linux/arch/s390/include/asm/syscall_wrapper.h
Heiko Carstens 2213d44e14 s390/syscalls: get rid of system call alias functions
bpftrace and friends only consider functions present in
/sys/kernel/tracing/available_filter_functions.

For system calls there is the s390 specific problem that the system call
function itself is present via __se_sys##name() while the system call
itself is wired up via an __s390x_sys##name() alias. The required DWARF
debug information however is only available for the original function, not
the alias, but within available_filter_functions only the functions with
__s390x_ prefix are available. Which means the required DWARF debug
information cannot be found.
While this could be solved via tooling, it is easier to change the s390
specific system call wrapper handling.

Therefore get rid of this alias handling and implement system call wrappers
like most other architectures are doing. In result the implementation
generates the following functions:

long __s390x_sys##name(struct pt_regs *regs)
static inline long __se_sys##name(...)
static inline long __do_sys##name(...)

__s390x_sys##name() is the visible system call function which is also wired
up in the system call table. Its only parameter is a pt_regs variable.

This function calls the corresponding __se_sys##name() function, which has
as many parameters like the system call definition. This function in turn
performs all zero and sign extensions of all system call parameters, taken
from the pt_regs structure, and finally calls __do_sys##name().

__do_sys##name() is the actual inlined system call function implementation.

For all 64 bit system calls there is a 31/32 bit system call function
__s390_sys##name() generated, which handles all system call parameters
correctly as required by compat handling. This function may be wired
up within the compat system call table, unless there exists an
explicit compat system call function, which is then used instead.

Reported-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-01-25 20:51:11 +01:00

152 lines
5.0 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
/* Mapping of registers to parameters for syscalls */
#define SC_S390_REGS_TO_ARGS(x, ...) \
__MAP(x, __SC_ARGS \
,, regs->orig_gpr2,, regs->gprs[3],, regs->gprs[4] \
,, regs->gprs[5],, regs->gprs[6],, regs->gprs[7])
#ifdef CONFIG_COMPAT
#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; \
})
/*
* To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias
* named __s390x_sys_*()
*/
#define COMPAT_SYSCALL_DEFINE0(sname) \
long __s390_compat_sys_##sname(void); \
ALLOW_ERROR_INJECTION(__s390_compat_sys_##sname, ERRNO); \
long __s390_compat_sys_##sname(void)
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
long __s390_sys_##sname(void); \
ALLOW_ERROR_INJECTION(__s390_sys_##sname, ERRNO); \
long __s390x_sys_##sname(void); \
ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \
static inline long __do_sys_##sname(void); \
long __s390_sys_##sname(void) \
{ \
return __do_sys_##sname(); \
} \
long __s390x_sys_##sname(void) \
{ \
return __do_sys_##sname(); \
} \
static inline long __do_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, ...) \
long __s390_compat_sys##name(struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__s390_compat_sys##name, ERRNO); \
static inline long __se_compat_sys##name(__MAP(x, __SC_LONG, __VA_ARGS__)); \
static inline long __do_compat_sys##name(__MAP(x, __SC_DECL, __VA_ARGS__)); \
long __s390_compat_sys##name(struct pt_regs *regs) \
{ \
return __se_compat_sys##name(SC_S390_REGS_TO_ARGS(x, __VA_ARGS__)); \
} \
static inline long __se_compat_sys##name(__MAP(x, __SC_LONG, __VA_ARGS__)) \
{ \
__MAP(x, __SC_TEST, __VA_ARGS__); \
return __do_compat_sys##name(__MAP(x, __SC_DELOUSE, __VA_ARGS__)); \
} \
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)
#define __S390_SYS_STUBx(x, name, ...) \
long __s390_sys##name(struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__s390_sys##name, ERRNO); \
static inline long ___se_sys##name(__MAP(x, __SC_LONG, __VA_ARGS__)); \
long __s390_sys##name(struct pt_regs *regs) \
{ \
return ___se_sys##name(SC_S390_REGS_TO_ARGS(x, __VA_ARGS__)); \
} \
static inline long ___se_sys##name(__MAP(x, __SC_LONG, __VA_ARGS__)) \
{ \
__MAP(x, __SC_TEST, __VA_ARGS__); \
return __do_sys##name(__MAP(x, __SC_COMPAT_CAST, __VA_ARGS__)); \
}
#else /* CONFIG_COMPAT */
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
long __s390x_sys_##sname(void); \
ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \
static inline long __do_sys_##sname(void); \
long __s390x_sys_##sname(void) \
{ \
return __do_sys_##sname(); \
} \
static inline long __do_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)
#define __S390_SYS_STUBx(x, fullname, name, ...)
#endif /* CONFIG_COMPAT */
#define __SYSCALL_DEFINEx(x, name, ...) \
long __s390x_sys##name(struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__s390x_sys##name, ERRNO); \
static inline 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__); \
long __s390x_sys##name(struct pt_regs *regs) \
{ \
return __se_sys##name(SC_S390_REGS_TO_ARGS(x, __VA_ARGS__)); \
} \
static inline long __se_sys##name(__MAP(x, __SC_LONG, __VA_ARGS__)) \
{ \
__MAP(x, __SC_TEST, __VA_ARGS__); \
return __do_sys##name(__MAP(x, __SC_CAST, __VA_ARGS__)); \
} \
static inline long __do_sys##name(__MAP(x, __SC_DECL, __VA_ARGS__))
#endif /* _ASM_S390_SYSCALL_WRAPPER_H */