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    SubjectRe: [RFC PATCH] arm64: Fix __addr_ok and __range_ok macros
    On Wed, Mar 05, 2014 at 05:41:28PM -0500, Christopher Covington wrote:
    > Without this, the following scenario is incorrectly determined
    > to be invalid.
    >
    > addr 0x7f_ffffe000 size 8192 addr_limit 0x80_00000000
    >
    > This behavior was observed while trying to vmsplice the stack
    > as part of a CRIU dump of a process.
    >
    > Signed-off-by: Christopher Covington <cov@codeaurora.org>
    > ---
    > arch/arm64/include/asm/uaccess.h | 8 ++++----
    > 1 file changed, 4 insertions(+), 4 deletions(-)
    >
    > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
    > index edb3d5c..9309024 100644
    > --- a/arch/arm64/include/asm/uaccess.h
    > +++ b/arch/arm64/include/asm/uaccess.h
    > @@ -66,12 +66,12 @@ static inline void set_fs(mm_segment_t fs)
    > #define segment_eq(a,b) ((a) == (b))
    >
    > /*
    > - * Return 1 if addr < current->addr_limit, 0 otherwise.
    > + * Return 1 if addr <= current->addr_limit, 0 otherwise.
    > */
    > #define __addr_ok(addr) \
    > ({ \
    > unsigned long flag; \
    > - asm("cmp %1, %0; cset %0, lo" \
    > + asm("cmp %1, %0; cset %0, ls" \
    > : "=&r" (flag) \
    > : "r" (addr), "0" (current_thread_info()->addr_limit) \
    > : "cc"); \


    BTW can this use mov %0, #0 like arch/arm/include/asm/uaccess.h does?
    Would make it more portable ...


    > @@ -83,7 +83,7 @@ static inline void set_fs(mm_segment_t fs)
    > * Returns 1 if the range is valid, 0 otherwise.
    > *
    > * This is equivalent to the following test:
    > - * (u65)addr + (u65)size < (u65)current->addr_limit
    > + * (u65)addr + (u65)size <= current->addr_limit
    > *
    > * This needs 65-bit arithmetic.
    > */
    > @@ -91,7 +91,7 @@ static inline void set_fs(mm_segment_t fs)
    > ({ \
    > unsigned long flag, roksum; \
    > __chk_user_ptr(addr); \
    > - asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, cc" \
    > + asm("adds %1, %1, %3; ccmp %1, %4, #3, cc; cset %0, ls" \
    > : "=&r" (flag), "=&r" (roksum) \
    > : "1" (addr), "Ir" (size), \
    > "r" (current_thread_info()->addr_limit) \
    > --
    > Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
    > hosted by the Linux Foundation.


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