mirror of https://github.com/hak5/openwrt.git
89 lines
3.9 KiB
Diff
89 lines
3.9 KiB
Diff
|
From: Arnd Bergmann <arnd@arndb.de>
|
||
|
|
Date: Tue, 19 Jun 2018 13:14:57 -0700
|
||
|
|
Subject: [PATCH] disable -Wattribute-alias warning for SYSCALL_DEFINEx()
|
||
|
|
|
||
|
|
gcc-8 warns for every single definition of a system call entry
|
||
|
|
point, e.g.:
|
||
|
|
|
||
|
|
include/linux/compat.h:56:18: error: 'compat_sys_rt_sigprocmask' alias between functions of incompatible types 'long int(int, compat_sigset_t *, compat_sigset_t *, compat_size_t)' {aka 'long int(int, struct <anonymous> *, struct <anonymous> *, unsigned int)'} and 'long int(long int, long int, long int, long int)' [-Werror=attribute-alias]
|
||
|
|
asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\
|
||
|
|
^~~~~~~~~~
|
||
|
|
include/linux/compat.h:45:2: note: in expansion of macro 'COMPAT_SYSCALL_DEFINEx'
|
||
|
|
COMPAT_SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
|
||
|
|
^~~~~~~~~~~~~~~~~~~~~~
|
||
|
|
kernel/signal.c:2601:1: note: in expansion of macro 'COMPAT_SYSCALL_DEFINE4'
|
||
|
|
COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
|
||
|
|
^~~~~~~~~~~~~~~~~~~~~~
|
||
|
|
include/linux/compat.h:60:18: note: aliased declaration here
|
||
|
|
asmlinkage long compat_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__))\
|
||
|
|
^~~~~~~~~~
|
||
|
|
|
||
|
|
The new warning seems reasonable in principle, but it doesn't
|
||
|
|
help us here, since we rely on the type mismatch to sanitize the
|
||
|
|
system call arguments. After I reported this as GCC PR82435, a new
|
||
|
|
-Wno-attribute-alias option was added that could be used to turn the
|
||
|
|
warning off globally on the command line, but I'd prefer to do it a
|
||
|
|
little more fine-grained.
|
||
|
|
|
||
|
|
Interestingly, turning a warning off and on again inside of
|
||
|
|
a single macro doesn't always work, in this case I had to add
|
||
|
|
an extra statement inbetween and decided to copy the __SC_TEST
|
||
|
|
one from the native syscall to the compat syscall macro. See
|
||
|
|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 for more details
|
||
|
|
about this.
|
||
|
|
|
||
|
|
[paul.burton@mips.com:
|
||
|
|
- Rebase atop current master.
|
||
|
|
- Split GCC & version arguments to __diag_ignore() in order to match
|
||
|
|
changes to the preceding patch.
|
||
|
|
- Add the comment argument to match the preceding patch.]
|
||
|
|
|
||
|
|
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82435
|
||
|
|
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
||
|
|
Signed-off-by: Paul Burton <paul.burton@mips.com>
|
||
|
|
Tested-by: Christophe Leroy <christophe.leroy@c-s.fr>
|
||
|
|
Tested-by: Stafford Horne <shorne@gmail.com>
|
||
|
|
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
|
||
|
|
---
|
||
|
|
|
||
|
|
--- a/include/linux/compat.h
|
||
|
|
+++ b/include/linux/compat.h
|
||
|
|
@@ -47,6 +47,9 @@
|
||
|
|
COMPAT_SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
|
||
|
|
|
||
|
|
#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
|
||
|
|
+ __diag_push(); \
|
||
|
|
+ __diag_ignore(GCC, 8, "-Wattribute-alias", \
|
||
|
|
+ "Type aliasing is used to sanitize syscall arguments");\
|
||
|
|
asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\
|
||
|
|
__attribute__((alias(__stringify(compat_SyS##name)))); \
|
||
|
|
static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
|
||
|
|
@@ -55,6 +58,7 @@
|
||
|
|
{ \
|
||
|
|
return C_SYSC##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \
|
||
|
|
} \
|
||
|
|
+ __diag_pop(); \
|
||
|
|
static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
|
||
|
|
|
||
|
|
#ifndef compat_user_stack_pointer
|
||
|
|
--- a/include/linux/syscalls.h
|
||
|
|
+++ b/include/linux/syscalls.h
|
||
|
|
@@ -192,6 +192,9 @@ extern struct trace_event_functions exit
|
||
|
|
|
||
|
|
#define __PROTECT(...) asmlinkage_protect(__VA_ARGS__)
|
||
|
|
#define __SYSCALL_DEFINEx(x, name, ...) \
|
||
|
|
+ __diag_push(); \
|
||
|
|
+ __diag_ignore(GCC, 8, "-Wattribute-alias", \
|
||
|
|
+ "Type aliasing is used to sanitize syscall arguments");\
|
||
|
|
asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
|
||
|
|
__attribute__((alias(__stringify(SyS##name)))); \
|
||
|
|
static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
|
||
|
|
@@ -203,6 +206,7 @@ extern struct trace_event_functions exit
|
||
|
|
__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
|
||
|
|
return ret; \
|
||
|
|
} \
|
||
|
|
+ __diag_pop(); \
|
||
|
|
static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
|
||
|
|
|
||
|
|
asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
|