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| author | Daniel Thompson <daniel.thompson@linaro.org> | 2014-07-10 23:58:08 +0400 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-07-18 15:29:34 +0400 |
| commit | e38361d032f12f42ddc6d8e2028f6668da696d14 (patch) | |
| tree | 43b60217fbff7e9edc93f6466647548e5e5b8da3 /arch/arm/include | |
| parent | bc994c77ce82576209dcf08f71de9ae51b0b100f (diff) | |
| download | linux-e38361d032f12f42ddc6d8e2028f6668da696d14.tar.xz | |
ARM: 8091/2: add get_user() support for 8 byte types
Recent contributions, including to DRM and binder, introduce 64-bit
values in their interfaces. A common motivation for this is to allow
the same ABI for 32- and 64-bit userspaces (and therefore also a shared
ABI for 32/64 hybrid userspaces). Anyhow, the developers would like to
avoid gotchas like having to use copy_from_user().
This feature is already implemented on x86-32 and the majority of other
32-bit architectures. The current list of get_user_8 hold out
architectures are: arm, avr32, blackfin, m32r, metag, microblaze,
mn10300, sh.
Credit:
My name sits rather uneasily at the top of this patch. The v1 and
v2 versions of the patch were written by Rob Clark and to produce v4
I mostly copied code from Russell King and H. Peter Anvin. However I
have mangled the patch sufficiently that *blame* is rightfully mine
even if credit should more widely shared.
Changelog:
v5: updated to use the ret macro (requested by Russell King)
v4: remove an inlined add on big endian systems (spotted by Russell King),
used __ARMEB__ rather than BIG_ENDIAN (to match rest of file),
cleared r3 on EFAULT during __get_user_8.
v3: fix a couple of checkpatch issues
v2: pass correct size to check_uaccess, and better handling of narrowing
double word read with __get_user_xb() (Russell King's suggestion)
v1: original
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include')
| -rw-r--r-- | arch/arm/include/asm/uaccess.h | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 75d95799b6e6..7057cf8b87d0 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -107,6 +107,8 @@ static inline void set_fs(mm_segment_t fs) extern int __get_user_1(void *); extern int __get_user_2(void *); extern int __get_user_4(void *); +extern int __get_user_lo8(void *); +extern int __get_user_8(void *); #define __GUP_CLOBBER_1 "lr", "cc" #ifdef CONFIG_CPU_USE_DOMAINS @@ -115,6 +117,8 @@ extern int __get_user_4(void *); #define __GUP_CLOBBER_2 "lr", "cc" #endif #define __GUP_CLOBBER_4 "lr", "cc" +#define __GUP_CLOBBER_lo8 "lr", "cc" +#define __GUP_CLOBBER_8 "lr", "cc" #define __get_user_x(__r2,__p,__e,__l,__s) \ __asm__ __volatile__ ( \ @@ -125,11 +129,19 @@ extern int __get_user_4(void *); : "0" (__p), "r" (__l) \ : __GUP_CLOBBER_##__s) +/* narrowing a double-word get into a single 32bit word register: */ +#ifdef __ARMEB__ +#define __get_user_xb(__r2, __p, __e, __l, __s) \ + __get_user_x(__r2, __p, __e, __l, lo8) +#else +#define __get_user_xb __get_user_x +#endif + #define __get_user_check(x,p) \ ({ \ unsigned long __limit = current_thread_info()->addr_limit - 1; \ register const typeof(*(p)) __user *__p asm("r0") = (p);\ - register unsigned long __r2 asm("r2"); \ + register typeof(x) __r2 asm("r2"); \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \ switch (sizeof(*(__p))) { \ @@ -142,6 +154,12 @@ extern int __get_user_4(void *); case 4: \ __get_user_x(__r2, __p, __e, __l, 4); \ break; \ + case 8: \ + if (sizeof((x)) < 8) \ + __get_user_xb(__r2, __p, __e, __l, 4); \ + else \ + __get_user_x(__r2, __p, __e, __l, 8); \ + break; \ default: __e = __get_user_bad(); break; \ } \ x = (typeof(*(p))) __r2; \ |