From 7017858eb2d7ed7a295be02c71124049a6409295 Mon Sep 17 00:00:00 2001 From: Greentime Hu Date: Mon, 5 Jun 2023 11:07:05 +0000 Subject: [PATCH] riscv: Introduce riscv_v_vsize to record size of Vector context This patch is used to detect the size of CPU vector registers and use riscv_v_vsize to save the size of all the vector registers. It assumes all harts has the same capabilities in a SMP system. If a core detects VLENB that is different from the boot core, then it warns and turns off V support for user space. Co-developed-by: Guo Ren Signed-off-by: Guo Ren Co-developed-by: Vincent Chen Signed-off-by: Vincent Chen Signed-off-by: Greentime Hu Signed-off-by: Andy Chiu Reviewed-by: Conor Dooley Reviewed-by: Heiko Stuebner Tested-by: Heiko Stuebner Reviewed-by: Palmer Dabbelt Link: https://lore.kernel.org/r/20230605110724.21391-9-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/vector.h | 8 ++++++++ arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/cpufeature.c | 2 ++ arch/riscv/kernel/smpboot.c | 7 +++++++ arch/riscv/kernel/vector.c | 36 ++++++++++++++++++++++++++++++++++++ 5 files changed, 54 insertions(+) create mode 100644 arch/riscv/kernel/vector.c diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h index 51bb372..df3b5ca 100644 --- a/arch/riscv/include/asm/vector.h +++ b/arch/riscv/include/asm/vector.h @@ -7,12 +7,16 @@ #define __ASM_RISCV_VECTOR_H #include +#include #ifdef CONFIG_RISCV_ISA_V #include #include +extern unsigned long riscv_v_vsize; +int riscv_v_setup_vsize(void); + static __always_inline bool has_vector(void) { return riscv_has_extension_unlikely(RISCV_ISA_EXT_v); @@ -30,7 +34,11 @@ static __always_inline void riscv_v_disable(void) #else /* ! CONFIG_RISCV_ISA_V */ +struct pt_regs; + +static inline int riscv_v_setup_vsize(void) { return -EOPNOTSUPP; } static __always_inline bool has_vector(void) { return false; } +#define riscv_v_vsize (0) #endif /* CONFIG_RISCV_ISA_V */ diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index fbdccc21..c51f34c 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -56,6 +56,7 @@ obj-$(CONFIG_MMU) += vdso.o vdso/ obj-$(CONFIG_RISCV_M_MODE) += traps_misaligned.o obj-$(CONFIG_FPU) += fpu.o +obj-$(CONFIG_RISCV_ISA_V) += vector.o obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_SMP) += cpu_ops.o diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 7aaf92f..28032b0 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -18,6 +18,7 @@ #include #include #include +#include #define NUM_ALPHA_EXTS ('z' - 'a' + 1) @@ -269,6 +270,7 @@ void __init riscv_fill_hwcap(void) } if (elf_hwcap & COMPAT_HWCAP_ISA_V) { + riscv_v_setup_vsize(); /* * ISA string in device tree might have 'v' flag, but * CONFIG_RISCV_ISA_V is disabled in kernel. diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index 445a4ef..66011bf 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -31,6 +31,8 @@ #include #include #include +#include +#include #include "head.h" @@ -169,6 +171,11 @@ asmlinkage __visible void smp_callin(void) set_cpu_online(curr_cpuid, 1); probe_vendor_features(curr_cpuid); + if (has_vector()) { + if (riscv_v_setup_vsize()) + elf_hwcap &= ~COMPAT_HWCAP_ISA_V; + } + /* * Remote TLB flushes are ignored while the CPU is offline, so emit * a local TLB flush right now just in case. diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c new file mode 100644 index 0000000..120f1ce --- /dev/null +++ b/arch/riscv/kernel/vector.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2023 SiFive + * Author: Andy Chiu + */ +#include + +#include +#include +#include +#include + +unsigned long riscv_v_vsize __read_mostly; +EXPORT_SYMBOL_GPL(riscv_v_vsize); + +int riscv_v_setup_vsize(void) +{ + unsigned long this_vsize; + + /* There are 32 vector registers with vlenb length. */ + riscv_v_enable(); + this_vsize = csr_read(CSR_VLENB) * 32; + riscv_v_disable(); + + if (!riscv_v_vsize) { + riscv_v_vsize = this_vsize; + return 0; + } + + if (riscv_v_vsize != this_vsize) { + WARN(1, "RISCV_ISA_V only supports one vlenb on SMP systems"); + return -EOPNOTSUPP; + } + + return 0; +} -- 2.7.4