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linux-next/arch/s390/include/asm/syscall_wrapper.h
Arnd Bergmann aa0d6e70d3 s390: autogenerate compat syscall wrappers
Any system call that takes a pointer argument on s390 requires
a wrapper function to do a 31-to-64 zero-extension, these are
currently generated in arch/s390/kernel/compat_wrapper.c.

On arm64 and x86, we already generate similar wrappers for all
system calls in the place of their definition, just for a different
purpose (they load the arguments from pt_regs).

We can do the same thing here, by adding an asm/syscall_wrapper.h
file with a copy of all the relevant macros to override the generic
version. Besides the addition of the compat entry point, these also
rename the entry points with a __s390_ or __s390x_ prefix, similar
to what we do on arm64 and x86. This in turn requires renaming
a few things, and adding a proper ni_syscall() entry point.

In order to still compile system call definitions that pass an
loff_t argument, the __SC_COMPAT_CAST() macro checks for that
and forces an -ENOSYS error, which was the best I could come up
with. Those functions must obviously not get called from user
space, but instead require hand-written compat_sys_*() handlers,
which fortunately already exist.

Link: https://lore.kernel.org/lkml/20190116131527.2071570-5-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
[heiko.carstens@de.ibm.com: compile fix for !CONFIG_COMPAT]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-01-18 09:33:19 +01:00

136 lines
4.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* syscall_wrapper.h - s390 specific wrappers to syscall definitions
*
*/
#ifndef _ASM_S390_SYSCALL_WRAPPER_H
#define _ASM_S390_SYSCALL_WRAPPER_H
#ifdef CONFIG_COMPAT
#define __SC_COMPAT_TYPE(t, a) \
__typeof(__builtin_choose_expr(sizeof(t) > 4, 0L, (t)0)) a
#define __SC_COMPAT_CAST(t, a) \
({ \
long __ReS = a; \
\
BUILD_BUG_ON((sizeof(t) > 4) && !__TYPE_IS_L(t) && \
!__TYPE_IS_UL(t) && !__TYPE_IS_PTR(t) && \
!__TYPE_IS_LL(t)); \
if (__TYPE_IS_L(t)) \
__ReS = (s32)a; \
if (__TYPE_IS_UL(t)) \
__ReS = (u32)a; \
if (__TYPE_IS_PTR(t)) \
__ReS = a & 0x7fffffff; \
if (__TYPE_IS_LL(t)) \
return -ENOSYS; \
(t)__ReS; \
})
#define __S390_SYS_STUBx(x, name, ...) \
asmlinkage long __s390_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))\
ALLOW_ERROR_INJECTION(__s390_sys##name, ERRNO); \
asmlinkage long __s390_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))\
{ \
long ret = __s390x_sys##name(__MAP(x,__SC_COMPAT_CAST,__VA_ARGS__));\
__MAP(x,__SC_TEST,__VA_ARGS__); \
return ret; \
}
/*
* To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias
* named __s390x_sys_*()
*/
#define COMPAT_SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long __s390_compat_sys_##sname(void); \
ALLOW_ERROR_INJECTION(__s390_compat__sys_##sname, ERRNO); \
asmlinkage long __s390_compat_sys_##sname(void)
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long __s390x_sys_##sname(void); \
ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \
asmlinkage long __s390_sys_##sname(void) \
__attribute__((alias(__stringify(__s390x_sys_##sname)))); \
asmlinkage long __s390x_sys_##sname(void)
#define COND_SYSCALL(name) \
cond_syscall(__s390x_sys_##name); \
cond_syscall(__s390_sys_##name)
#define SYS_NI(name) \
SYSCALL_ALIAS(__s390x_sys_##name, sys_ni_posix_timers); \
SYSCALL_ALIAS(__s390_sys_##name, sys_ni_posix_timers)
#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
__diag_push(); \
__diag_ignore(GCC, 8, "-Wattribute-alias", \
"Type aliasing is used to sanitize syscall arguments");\
asmlinkage long __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
asmlinkage long __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
__attribute__((alias(__stringify(__se_compat_sys##name)))); \
ALLOW_ERROR_INJECTION(compat_sys##name, ERRNO); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
asmlinkage long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
asmlinkage long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
{ \
long ret = __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\
__MAP(x,__SC_TEST,__VA_ARGS__); \
return ret; \
} \
__diag_pop(); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
/*
* As some compat syscalls may not be implemented, we need to expand
* COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in
* kernel/time/posix-stubs.c to cover this case as well.
*/
#define COND_SYSCALL_COMPAT(name) \
cond_syscall(__s390_compat_sys_##name)
#define COMPAT_SYS_NI(name) \
SYSCALL_ALIAS(__s390_compat_sys_##name, sys_ni_posix_timers)
#else /* CONFIG_COMPAT */
#define __S390_SYS_STUBx(x, fullname, name, ...)
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long __s390x_sys_##sname(void); \
ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \
asmlinkage long __s390x_sys_##sname(void)
#define COND_SYSCALL(name) \
cond_syscall(__s390x_sys_##name)
#define SYS_NI(name) \
SYSCALL_ALIAS(__s390x_sys_##name, sys_ni_posix_timers);
#endif /* CONFIG_COMPAT */
#define __SYSCALL_DEFINEx(x, name, ...) \
__diag_push(); \
__diag_ignore(GCC, 8, "-Wattribute-alias", \
"Type aliasing is used to sanitize syscall arguments");\
asmlinkage long __s390x_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
__attribute__((alias(__stringify(__se_sys##name)))); \
ALLOW_ERROR_INJECTION(__s390x_sys##name, ERRNO); \
static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
__S390_SYS_STUBx(x, name, __VA_ARGS__) \
asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
{ \
long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \
__MAP(x,__SC_TEST,__VA_ARGS__); \
return ret; \
} \
__diag_pop(); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
#endif /* _ASM_X86_SYSCALL_WRAPPER_H */