Making it easy to add system calls
PATCH 1/1 Making it easy to add system calls
The attached patch defines a new file (.../include/asm-i386/sys_calls.h) which defines all the system call names and numbers. The number is defined via "enum". The normal call has a well defined entry point to name relationship, but not all do, so a way to do the "non-confroming" calls is included. To add a new call all one needs to do is to add a line at the end of the list in this header file, for example:
SYS_CALL(clock_nanosleep) \
This will put "sys_clock_nanosleep" in the call table in entry.S and define the "__NR_clock_nanosleep" for unistd. The last entry of the enum is NR_syscalls, thus defineing and keeping this symbol current.
Of course we will be adding no more system calls, but it does make things a _lot_ easier.
The binary from entry.S was compared to the prior binary and found to be the same. A small set of the library stubs was produced and also compared. And a system was built and tested. All worked fine.
Signature · 3 lines
George Anzinger [email protected] High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
arch/i386/kernel/entry.S +4 -269
@@ -562,274 +562,9 @@ .data ENTRY(sys_call_table) - .long sys_restart_syscall /* 0 - old "setup()" system call, used for restarting */ - .long sys_exit - .long sys_fork - .long sys_read - .long sys_write - .long sys_open /* 5 */ - .long sys_close - .long sys_waitpid - .long sys_creat - .long sys_link - .long sys_unlink /* 10 */ - .long sys_execve - .long sys_chdir - .long sys_time - .long sys_mknod - .long sys_chmod /* 15 */ - .long sys_lchown16 - .long sys_ni_syscall /* old break syscall holder */ - .long sys_stat - .long sys_lseek - .long sys_getpid /* 20 */ - .long sys_mount - .long sys_oldumount - .long sys_setuid16 - .long sys_getuid16 - .long sys_stime /* 25 */ - .long sys_ptrace - .long sys_alarm - .long sys_fstat - .long sys_pause - .long sys_utime /* 30 */ - .long sys_ni_syscall /* old stty syscall holder */ - .long sys_ni_syscall /* old gtty syscall holder */ - .long sys_access - .long sys_nice - .long sys_ni_syscall /* 35 - old ftime syscall holder */ - .long sys_sync - .long sys_kill - .long sys_rename - .long sys_mkdir - .long sys_rmdir /* 40 */ - .long sys_dup - .long sys_pipe - .long sys_times - .long sys_ni_syscall /* old prof syscall holder */ - .long sys_brk /* 45 */ - .long sys_setgid16 - .long sys_getgid16 - .long sys_signal - .long sys_geteuid16 - .long sys_getegid16 /* 50 */ - .long sys_acct - .long sys_umount /* recycled never used phys() */ - .long sys_ni_syscall /* old lock syscall holder */ - .long sys_ioctl - .long sys_fcntl /* 55 */ - .long sys_ni_syscall /* old mpx syscall holder */ - .long sys_setpgid - .long sys_ni_syscall /* old ulimit syscall holder */ - .long sys_olduname - .long sys_umask /* 60 */ - .long sys_chroot - .long sys_ustat - .long sys_dup2 - .long sys_getppid - .long sys_getpgrp /* 65 */ - .long sys_setsid - .long sys_sigaction - .long sys_sgetmask - .long sys_ssetmask - .long sys_setreuid16 /* 70 */ - .long sys_setregid16 - .long sys_sigsuspend - .long sys_sigpending - .long sys_sethostname - .long sys_setrlimit /* 75 */ - .long sys_old_getrlimit - .long sys_getrusage - .long sys_gettimeofday - .long sys_settimeofday - .long sys_getgroups16 /* 80 */ - .long sys_setgroups16 - .long old_select - .long sys_symlink - .long sys_lstat - .long sys_readlink /* 85 */ - .long sys_uselib - .long sys_swapon - .long sys_reboot - .long old_readdir - .long old_mmap /* 90 */ - .long sys_munmap - .long sys_truncate - .long sys_ftruncate - .long sys_fchmod - .long sys_fchown16 /* 95 */ - .long sys_getpriority - .long sys_setpriority - .long sys_ni_syscall /* old profil syscall holder */ - .long sys_statfs - .long sys_fstatfs /* 100 */ - .long sys_ioperm - .long sys_socketcall - .long sys_syslog - .long sys_setitimer - .long sys_getitimer /* 105 */ - .long sys_newstat - .long sys_newlstat - .long sys_newfstat - .long sys_uname - .long sys_iopl /* 110 */ - .long sys_vhangup - .long sys_ni_syscall /* old "idle" system call */ - .long sys_vm86old - .long sys_wait4 - .long sys_swapoff /* 115 */ - .long sys_sysinfo - .long sys_ipc - .long sys_fsync - .long sys_sigreturn - .long sys_clone /* 120 */ - .long sys_setdomainname - .long sys_newuname - .long sys_modify_ldt - .long sys_adjtimex - .long sys_mprotect /* 125 */ - .long sys_sigprocmask - .long sys_ni_syscall /* old "create_module" */ - .long sys_init_module - .long sys_delete_module - .long sys_ni_syscall /* 130: old "get_kernel_syms" */ - .long sys_quotactl - .long sys_getpgid - .long sys_fchdir - .long sys_bdflush - .long sys_sysfs /* 135 */ - .long sys_personality - .long sys_ni_syscall /* reserved for afs_syscall */ - .long sys_setfsuid16 - .long sys_setfsgid16 - .long sys_llseek /* 140 */ - .long sys_getdents - .long sys_select - .long sys_flock - .long sys_msync - .long sys_readv /* 145 */ - .long sys_writev - .long sys_getsid - .long sys_fdatasync - .long sys_sysctl - .long sys_mlock /* 150 */ - .long sys_munlock - .long sys_mlockall - .long sys_munlockall - .long sys_sched_setparam - .long sys_sched_getparam /* 155 */ - .long sys_sched_setscheduler - .long sys_sched_getscheduler - .long sys_sched_yield - .long sys_sched_get_priority_max - .long sys_sched_get_priority_min /* 160 */ - .long sys_sched_rr_get_interval - .long sys_nanosleep - .long sys_mremap - .long sys_setresuid16 - .long sys_getresuid16 /* 165 */ - .long sys_vm86 - .long sys_ni_syscall /* Old sys_query_module */ - .long sys_poll - .long sys_nfsservctl - .long sys_setresgid16 /* 170 */ - .long sys_getresgid16 - .long sys_prctl - .long sys_rt_sigreturn - .long sys_rt_sigaction - .long sys_rt_sigprocmask /* 175 */ - .long sys_rt_sigpending - .long sys_rt_sigtimedwait - .long sys_rt_sigqueueinfo - .long sys_rt_sigsuspend - .long sys_pread64 /* 180 */ - .long sys_pwrite64 - .long sys_chown16 - .long sys_getcwd - .long sys_capget - .long sys_capset /* 185 */ - .long sys_sigaltstack - .long sys_sendfile - .long sys_ni_syscall /* reserved for streams1 */ - .long sys_ni_syscall /* reserved for streams2 */ - .long sys_vfork /* 190 */ - .long sys_getrlimit - .long sys_mmap2 - .long sys_truncate64 - .long sys_ftruncate64 - .long sys_stat64 /* 195 */ - .long sys_lstat64 - .long sys_fstat64 - .long sys_lchown - .long sys_getuid - .long sys_getgid /* 200 */ - .long sys_geteuid - .long sys_getegid - .long sys_setreuid - .long sys_setregid - .long sys_getgroups /* 205 */ - .long sys_setgroups - .long sys_fchown - .long sys_setresuid - .long sys_getresuid - .long sys_setresgid /* 210 */ - .long sys_getresgid - .long sys_chown - .long sys_setuid - .long sys_setgid - .long sys_setfsuid /* 215 */ - .long sys_setfsgid - .long sys_pivot_root - .long sys_mincore - .long sys_madvise - .long sys_getdents64 /* 220 */ - .long sys_fcntl64 - .long sys_ni_syscall /* reserved for TUX */ - .long sys_ni_syscall - .long sys_gettid - .long sys_readahead /* 225 */ - .long sys_setxattr - .long sys_lsetxattr - .long sys_fsetxattr - .long sys_getxattr - .long sys_lgetxattr /* 230 */ - .long sys_fgetxattr - .long sys_listxattr - .long sys_llistxattr - .long sys_flistxattr - .long sys_removexattr /* 235 */ - .long sys_lremovexattr - .long sys_fremovexattr - .long sys_tkill - .long sys_sendfile64 - .long sys_futex /* 240 */ - .long sys_sched_setaffinity - .long sys_sched_getaffinity - .long sys_set_thread_area - .long sys_get_thread_area - .long sys_io_setup /* 245 */ - .long sys_io_destroy - .long sys_io_getevents - .long sys_io_submit - .long sys_io_cancel - .long sys_fadvise64 /* 250 */ - .long sys_ni_syscall - .long sys_exit_group - .long sys_lookup_dcookie - .long sys_epoll_create - .long sys_epoll_ctl /* 255 */ - .long sys_epoll_wait - .long sys_remap_file_pages - .long sys_set_tid_address - .long sys_timer_create - .long sys_timer_settime /* 260 */ - .long sys_timer_gettime - .long sys_timer_getoverrun - .long sys_timer_delete - .long sys_clock_settime - .long sys_clock_gettime /* 265 */ - .long sys_clock_getres - .long sys_clock_nanosleep - + +#define SYS_CALL_PTRS +#include <asm/sys_calls.h> + nr_syscalls=(.-sys_call_table)/4
include/asm-i386/sys_calls.h +311 -0
311 lines not on this page · raw message
include/asm-i386/unistd.h +2 -271
279 lines not on this page · raw message
Binary files linux-2.5.64-kb/lib/gen_crc32table and linux/lib/gen_crc32table differ Binary files linux-2.5.64-kb/scripts/docproc and linux/scripts/docproc differ Binary files linux-2.5.64-kb/scripts/fixdep and linux/scripts/fixdep differ
Binary files linux-2.5.64-kb/scripts/kallsyms and linux/scripts/kallsyms differ Binary files linux-2.5.64-kb/scripts/mk_elfconfig and linux/scripts/mk_elfconfig differ Binary files linux-2.5.64-kb/scripts/modpost and linux/scripts/modpost differ Binary files linux-2.5.64-kb/usr/gen_init_cpio and linux/usr/gen_init_cpio differ Binary files linux-2.5.64-kb/usr/initramfs_data.cpio.gz and linux/usr/initramfs_data.cpio.gz differ
Your patch makes it impossible to tell at an easy glance which syscall is which number. The current code makes it quite obvious which numbers are assigned to which syscalls, and which syscall numbers are available for use. We lose valuable information with this patch, even if it does wind up to be functionally equivalent.
Jeff
Quoted 2 lines · Jeff Garzik
Your patch makes it impossible to tell at an easy glance which syscall is which number. The current code makes it quite obvious which numbers are assigned to which syscalls, and which syscall numbers are available for use. We lose valuable information with this patch, even if it does wind up to be functionally equivalent.
Of course the numbers as well as comments on the inactive or unused entries could be added, just as they are today. I had also considered the possiblility of adding the system call proto type as a parameter in the macro. This could lead to a rather complete one entry description of the call.
Still, it seems to not be in favor, so I will let it drop.
Signature · 3 lines
George Anzinger [email protected] High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
Quoted 6 lines · george anzinger
SYS_CALL(clock_nanosleep)\This will put "
sys_clock_nanosleep" in the call table inentry.Sand define the "__NR_clock_nanosleep" for unistd. The last entry of the enum isNR_syscalls, thus defineing and keeping this symbol current.
Me no likee.
The fact is, we add system calls maybe a few times a year. Having to update two places instead of just one is not very onerous.
More importantly, the system call numbers should be something you have to think about, and a setup that makes it easy to merge new system calls with different numbers "by mistake" is a _bad_ setup.
Don't get me wrong - I'm not saying that "system calls should be hard to add, because only real men should add system calls". But I _am_ saying that it should be damn hard to add a system call by mistake at the wrong number, which is something your patch makes a lot easier than the current situation.
And I do believe that adding system calls should inherently be something that you have to think twice about, even if one of the thoughs is just literally writing out the number that you decided on. So while I don't think it should be "hard", it should definitely not be made any easier than it already is.
Linus
Quoted 9 lines · Linus Torvalds
Quoted 3 lines · george anzinger
SYS_CALL(clock_nanosleep)\This will put "
sys_clock_nanosleep" in the call table inentry.Sand define the "__NR_clock_nanosleep" for unistd. The last entry of the enum isNR_syscalls, thus defineing and keeping this symbol current.Me no likee.
Cool. It was just a thought that I could not put down with out doing the code :)
Signature · 3 lines
George Anzinger [email protected] High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
Quoted 4 lines · george anzinger
Quoted 1 line
Me no likee.
Cool. It was just a thought that I could not put down with out doing the code :)
It would be nice to have a single list of non-architecture-specific system calls though. Think of the number of times a system call has been added to many architectures but left out, quite by accident, of one or two until someone notices.
-- Jamie