lkml.org 
[lkml]   [2015]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v13 22/23] x86/uaccess: Add stack frame output operand in get_user inline asm
    Date
    From: Chris J Arges <chris.j.arges@canonical.com>

    Numerous 'call without frame pointer save/setup' warnings are introduced by
    stacktool because of functions using the get_user macro. Bad stack traces could
    occur due to lack of or misplacement of stack frame setup code.

    This patch forces a stack frame to be created before the inline asm code if
    CONFIG_FRAME_POINTER is enabled by listing the stack pointer as an output
    operand for the get_user inline assembly statement.

    Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
    Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
    ---
    arch/x86/include/asm/uaccess.h | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
    index a8df874..55b8db5 100644
    --- a/arch/x86/include/asm/uaccess.h
    +++ b/arch/x86/include/asm/uaccess.h
    @@ -176,10 +176,11 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
    ({ \
    int __ret_gu; \
    register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
    + register void *__sp asm(_ASM_SP); \
    __chk_user_ptr(ptr); \
    might_fault(); \
    - asm volatile("call __get_user_%P3" \
    - : "=a" (__ret_gu), "=r" (__val_gu) \
    + asm volatile("call __get_user_%P4" \
    + : "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp) \
    : "0" (ptr), "i" (sizeof(*(ptr)))); \
    (x) = (__force __typeof__(*(ptr))) __val_gu; \
    __ret_gu; \
    --
    2.4.3


    \
     
     \ /
      Last update: 2015-09-22 18:01    [W:4.180 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site