From 1ee3630a3e57f38f688a6f0a5f9edbd8a0d7201f Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Tue, 29 Sep 2015 12:19:48 +0200 Subject: 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/lib/bswapsi.c | 11 +++++++++++ 1 file changed, 11 insertions(+) create mode 100644 arch/mips/lib/bswapsi.c (limited to 'arch/mips/lib/bswapsi.c') 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); -- cgit v1.2.3