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    Subject[PATCH v11 18/20] x86/asm: Create stack frames in rwsem functions
    Date
    rwsem.S has several callable non-leaf functions which don't honor
    CONFIG_FRAME_POINTER, which can result in bad stack traces.

    Create stack frames for them when CONFIG_FRAME_POINTER is enabled.

    Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
    ---
    arch/x86/lib/rwsem.S | 11 ++++++++++-
    1 file changed, 10 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/lib/rwsem.S b/arch/x86/lib/rwsem.S
    index 40027db..be110ef 100644
    --- a/arch/x86/lib/rwsem.S
    +++ b/arch/x86/lib/rwsem.S
    @@ -15,6 +15,7 @@

    #include <linux/linkage.h>
    #include <asm/alternative-asm.h>
    +#include <asm/frame.h>

    #define __ASM_HALF_REG(reg) __ASM_SEL(reg, e##reg)
    #define __ASM_HALF_SIZE(inst) __ASM_SEL(inst##w, inst##l)
    @@ -84,24 +85,29 @@

    /* Fix up special calling conventions */
    ENTRY(call_rwsem_down_read_failed)
    + FRAME_BEGIN
    save_common_regs
    __ASM_SIZE(push,) %__ASM_REG(dx)
    movq %rax,%rdi
    call rwsem_down_read_failed
    __ASM_SIZE(pop,) %__ASM_REG(dx)
    restore_common_regs
    + FRAME_END
    ret
    ENDPROC(call_rwsem_down_read_failed)

    ENTRY(call_rwsem_down_write_failed)
    + FRAME_BEGIN
    save_common_regs
    movq %rax,%rdi
    call rwsem_down_write_failed
    restore_common_regs
    + FRAME_END
    ret
    ENDPROC(call_rwsem_down_write_failed)

    ENTRY(call_rwsem_wake)
    + FRAME_BEGIN
    /* do nothing if still outstanding active readers */
    __ASM_HALF_SIZE(dec) %__ASM_HALF_REG(dx)
    jnz 1f
    @@ -109,15 +115,18 @@ ENTRY(call_rwsem_wake)
    movq %rax,%rdi
    call rwsem_wake
    restore_common_regs
    -1: ret
    +1: FRAME_END
    + ret
    ENDPROC(call_rwsem_wake)

    ENTRY(call_rwsem_downgrade_wake)
    + FRAME_BEGIN
    save_common_regs
    __ASM_SIZE(push,) %__ASM_REG(dx)
    movq %rax,%rdi
    call rwsem_downgrade_wake
    __ASM_SIZE(pop,) %__ASM_REG(dx)
    restore_common_regs
    + FRAME_END
    ret
    ENDPROC(call_rwsem_downgrade_wake)
    --
    2.4.3


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