Commit 41f4f0e2 authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

ipc: add semtimedop syscall/compat_syscall wrappers 

Provide ksys_semtimedop() and compat_ksys_semtimedop() wrappers to avoid
in-kernel calls to these syscalls. The ksys_ prefix denotes that these
functions are meant as a drop-in replacement for the syscalls. In
particular, they use the same calling convention as sys_semtimedop() and
compat_sys_semtimedop().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net



Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
parent 6df35465

ipc/sem.c

+18 −5
Original line number Diff line number Diff line
@@ -2120,8 +2120,8 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, 
	return error;

}



SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,

		unsigned, nsops, const struct timespec __user *, timeout)

long ksys_semtimedop(int semid, struct sembuf __user *tsops,

		     unsigned int nsops, const struct timespec __user *timeout)

{

	if (timeout) {

		struct timespec64 ts;
@@ -2132,10 +2132,16 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, 
	return do_semtimedop(semid, tsops, nsops, NULL);

}



SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,

		unsigned int, nsops, const struct timespec __user *, timeout)

{

	return ksys_semtimedop(semid, tsops, nsops, timeout);

}



#ifdef CONFIG_COMPAT

COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems,

		       unsigned, nsops,

		       const struct compat_timespec __user *, timeout)

long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,

			    unsigned int nsops,

			    const struct compat_timespec __user *timeout)

{

	if (timeout) {

		struct timespec64 ts;
@@ -2145,6 +2151,13 @@ COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems, 
	}

	return do_semtimedop(semid, tsems, nsops, NULL);

}



COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems,

		       unsigned int, nsops,

		       const struct compat_timespec __user *, timeout)

{

	return compat_ksys_semtimedop(semid, tsems, nsops, timeout);

}

#endif



SYSCALL_DEFINE3(semop, int, semid, struct sembuf __user *, tsops,

ipc/syscall.c

+10 −7
Original line number Diff line number Diff line
@@ -7,6 +7,9 @@ 
 */

#include <linux/unistd.h>

#include <linux/syscalls.h>

#include <linux/security.h>

#include <linux/ipc_namespace.h>

#include "util.h"



#ifdef __ARCH_WANT_SYS_IPC

#include <linux/errno.h>
@@ -24,10 +27,10 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, 


	switch (call) {

	case SEMOP:

		return sys_semtimedop(first, (struct sembuf __user *)ptr,

		return ksys_semtimedop(first, (struct sembuf __user *)ptr,

				       second, NULL);

	case SEMTIMEDOP:

		return sys_semtimedop(first, (struct sembuf __user *)ptr,

		return ksys_semtimedop(first, (struct sembuf __user *)ptr,

				       second,

				       (const struct timespec __user *)fifth);
@@ -124,9 +127,9 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, 
	switch (call) {

	case SEMOP:

		/* struct sembuf is the same on 32 and 64bit :)) */

		return sys_semtimedop(first, compat_ptr(ptr), second, NULL);

		return ksys_semtimedop(first, compat_ptr(ptr), second, NULL);

	case SEMTIMEDOP:

		return compat_sys_semtimedop(first, compat_ptr(ptr), second,

		return compat_ksys_semtimedop(first, compat_ptr(ptr), second,

						compat_ptr(fifth));

	case SEMGET:

		return sys_semget(first, second, third);

ipc/util.h

+13 −0
Original line number Diff line number Diff line
@@ -235,4 +235,17 @@ static inline int compat_ipc_parse_version(int *cmd) 
#endif

}

#endif



/* for __ARCH_WANT_SYS_IPC */

long ksys_semtimedop(int semid, struct sembuf __user *tsops,

		     unsigned int nsops,

		     const struct timespec __user *timeout);



/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */

#ifdef CONFIG_COMPAT

long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,

			    unsigned int nsops,

			    const struct compat_timespec __user *timeout);

#endif /* CONFIG_COMPAT */



#endif