mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-24 23:34:40 +07:00
921ebd8f2c
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. This patch adds both a system call and a VDSO entry. If possible, we'd like to avoid having the system call be considered part of the user-facing ABI and instead restrict that to the VDSO entry -- both just in general to avoid having additional user-visible ABI to maintain, and because we'd prefer that users just call the VDSO entry because there might be a better way to do this in the future (ie, one that doesn't require entering the kernel). Signed-off-by: Andrew Waterman <andrew@sifive.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
46 lines
1.5 KiB
C
46 lines
1.5 KiB
C
/*
|
|
* Copyright (C) 2012 ARM Limited
|
|
* Copyright (C) 2014 Regents of the University of California
|
|
* 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_H
|
|
#define _ASM_RISCV_VDSO_H
|
|
|
|
#include <linux/types.h>
|
|
|
|
struct vdso_data {
|
|
};
|
|
|
|
/*
|
|
* The VDSO symbols are mapped into Linux so we can just use regular symbol
|
|
* addressing to get their offsets in userspace. The symbols are mapped at an
|
|
* offset of 0, but since the linker must support setting weak undefined
|
|
* symbols to the absolute address 0 it also happens to support other low
|
|
* addresses even when the code model suggests those low addresses would not
|
|
* otherwise be availiable.
|
|
*/
|
|
#define VDSO_SYMBOL(base, name) \
|
|
({ \
|
|
extern const char __vdso_##name[]; \
|
|
(void __user *)((unsigned long)(base) + __vdso_##name); \
|
|
})
|
|
|
|
#ifdef CONFIG_SMP
|
|
asmlinkage long sys_riscv_flush_icache(uintptr_t, uintptr_t, uintptr_t);
|
|
#endif
|
|
|
|
#endif /* _ASM_RISCV_VDSO_H */
|