From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf0-x243.google.com ([2607:f8b0:400e:c00::243]) by merlin.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fSqJ8-0007FB-9m for barebox@lists.infradead.org; Tue, 12 Jun 2018 20:54:26 +0000 Received: by mail-pf0-x243.google.com with SMTP id y8-v6so149482pfm.10 for ; Tue, 12 Jun 2018 13:54:16 -0700 (PDT) From: Andrey Smirnov Date: Tue, 12 Jun 2018 13:52:55 -0700 Message-Id: <20180612205310.25745-40-andrew.smirnov@gmail.com> In-Reply-To: <20180612205310.25745-1-andrew.smirnov@gmail.com> References: <20180612205310.25745-1-andrew.smirnov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH v5 39/54] ARM: lib64: Make string functions aware of MMU configuration To: barebox@lists.infradead.org Cc: Andrey Smirnov Optimized version of memset() in memset.S if called as: memset(foo, 0, size) will try to explicitly zero out data cache with: dc zva, dst which will result in Alignement Exception (DABT) if MMU is not enabled. For more info see: - C4.4.8 "DC ZVA, Data Cache Zero by VA" - D5.2.8 "The effects of disabling a stage of address translation" in "ARM Architecture Reference Manual. ARMv8, for ARMv8-A architecture profile" In similar vein, using optimized version of memcpy() could lead to a unaligned 16-byte write (using 'stp'), which is not allowed for Device-nGnRnE type of memory (see D5.2.8) and would liead to Alignement Exception. To fix both problems expose non-optimized and optimzied versions of the function and created a wrapper to dispatch the call to either one based on if MMU is enabled or not. Signed-off-by: Andrey Smirnov --- arch/arm/Kconfig | 7 +++++++ arch/arm/lib64/Makefile | 2 +- arch/arm/lib64/memcpy.S | 6 +++--- arch/arm/lib64/memset.S | 4 ++-- arch/arm/lib64/string.c | 22 ++++++++++++++++++++++ include/string.h | 3 +++ lib/string.c | 18 ++++++++++++------ 7 files changed, 50 insertions(+), 12 deletions(-) create mode 100644 arch/arm/lib64/string.c diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index bd736284f..c330a5a18 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -353,6 +353,13 @@ menu "ARM specific settings" config ARM_OPTIMZED_STRING_FUNCTIONS bool "use assembler optimized string functions" + # + # memset() and memcpy() in arm/lib64/mem[set|cpy].S are + # written with assumption of enabled MMU and cache. Depending + # on the inputs in may fail with Alignement exception if used + # without MMU + # + depends on !CPU_V8 || MMU help Say yes here to use assembler optimized memcpy / memset functions. These functions work much faster than the normal versions but diff --git a/arch/arm/lib64/Makefile b/arch/arm/lib64/Makefile index 77647128a..4c0019fab 100644 --- a/arch/arm/lib64/Makefile +++ b/arch/arm/lib64/Makefile @@ -2,7 +2,7 @@ obj-y += stacktrace.o obj-$(CONFIG_ARM_LINUX) += armlinux.o obj-y += div0.o obj-$(CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS) += memcpy.o -obj-$(CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS) += memset.o +obj-$(CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS) += memset.o string.o extra-y += barebox.lds obj-pbl-y += runtime-offset.o diff --git a/arch/arm/lib64/memcpy.S b/arch/arm/lib64/memcpy.S index cfed3191c..a70e96ca2 100644 --- a/arch/arm/lib64/memcpy.S +++ b/arch/arm/lib64/memcpy.S @@ -67,8 +67,8 @@ stp \ptr, \regB, [\regC], \val .endm - .weak memcpy -ENTRY(memcpy) + .weak __arch_memcpy +ENTRY(__arch_memcpy) #include "copy_template.S" ret -ENDPROC(memcpy) +ENDPROC(__arch_memcpy) diff --git a/arch/arm/lib64/memset.S b/arch/arm/lib64/memset.S index 380a54097..d17bcc612 100644 --- a/arch/arm/lib64/memset.S +++ b/arch/arm/lib64/memset.S @@ -54,7 +54,7 @@ tmp3w .req w9 tmp3 .req x9 .weak memset -ENTRY(memset) +ENTRY(__arch_memset) mov dst, dstin /* Preserve return value. */ and A_lw, val, #255 orr A_lw, A_lw, A_lw, lsl #8 @@ -212,4 +212,4 @@ ENTRY(memset) ands count, count, zva_bits_x b.ne .Ltail_maybe_long ret -ENDPROC(memset) +ENDPROC(__arch_memset) diff --git a/arch/arm/lib64/string.c b/arch/arm/lib64/string.c new file mode 100644 index 000000000..cb2633152 --- /dev/null +++ b/arch/arm/lib64/string.c @@ -0,0 +1,22 @@ +#include +#include +#include + +void *__arch_memset(void *dst, int c, __kernel_size_t size); +void *__arch_memcpy(void * dest, const void *src, size_t count); + +void *memset(void *dst, int c, __kernel_size_t size) +{ + if (likely(get_cr() & CR_M)) + return __arch_memset(dst, c, size); + + return __default_memset(dst, c, size); +} + +void *memcpy(void * dest, const void *src, size_t count) +{ + if (likely(get_cr() & CR_M)) + return __arch_memcpy(dest, src, count); + + return __default_memcpy(dest, src, count); +} \ No newline at end of file diff --git a/include/string.h b/include/string.h index 0c557d6f1..6ceb33224 100644 --- a/include/string.h +++ b/include/string.h @@ -6,4 +6,7 @@ void *memdup(const void *, size_t); int strtobool(const char *str, int *val); +void *__default_memset(void *, int, __kernel_size_t); +void *__default_memcpy(void * dest,const void *src,size_t count); + #endif /* __STRING_H */ diff --git a/lib/string.c b/lib/string.c index f588933e8..717b59aa5 100644 --- a/lib/string.c +++ b/lib/string.c @@ -479,7 +479,6 @@ char *strswab(const char *s) } #endif -#ifndef __HAVE_ARCH_MEMSET /** * memset - Fill a region of memory with the given value * @s: Pointer to the start of the area. @@ -488,7 +487,7 @@ char *strswab(const char *s) * * Do not use memset() to access IO space, use memset_io() instead. */ -void * memset(void * s,int c,size_t count) +void *__default_memset(void * s,int c,size_t count) { char *xs = (char *) s; @@ -497,10 +496,12 @@ void * memset(void * s,int c,size_t count) return s; } +EXPORT_SYMBOL(__default_memset); + +#ifndef __HAVE_ARCH_MEMSET +void *memset(void *s, int c, size_t count) __alias(__default_memset); #endif -EXPORT_SYMBOL(memset); -#ifndef __HAVE_ARCH_MEMCPY /** * memcpy - Copy one area of memory to another * @dest: Where to copy to @@ -510,7 +511,7 @@ EXPORT_SYMBOL(memset); * You should not use this function to access IO space, use memcpy_toio() * or memcpy_fromio() instead. */ -void * memcpy(void * dest,const void *src,size_t count) +void *__default_memcpy(void * dest,const void *src,size_t count) { char *tmp = (char *) dest, *s = (char *) src; @@ -519,9 +520,14 @@ void * memcpy(void * dest,const void *src,size_t count) return dest; } -#endif EXPORT_SYMBOL(memcpy); +#ifndef __HAVE_ARCH_MEMCPY +void *memcpy(void * dest, const void *src, size_t count) + __alias(__default_memcpy); +#endif + + #ifndef __HAVE_ARCH_MEMMOVE /** * memmove - Copy one area of memory to another -- 2.17.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox