From aa0d6e70d3b34e710a6a57a53a3096cb2e0ea99f Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 16 Jan 2019 14:15:22 +0100 Subject: 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 Reviewed-by: Heiko Carstens [heiko.carstens@de.ibm.com: compile fix for !CONFIG_COMPAT] Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/compat_wrapper.c | 23 ++++------------------- arch/s390/kernel/entry.S | 4 ++-- arch/s390/kernel/sys_s390.c | 5 +++++ 3 files changed, 11 insertions(+), 21 deletions(-) (limited to 'arch/s390/kernel') 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 fd0cbbed4d9f..202fa73ac167 100644 --- a/arch/s390/kernel/sys_s390.c +++ b/arch/s390/kernel/sys_s390.c @@ -95,3 +95,8 @@ SYSCALL_DEFINE1(s390_personality, unsigned int, personality) return ret; } + +SYSCALL_DEFINE0(ni_syscall) +{ + return -ENOSYS; +} -- cgit v1.2.3