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    Subject[PATCH 5.4 129/475] uaccess: fix nios2 and microblaze get_user_8()
    Date
    From: Arnd Bergmann <arnd@arndb.de>

    [ Upstream commit a97b693c3712f040c5802f32b2d685352e08cefa ]

    These two architectures implement 8-byte get_user() through
    a memcpy() into a four-byte variable, which won't fit.

    Use a temporary 64-bit variable instead here, and use a double
    cast the way that risc-v and openrisc do to avoid compile-time
    warnings.

    Fixes: 6a090e97972d ("arch/microblaze: support get_user() of size 8 bytes")
    Fixes: 5ccc6af5e88e ("nios2: Memory management")
    Reviewed-by: Christoph Hellwig <hch@lst.de>
    Acked-by: Dinh Nguyen <dinguyen@kernel.org>
    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/microblaze/include/asm/uaccess.h | 18 +++++++++---------
    arch/nios2/include/asm/uaccess.h | 26 ++++++++++++++++----------
    2 files changed, 25 insertions(+), 19 deletions(-)

    diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
    index a1f206b90753..c8cd66c8d257 100644
    --- a/arch/microblaze/include/asm/uaccess.h
    +++ b/arch/microblaze/include/asm/uaccess.h
    @@ -171,27 +171,27 @@ extern long __user_bad(void);

    #define __get_user(x, ptr) \
    ({ \
    - unsigned long __gu_val = 0; \
    long __gu_err; \
    switch (sizeof(*(ptr))) { \
    case 1: \
    - __get_user_asm("lbu", (ptr), __gu_val, __gu_err); \
    + __get_user_asm("lbu", (ptr), x, __gu_err); \
    break; \
    case 2: \
    - __get_user_asm("lhu", (ptr), __gu_val, __gu_err); \
    + __get_user_asm("lhu", (ptr), x, __gu_err); \
    break; \
    case 4: \
    - __get_user_asm("lw", (ptr), __gu_val, __gu_err); \
    + __get_user_asm("lw", (ptr), x, __gu_err); \
    break; \
    - case 8: \
    - __gu_err = __copy_from_user(&__gu_val, ptr, 8); \
    - if (__gu_err) \
    - __gu_err = -EFAULT; \
    + case 8: { \
    + __u64 __x = 0; \
    + __gu_err = raw_copy_from_user(&__x, ptr, 8) ? \
    + -EFAULT : 0; \
    + (x) = (typeof(x))(typeof((x) - (x)))__x; \
    break; \
    + } \
    default: \
    /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
    } \
    - x = (__force __typeof__(*(ptr))) __gu_val; \
    __gu_err; \
    })

    diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h
    index e83f831a76f9..6be5e913c42e 100644
    --- a/arch/nios2/include/asm/uaccess.h
    +++ b/arch/nios2/include/asm/uaccess.h
    @@ -89,6 +89,7 @@ extern __must_check long strnlen_user(const char __user *s, long n);
    /* Optimized macros */
    #define __get_user_asm(val, insn, addr, err) \
    { \
    + unsigned long __gu_val; \
    __asm__ __volatile__( \
    " movi %0, %3\n" \
    "1: " insn " %1, 0(%2)\n" \
    @@ -97,14 +98,20 @@ extern __must_check long strnlen_user(const char __user *s, long n);
    " .section __ex_table,\"a\"\n" \
    " .word 1b, 2b\n" \
    " .previous" \
    - : "=&r" (err), "=r" (val) \
    + : "=&r" (err), "=r" (__gu_val) \
    : "r" (addr), "i" (-EFAULT)); \
    + val = (__force __typeof__(*(addr)))__gu_val; \
    }

    -#define __get_user_unknown(val, size, ptr, err) do { \
    +extern void __get_user_unknown(void);
    +
    +#define __get_user_8(val, ptr, err) do { \
    + u64 __val = 0; \
    err = 0; \
    - if (__copy_from_user(&(val), ptr, size)) { \
    + if (raw_copy_from_user(&(__val), ptr, sizeof(val))) { \
    err = -EFAULT; \
    + } else { \
    + val = (typeof(val))(typeof((val) - (val)))__val; \
    } \
    } while (0)

    @@ -120,8 +127,11 @@ do { \
    case 4: \
    __get_user_asm(val, "ldw", ptr, err); \
    break; \
    + case 8: \
    + __get_user_8(val, ptr, err); \
    + break; \
    default: \
    - __get_user_unknown(val, size, ptr, err); \
    + __get_user_unknown(); \
    break; \
    } \
    } while (0)
    @@ -130,9 +140,7 @@ do { \
    ({ \
    long __gu_err = -EFAULT; \
    const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
    - unsigned long __gu_val = 0; \
    - __get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\
    - (x) = (__force __typeof__(x))__gu_val; \
    + __get_user_common(x, sizeof(*(ptr)), __gu_ptr, __gu_err); \
    __gu_err; \
    })

    @@ -140,11 +148,9 @@ do { \
    ({ \
    long __gu_err = -EFAULT; \
    const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
    - unsigned long __gu_val = 0; \
    if (access_ok( __gu_ptr, sizeof(*__gu_ptr))) \
    - __get_user_common(__gu_val, sizeof(*__gu_ptr), \
    + __get_user_common(x, sizeof(*__gu_ptr), \
    __gu_ptr, __gu_err); \
    - (x) = (__force __typeof__(x))__gu_val; \
    __gu_err; \
    })

    --
    2.34.1


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