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authorDaniel Thompson <daniel.thompson@linaro.org>2014-07-10 20:58:08 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-07-18 12:29:34 +0100
commite38361d032f12f42ddc6d8e2028f6668da696d14 (patch)
tree43b60217fbff7e9edc93f6466647548e5e5b8da3 /arch/arm/lib
parentbc994c77ce82576209dcf08f71de9ae51b0b100f (diff)
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')
-rw-r--r--arch/arm/lib/getuser.S37
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