diff options
| -rw-r--r-- | arch/arm/Kconfig | 7 | ||||
| -rw-r--r-- | arch/arm/include/asm/neon.h | 36 | ||||
| -rw-r--r-- | arch/arm/include/asm/xor.h | 73 | ||||
| -rw-r--r-- | arch/arm/lib/Makefile | 6 | ||||
| -rw-r--r-- | arch/arm/lib/xor-neon.c | 42 | ||||
| -rw-r--r-- | arch/arm/vfp/vfphw.S | 5 | ||||
| -rw-r--r-- | arch/arm/vfp/vfpmodule.c | 69 | ||||
| -rw-r--r-- | include/linux/raid/pq.h | 5 | ||||
| -rw-r--r-- | lib/raid6/.gitignore | 1 | ||||
| -rw-r--r-- | lib/raid6/Makefile | 40 | ||||
| -rw-r--r-- | lib/raid6/algos.c | 6 | ||||
| -rw-r--r-- | lib/raid6/neon.c | 58 | ||||
| -rw-r--r-- | lib/raid6/neon.uc | 80 | ||||
| -rw-r--r-- | lib/raid6/test/Makefile | 26 |
14 files changed, 452 insertions, 2 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index ba412e0..ccc388d 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -2176,6 +2176,13 @@ config NEON Say Y to include support code for NEON, the ARMv7 Advanced SIMD Extension. +config KERNEL_MODE_NEON + bool "Support for NEON in kernel mode" + default n + depends on NEON + help + Say Y to include support for NEON in kernel mode. + endmenu menu "Userspace binary formats" diff --git a/arch/arm/include/asm/neon.h b/arch/arm/include/asm/neon.h new file mode 100644 index 0000000..8f730fe --- /dev/null +++ b/arch/arm/include/asm/neon.h @@ -0,0 +1,36 @@ +/* + * linux/arch/arm/include/asm/neon.h + * + * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <asm/hwcap.h> + +#define cpu_has_neon() (!!(elf_hwcap & HWCAP_NEON)) + +#ifdef __ARM_NEON__ + +/* + * If you are affected by the BUILD_BUG below, it probably means that you are + * using NEON code /and/ calling the kernel_neon_begin() function from the same + * compilation unit. To prevent issues that may arise from GCC reordering or + * generating(1) NEON instructions outside of these begin/end functions, the + * only supported way of using NEON code in the kernel is by isolating it in a + * separate compilation unit, and calling it from another unit from inside a + * kernel_neon_begin/kernel_neon_end pair. + * + * (1) Current GCC (4.7) might generate NEON instructions at O3 level if + * -mpfu=neon is set. + */ + +#define kernel_neon_begin() \ + BUILD_BUG_ON_MSG(1, "kernel_neon_begin() called from NEON code") + +#else +void kernel_neon_begin(void); +#endif +void kernel_neon_end(void); diff --git a/arch/arm/include/asm/xor.h b/arch/arm/include/asm/xor.h index 7604673..4ffb26d 100644 --- a/arch/arm/include/asm/xor.h +++ b/arch/arm/include/asm/xor.h @@ -7,7 +7,10 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ +#include <linux/hardirq.h> #include <asm-generic/xor.h> +#include <asm/hwcap.h> +#include <asm/neon.h> #define __XOR(a1, a2) a1 ^= a2 @@ -138,4 +141,74 @@ static struct xor_block_template xor_block_arm4regs = { xor_speed(&xor_block_arm4regs); \ xor_speed(&xor_block_8regs); \ xor_speed(&xor_block_32regs); \ + NEON_TEMPLATES; \ } while (0) + +#ifdef CONFIG_KERNEL_MODE_NEON + +extern struct xor_block_template const xor_block_neon_inner; + +static void +xor_neon_2(unsigned long bytes, unsigned long *p1, unsigned long *p2) +{ + if (in_interrupt()) { + xor_arm4regs_2(bytes, p1, p2); + } else { + kernel_neon_begin(); + xor_block_neon_inner.do_2(bytes, p1, p2); + kernel_neon_end(); + } +} + +static void +xor_neon_3(unsigned long bytes, unsigned long *p1, unsigned long *p2, + unsigned long *p3) +{ + if (in_interrupt()) { + xor_arm4regs_3(bytes, p1, p2, p3); + } else { + kernel_neon_begin(); + xor_block_neon_inner.do_3(bytes, p1, p2, p3); + kernel_neon_end(); + } +} + +static void +xor_neon_4(unsigned long bytes, unsigned long *p1, unsigned long *p2, + unsigned long *p3, unsigned long *p4) +{ + if (in_interrupt()) { + xor_arm4regs_4(bytes, p1, p2, p3, p4); + } else { + kernel_neon_begin(); + xor_block_neon_inner.do_4(bytes, p1, p2, p3, p4); + kernel_neon_end(); + } +} + +static void +xor_neon_5(unsigned long bytes, unsigned long *p1, unsigned long *p2, + unsigned long *p3, unsigned long *p4, unsigned long *p5) +{ + if (in_interrupt()) { + xor_arm4regs_5(bytes, p1, p2, p3, p4, p5); + } else { + kernel_neon_begin(); + xor_block_neon_inner.do_5(bytes, p1, p2, p3, p4, p5); + kernel_neon_end(); + } +} + +static struct xor_block_template xor_block_neon = { + .name = "neon", + .do_2 = xor_neon_2, + .do_3 = xor_neon_3, + .do_4 = xor_neon_4, + .do_5 = xor_neon_5 +}; + +#define NEON_TEMPLATES \ + do { if (cpu_has_neon()) xor_speed(&xor_block_neon); } while (0) +#else +#define NEON_TEMPLATES +#endif diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index af72969..aaf3a87 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -45,3 +45,9 @@ lib-$(CONFIG_ARCH_SHARK) += io-shark.o $(obj)/csumpartialcopy.o: $(obj)/csumpartialcopygeneric.S $(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S + +ifeq ($(CONFIG_KERNEL_MODE_NEON),y) + NEON_FLAGS := -mfloat-abi=softfp -mfpu=neon + CFLAGS_xor-neon.o += $(NEON_FLAGS) + lib-$(CONFIG_XOR_BLOCKS) += xor-neon.o +endif diff --git a/arch/arm/lib/xor-neon.c b/arch/arm/lib/xor-neon.c new file mode 100644 index 0000000..f485e5a --- /dev/null +++ b/arch/arm/lib/xor-neon.c @@ -0,0 +1,42 @@ +/* + * linux/arch/arm/lib/xor-neon.c + * + * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/raid/xor.h> + +#ifndef __ARM_NEON__ +#error You should compile this file with '-mfloat-abi=softfp -mfpu=neon' +#endif + +/* + * Pull in the reference implementations while instructing GCC (through + * -ftree-vectorize) to attempt to exploit implicit parallelism and emit + * NEON instructions. + */ +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6) +#pragma GCC optimize "tree-vectorize" +#else +/* + * While older versions of GCC do not generate incorrect code, they fail to + * recognize the parallel nature of these functions, and emit plain ARM code, + * which is known to be slower than the optimized ARM code in asm-arm/xor.h. + */ +#warning This code requires at least version 4.6 of GCC +#endif + +#pragma GCC diagnostic ignored "-Wunused-variable" +#include <asm-generic/xor.h> + +struct xor_block_template const xor_block_neon_inner = { + .name = "__inner_neon__", + .do_2 = xor_8regs_2, + .do_3 = xor_8regs_3, + .do_4 = xor_8regs_4, + .do_5 = xor_8regs_5, +}; diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S index 8d10dc8..3e5d311 100644 --- a/arch/arm/vfp/vfphw.S +++ b/arch/arm/vfp/vfphw.S @@ -78,6 +78,11 @@ ENTRY(vfp_support_entry) DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10 + ldr r3, [sp, #S_PSR] @ Neither lazy restore nor FP exceptions + and r3, r3, #MODE_MASK @ are supported in kernel mode + teq r3, #USR_MODE + bne vfp_kmode_exception @ Returns through lr + VFPFMRX r1, FPEXC @ Is the VFP enabled? DBGSTR1 "fpexc %08x", r1 tst r1, #FPEXC_EN diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 5dfbb0b..52b8f40 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -20,6 +20,7 @@ #include <linux/init.h> #include <linux/uaccess.h> #include <linux/user.h> +#include <linux/export.h> #include <asm/cp15.h> #include <asm/cputype.h> @@ -648,6 +649,72 @@ static int vfp_hotplug(struct notifier_block *b, unsigned long action, return NOTIFY_OK; } +void vfp_kmode_exception(void) +{ + /* + * If we reach this point, a floating point exception has been raised + * while running in kernel mode. If the NEON/VFP unit was enabled at the + * time, it means a VFP instruction has been issued that requires + * software assistance to complete, something which is not currently + * supported in kernel mode. + * If the NEON/VFP unit was disabled, and the location pointed to below + * is properly preceded by a call to kernel_neon_begin(), something has + * caused the task to be scheduled out and back in again. In this case, + * rebuilding and running with CONFIG_DEBUG_ATOMIC_SLEEP enabled should + * be helpful in localizing the problem. + */ + if (fmrx(FPEXC) & FPEXC_EN) + pr_crit("BUG: unsupported FP instruction in kernel mode\n"); + else + pr_crit("BUG: FP instruction issued in kernel mode with FP unit disabled\n"); +} + +#ifdef CONFIG_KERNEL_MODE_NEON + +/* + * Kernel-side NEON support functions + */ +void kernel_neon_begin(void) +{ + struct thread_info *thread = current_thread_info(); + unsigned int cpu; + u32 fpexc; + + /* + * Kernel mode NEON is only allowed outside of interrupt context + * with preemption disabled. This will make sure that the kernel + * mode NEON register contents never need to be preserved. + */ + BUG_ON(in_interrupt()); + cpu = get_cpu(); + + fpexc = fmrx(FPEXC) | FPEXC_EN; + fmxr(FPEXC, fpexc); + + /* + * Save the userland NEON/VFP state. Under UP, + * the owner could be a task other than 'current' + */ + if (vfp_state_in_hw(cpu, thread)) + vfp_save_state(&thread->vfpstate, fpexc); +#ifndef CONFIG_SMP + else if (vfp_current_hw_state[cpu] != NULL) + vfp_save_state(vfp_current_hw_state[cpu], fpexc); +#endif + vfp_current_hw_state[cpu] = NULL; +} +EXPORT_SYMBOL(kernel_neon_begin); + +void kernel_neon_end(void) +{ + /* Disable the NEON/VFP unit. */ + fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN); + put_cpu(); +} +EXPORT_SYMBOL(kernel_neon_end); + +#endif /* CONFIG_KERNEL_MODE_NEON */ + /* * VFP support code initialisation. */ @@ -731,4 +798,4 @@ static int __init vfp_init(void) return 0; } -late_initcall(vfp_init); +core_initcall(vfp_init); diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h index 8dfaa2c..0f42469 100644 --- a/include/linux/raid/pq.h +++ b/include/linux/raid/pq.h @@ -114,6 +114,11 @@ extern const struct raid6_recov_calls raid6_recov_intx1; extern const struct raid6_recov_calls raid6_recov_ssse3; extern const struct raid6_recov_calls raid6_recov_avx2; +extern const struct raid6_calls raid6_neonx1; +extern const struct raid6_calls raid6_neonx2; +extern const struct raid6_calls raid6_neonx4; +extern const struct raid6_calls raid6_neonx8; + /* Algorithm list */ extern const struct raid6_calls * const raid6_algos[]; extern const struct raid6_recov_calls *const raid6_recov_algos[]; diff --git a/lib/raid6/.gitignore b/lib/raid6/.gitignore index 162beca..0a7e494 100644 --- a/lib/raid6/.gitignore +++ b/lib/raid6/.gitignore @@ -2,3 +2,4 @@ mktables altivec*.c int*.c tables.c +neon?.c diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile index 9f7c184..b462578 100644 --- a/lib/raid6/Makefile +++ b/lib/raid6/Makefile @@ -5,6 +5,7 @@ raid6_pq-y += algos.o recov.o tables.o int1.o int2.o int4.o \ raid6_pq-$(CONFIG_X86) += recov_ssse3.o recov_avx2.o mmx.o sse1.o sse2.o avx2.o raid6_pq-$(CONFIG_ALTIVEC) += altivec1.o altivec2.o altivec4.o altivec8.o +raid6_pq-$(CONFIG_KERNEL_MODE_NEON) += neon.o neon1.o neon2.o neon4.o neon8.o hostprogs-y += mktables @@ -16,6 +17,21 @@ ifeq ($(CONFIG_ALTIVEC),y) altivec_flags := -maltivec -mabi=altivec endif +# The GCC option -ffreestanding is required in order to compile code containing +# ARM/NEON intrinsics in a non C99-compliant environment (such as the kernel) +ifeq ($(CONFIG_KERNEL_MODE_NEON),y) +NEON_FLAGS := -ffreestanding +ifeq ($(ARCH),arm) +NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon +endif +ifeq ($(ARCH),arm64) +CFLAGS_REMOVE_neon1.o += -mgeneral-regs-only +CFLAGS_REMOVE_neon2.o += -mgeneral-regs-only +CFLAGS_REMOVE_neon4.o += -mgeneral-regs-only +CFLAGS_REMOVE_neon8.o += -mgeneral-regs-only +endif +endif + targets += int1.c $(obj)/int1.c: UNROLL := 1 $(obj)/int1.c: $(src)/int.uc $(src)/unroll.awk FORCE @@ -70,6 +86,30 @@ $(obj)/altivec8.c: UNROLL := 8 $(obj)/altivec8.c: $(src)/altivec.uc $(src)/unroll.awk FORCE $(call if_changed,unroll) +CFLAGS_neon1.o += $(NEON_FLAGS) +targets += neon1.c +$(obj)/neon1.c: UNROLL := 1 +$(obj)/neon1.c: $(src)/neon.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + +CFLAGS_neon2.o += $(NEON_FLAGS) +targets += neon2.c +$(obj)/neon2.c: UNROLL := 2 +$(obj)/neon2.c: $(src)/neon.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + +CFLAGS_neon4.o += $(NEON_FLAGS) +targets += neon4.c +$(obj)/neon4.c: UNROLL := 4 +$(obj)/neon4.c: $(src)/neon.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + +CFLAGS_neon8.o += $(NEON_FLAGS) +targets += neon8.c +$(obj)/neon8.c: UNROLL := 8 +$(obj)/neon8.c: $(src)/neon.uc $(src)/unroll.awk FORCE + $(call if_changed,unroll) + quiet_cmd_mktable = TABLE $@ cmd_mktable = $(obj)/mktables > $@ || ( rm -f $@ && exit 1 ) diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c index 6d7316f..74e6f56 100644 --- a/lib/raid6/algos.c +++ b/lib/raid6/algos.c @@ -70,6 +70,12 @@ const struct raid6_calls * const raid6_algos[] = { &raid6_intx2, &raid6_intx4, &raid6_intx8, +#ifdef CONFIG_KERNEL_MODE_NEON + &raid6_neonx1, + &raid6_neonx2, + &raid6_neonx4, + &raid6_neonx8, +#endif NULL }; diff --git a/lib/raid6/neon.c b/lib/raid6/neon.c new file mode 100644 index 0000000..36ad470 --- /dev/null +++ b/lib/raid6/neon.c @@ -0,0 +1,58 @@ +/* + * linux/lib/raid6/neon.c - RAID6 syndrome calculation using ARM NEON intrinsics + * + * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/raid/pq.h> + +#ifdef __KERNEL__ +#include <asm/neon.h> +#else +#define kernel_neon_begin() +#define kernel_neon_end() +#define cpu_has_neon() (1) +#endif + +/* + * There are 2 reasons these wrappers are kept in a separate compilation unit + * from the actual implementations in neonN.c (generated from neon.uc by + * unroll.awk): + * - the actual implementations use NEON intrinsics, and the GCC support header + * (arm_neon.h) is not fully compatible (type wise) with the kernel; + * - the neonN.c files are compiled with -mfpu=neon and optimization enabled, + * and we have to make sure that we never use *any* NEON/VFP instructions + * outside a kernel_neon_begin()/kernel_neon_end() pair. + */ + +#define RAID6_NEON_WRAPPER(_n) \ + static void raid6_neon ## _n ## _gen_syndrome(int disks, \ + size_t bytes, void **ptrs) \ + { \ + void raid6_neon ## _n ## _gen_syndrome_real(int, \ + unsigned long, void**); \ + kernel_neon_begin(); \ + raid6_neon ## _n ## _gen_syndrome_real(disks, \ + (unsigned long)bytes, ptrs); \ + kernel_neon_end(); \ + } \ + struct raid6_calls const raid6_neonx ## _n = { \ + raid6_neon ## _n ## _gen_syndrome, \ + raid6_have_neon, \ + "neonx" #_n, \ + 0 \ + } + +static int raid6_have_neon(void) +{ + return cpu_has_neon(); +} + +RAID6_NEON_WRAPPER(1); +RAID6_NEON_WRAPPER(2); +RAID6_NEON_WRAPPER(4); +RAID6_NEON_WRAPPER(8); diff --git a/lib/raid6/neon.uc b/lib/raid6/neon.uc new file mode 100644 index 0000000..1b9ed79 --- /dev/null +++ b/lib/raid6/neon.uc @@ -0,0 +1,80 @@ +/* ----------------------------------------------------------------------- + * + * neon.uc - RAID-6 syndrome calculation using ARM NEON instructions + * + * Copyright (C) 2012 Rob Herring + * + * Based on altivec.uc: + * Copyright 2002-2004 H. Peter Anvin - All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, Inc., 53 Temple Place Ste 330, + * Boston MA 02111-1307, USA; either version 2 of the License, or + * (at your option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * neon$#.c + * + * $#-way unrolled NEON intrinsics math RAID-6 instruction set + * + * This file is postprocessed using unroll.awk + */ + +#include <arm_neon.h> + +typedef uint8x16_t unative_t; + +#define NBYTES(x) ((unative_t){x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x}) +#define NSIZE sizeof(unative_t) + +/* + * The SHLBYTE() operation shifts each byte left by 1, *not* + * rolling over into the next byte + */ +static inline unative_t SHLBYTE(unative_t v) +{ + return vshlq_n_u8(v, 1); +} + +/* + * The MASK() operation returns 0xFF in any byte for which the high + * bit is 1, 0x00 for any byte for which the high bit is 0. + */ +static inline unative_t MASK(unative_t v) +{ + const uint8x16_t temp = NBYTES(0); + return (unative_t)vcltq_s8((int8x16_t)v, (int8x16_t)temp); +} + +void raid6_neon$#_gen_syndrome_real(int disks, unsigned long bytes, void **ptrs) +{ + uint8_t **dptr = (uint8_t **)ptrs; + uint8_t *p, *q; + int d, z, z0; + + register unative_t wd$$, wq$$, wp$$, w1$$, w2$$; + const unative_t x1d = NBYTES(0x1d); + + z0 = disks - 3; /* Highest data disk */ + p = dptr[z0+1]; /* XOR parity */ + q = dptr[z0+2]; /* RS syndrome */ + + for ( d = 0 ; d < bytes ; d += NSIZE*$# ) { + wq$$ = wp$$ = vld1q_u8(&dptr[z0][d+$$*NSIZE]); + for ( z = z0-1 ; z >= 0 ; z-- ) { + wd$$ = vld1q_u8(&dptr[z][d+$$*NSIZE]); + wp$$ = veorq_u8(wp$$, wd$$); + w2$$ = MASK(wq$$); + w1$$ = SHLBYTE(wq$$); + + w2$$ = vandq_u8(w2$$, x1d); + w1$$ = veorq_u8(w1$$, w2$$); + wq$$ = veorq_u8(w1$$, wd$$); + } + vst1q_u8(&p[d+NSIZE*$$], wp$$); + vst1q_u8(&q[d+NSIZE*$$], wq$$); + } +} diff --git a/lib/raid6/test/Makefile b/lib/raid6/test/Makefile index 087332d..28afa1a 100644 --- a/lib/raid6/test/Makefile +++ b/lib/raid6/test/Makefile @@ -22,11 +22,23 @@ ifeq ($(ARCH),x86_64) IS_X86 = yes endif +ifeq ($(ARCH),arm) + CFLAGS += -I../../../arch/arm/include -mfpu=neon + HAS_NEON = yes +endif +ifeq ($(ARCH),arm64) + CFLAGS += -I../../../arch/arm64/include + HAS_NEON = yes +endif + ifeq ($(IS_X86),yes) OBJS += mmx.o sse1.o sse2.o avx2.o recov_ssse3.o recov_avx2.o CFLAGS += $(shell echo "vpbroadcastb %xmm0, %ymm1" | \ gcc -c -x assembler - >&/dev/null && \ rm ./-.o && echo -DCONFIG_AS_AVX2=1) +else ifeq ($(HAS_NEON),yes) + OBJS += neon.o neon1.o neon2.o neon4.o neon8.o + CFLAGS += -DCONFIG_KERNEL_MODE_NEON=1 else HAS_ALTIVEC := $(shell echo -e '\#include <altivec.h>\nvector int a;' |\ gcc -c -x c - >&/dev/null && \ @@ -55,6 +67,18 @@ raid6.a: $(OBJS) raid6test: test.c raid6.a $(CC) $(CFLAGS) -o raid6test $^ +neon1.c: neon.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=1 < neon.uc > $@ + +neon2.c: neon.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=2 < neon.uc > $@ + +neon4.c: neon.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=4 < neon.uc > $@ + +neon8.c: neon.uc ../unroll.awk + $(AWK) ../unroll.awk -vN=8 < neon.uc > $@ + altivec1.c: altivec.uc ../unroll.awk $(AWK) ../unroll.awk -vN=1 < altivec.uc > $@ @@ -89,7 +113,7 @@ tables.c: mktables ./mktables > tables.c clean: - rm -f *.o *.a mktables mktables.c *.uc int*.c altivec*.c tables.c raid6test + rm -f *.o *.a mktables mktables.c *.uc int*.c altivec*.c neon*.c tables.c raid6test spotless: clean rm -f *~ |
