From e3f2b1a93211811567a2db0938b814758401b358 Mon Sep 17 00:00:00 2001 From: Alexei Fedorov Date: Tue, 1 Sep 2020 15:38:32 +0100 Subject: [PATCH] plat/arm: Introduce and use libc_asm.mk makefile Trace analysis of FVP_Base_AEMv8A 0.0/6063 model running in Aarch32 mode with the build options listed below: TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 ARM_ROTPK_LOCATION=devel_ecdsa KEY_ALG=ecdsa ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_ecdsa.pem shows that when auth_signature() gets called 71.99% of CPU execution time is spent in memset() function written in C using single byte write operations, see lib\libc\memset.c. This patch introduces new libc_asm.mk makefile which replaces C memset() implementation with assembler version giving the following results: - for Aarch32 in auth_signature() call memset() CPU time reduced to 20.56%. The number of CPU instructions (Inst) executed during TF-A boot stage before start of BL33 in RELEASE builds for different versions is presented in the tables below, where: - C TF-A: existing TF-A C code; - C musl: "lightweight code" C "implementation of the standard library for Linux-based systems" https://git.musl-libc.org/cgit/musl/tree/src/string/memset.c - Asm Opt: assemler version from "Arm Optimized Routines" project https://github.com/ARM-software/optimized-routines/blob/ master/string/arm/memset.S - Asm Linux: assembler version from Linux kernel https://github.com/torvalds/linux/blob/master/arch/arm/lib/memset.S - Asm TF-A: assembler version from this patch Aarch32: +-----------+------+------+--------------+----------+ | Variant | Set | Size | Inst | Ratio | +-----------+------+------+--------------+----------+ | C TF-A | T32 | 16 | 2122110003 | 1.000000 | | C musl | T32 | 156 | 1643917668 | 0.774662 | | Asm Opt | T32 | 84 | 1604810003 | 0.756233 | | Asm Linux | A32 | 168 | 1566255018 | 0.738065 | | Asm TF-A | A32 | 160 | 1525865101 | 0.719032 | +-----------+------+------+--------------+----------+ AArch64: +-----------+------+------------+----------+ | Variant | Size | Inst | Ratio | +-----------+------+------------+----------+ | C TF-A | 28 | 2732497518 | 1.000000 | | C musl | 212 | 1802999999 | 0.659836 | | Asm TF-A | 140 | 1680260003 | 0.614917 | +-----------+------+------------+----------+ This patch modifies 'plat\arm\common\arm_common.mk' by overriding libc.mk makefile with libc_asm.mk and does not effect other platforms. Change-Id: Ie89dd0b74ba1079420733a0d76b7366ad0157c2e Signed-off-by: Alexei Fedorov --- lib/libc/aarch32/memset.S | 74 +++++++++++++++++++++++++++++++++++ lib/libc/aarch64/memset.S | 64 ++++++++++++++++++++++++++++++ lib/libc/libc_asm.mk | 38 ++++++++++++++++++ plat/arm/common/arm_common.mk | 6 +++ 4 files changed, 182 insertions(+) create mode 100644 lib/libc/aarch32/memset.S create mode 100644 lib/libc/aarch64/memset.S create mode 100644 lib/libc/libc_asm.mk diff --git a/lib/libc/aarch32/memset.S b/lib/libc/aarch32/memset.S new file mode 100644 index 000000000..880ba8382 --- /dev/null +++ b/lib/libc/aarch32/memset.S @@ -0,0 +1,74 @@ +/* + * Copyright (c) 2020, Arm Limited. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include + + .syntax unified + .global memset + +/* ----------------------------------------------------------------------- + * void *memset(void *dst, int val, size_t count) + * + * Copy the value of 'val' (converted to an unsigned char) into + * each of the first 'count' characters of the object pointed to by 'dst'. + * + * Returns the value of 'dst'. + * ----------------------------------------------------------------------- + */ +func memset + mov r12, r0 /* keep r0 */ + tst r0, #3 + beq aligned /* 4-bytes aligned */ + + /* Unaligned 'dst' */ +unaligned: + subs r2, r2, #1 + strbhs r1, [r12], #1 + bxls lr /* return if 0 */ + tst r12, #3 + bne unaligned /* continue while unaligned */ + + /* 4-bytes aligned */ +aligned:bfi r1, r1, #8, #8 /* propagate 'val' */ + bfi r1, r1, #16, #16 + + mov r3, r1 + + cmp r2, #16 + blo less_16 /* < 16 */ + + push {r4, lr} + mov r4, r1 + mov lr, r1 + +write_32: + subs r2, r2, #32 + stmiahs r12!, {r1, r3, r4, lr} + stmiahs r12!, {r1, r3, r4, lr} + bhi write_32 /* write 32 bytes in a loop */ + popeq {r4, pc} /* return if 0 */ + lsls r2, r2, #28 /* C = r2[4]; N = r2[3]; Z = r2[3:0] */ + stmiacs r12!, {r1, r3, r4, lr} /* write 16 bytes */ + popeq {r4, pc} /* return if 16 */ + stmiami r12!, {r1, r3} /* write 8 bytes */ + lsls r2, r2, #2 /* C = r2[2]; N = r2[1]; Z = r2[1:0] */ + strcs r1, [r12], #4 /* write 4 bytes */ + popeq {r4, pc} /* return if 8 or 4 */ + strhmi r1, [r12], #2 /* write 2 bytes */ + lsls r2, r2, #1 /* N = Z = r2[0] */ + strbmi r1, [r12] /* write 1 byte */ + pop {r4, pc} + +less_16:lsls r2, r2, #29 /* C = r2[3]; N = r2[2]; Z = r2[2:0] */ + stmiacs r12!, {r1, r3} /* write 8 bytes */ + bxeq lr /* return if 8 */ + strmi r1, [r12], #4 /* write 4 bytes */ + lsls r2, r2, #2 /* C = r2[1]; N = Z = r2[0] */ + strhcs r1, [r12], #2 /* write 2 bytes */ + strbmi r1, [r12] /* write 1 byte */ + bx lr + +endfunc memset diff --git a/lib/libc/aarch64/memset.S b/lib/libc/aarch64/memset.S new file mode 100644 index 000000000..05437041d --- /dev/null +++ b/lib/libc/aarch64/memset.S @@ -0,0 +1,64 @@ +/* + * Copyright (c) 2020, Arm Limited. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include + + .global memset + +/* ----------------------------------------------------------------------- + * void *memset(void *dst, int val, size_t count) + * + * Copy the value of 'val' (converted to an unsigned char) into + * each of the first 'count' characters of the object pointed to by 'dst'. + * + * Returns the value of 'dst'. + * ----------------------------------------------------------------------- + */ +func memset + cbz x2, exit /* exit if 'count' = 0 */ + mov x3, x0 /* keep x0 */ + tst x0, #7 + b.eq aligned /* 8-bytes aligned */ + + /* Unaligned 'dst' */ +unaligned: + strb w1, [x3], #1 + subs x2, x2, #1 + b.eq exit /* exit if 0 */ + tst x3, #7 + b.ne unaligned /* continue while unaligned */ + + /* 8-bytes aligned */ +aligned:cbz x1, x1_zero + bfi w1, w1, #8, #8 /* propagate 'val' */ + bfi w1, w1, #16, #16 + bfi x1, x1, #32, #32 + +x1_zero:ands x4, x2, #~0x3f + b.eq less_64 + +write_64: + .rept 4 + stp x1, x1, [x3], #16 /* write 64 bytes in a loop */ + .endr + subs x4, x4, #64 + b.ne write_64 +less_64:tbz w2, #5, less_32 /* < 32 bytes */ + stp x1, x1, [x3], #16 /* write 32 bytes */ + stp x1, x1, [x3], #16 +less_32:tbz w2, #4, less_16 /* < 16 bytes */ + stp x1, x1, [x3], #16 /* write 16 bytes */ +less_16:tbz w2, #3, less_8 /* < 8 bytes */ + str x1, [x3], #8 /* write 8 bytes */ +less_8: tbz w2, #2, less_4 /* < 4 bytes */ + str w1, [x3], #4 /* write 4 bytes */ +less_4: tbz w2, #1, less_2 /* < 2 bytes */ + strh w1, [x3], #2 /* write 2 bytes */ +less_2: tbz w2, #0, exit + strb w1, [x3] /* write 1 byte */ +exit: ret + +endfunc memset diff --git a/lib/libc/libc_asm.mk b/lib/libc/libc_asm.mk new file mode 100644 index 000000000..6416a3c84 --- /dev/null +++ b/lib/libc/libc_asm.mk @@ -0,0 +1,38 @@ +# +# Copyright (c) 2020, Arm Limited. All rights reserved. +# +# SPDX-License-Identifier: BSD-3-Clause +# + +LIBC_SRCS := $(addprefix lib/libc/, \ + abort.c \ + assert.c \ + exit.c \ + memchr.c \ + memcmp.c \ + memcpy.c \ + memmove.c \ + memrchr.c \ + printf.c \ + putchar.c \ + puts.c \ + snprintf.c \ + strchr.c \ + strcmp.c \ + strlcpy.c \ + strlen.c \ + strncmp.c \ + strnlen.c \ + strrchr.c) + +ifeq (${ARCH},aarch64) +LIBC_SRCS += $(addprefix lib/libc/aarch64/, \ + memset.S \ + setjmp.S) +else +LIBC_SRCS += $(addprefix lib/libc/aarch32/, \ + memset.S) +endif + +INCLUDES += -Iinclude/lib/libc \ + -Iinclude/lib/libc/$(ARCH) \ diff --git a/plat/arm/common/arm_common.mk b/plat/arm/common/arm_common.mk index 96ab2d300..224de9d11 100644 --- a/plat/arm/common/arm_common.mk +++ b/plat/arm/common/arm_common.mk @@ -121,6 +121,12 @@ endif ENABLE_PSCI_STAT := 1 ENABLE_PMF := 1 +# Override the standard libc with optimised libc_asm +OVERRIDE_LIBC := 1 +ifeq (${OVERRIDE_LIBC},1) + include lib/libc/libc_asm.mk +endif + # On ARM platforms, separate the code and read-only data sections to allow # mapping the former as executable and the latter as execute-never. SEPARATE_CODE_AND_RODATA := 1