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| author | Daniel Thompson <daniel.thompson@linaro.org> | 2014-07-10 20:58:08 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-07-18 12:29:34 +0100 |
| commit | e38361d032f12f42ddc6d8e2028f6668da696d14 (patch) | |
| tree | 43b60217fbff7e9edc93f6466647548e5e5b8da3 /arch/arm/lib/getuser.S | |
| parent | bc994c77ce82576209dcf08f71de9ae51b0b100f (diff) | |
| download | linux-e38361d032f12f42ddc6d8e2028f6668da696d14.tar.bz2 | |
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/lib/getuser.S')
| -rw-r--r-- | arch/arm/lib/getuser.S | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S index 0f958e3d8180..938600098b88 100644 --- a/arch/arm/lib/getuser.S +++ b/arch/arm/lib/getuser.S @@ -18,7 +18,7 @@ * Inputs: r0 contains the address * r1 contains the address limit, which must be preserved * Outputs: r0 is the error code - * r2 contains the zero-extended value + * r2, r3 contains the zero-extended value * lr corrupted * * No other registers must be altered. (see <asm/uaccess.h> @@ -66,15 +66,50 @@ ENTRY(__get_user_4) ret lr ENDPROC(__get_user_4) +ENTRY(__get_user_8) + check_uaccess r0, 8, r1, r2, __get_user_bad +#ifdef CONFIG_THUMB2_KERNEL +5: TUSER(ldr) r2, [r0] +6: TUSER(ldr) r3, [r0, #4] +#else +5: TUSER(ldr) r2, [r0], #4 +6: TUSER(ldr) r3, [r0] +#endif + mov r0, #0 + ret lr +ENDPROC(__get_user_8) + +#ifdef __ARMEB__ +ENTRY(__get_user_lo8) + check_uaccess r0, 8, r1, r2, __get_user_bad +#ifdef CONFIG_CPU_USE_DOMAINS + add r0, r0, #4 +7: ldrt r2, [r0] +#else +7: ldr r2, [r0, #4] +#endif + mov r0, #0 + ret lr +ENDPROC(__get_user_lo8) +#endif + +__get_user_bad8: + mov r3, #0 __get_user_bad: mov r2, #0 mov r0, #-EFAULT ret lr ENDPROC(__get_user_bad) +ENDPROC(__get_user_bad8) .pushsection __ex_table, "a" .long 1b, __get_user_bad .long 2b, __get_user_bad .long 3b, __get_user_bad .long 4b, __get_user_bad + .long 5b, __get_user_bad8 + .long 6b, __get_user_bad8 +#ifdef __ARMEB__ + .long 7b, __get_user_bad +#endif .popsection |