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    Subject[PATCH 2/2] x86/acpi: Call acpi_enter_sleep_state via an asmlinkage C function from assembler.
    Date
    With commit a2ef5c4fd44ce3922435139393b89f2cce47f576
    "ACPI: Move module parameter gts and bfs to sleep.c" the
    wake_sleep_flags is required when calling acpi_enter_sleep_state.

    The assembler code in wakeup_*.S did not do that. One solution
    is to call it from assembler and stick the wake_sleep_flags on
    the stack (for 32-bit) or in %esi (for 64-bit). hpa and rafael
    both suggested however to create a wrapper function to call
    acpi_enter_sleep_state and call said wrapper function
    ("acpi_enter_s3") from assembler.

    For 32-bit, the acpi_enter_s3 ends up looking as so:

    push %ebp
    mov %esp,%ebp
    sub $0x8,%esp
    movzbl 0xc1809314,%eax [wake_sleep_flags]
    movl $0x3,(%esp)
    mov %eax,0x4(%esp)
    call 0xc12d1fa0 <acpi_enter_sleep_state>
    leave
    ret

    And 64-bit:

    movzbl 0x9afde1(%rip),%esi [wake_sleep_flags]
    push %rbp
    mov $0x3,%edi
    mov %rsp,%rbp
    callq 0xffffffff812e9800 <acpi_enter_sleep_state>
    leaveq
    retq

    Suggested-by: H. Peter Anvin <hpa@zytor.com>
    [v2: Remove extra assembler operations, per hpa review]
    Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    ---
    arch/x86/kernel/acpi/sleep.c | 4 ++++
    arch/x86/kernel/acpi/sleep.h | 2 ++
    arch/x86/kernel/acpi/wakeup_32.S | 4 +---
    arch/x86/kernel/acpi/wakeup_64.S | 4 +---
    4 files changed, 8 insertions(+), 6 deletions(-)

    diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
    index 103b6ab..146a49c 100644
    --- a/arch/x86/kernel/acpi/sleep.c
    +++ b/arch/x86/kernel/acpi/sleep.c
    @@ -24,6 +24,10 @@ unsigned long acpi_realmode_flags;
    static char temp_stack[4096];
    #endif

    +asmlinkage void acpi_enter_s3(void)
    +{
    + acpi_enter_sleep_state(3, wake_sleep_flags);
    +}
    /**
    * acpi_suspend_lowlevel - save kernel state
    *
    diff --git a/arch/x86/kernel/acpi/sleep.h b/arch/x86/kernel/acpi/sleep.h
    index fe5fdda..d68677a 100644
    --- a/arch/x86/kernel/acpi/sleep.h
    +++ b/arch/x86/kernel/acpi/sleep.h
    @@ -3,6 +3,7 @@
    */

    #include <asm/trampoline.h>
    +#include <linux/linkage.h>

    extern unsigned long saved_video_mode;
    extern long saved_magic;
    @@ -10,6 +11,7 @@ extern long saved_magic;
    extern int wakeup_pmode_return;

    extern u8 wake_sleep_flags;
    +extern asmlinkage void acpi_enter_s3(void);

    extern unsigned long acpi_copy_wakeup_routine(unsigned long);
    extern void wakeup_long64(void);
    diff --git a/arch/x86/kernel/acpi/wakeup_32.S b/arch/x86/kernel/acpi/wakeup_32.S
    index 13ab720..7261083 100644
    --- a/arch/x86/kernel/acpi/wakeup_32.S
    +++ b/arch/x86/kernel/acpi/wakeup_32.S
    @@ -74,9 +74,7 @@ restore_registers:
    ENTRY(do_suspend_lowlevel)
    call save_processor_state
    call save_registers
    - pushl $3
    - call acpi_enter_sleep_state
    - addl $4, %esp
    + call acpi_enter_s3

    # In case of S3 failure, we'll emerge here. Jump
    # to ret_point to recover
    diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
    index 8ea5164..014d1d2 100644
    --- a/arch/x86/kernel/acpi/wakeup_64.S
    +++ b/arch/x86/kernel/acpi/wakeup_64.S
    @@ -71,9 +71,7 @@ ENTRY(do_suspend_lowlevel)
    movq %rsi, saved_rsi

    addq $8, %rsp
    - movl $3, %edi
    - xorl %eax, %eax
    - call acpi_enter_sleep_state
    + call acpi_enter_s3
    /* in case something went wrong, restore the machine status and go on */
    jmp resume_point

    --
    1.7.7.5


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