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| author | Arnd Bergmann <arnd@arndb.de> | 2019-01-16 14:15:22 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2019-01-18 09:33:19 +0100 |
| commit | aa0d6e70d3b34e710a6a57a53a3096cb2e0ea99f (patch) | |
| tree | d89caa5e75f4e4c822e26f822208d87d1f0cf719 /arch/s390/kernel/compat_wrapper.c | |
| parent | s390: use generic UID16 implementation (diff) | |
| download | linux-aa0d6e70d3b34e710a6a57a53a3096cb2e0ea99f.tar.xz linux-aa0d6e70d3b34e710a6a57a53a3096cb2e0ea99f.zip | |
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/kernel/compat_wrapper.c')
| -rw-r--r-- | arch/s390/kernel/compat_wrapper.c | 23 |
1 files changed, 4 insertions, 19 deletions
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); |