From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751216AbaHUFhC (ORCPT ); Thu, 21 Aug 2014 01:37:02 -0400 Received: from mail-qc0-f181.google.com ([209.85.216.181]:48030 "EHLO mail-qc0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750769AbaHUFhA (ORCPT ); Thu, 21 Aug 2014 01:37:00 -0400 MIME-Version: 1.0 In-Reply-To: <1405021635-19179-1-git-send-email-daniel.thompson@linaro.org> References: <1403258510-5760-1-git-send-email-daniel.thompson@linaro.org> <1405021635-19179-1-git-send-email-daniel.thompson@linaro.org> Date: Wed, 20 Aug 2014 22:36:59 -0700 Message-ID: Subject: Re: [PATCH 3.16.0-rc3-rmk v5] ARM: add get_user() support for 8 byte types From: Victor Kamensky To: Daniel Thompson Cc: Russell King , Nicolas Pitre , "linaro-kernel@lists.linaro.org" , Patch Tracking , open list , Rob Clark , John Stultz , Arnd Bergmann , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10 July 2014 12:47, Daniel Thompson wrote: > 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 > Signed-off-by: Daniel Thompson > Cc: Russell King - ARM Linux > --- > arch/arm/include/asm/uaccess.h | 20 +++++++++++++++++++- > arch/arm/lib/getuser.S | 37 ++++++++++++++++++++++++++++++++++++- > 2 files changed, 55 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h > index 75d9579..7057cf8 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"); \ Above breaks V7 BE case when get_user called for target variable of 64 bit in size but '*__p' is 32 bit or smaller. Please look at [1] for more details. Thanks, Victor [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/280806.html > 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; \ > diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S > index 0f958e3..9386000 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 > @@ -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 > -- > 1.9.3 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel From mboxrd@z Thu Jan 1 00:00:00 1970 From: victor.kamensky@linaro.org (Victor Kamensky) Date: Wed, 20 Aug 2014 22:36:59 -0700 Subject: [PATCH 3.16.0-rc3-rmk v5] ARM: add get_user() support for 8 byte types In-Reply-To: <1405021635-19179-1-git-send-email-daniel.thompson@linaro.org> References: <1403258510-5760-1-git-send-email-daniel.thompson@linaro.org> <1405021635-19179-1-git-send-email-daniel.thompson@linaro.org> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10 July 2014 12:47, Daniel Thompson wrote: > 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 > Signed-off-by: Daniel Thompson > Cc: Russell King - ARM Linux > --- > arch/arm/include/asm/uaccess.h | 20 +++++++++++++++++++- > arch/arm/lib/getuser.S | 37 ++++++++++++++++++++++++++++++++++++- > 2 files changed, 55 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h > index 75d9579..7057cf8 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"); \ Above breaks V7 BE case when get_user called for target variable of 64 bit in size but '*__p' is 32 bit or smaller. Please look at [1] for more details. Thanks, Victor [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/280806.html > 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; \ > diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S > index 0f958e3..9386000 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 > @@ -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 > -- > 1.9.3 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel