On Wed, Jan 16, 2019 at 02:15:22PM +0100, Arnd Bergmann wrote: > 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@xxxxxxxx> > --- > 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 The patch below is needed as compile fix (allnoconfig). I will add this to your patch, no resend needed. diff --git a/arch/s390/include/asm/syscall_wrapper.h b/arch/s390/include/asm/syscall_wrapper.h index 27ebe871692f..873e7a7794b3 100644 --- a/arch/s390/include/asm/syscall_wrapper.h +++ b/arch/s390/include/asm/syscall_wrapper.h @@ -106,11 +106,10 @@ asmlinkage long __s390x_sys_##sname(void) #define COND_SYSCALL(name) \ - cond_syscall(__s390x_sys_##name) \ - cond_syscall(__s390_sys_##name) + cond_syscall(__s390x_sys_##name) #define SYS_NI(name) \ - SYSCALL_ALIAS(__s390_sys_##name, sys_ni_posix_timers); + SYSCALL_ALIAS(__s390x_sys_##name, sys_ni_posix_timers); #endif /* CONFIG_COMPAT */
