From 48b25c43e6eebb6c0edf72935e8720385beca76b Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Thu, 15 Mar 2012 13:13:38 -0400 Subject: [PATCH v3] ipc: provide generic compat versions of IPC syscalls 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 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. Reviewed-by: Arnd Bergmann Signed-off-by: Chris Metcalf --- include/linux/compat.h | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/compat.h b/include/linux/compat.h index 7e05fcee75a1..35c2dbf2448a 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); -- cgit v1.2.3 From 1631fcea8399da5e80a80084b3b8c5bfd99d21e7 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Mon, 26 Mar 2012 16:26:12 -0400 Subject: compat: use sys_sendfile64() implementation for sendfile syscall was set up to use sys_sendfile() for the 32-bit compat API instead of sys_sendfile64(), but in fact the right thing to do is to use sys_sendfile64() in all cases. The 32-bit sendfile64() API in glibc uses the sendfile64 syscall, so it has to be capable of doing full 64-bit operations. But the sys_sendfile() kernel implementation has a MAX_NON_LFS test in it which explicitly limits the offset to 2^32. So, we need to use the sys_sendfile64() implementation in the kernel for this case. Cc: Acked-by: Arnd Bergmann Signed-off-by: Chris Metcalf --- include/asm-generic/unistd.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/asm-generic/unistd.h b/include/asm-generic/unistd.h index 2292d1af9d70..991ef01cd77e 100644 --- a/include/asm-generic/unistd.h +++ b/include/asm-generic/unistd.h @@ -218,7 +218,7 @@ __SC_COMP(__NR_pwritev, sys_pwritev, compat_sys_pwritev) /* fs/sendfile.c */ #define __NR3264_sendfile 71 -__SC_3264(__NR3264_sendfile, sys_sendfile64, sys_sendfile) +__SYSCALL(__NR3264_sendfile, sys_sendfile64) /* fs/select.c */ #define __NR_pselect6 72 -- cgit v1.2.3