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.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- arch/s390/Kconfig | 1 + arch/s390/include/asm/syscall_wrapper.h | 136 ++++++++++++++++++++++++ arch/s390/kernel/compat_wrapper.c | 23 +--- arch/s390/kernel/entry.S | 4 +- arch/s390/kernel/sys_s390.c | 5 + 5 files changed, 148 insertions(+), 21 deletions(-) create mode 100644 arch/s390/include/asm/syscall_wrapper.h
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 41cafd245bbc..b6e3d0653002 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -75,6 +75,7 @@ config S390 select ARCH_HAS_SET_MEMORY select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_HAS_STRICT_MODULE_RWX + select ARCH_HAS_SYSCALL_WRAPPER select ARCH_HAS_UBSAN_SANITIZE_ALL select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_INLINE_READ_LOCK diff --git a/arch/s390/include/asm/syscall_wrapper.h b/arch/s390/include/asm/syscall_wrapper.h new file mode 100644 index 000000000000..27ebe871692f --- /dev/null +++ b/arch/s390/include/asm/syscall_wrapper.h @@ -0,0 +1,136 @@ +/* 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) \ + cond_syscall(__s390_sys_##name) + +#define SYS_NI(name) \ + SYSCALL_ALIAS(__s390_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 */ diff --git a/arch/s390/kernel/compat_wrapper.c b/arch/s390/kernel/compat_wrapper.c index f54b7b73f316..9d07cd553fc7 100644 --- a/arch/s390/kernel/compat_wrapper.c +++ b/arch/s390/kernel/compat_wrapper.c @@ -25,21 +25,6 @@ #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)); \ - if (__TYPE_IS_L(t)) \ - __ReS = (s32)a; \ - if (__TYPE_IS_UL(t)) \ - __ReS = (u32)a; \ - if (__TYPE_IS_PTR(t)) \ - __ReS = a & 0x7fffffff; \ - (t)__ReS; \ -}) - /* * The COMPAT_SYSCALL_WRAP macro generates system call wrappers to be used by * compat tasks. These wrappers will only be used for system calls where only @@ -53,11 +38,11 @@ * the regular system call wrappers. */ #define COMPAT_SYSCALL_WRAPx(x, name, ...) \ -asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \ -asmlinkage long notrace compat_sys##name(__MAP(x,__SC_COMPAT_TYPE,__VA_ARGS__));\ -asmlinkage long notrace compat_sys##name(__MAP(x,__SC_COMPAT_TYPE,__VA_ARGS__)) \ +asmlinkage long __s390_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \ +asmlinkage long notrace __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ +asmlinkage long notrace __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \ { \ - return sys##name(__MAP(x,__SC_COMPAT_CAST,__VA_ARGS__)); \ + return __s390_sys##name(__MAP(x,__SC_ARGS,__VA_ARGS__)); \ }
COMPAT_SYSCALL_WRAP2(creat, const char __user *, pathname, umode_t, mode); diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 39191a0feed1..583d65ef5007 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -1512,7 +1512,7 @@ cleanup_critical: .quad .Lsie_skip - .Lsie_entry #endif .section .rodata, "a" -#define SYSCALL(esame,emu) .long esame +#define SYSCALL(esame,emu) .long __s390x_ ## esame .globl sys_call_table sys_call_table: #include "asm/syscall_table.h" @@ -1520,7 +1520,7 @@ sys_call_table:
#ifdef CONFIG_COMPAT
-#define SYSCALL(esame,emu) .long emu +#define SYSCALL(esame,emu) .long __s390_ ## emu .globl sys_call_table_emu sys_call_table_emu: #include "asm/syscall_table.h" diff --git a/arch/s390/kernel/sys_s390.c b/arch/s390/kernel/sys_s390.c index 6aa8fe00b39e..a8c2cc858864 100644 --- a/arch/s390/kernel/sys_s390.c +++ b/arch/s390/kernel/sys_s390.c @@ -93,3 +93,8 @@ SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
return ret; } + +SYSCALL_DEFINE0(ni_syscall) +{ + return -ENOSYS; +}