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authorArnd Bergmann <arnd@arndb.de>2019-01-16 13:15:22 (GMT)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2019-01-18 08:33:19 (GMT)
commitaa0d6e70d3b34e710a6a57a53a3096cb2e0ea99f (patch)
treed89caa5e75f4e4c822e26f822208d87d1f0cf719 /arch/s390/include
parentfef747bab3c09b30b82f76a391ee0ed83d2d6965 (diff)
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>
Diffstat (limited to 'arch/s390/include')
-rw-r--r--arch/s390/include/asm/syscall_wrapper.h135
1 files changed, 135 insertions, 0 deletions
diff --git a/arch/s390/include/asm/syscall_wrapper.h b/arch/s390/include/asm/syscall_wrapper.h
new file mode 100644
index 0000000..5596c5c
--- /dev/null
+++ b/arch/s390/include/asm/syscall_wrapper.h
@@ -0,0 +1,135 @@
+/* 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 */

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