From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: Dennis Zhou <dennis@kernel.org>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
Nicholas Piggin <npiggin@gmail.com>,
Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH] fix __percpu annotation in asm-generic
Date: Tue, 26 Nov 2019 21:06:19 +0100 [thread overview]
Message-ID: <20191126200619.63348-1-luc.vanoostenryck@gmail.com> (raw)
The generic implementation of raw_cpu_generic_add_return() is:
#define raw_cpu_generic_add_return(pcp, val) \
({ \
typeof(&(pcp)) __p = raw_cpu_ptr(&(pcp)); \
\
*__p += val; \
*__p; \
})
where the 'pcp' argument is a __percpu lvalue.
There, the variable '__p' is declared as a __percpu pointer
the type of the address of 'pcp') but:
1) the value assigned to it, the return value of raw_cpu_ptr(), is
a plain (__kernel) pointer, not a __percpu one.
2) the variable is dereferenced just after while a __percpu pointer
is implicitly __noderef.
So, fix the declaration of the 'pcp' variable to its correct type:
the plain (non-percpu) pointer corresponding to its address.
Same for raw_cpu_generic_xchg(), raw_cpu_generic_cmpxchg() &
raw_cpu_generic_cmpxchg_double().
This remove 209 warnings on ARM, 460 on x86 & 2600+ on ppc64.
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Reported-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
include/asm-generic/percpu.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index c2de013b2cf4..4ae5f89a0e61 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -74,7 +74,7 @@ do { \
#define raw_cpu_generic_add_return(pcp, val) \
({ \
- typeof(&(pcp)) __p = raw_cpu_ptr(&(pcp)); \
+ typeof(pcp) __kernel __force *__p = raw_cpu_ptr(&(pcp)); \
\
*__p += val; \
*__p; \
@@ -82,7 +82,7 @@ do { \
#define raw_cpu_generic_xchg(pcp, nval) \
({ \
- typeof(&(pcp)) __p = raw_cpu_ptr(&(pcp)); \
+ typeof(pcp) __kernel __force *__p = raw_cpu_ptr(&(pcp)); \
typeof(pcp) __ret; \
__ret = *__p; \
*__p = nval; \
@@ -91,7 +91,7 @@ do { \
#define raw_cpu_generic_cmpxchg(pcp, oval, nval) \
({ \
- typeof(&(pcp)) __p = raw_cpu_ptr(&(pcp)); \
+ typeof(pcp) __kernel __force *__p = raw_cpu_ptr(&(pcp)); \
typeof(pcp) __ret; \
__ret = *__p; \
if (__ret == (oval)) \
@@ -101,8 +101,8 @@ do { \
#define raw_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
({ \
- typeof(&(pcp1)) __p1 = raw_cpu_ptr(&(pcp1)); \
- typeof(&(pcp2)) __p2 = raw_cpu_ptr(&(pcp2)); \
+ typeof(pcp1) __kernel __force *__p1 = raw_cpu_ptr(&(pcp1)); \
+ typeof(pcp2) __kernel __force *__p2 = raw_cpu_ptr(&(pcp2)); \
int __ret = 0; \
if (*__p1 == (oval1) && *__p2 == (oval2)) { \
*__p1 = nval1; \
--
2.24.0
next reply other threads:[~2019-11-26 20:06 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 20:06 Luc Van Oostenryck [this message]
2019-11-26 20:06 ` [PATCH] fix __percpu annotation in asm-generic Luc Van Oostenryck
2019-11-27 15:55 ` Christopher Lameter
2019-11-27 15:55 ` Christopher Lameter
2019-11-27 17:53 ` Dennis Zhou
2019-11-27 17:53 ` Dennis Zhou
2019-11-27 22:54 ` Luc Van Oostenryck
2019-11-27 22:54 ` Luc Van Oostenryck
2019-11-29 18:11 ` Christopher Lameter
2019-11-29 18:11 ` Christopher Lameter
2019-11-30 0:00 ` Luc Van Oostenryck
2019-11-30 0:00 ` Luc Van Oostenryck
2019-12-02 19:07 ` Dennis Zhou
2019-12-02 19:07 ` Dennis Zhou
2019-12-02 19:42 ` Christopher Lameter
2019-12-02 19:42 ` Christopher Lameter
2019-12-03 3:01 ` Luc Van Oostenryck
2019-12-03 3:01 ` Luc Van Oostenryck
2020-03-24 4:13 ` Jason A. Donenfeld
2020-03-24 6:44 ` Luc Van Oostenryck
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=20191126200619.63348-1-luc.vanoostenryck@gmail.com \
--to=luc.vanoostenryck@gmail.com \
--cc=arnd@arndb.de \
--cc=ben.dooks@codethink.co.uk \
--cc=cl@linux.com \
--cc=dennis@kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=npiggin@gmail.com \
--cc=tj@kernel.org \
/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