ ENTRY(acpi_copy_wakeup_routine)
movq $0x123456789abcdef0, %rdx
movq %rdx, saved_magic

- movl saved_magic - __START_KERNEL_map, %eax
- cmpl $0x9abcdef0, %eax
- jne bogus_32_magic
-
- # make sure %cr4 is set correctly (features, etc)
- movl saved_cr4 - __START_KERNEL_map, %eax
- movq %rax, %cr4
-
- movl saved_cr0 - __START_KERNEL_map, %eax
- movq %rax, %cr0
- jmp 1f # Flush pipelines
-1:
+ movq saved_magic, %rax
+ movq $0x123456789abcdef0, %rdx
+ cmpq %rdx, %rax
+ jne bogus_64_magic
+
# restore the regs we used
popq %rdx
popq %rcx
@@ -450,13 +424,13 @@ do_suspend_lowlevel:
movq %r15, saved_context_r15(%rip)
pushfq ; popq saved_context_eflags(%rip)

- movq $.L97, saved_eip(%rip)
+ movq $.L97, saved_rip(%rip)

- movq %rsp,saved_esp
- movq %rbp,saved_ebp
- movq %rbx,saved_ebx
- movq %rdi,saved_edi
- movq %rsi,saved_esi
+ movq %rsp,saved_rsp
+ movq %rbp,saved_rbp
+ movq %rbx,saved_rbx
+ movq %rdi,saved_rdi
+ movq %rsi,saved_rsi

addq $8, %rsp
movl $3, %edi
@@ -503,25 +477,12 @@ do_suspend_lowlevel:

.data
ALIGN
-ENTRY(saved_ebp) .quad 0
-ENTRY(saved_esi) .quad 0
-ENTRY(saved_edi) .quad 0
-ENTRY(saved_ebx) .quad 0
+ENTRY(saved_rbp) .quad 0
+ENTRY(saved_rsi) .quad 0
+ENTRY(saved_rdi) .quad 0
+ENTRY(saved_rbx) .quad 0

-ENTRY(saved_eip) .quad 0
-ENTRY(saved_esp) .quad 0
+ENTRY(saved_rip) .quad 0
+ENTRY(saved_rsp) .quad 0

ENTRY(saved_magic) .quad 0
-
-ALIGN
-# saved registers
-saved_gdt: .quad 0,0
-saved_idt: .quad 0,0
-saved_ldt: .quad 0
-saved_tss: .quad 0
-
-saved_cr0: .quad 0
-saved_cr3: .quad 0
-saved_cr4: .quad 0
-saved_efer: .quad 0
-saved_efer2: .quad 0
diff -puN arch/x86_64/kernel/head.S~x86_64-64bit-PIC-ACPI-wakeup arch/x86_64/kernel/head.S
--- linux-2.6.19-rc5-reloc/arch/x86_64/kernel/head.S~x86_64-64bit-PIC-ACPI-wakeup 2006-11-09 22:59:48.000000000 -0500
+++ linux-2.6.19-rc5-reloc-root/arch/x86_64/kernel/head.S 2006-11-09 22:59:48.000000000 -0500
@@ -300,15 +300,6 @@ NEXT_PAGE(level2_kernel_pgt)

.data

-#ifdef CONFIG_ACPI_SLEEP
- .align PAGE_SIZE
-ENTRY(wakeup_level4_pgt)
- .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
- .fill 510,8,0
- /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
- .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
-#endif
-
#ifndef CONFIG_HOTPLUG_CPU
__INITDATA
#endif
diff -puN include/asm-x86_64/suspend.h~x86_64-64bit-PIC-ACPI-wakeup include/asm-x86_64/suspend.h
--- linux-2.6.19-rc5-reloc/include/asm-x86_64/suspend.h~x86_64-64bit-PIC-ACPI-wakeup 2006-11-09 22:59:48.000000000 -0500
+++ linux-2.6.19-rc5-reloc-root/include/asm-x86_64/suspend.h 2006-11-09 22:59:48.000000000 -0500
@@ -45,12 +45,12 @@ extern unsigned long saved_context_eflag
extern void fix_processor_context(void);

#ifdef CONFIG_ACPI_SLEEP
-extern unsigned long saved_eip;
-extern unsigned long saved_esp;
-extern unsigned long saved_ebp;
-extern unsigned long saved_ebx;
-extern unsigned long saved_esi;
-extern unsigned long saved_edi;
+extern unsigned long saved_rip;
+extern unsigned long saved_rsp;
+extern unsigned long saved_rbp;
+extern unsigned long saved_rbx;
+extern unsigned long saved_rsi;
+extern unsigned long saved_rdi;

/* routines for saving/restoring kernel state */
extern int acpi_save_state_mem(void);
_
-
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/