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ipc: rename old-style shmctl/semctl/msgctl syscalls

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The behavior of these system calls is slightly different between
architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION
symbol. Most architectures that implement the split IPC syscalls don't set
that symbol and only get the modern version, but alpha, arm, microblaze,
mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag.

For the architectures that so far only implement sys_ipc(), i.e. m68k,
mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior
when adding the split syscalls, so we need to distinguish between the
two groups of architectures.

The method I picked for this distinction is to have a separate system call
entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl()
does not. The system call tables of the five architectures are changed
accordingly.

As an additional benefit, we no longer need the configuration specific
definition for ipc_parse_version(), it always does the same thing now,
but simply won't get called on architectures with the modern interface.

A small downside is that on architectures that do set
ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points
that are never called. They only add a few bytes of bloat, so it seems
better to keep them compared to adding yet another Kconfig symbol.
I considered adding new syscall numbers for the IPC_64 variants for
consistency, but decided against that for now.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann
2018-12-31 22:22:40 +01:00
parent 73a66023c9
commit 275f22148e
14 changed files with 137 additions and 62 deletions
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12
ipc/syscall.c
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@@ -47,7 +47,7 @@ int ksys_ipc(unsigned int call, int first, unsigned long second,
return -EINVAL;
if (get_user(arg, (unsigned long __user *) ptr))
return -EFAULT;
return ksys_semctl(first, second, third, arg);
return ksys_old_semctl(first, second, third, arg);
}
case MSGSND:
@@ -75,7 +75,7 @@ int ksys_ipc(unsigned int call, int first, unsigned long second,
case MSGGET:
return ksys_msgget((key_t) first, second);
case MSGCTL:
return ksys_msgctl(first, second,
return ksys_old_msgctl(first, second,
(struct msqid_ds __user *)ptr);
case SHMAT:
@@ -100,7 +100,7 @@ int ksys_ipc(unsigned int call, int first, unsigned long second,
case SHMGET:
return ksys_shmget(first, second, third);
case SHMCTL:
return ksys_shmctl(first, second,
return ksys_old_shmctl(first, second,
(struct shmid_ds __user *) ptr);
default:
return -ENOSYS;
@@ -152,7 +152,7 @@ int compat_ksys_ipc(u32 call, int first, int second,
return -EINVAL;
if (get_user(pad, (u32 __user *) compat_ptr(ptr)))
return -EFAULT;
return compat_ksys_semctl(first, second, third, pad);
return compat_ksys_old_semctl(first, second, third, pad);
case MSGSND:
return compat_ksys_msgsnd(first, ptr, second, third);
@@ -177,7 +177,7 @@ int compat_ksys_ipc(u32 call, int first, int second,
case MSGGET:
return ksys_msgget(first, second);
case MSGCTL:
return compat_ksys_msgctl(first, second, compat_ptr(ptr));
return compat_ksys_old_msgctl(first, second, compat_ptr(ptr));
case SHMAT: {
int err;
@@ -196,7 +196,7 @@ int compat_ksys_ipc(u32 call, int first, int second,
case SHMGET:
return ksys_shmget(first, (unsigned int)second, third);
case SHMCTL:
return compat_ksys_shmctl(first, second, compat_ptr(ptr));
return compat_ksys_old_shmctl(first, second, compat_ptr(ptr));
}
return -ENOSYS;