OpenWrt – Rev 1

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From: Felix Fietkau <nbd@nbd.name>
Subject: [PATCH] mips: allow the compiler to optimize memset, memcmp, memcpy  for better performance and (in some instances) smaller code

lede-commit: 07e59c7bc7f375f792ec9734be42fe4fa391a8bb
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 arch/mips/boot/compressed/Makefile |  3 ++-
 arch/mips/include/asm/string.h     | 38 ++++++++++++++++++++++++++++++++++++++
 arch/mips/lib/Makefile             |  2 +-
 arch/mips/lib/memcmp.c             | 22 ++++++++++++++++++++++
 4 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 arch/mips/lib/memcmp.c

--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -23,7 +23,8 @@ KBUILD_CFLAGS := $(shell echo $(KBUILD_C
 KBUILD_CFLAGS := $(filter-out -fstack-protector, $(KBUILD_CFLAGS))
 
 KBUILD_CFLAGS := $(LINUXINCLUDE) $(KBUILD_CFLAGS) -D__KERNEL__ \
-       -DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) -D"VMLINUX_LOAD_ADDRESS_ULL=$(VMLINUX_LOAD_ADDRESS)ull"
+       -DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) -D"VMLINUX_LOAD_ADDRESS_ULL=$(VMLINUX_LOAD_ADDRESS)ull" \
+       -D__ZBOOT__
 
 KBUILD_AFLAGS := $(LINUXINCLUDE) $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
        -DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) \
--- a/arch/mips/include/asm/string.h
+++ b/arch/mips/include/asm/string.h
@@ -140,4 +140,42 @@ extern void *memcpy(void *__to, __const_
 #define __HAVE_ARCH_MEMMOVE
 extern void *memmove(void *__dest, __const__ void *__src, size_t __n);
 
+#ifndef __ZBOOT__
+#define memset(__s, __c, len)                                  \
+({                                                             \
+       size_t __len = (len);                                   \
+       void *__ret;                                            \
+       if (__builtin_constant_p(len) && __len >= 64)           \
+               __ret = memset((__s), (__c), __len);            \
+       else                                                    \
+               __ret = __builtin_memset((__s), (__c), __len);  \
+       __ret;                                                  \
+})
+
+#define memcpy(dst, src, len)                                  \
+({                                                             \
+       size_t __len = (len);                                   \
+       void *__ret;                                            \
+       if (__builtin_constant_p(len) && __len >= 64)           \
+               __ret = memcpy((dst), (src), __len);            \
+       else                                                    \
+               __ret = __builtin_memcpy((dst), (src), __len);  \
+       __ret;                                                  \
+})
+
+#define memmove(dst, src, len)                                 \
+({                                                             \
+       size_t __len = (len);                                   \
+       void *__ret;                                            \
+       if (__builtin_constant_p(len) && __len >= 64)           \
+               __ret = memmove((dst), (src), __len);           \
+       else                                                    \
+               __ret = __builtin_memmove((dst), (src), __len); \
+       __ret;                                                  \
+})
+
+#define __HAVE_ARCH_MEMCMP
+#define memcmp(src1, src2, len) __builtin_memcmp((src1), (src2), (len))
+#endif
+
 #endif /* _ASM_STRING_H */
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -4,7 +4,7 @@
 
 lib-y  += bitops.o csum_partial.o delay.o memcpy.o memset.o \
           mips-atomic.o strlen_user.o strncpy_user.o \
-          strnlen_user.o uncached.o
+          strnlen_user.o uncached.o memcmp.o
 
 obj-y                  += iomap.o
 obj-$(CONFIG_PCI)      += iomap-pci.o
--- /dev/null
+++ b/arch/mips/lib/memcmp.c
@@ -0,0 +1,22 @@
+/*
+ *  copied from linux/lib/string.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+
+#undef memcmp
+int memcmp(const void *cs, const void *ct, size_t count)
+{
+       const unsigned char *su1, *su2;
+       int res = 0;
+
+       for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
+               if ((res = *su1 - *su2) != 0)
+                       break;
+       return res;
+}
+EXPORT_SYMBOL(memcmp);
+

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