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Subject[PATCH 30/45] ipc: add semtimedop syscall/compat_syscall wrappers
Date
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 tries to remove in-kernel calls to
syscalls. On this basis, the syscall entry path can be streamlined.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
ipc/sem.c | 23 ++++++++++++++++++-----
ipc/syscall.c | 17 ++++++++++-------
ipc/util.h | 13 +++++++++++++
3 files changed, 41 insertions(+), 12 deletions(-)

diff --git a/ipc/sem.c b/ipc/sem.c
index a4af04979fd2..e21ceb8b4af1 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -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,
diff --git a/ipc/syscall.c b/ipc/syscall.c
index 3763b4293b74..84d6a7691baa 100644
--- a/ipc/syscall.c
+++ b/ipc/syscall.c
@@ -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>
@@ -24,12 +27,12 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,

switch (call) {
case SEMOP:
- return sys_semtimedop(first, (struct sembuf __user *)ptr,
- second, NULL);
+ return ksys_semtimedop(first, (struct sembuf __user *)ptr,
+ second, NULL);
case SEMTIMEDOP:
- return sys_semtimedop(first, (struct sembuf __user *)ptr,
- second,
- (const struct timespec __user *)fifth);
+ return ksys_semtimedop(first, (struct sembuf __user *)ptr,
+ second,
+ (const struct timespec __user *)fifth);

case SEMGET:
return sys_semget(first, second, third);
@@ -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);
diff --git a/ipc/util.h b/ipc/util.h
index 89b8ec176fc4..6deadf77547e 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -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
--
2.16.2
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