From 1ee3630a3e57f38f688a6f0a5f9edbd8a0d7201f Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Tue, 29 Sep 2015 12:19:48 +0200 Subject: [PATCH] MIPS: Use ARCH_USE_BUILTIN_BSWAP. ARCH_USE_BUILTIN_BSWAP will use __builtin_bswap16(), __builtin_bswap32() and __builtin_bswap64() where available. This allows better instruction scheduling. On pre-R2 processors it will result in 32 bit and 64 bit swapping being performed in a call to a __bswapsi2() rsp. __bswapdi2() functions, so we add these, too. For a 4.2 kernel with GCC 4.9 this yields the following kernel sizes: text data bss dec hex filename 3996071 155804 88992 4240867 40b5e3 vmlinux ip22 baseline 3985687 159900 88992 4234579 409d53 vmlinux ip22 + bswap patch 6913157 378552 251024 7542733 7317cd vmlinux ip27 baseline 6878581 378552 251024 7508157 7290bd vmlinux ip27 + bswap patch 5773777 268752 187424 6229953 5f0fc1 vmlinux malta baseline 5773401 268752 187424 6229577 5f0e49 vmlinux malta + bswap patch Presumably the code size improvments yield better cache hit rate thus better performance compensating for the extra function call but this will still need to be benchmarked. Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 1 + arch/mips/lib/Makefile | 2 +- arch/mips/lib/bswapdi.c | 15 +++++++++++++++ arch/mips/lib/bswapsi.c | 11 +++++++++++ 4 files changed, 28 insertions(+), 1 deletion(-) create mode 100644 arch/mips/lib/bswapdi.c create mode 100644 arch/mips/lib/bswapsi.c diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index e3aa5b0b4ef1..c08e7016c77a 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -5,6 +5,7 @@ config MIPS select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO select ARCH_USE_CMPXCHG_LOCKREF if 64BIT + select ARCH_USE_BUILTIN_BSWAP select HAVE_CONTEXT_TRACKING select HAVE_GENERIC_DMA_COHERENT select HAVE_IDE diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile index 1e9e900cd3c3..0344e575f522 100644 --- a/arch/mips/lib/Makefile +++ b/arch/mips/lib/Makefile @@ -15,4 +15,4 @@ obj-$(CONFIG_CPU_R3000) += r3k_dump_tlb.o obj-$(CONFIG_CPU_TX39XX) += r3k_dump_tlb.o # libgcc-style stuff needed in the kernel -obj-y += ashldi3.o ashrdi3.o cmpdi2.o lshrdi3.o ucmpdi2.o +obj-y += ashldi3.o ashrdi3.o bswapsi.o bswapdi.o cmpdi2.o lshrdi3.o ucmpdi2.o diff --git a/arch/mips/lib/bswapdi.c b/arch/mips/lib/bswapdi.c new file mode 100644 index 000000000000..77e5f9c1f005 --- /dev/null +++ b/arch/mips/lib/bswapdi.c @@ -0,0 +1,15 @@ +#include + +unsigned long long __bswapdi2(unsigned long long u) +{ + return (((u) & 0xff00000000000000ull) >> 56) | + (((u) & 0x00ff000000000000ull) >> 40) | + (((u) & 0x0000ff0000000000ull) >> 24) | + (((u) & 0x000000ff00000000ull) >> 8) | + (((u) & 0x00000000ff000000ull) << 8) | + (((u) & 0x0000000000ff0000ull) << 24) | + (((u) & 0x000000000000ff00ull) << 40) | + (((u) & 0x00000000000000ffull) << 56); +} + +EXPORT_SYMBOL(__bswapdi2); diff --git a/arch/mips/lib/bswapsi.c b/arch/mips/lib/bswapsi.c new file mode 100644 index 000000000000..2b302ff121d2 --- /dev/null +++ b/arch/mips/lib/bswapsi.c @@ -0,0 +1,11 @@ +#include + +unsigned int __bswapsi2(unsigned int u) +{ + return (((u) & 0xff000000) >> 24) | + (((u) & 0x00ff0000) >> 8) | + (((u) & 0x0000ff00) << 8) | + (((u) & 0x000000ff) << 24); +} + +EXPORT_SYMBOL(__bswapsi2); -- 2.34.1