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Unverified Commit e45c7aca authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

RISC-V: Don't use a global include guard for uapi/asm/syscalls.h 



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!

Cc: Marcus Comstedt <marcus@mc.pp.se>
Signed-off-by: default avatarPalmer Dabbelt <palmer@sifive.com>
parent 7847e705

arch/riscv/include/asm/unistd.h

+5 −0
Original line number Diff line number Diff line
@@ -11,6 +11,11 @@ 
 *   GNU General Public License for more details.

 */



/*

 * There is explicitly no include guard here because this file is expected to

 * be included multiple times.  See uapi/asm/syscalls.h for more info.

 */



#define __ARCH_WANT_SYS_CLONE

#include <uapi/asm/unistd.h>

#include <uapi/asm/syscalls.h>

arch/riscv/include/uapi/asm/syscalls.h

+8 −5
Original line number Diff line number Diff line 
/* 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 +23,7 @@ 
 * 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)