Commit da1e2744 authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

ipc: add shmdt syscall wrapper 

Provide ksys_shmdt() wrapper to avoid in-kernel calls to this syscall.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_shmdt().

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 65749e0b

ipc/shm.c

+6 −1
Original line number Diff line number Diff line
@@ -1481,7 +1481,7 @@ COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg) 
 * detach and kill segment if marked destroyed.

 * The work is done in shm_close.

 */

SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)

long ksys_shmdt(char __user *shmaddr)

{

	struct mm_struct *mm = current->mm;

	struct vm_area_struct *vma;
@@ -1588,6 +1588,11 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) 
	return retval;

}



SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)

{

	return ksys_shmdt(shmaddr);

}



#ifdef CONFIG_PROC_FS

static int sysvipc_shm_proc_show(struct seq_file *s, void *it)

{

ipc/syscall.c

+2 −2
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, 
			return -EINVAL;

		}

	case SHMDT:

		return sys_shmdt((char __user *)ptr);

		return ksys_shmdt((char __user *)ptr);

	case SHMGET:

		return ksys_shmget(first, second, third);

	case SHMCTL:
@@ -178,7 +178,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, 
		return put_user(raddr, (compat_ulong_t __user *)compat_ptr(third));

	}

	case SHMDT:

		return sys_shmdt(compat_ptr(ptr));

		return ksys_shmdt(compat_ptr(ptr));

	case SHMGET:

		return ksys_shmget(first, (unsigned int)second, third);

	case SHMCTL:

ipc/util.h

+1 −0
Original line number Diff line number Diff line
@@ -244,6 +244,7 @@ long ksys_semget(key_t key, int nsems, int semflg); 
long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg);

long ksys_msgget(key_t key, int msgflg);

long ksys_shmget(key_t key, size_t size, int shmflg);

long ksys_shmdt(char __user *shmaddr);



/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */

#ifdef CONFIG_COMPAT