From 921ebd8f2c081b3cf6c3b29ef4103eef3ff26054 Mon Sep 17 00:00:00 2001 From: Andrew Waterman Date: Wed, 25 Oct 2017 14:32:16 -0700 Subject: RISC-V: Allow userspace to flush the instruction cache 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 Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/syscall_table.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/riscv/kernel/syscall_table.c') diff --git a/arch/riscv/kernel/syscall_table.c b/arch/riscv/kernel/syscall_table.c index 4e30dc5fb593..a5bd6401f95e 100644 --- a/arch/riscv/kernel/syscall_table.c +++ b/arch/riscv/kernel/syscall_table.c @@ -15,6 +15,7 @@ #include #include #include +#include #undef __SYSCALL #define __SYSCALL(nr, call) [nr] = (call), @@ -22,4 +23,5 @@ void *sys_call_table[__NR_syscalls] = { [0 ... __NR_syscalls - 1] = sys_ni_syscall, #include +#include }; -- cgit