From 9e49a4ed072ab67b17238c5a45d7cba7f848659e Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt <palmer@dabbelt.com> Date: Tue, 26 Dec 2017 19:11:22 -0800 Subject: RISC-V: Make __NR_riscv_flush_icache visible to userspace We were hoping to avoid making this visible to userspace, but it looks like we're going to have to because QEMU's user-mode emulation doesn't want to emulate a vDSO. Having vDSO-only system calls was a bit unothodox anyway, so I think in this case it's OK to just make the actual system call number public. This patch simply moves the definition of __NR_riscv_flush_icache availiable to userspace, which results in the deletion of the now empty vdso-syscalls.h. Changes since v1: * I've moved the definition into uapi/asm/syscalls.h rathen than uapi/asm/unistd.h. This allows me to keep asm/unistd.h, so we can keep the syscall table macros sane. * As a side effect of the above, this no longer disables all system calls on RISC-V. Whoops! Signed-off-by: Palmer Dabbelt <palmer@sifive.com> --- arch/riscv/include/asm/unistd.h | 1 + arch/riscv/include/asm/vdso-syscalls.h | 28 ---------------------------- arch/riscv/include/uapi/asm/syscalls.h | 26 ++++++++++++++++++++++++++ arch/riscv/kernel/syscall_table.c | 1 - arch/riscv/kernel/vdso/flush_icache.S | 1 - 5 files changed, 27 insertions(+), 30 deletions(-) delete mode 100644 arch/riscv/include/asm/vdso-syscalls.h create mode 100644 arch/riscv/include/uapi/asm/syscalls.h diff --git a/arch/riscv/include/asm/unistd.h b/arch/riscv/include/asm/unistd.h index 9f250ed007cd..2f704a5c4196 100644 --- a/arch/riscv/include/asm/unistd.h +++ b/arch/riscv/include/asm/unistd.h @@ -14,3 +14,4 @@ #define __ARCH_HAVE_MMU #define __ARCH_WANT_SYS_CLONE #include <uapi/asm/unistd.h> +#include <uapi/asm/syscalls.h> diff --git a/arch/riscv/include/asm/vdso-syscalls.h b/arch/riscv/include/asm/vdso-syscalls.h deleted file mode 100644 index a2ccf1894929..000000000000 --- a/arch/riscv/include/asm/vdso-syscalls.h +++ /dev/null @@ -1,28 +0,0 @@ -/* - * Copyright (C) 2017 SiFive - * - * 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. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see <http://www.gnu.org/licenses/>. - */ - -#ifndef _ASM_RISCV_VDSO_SYSCALLS_H -#define _ASM_RISCV_VDSO_SYSCALLS_H - -#ifdef CONFIG_SMP - -/* These syscalls are only used by the vDSO and are not in the uapi. */ -#define __NR_riscv_flush_icache (__NR_arch_specific_syscall + 15) -__SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache) - -#endif - -#endif /* _ASM_RISCV_VDSO_H */ diff --git a/arch/riscv/include/uapi/asm/syscalls.h b/arch/riscv/include/uapi/asm/syscalls.h new file mode 100644 index 000000000000..818655b0d535 --- /dev/null +++ b/arch/riscv/include/uapi/asm/syscalls.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2017 SiFive + */ + +#ifndef _ASM__UAPI__SYSCALLS_H +#define _ASM__UAPI__SYSCALLS_H + +/* + * Allows the instruction cache to be flushed from userspace. Despite RISC-V + * having a direct 'fence.i' instruction available to userspace (which we + * can't trap!), that's not actually viable when running on Linux because the + * kernel might schedule a process on another hart. There is no way for + * userspace to handle this without invoking the kernel (as it doesn't know the + * thread->hart mappings), so we've defined a RISC-V specific system call to + * flush the instruction cache. + * + * __NR_riscv_flush_icache is defined to flush the instruction cache over an + * address range, with the flush applying to either all threads or just the + * caller. We don't currently do anything with the address range, that's just + * in there for forwards compatibility. + */ +#define __NR_riscv_flush_icache (__NR_arch_specific_syscall + 15) +__SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache) + +#endif diff --git a/arch/riscv/kernel/syscall_table.c b/arch/riscv/kernel/syscall_table.c index a5bd6401f95e..ade52b903a43 100644 --- a/arch/riscv/kernel/syscall_table.c +++ b/arch/riscv/kernel/syscall_table.c @@ -23,5 +23,4 @@ void *sys_call_table[__NR_syscalls] = { [0 ... __NR_syscalls - 1] = sys_ni_syscall, #include <asm/unistd.h> -#include <asm/vdso-syscalls.h> }; diff --git a/arch/riscv/kernel/vdso/flush_icache.S b/arch/riscv/kernel/vdso/flush_icache.S index b0fbad74e873..023e4d4aef58 100644 --- a/arch/riscv/kernel/vdso/flush_icache.S +++ b/arch/riscv/kernel/vdso/flush_icache.S @@ -13,7 +13,6 @@ #include <linux/linkage.h> #include <asm/unistd.h> -#include <asm/vdso-syscalls.h> .text /* int __vdso_flush_icache(void *start, void *end, unsigned long flags); */ -- cgit v1.2.3