Create new syscalls for mmap(), lseek(), pread(), pwrite(), truncate() and

ftruncate(), but without the pad arg.

There are several reasons for this.  Consider 'mmap()'.  On AMD64, the
function call (and syscall) ABI allow for 6 register arguments.  Additional
arguments go on the stack.  mmap(2) has 6 arguments.  However, the syscall
definition has an extra 'int pad' argument.  This pushes it to 7 arguments,
which means one must spill into the memory stack.  Since the kernel API
doesn't match userland API, we have a hack in libc - libc/sys/mmap.c.
This implements the userland API by calling __syscall() with an extra
argument and the pad argument, for a total of 8 args.  This is all
unnecessary and inconvenient for several things, including the kernel's
syscall handler code which now has to handle merging stack arguments with
register arguments.  It is a big deal for certain 3rd party code.

I'm adding libc glue to make the transition totally painless.  I had
intended to mark the old syscalls as COMPAT6, but the potential to shoot
your feet by building a new kernel without COMPAT_FREEBSD6 but with a
slighly older userland was too great.  For now, they have manual
"freebsd6_" prefixes rather than being COMPAT6.  They will go back to
being marked 'COMPAT6' after 7-stable starts.

Approved by: re (kensmith)

1 files changed, 20 insertions, 9 deletions

diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index dd9e25f..f9c7849 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -334,9 +334,10 @@
 				    int a4); }
 ; XXX should be	{ int shmsys(int which, ...); }
 172	AUE_NULL	UNIMPL	nosys
-173	AUE_PREAD	STD	{ ssize_t pread(int fd, void *buf, \
+173	AUE_PREAD	STD	{ ssize_t freebsd6_pread(int fd, void *buf, \
 				    size_t nbyte, int pad, off_t offset); }
-174	AUE_PWRITE	STD	{ ssize_t pwrite(int fd, const void *buf, \
+174	AUE_PWRITE	STD	{ ssize_t freebsd6_pwrite(int fd, \
+				    const void *buf, \
 				    size_t nbyte, int pad, off_t offset); }
 175	AUE_NULL	UNIMPL	nosys
 176	AUE_NTP_ADJTIME	STD	{ int ntp_adjtime(struct timex *tp); }
@@ -367,16 +368,16 @@
 				    __setrlimit_args int
 196	AUE_GETDIRENTRIES	STD	{ int getdirentries(int fd, char *buf, \
 				    u_int count, long *basep); }
-197	AUE_MMAP	STD	{ caddr_t mmap(caddr_t addr, size_t len, \
-				    int prot, int flags, int fd, int pad, \
-				    off_t pos); }
+197	AUE_MMAP	STD	{ caddr_t freebsd6_mmap(caddr_t addr, \
+				    size_t len, int prot, int flags, int fd, \
+				    int pad, off_t pos); }
 198	AUE_NULL	STD	{ int nosys(void); } __syscall \
 				    __syscall_args int
-199	AUE_LSEEK	STD	{ off_t lseek(int fd, int pad, off_t offset, \
-				    int whence); }
-200	AUE_TRUNCATE	STD	{ int truncate(char *path, int pad, \
+199	AUE_LSEEK	STD	{ off_t freebsd6_lseek(int fd, int pad, \
+				    off_t offset, int whence); }
+200	AUE_TRUNCATE	STD	{ int freebsd6_truncate(char *path, int pad, \
 				    off_t length); }
-201	AUE_FTRUNCATE	STD	{ int ftruncate(int fd, int pad, \
+201	AUE_FTRUNCATE	STD	{ int freebsd6_ftruncate(int fd, int pad, \
 				    off_t length); }
 202	AUE_SYSCTL	STD	{ int __sysctl(int *name, u_int namelen, \
 				    void *old, size_t *oldlenp, void *new, \
@@ -835,5 +836,15 @@
 474     AUE_NULL        STD    { int sctp_generic_recvmsg(int sd, struct iovec *iov, int iovlen, \
 				    struct sockaddr * from, __socklen_t *fromlenaddr, \
 				    struct sctp_sndrcvinfo *sinfo, int *msg_flags); }
+475	AUE_PREAD	STD	{ ssize_t pread(int fd, void *buf, \
+				    size_t nbyte, off_t offset); }
+476	AUE_PWRITE	STD	{ ssize_t pwrite(int fd, const void *buf, \
+				    size_t nbyte, off_t offset); }
+477	AUE_MMAP	STD	{ caddr_t mmap(caddr_t addr, size_t len, \
+				    int prot, int flags, int fd, off_t pos); }
+478	AUE_LSEEK	STD	{ off_t lseek(int fd, off_t offset, \
+				    int whence); }
+479	AUE_TRUNCATE	STD	{ int truncate(char *path, off_t length); }
+480	AUE_FTRUNCATE	STD	{ int ftruncate(int fd, off_t length); }
 ; Please copy any additions and changes to the following compatability tables:
 ; sys/compat/freebsd32/syscalls.master