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Message-ID: <4F6144B8.5010601@tilera.com>
Date: Wed, 14 Mar 2012 21:24:08 -0400
From: Chris Metcalf <cmetcalf@...era.com>
To: Arnd Bergmann <arnd@...db.de>, Ralf Baechle <ralf@...ux-mips.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
<linux390@...ibm.com>, "David S. Miller" <davem@...emloft.net>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, <x86@...nel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Christoph Hellwig <hch@....de>,
Lucas De Marchi <lucas.demarchi@...fusion.mobi>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
"J. Bruce Fields" <bfields@...hat.com>, NeilBrown <neilb@...e.de>,
<linux-mips@...ux-mips.org>, <linux-kernel@...r.kernel.org>,
<linuxppc-dev@...ts.ozlabs.org>, <linux-s390@...r.kernel.org>,
<sparclinux@...r.kernel.org>
Subject: Re: [PATCH v3] ipc: provide generic compat versions of IPC syscalls
Somewhat belatedly, I'm looking to push this through the "tile" tree.
Andrew Morton has been keeping it in his tree but I figure I should push it
since it directly affects "tile" and currently no one else.
However, it would be nice if anyone could provide a Reviewed-by or Acked-by
on the patch. Thanks!
On 12/9/2011 10:29 AM, Chris Metcalf wrote:
> When using the "compat" APIs, architectures will generally want to
> be able to make direct syscalls to msgsnd(), shmctl(), etc., and
> in the kernel we would want them to be handled directly by
> compat_sys_xxx() functions, as is true for other compat syscalls.
>
> However, for historical reasons, several of the existing compat IPC
> syscalls do not do this. semctl() expects a pointer to the fourth
> argument, instead of the fourth argument itself. msgsnd(), msgrcv()
> and shmat() expect arguments in different order.
>
> This change adds an ARCH_WANT_OLD_COMPAT_IPC config option that can be
> set to preserve this behavior for ports that use it (x86, sparc, powerpc,
> s390, and mips). No actual semantics are changed for those architectures,
> and there is only a minimal amount of code refactoring in ipc/compat.c.
>
> Newer architectures like tile (and perhaps future architectures such
> as arm64 and unicore64) should not select this option, and thus can
> avoid having any IPC-specific code at all in their architecture-specific
> compat layer. In the same vein, if this option is not selected, IPC_64
> mode is assumed, since that's what the <asm-generic> headers expect.
>
> The workaround code in "tile" for msgsnd() and msgrcv() is removed
> with this change; it also fixes the bug that shmat() and semctl() were
> not being properly handled.
>
> Signed-off-by: Chris Metcalf <cmetcalf@...era.com>
> ---
> arch/Kconfig | 3 ++
> arch/mips/Kconfig | 1 +
> arch/powerpc/Kconfig | 1 +
> arch/s390/Kconfig | 1 +
> arch/sparc/Kconfig | 1 +
> arch/tile/include/asm/compat.h | 11 ------
> arch/tile/kernel/compat.c | 43 ------------------------
> arch/x86/Kconfig | 1 +
> include/linux/compat.h | 12 ++++++-
> ipc/compat.c | 70 ++++++++++++++++++++++++++++++++++++---
> 10 files changed, 83 insertions(+), 61 deletions(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 4b0669c..dfb1e07 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -181,4 +181,7 @@ config HAVE_RCU_TABLE_FREE
> config ARCH_HAVE_NMI_SAFE_CMPXCHG
> bool
>
> +config ARCH_WANT_OLD_COMPAT_IPC
> + bool
> +
> source "kernel/gcov/Kconfig"
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index d46f1da..ad2af82 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -2420,6 +2420,7 @@ config MIPS32_COMPAT
> config COMPAT
> bool
> depends on MIPS32_COMPAT
> + select ARCH_WANT_OLD_COMPAT_IPC
> default y
>
> config SYSVIPC_COMPAT
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 951e18f..e2be710 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -146,6 +146,7 @@ config COMPAT
> bool
> default y if PPC64
> select COMPAT_BINFMT_ELF
> + select ARCH_WANT_OLD_COMPAT_IPC
>
> config SYSVIPC_COMPAT
> bool
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 373679b..2fc3bca 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -221,6 +221,7 @@ config COMPAT
> prompt "Kernel support for 31 bit emulation"
> depends on 64BIT
> select COMPAT_BINFMT_ELF
> + select ARCH_WANT_OLD_COMPAT_IPC
> help
> Select this option if you want to enable your system kernel to
> handle system-calls from ELF binaries for 31 bit ESA. This option
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index f92602e..846cb5c 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -577,6 +577,7 @@ config COMPAT
> depends on SPARC64
> default y
> select COMPAT_BINFMT_ELF
> + select ARCH_WANT_OLD_COMPAT_IPC
>
> config SYSVIPC_COMPAT
> bool
> diff --git a/arch/tile/include/asm/compat.h b/arch/tile/include/asm/compat.h
> index bf95f55..4b4b289 100644
> --- a/arch/tile/include/asm/compat.h
> +++ b/arch/tile/include/asm/compat.h
> @@ -242,17 +242,6 @@ long compat_sys_fallocate(int fd, int mode,
> long compat_sys_sched_rr_get_interval(compat_pid_t pid,
> struct compat_timespec __user *interval);
>
> -/* Versions of compat functions that differ from generic Linux. */
> -struct compat_msgbuf;
> -long tile_compat_sys_msgsnd(int msqid,
> - struct compat_msgbuf __user *msgp,
> - size_t msgsz, int msgflg);
> -long tile_compat_sys_msgrcv(int msqid,
> - struct compat_msgbuf __user *msgp,
> - size_t msgsz, long msgtyp, int msgflg);
> -long tile_compat_sys_ptrace(compat_long_t request, compat_long_t pid,
> - compat_long_t addr, compat_long_t data);
> -
> /* Tilera Linux syscalls that don't have "compat" versions. */
> #define compat_sys_flush_cache sys_flush_cache
>
> diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
> index bf5e9d7..d67459b 100644
> --- a/arch/tile/kernel/compat.c
> +++ b/arch/tile/kernel/compat.c
> @@ -16,7 +16,6 @@
> #define __SYSCALL_COMPAT
>
> #include <linux/compat.h>
> -#include <linux/msg.h>
> #include <linux/syscalls.h>
> #include <linux/kdev_t.h>
> #include <linux/fs.h>
> @@ -95,52 +94,10 @@ long compat_sys_sched_rr_get_interval(compat_pid_t pid,
> return ret;
> }
>
> -/*
> - * The usual compat_sys_msgsnd() and _msgrcv() seem to be assuming
> - * some different calling convention than our normal 32-bit tile code.
> - */
> -
> -/* Already defined in ipc/compat.c, but we need it here. */
> -struct compat_msgbuf {
> - compat_long_t mtype;
> - char mtext[1];
> -};
> -
> -long tile_compat_sys_msgsnd(int msqid,
> - struct compat_msgbuf __user *msgp,
> - size_t msgsz, int msgflg)
> -{
> - compat_long_t mtype;
> -
> - if (get_user(mtype, &msgp->mtype))
> - return -EFAULT;
> - return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
> -}
> -
> -long tile_compat_sys_msgrcv(int msqid,
> - struct compat_msgbuf __user *msgp,
> - size_t msgsz, long msgtyp, int msgflg)
> -{
> - long err, mtype;
> -
> - err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
> - if (err < 0)
> - goto out;
> -
> - if (put_user(mtype, &msgp->mtype))
> - err = -EFAULT;
> - out:
> - return err;
> -}
> -
> /* Provide the compat syscall number to call mapping. */
> #undef __SYSCALL
> #define __SYSCALL(nr, call) [nr] = (call),
>
> -/* The generic versions of these don't work for Tile. */
> -#define compat_sys_msgrcv tile_compat_sys_msgrcv
> -#define compat_sys_msgsnd tile_compat_sys_msgsnd
> -
> /* See comments in sys.c */
> #define compat_sys_fadvise64_64 sys32_fadvise64_64
> #define compat_sys_readahead sys32_readahead
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index cb9a104..0e1f474 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2131,6 +2131,7 @@ config IA32_AOUT
> config COMPAT
> def_bool y
> depends on IA32_EMULATION
> + select ARCH_WANT_OLD_COMPAT_IPC
>
> config COMPAT_FOR_U64_ALIGNMENT
> def_bool COMPAT
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index 66ed067..f295dae 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -224,6 +224,7 @@ struct compat_sysinfo;
> struct compat_sysctl_args;
> struct compat_kexec_segment;
> struct compat_mq_attr;
> +struct compat_msgbuf;
>
> extern void compat_exit_robust_list(struct task_struct *curr);
>
> @@ -234,13 +235,22 @@ asmlinkage long
> compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
> compat_size_t __user *len_ptr);
>
> +#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
> long compat_sys_semctl(int first, int second, int third, void __user *uptr);
> long compat_sys_msgsnd(int first, int second, int third, void __user *uptr);
> long compat_sys_msgrcv(int first, int second, int msgtyp, int third,
> int version, void __user *uptr);
> -long compat_sys_msgctl(int first, int second, void __user *uptr);
> long compat_sys_shmat(int first, int second, compat_uptr_t third, int version,
> void __user *uptr);
> +#else
> +long compat_sys_semctl(int semid, int semnum, int cmd, int arg);
> +long compat_sys_msgsnd(int msqid, struct compat_msgbuf __user *msgp,
> + size_t msgsz, int msgflg);
> +long compat_sys_msgrcv(int msqid, struct compat_msgbuf __user *msgp,
> + size_t msgsz, long msgtyp, int msgflg);
> +long compat_sys_shmat(int shmid, compat_uptr_t shmaddr, int shmflg);
> +#endif
> +long compat_sys_msgctl(int first, int second, void __user *uptr);
> long compat_sys_shmctl(int first, int second, void __user *uptr);
> long compat_sys_semtimedop(int semid, struct sembuf __user *tsems,
> unsigned nsems, const struct compat_timespec __user *timeout);
> diff --git a/ipc/compat.c b/ipc/compat.c
> index 845a287..a6df704 100644
> --- a/ipc/compat.c
> +++ b/ipc/compat.c
> @@ -27,6 +27,7 @@
> #include <linux/msg.h>
> #include <linux/shm.h>
> #include <linux/syscalls.h>
> +#include <linux/ptrace.h>
>
> #include <linux/mutex.h>
> #include <asm/uaccess.h>
> @@ -117,6 +118,7 @@ extern int sem_ctls[];
>
> static inline int compat_ipc_parse_version(int *cmd)
> {
> +#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
> int version = *cmd & IPC_64;
>
> /* this is tricky: architectures that have support for the old
> @@ -128,6 +130,10 @@ static inline int compat_ipc_parse_version(int *cmd)
> *cmd &= ~IPC_64;
> #endif
> return version;
> +#else
> + /* With the asm-generic APIs, we always use the 64-bit versions. */
> + return IPC_64;
> +#endif
> }
>
> static inline int __get_compat_ipc64_perm(struct ipc64_perm *p64,
> @@ -232,10 +238,9 @@ static inline int put_compat_semid_ds(struct semid64_ds *s,
> return err;
> }
>
> -long compat_sys_semctl(int first, int second, int third, void __user *uptr)
> +static long do_compat_semctl(int first, int second, int third, u32 pad)
> {
> union semun fourth;
> - u32 pad;
> int err, err2;
> struct semid64_ds s64;
> struct semid64_ds __user *up64;
> @@ -243,10 +248,6 @@ long compat_sys_semctl(int first, int second, int third, void __user *uptr)
>
> memset(&s64, 0, sizeof(s64));
>
> - if (!uptr)
> - return -EINVAL;
> - if (get_user(pad, (u32 __user *) uptr))
> - return -EFAULT;
> if ((third & (~IPC_64)) == SETVAL)
> fourth.val = (int) pad;
> else
> @@ -305,6 +306,18 @@ long compat_sys_semctl(int first, int second, int third, void __user *uptr)
> return err;
> }
>
> +#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
> +long compat_sys_semctl(int first, int second, int third, void __user *uptr)
> +{
> + u32 pad;
> +
> + if (!uptr)
> + return -EINVAL;
> + if (get_user(pad, (u32 __user *) uptr))
> + return -EFAULT;
> + return do_compat_semctl(first, second, third, pad);
> +}
> +
> long compat_sys_msgsnd(int first, int second, int third, void __user *uptr)
> {
> struct compat_msgbuf __user *up = uptr;
> @@ -353,6 +366,37 @@ long compat_sys_msgrcv(int first, int second, int msgtyp, int third,
> out:
> return err;
> }
> +#else
> +long compat_sys_semctl(int semid, int semnum, int cmd, int arg)
> +{
> + return do_compat_semctl(semid, semnum, cmd, arg);
> +}
> +
> +long compat_sys_msgsnd(int msqid, struct compat_msgbuf __user *msgp,
> + size_t msgsz, int msgflg)
> +{
> + compat_long_t mtype;
> +
> + if (get_user(mtype, &msgp->mtype))
> + return -EFAULT;
> + return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
> +}
> +
> +long compat_sys_msgrcv(int msqid, struct compat_msgbuf __user *msgp,
> + size_t msgsz, long msgtyp, int msgflg)
> +{
> + long err, mtype;
> +
> + err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
> + if (err < 0)
> + goto out;
> +
> + if (put_user(mtype, &msgp->mtype))
> + err = -EFAULT;
> + out:
> + return err;
> +}
> +#endif
>
> static inline int get_compat_msqid64(struct msqid64_ds *m64,
> struct compat_msqid64_ds __user *up64)
> @@ -470,6 +514,7 @@ long compat_sys_msgctl(int first, int second, void __user *uptr)
> return err;
> }
>
> +#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
> long compat_sys_shmat(int first, int second, compat_uptr_t third, int version,
> void __user *uptr)
> {
> @@ -485,6 +530,19 @@ long compat_sys_shmat(int first, int second, compat_uptr_t third, int version,
> uaddr = compat_ptr(third);
> return put_user(raddr, uaddr);
> }
> +#else
> +long compat_sys_shmat(int shmid, compat_uptr_t shmaddr, int shmflg)
> +{
> + unsigned long ret;
> + long err;
> +
> + err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret);
> + if (err)
> + return err;
> + force_successful_syscall_return();
> + return (long)ret;
> +}
> +#endif
>
> static inline int get_compat_shmid64_ds(struct shmid64_ds *s64,
> struct compat_shmid64_ds __user *up64)
--
Chris Metcalf, Tilera Corp.
http://www.tilera.com
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