From: Palmer Dabbelt <palmer@sifive.com>
To: Christoph Hellwig <hch@infradead.org>, linux@roeck-us.net
Cc: Palmer Dabbelt <palmer@sifive.com>,
aou@eecs.berkeley.edu, Arnd Bergmann <arnd@arndb.de>,
tklauser@distanz.ch, Andrew Waterman <andrew@sifive.com>,
dan.carpenter@oracle.com, linux@dominikbrodowski.net,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
Marcus Comstedt <marcus@mc.pp.se>
Subject: [PATCH v2 2/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls.h
Date: Thu, 9 Aug 2018 13:25:24 -0700 [thread overview]
Message-ID: <20180809202524.1702-3-palmer@sifive.com> (raw)
In-Reply-To: <20180809202524.1702-1-palmer@sifive.com>
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 <marcus@mc.pp.se>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
---
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 <uapi/asm/unistd.h>
#include <uapi/asm/syscalls.h>
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
next prev parent reply other threads:[~2018-08-09 20:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-09 20:25 [PATCH v2 0/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls Palmer Dabbelt
2018-08-09 20:25 ` [PATCH v2 1/2] RISC-V: Define sys_riscv_flush_icache when SMP=n Palmer Dabbelt
2018-08-09 21:20 ` Guenter Roeck
2018-08-09 20:25 ` Palmer Dabbelt [this message]
2018-08-09 21:24 ` [PATCH v2 2/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls.h Guenter Roeck
2018-08-10 1:03 ` Palmer Dabbelt
2018-08-10 2:40 ` Guenter Roeck
2018-08-10 3:59 ` Palmer Dabbelt
2018-08-10 4:11 ` Guenter Roeck
2018-08-10 4:53 ` Guenter Roeck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180809202524.1702-3-palmer@sifive.com \
--to=palmer@sifive.com \
--cc=andrew@sifive.com \
--cc=aou@eecs.berkeley.edu \
--cc=arnd@arndb.de \
--cc=dan.carpenter@oracle.com \
--cc=hch@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux@dominikbrodowski.net \
--cc=linux@roeck-us.net \
--cc=marcus@mc.pp.se \
--cc=tklauser@distanz.ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).