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Message-Id: <20190116131527.2071570-5-arnd@arndb.de>
Date: Wed, 16 Jan 2019 14:15:22 +0100
From: Arnd Bergmann <arnd@...db.de>
To: linux-s390@...r.kernel.org,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Heiko Carstens <heiko.carstens@...ibm.com>
Cc: linux-kernel@...r.kernel.org, y2038@...ts.linaro.org,
Dominik Brodowski <linux@...inikbrodowski.net>,
Mark Rutland <mark.rutland@....com>,
Arnd Bergmann <arnd@...db.de>,
Masahiro Yamada <yamada.masahiro@...ionext.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Vasily Gorbik <gor@...ux.ibm.com>
Subject: [PATCH 4/5] 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.
Signed-off-by: Arnd Bergmann <arnd@...db.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;
+}
--
2.20.0
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