Re: [PATCH v3 2/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls.h
On Tue, 14 Aug 2018 06:40:27 PDT (-0700), Christoph Hellwig wrote: index 818655b0d535..690beb002d1d 100644 --- a/arch/riscv/include/uapi/asm/syscalls.h +++ b/arch/riscv/include/uapi/asm/syscalls.h @@ -1,10 +1,13 @@ -/* SPDX-License-Identifier: GPL-2.0 */ +// SPDX-License-Identifier: GPL-2.0 /* ... */ is the right style SPDX tag for headers, so please keep it as-is. Thanks, I didn't miss this one so I managed to fix it before the PR!
Re: [PATCH v3 2/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls.h
> index 818655b0d535..690beb002d1d 100644 > --- a/arch/riscv/include/uapi/asm/syscalls.h > +++ b/arch/riscv/include/uapi/asm/syscalls.h > @@ -1,10 +1,13 @@ > -/* SPDX-License-Identifier: GPL-2.0 */ > +// SPDX-License-Identifier: GPL-2.0 /* ... */ is the right style SPDX tag for headers, so please keep it as-is.
Re: [PATCH v3 2/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls.h
On Thu, Aug 09, 2018 at 03:19:52PM -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 > Signed-off-by: Palmer Dabbelt Tested-by: Guenter Roeck > --- > arch/riscv/include/asm/unistd.h| 5 + > arch/riscv/include/uapi/asm/syscalls.h | 15 +-- > 2 files changed, 14 insertions(+), 6 deletions(-) > > diff --git a/arch/riscv/include/asm/unistd.h b/arch/riscv/include/asm/unistd.h > index 080fb28061de..0caea01d5cca 100644 > --- a/arch/riscv/include/asm/unistd.h > +++ b/arch/riscv/include/asm/unistd.h > @@ -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 > #include > diff --git a/arch/riscv/include/uapi/asm/syscalls.h > b/arch/riscv/include/uapi/asm/syscalls.h > index 818655b0d535..690beb002d1d 100644 > --- a/arch/riscv/include/uapi/asm/syscalls.h > +++ b/arch/riscv/include/uapi/asm/syscalls.h > @@ -1,10 +1,13 @@ > -/* 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 +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) > -- > 2.16.4 >
[PATCH v3 2/2] 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! 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 Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/unistd.h| 5 + arch/riscv/include/uapi/asm/syscalls.h | 15 +-- 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/riscv/include/asm/unistd.h b/arch/riscv/include/asm/unistd.h index 080fb28061de..0caea01d5cca 100644 --- a/arch/riscv/include/asm/unistd.h +++ b/arch/riscv/include/asm/unistd.h @@ -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 #include diff --git a/arch/riscv/include/uapi/asm/syscalls.h b/arch/riscv/include/uapi/asm/syscalls.h index 818655b0d535..690beb002d1d 100644 --- a/arch/riscv/include/uapi/asm/syscalls.h +++ b/arch/riscv/include/uapi/asm/syscalls.h @@ -1,10 +1,13 @@ -/* 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 +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) -- 2.16.4
