On Fri, Aug 03, 2018 at 12:53:44PM -0700, Palmer Dabbelt wrote: > This file is expected to be included multiple times in the same file in > order to allow the __SYSCALL macro to generate system call tables. With > a global include guard we end up missing __NR_riscv_flush_icache in the > syscall table, which results in icache flushes that escape the vDSO call > to not actually do anything. > > The fix is to move to per-#define include guards, which allows the > system call tables to actually be populated. Thanks to Macrus Comstedt > for finding and fixing the bug! > > I also went ahead and fixed the SPDX header to use a //-style comment, > which I've been told is the canonical way to do it. > > Cc: Marcus Comstedt <mar...@mc.pp.se> > Signed-off-by: Palmer Dabbelt <pal...@sifive.com>
Fails to build riscv:allnoconfig. CC arch/riscv/kernel/syscall_table.o ./arch/riscv/include/uapi/asm/syscalls.h:29:36: error: ‘sys_riscv_flush_icache’ undeclared here (not in a function); did you mean ‘__NR_riscv_flush_icache’? Guenter > --- > arch/riscv/include/uapi/asm/syscalls.h | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/arch/riscv/include/uapi/asm/syscalls.h > b/arch/riscv/include/uapi/asm/syscalls.h > index 818655b0d535..882a6aa09a33 100644 > --- a/arch/riscv/include/uapi/asm/syscalls.h > +++ b/arch/riscv/include/uapi/asm/syscalls.h > @@ -1,10 +1,11 @@ > -/* SPDX-License-Identifier: GPL-2.0 */ > +// SPDX-License-Identifier: GPL-2.0 > /* > - * Copyright (C) 2017 SiFive > + * Copyright (C) 2017-2018 SiFive > */ > > -#ifndef _ASM__UAPI__SYSCALLS_H > -#define _ASM__UAPI__SYSCALLS_H > +/* There is explicitly no include guard here because this file is expected to > + * be included multiple times in order to define the syscall macros via > + * __SYSCALL. */ > > /* > * Allows the instruction cache to be flushed from userspace. Despite RISC-V > @@ -20,7 +21,7 @@ > * caller. We don't currently do anything with the address range, that's > just > * in there for forwards compatibility. > */ > +#ifndef __NR_riscv_flush_icache > #define __NR_riscv_flush_icache (__NR_arch_specific_syscall + 15) > -__SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache) > - > #endif > +__SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache)
