/* * arch/xtensa/kernel/syscall.c * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2005 Tensilica Inc. * Copyright (C) 2000 Silicon Graphics, Inc. * Copyright (C) 1995 - 2000 by Ralf Baechle * * Joe Taylor * Marc Gauthier * Chris Zankel * Kevin Chea * */ #define DEBUG 0 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern void do_syscall_trace(void); typedef int (*syscall_t)(void *a0,...); extern syscall_t sys_call_table[]; extern unsigned char sys_narg_table[]; /* * sys_pipe() is the normal C calling standard for creating a pipe. It's not * the way unix traditional does this, though. */ int sys_pipe(int __user *userfds) { int fd[2]; int error; error = do_pipe(fd); if (!error) { if (copy_to_user(userfds, fd, 2 * sizeof(int))) error = -EFAULT; } return error; } /* * Common code for old and new mmaps. */ long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, unsigned long fd, unsigned long pgoff) { int error = -EBADF; struct file * file = NULL; flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); if (!(flags & MAP_ANONYMOUS)) { file = fget(fd); if (!file) goto out; } down_write(¤t->mm->mmap_sem); error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); up_write(¤t->mm->mmap_sem); if (file) fput(file); out: return error; } int sys_clone(struct pt_regs *regs) { unsigned long clone_flags; unsigned long newsp; int __user *parent_tidptr, *child_tidptr; clone_flags = regs->areg[4]; newsp = regs->areg[3]; parent_tidptr = (int __user *)regs->areg[5]; child_tidptr = (int __user *)regs->areg[6]; if (!newsp) newsp = regs->areg[1]; return do_fork(clone_flags,newsp,regs,0,parent_tidptr,child_tidptr); } /* * sys_execve() executes a new program. */ int sys_execve(struct pt_regs *regs) { int error; char * filename; filename = getname((char *) (long)regs->areg[5]); error = PTR_ERR(filename); if (IS_ERR(filename)) goto out; error = do_execve(filename, (char **) (long)regs->areg[3], (char **) (long)regs->areg[4], regs); putname(filename); out: return error; } int sys_uname(struct old_utsname * name) { if (name && !copy_to_user(name, utsname(), sizeof (*name))) return 0; return -EFAULT; } /* * Build the string table for the builtin "poor man's strace". */ #if DEBUG #define SYSCALL(fun, narg) #fun, static char *sfnames[] = { #include "syscalls.h" }; #undef SYS #endif void system_call (struct pt_regs *regs) { syscall_t syscall; unsigned long parm0, parm1, parm2, parm3, parm4, parm5; int nargs, res; unsigned int syscallnr; int ps; #if DEBUG int i; unsigned long parms[6]; char *sysname; #endif regs->syscall = regs->areg[2]; do_syscall_trace(); /* Have to load after syscall_trace because strace * sometimes changes regs->syscall. */ syscallnr = regs->syscall; parm0 = parm1 = parm2 = parm3 = parm4 = parm5 = 0; /* Restore interrupt level to syscall invoker's. * If this were in assembly, we wouldn't disable * interrupts in the first place: */ local_save_flags (ps); local_irq_restore((ps & ~XCHAL_PS_INTLEVEL_MASK) | (regs->ps & XCHAL_PS_INTLEVEL_MASK) ); if (syscallnr > __NR_Linux_syscalls) { regs->areg[2] = -ENOSYS; return; } syscall = sys_call_table[syscallnr]; nargs = sys_narg_table[syscallnr]; if (syscall == NULL) { regs->areg[2] = -ENOSYS; return; } /* There shouldn't be more than six arguments in the table! */ if (nargs > 6) panic("Internal error - too many syscall arguments (%d)!\n", nargs); /* Linux takes system-call arguments in registers. The ABI * and Xtensa software conventions require the system-call * number in a2. If an argument exists in a2, we move it to * the next available register. Note that for improved * efficiency, we do NOT shift all parameters down one * register to maintain the original order. * * At best case (zero arguments), we just write the syscall * number to a2. At worst case (1 to 6 arguments), we move * the argument in a2 to the next available register, then * write the syscall number to a2. * * For clarity, the following truth table enumerates all * possibilities. * * arguments syscall number arg0, arg1, arg2, arg3, arg4, arg5 * --------- -------------- ---------------------------------- * 0 a2 * 1 a2 a3 * 2 a2 a4, a3 * 3 a2 a5, a3, a4 * 4 a2 a6, a3, a4, a5 * 5 a2 a7, a3, a4, a5, a6 * 6 a2 a8, a3, a4, a5, a6, a7 */ if (nargs) { parm0 = regs->areg[nargs+2]; parm1 = regs->areg[3]; parm2 = regs->areg[4]; parm3 = regs->areg[5]; parm4 = regs->areg[6]; parm5 = regs->areg[7]; } else /* nargs == 0 */ parm0 = (unsigned long) regs; #if DEBUG parms[0] = parm0; parms[1] = parm1; parms[2] = parm2; parms[3] = parm3; parms[4] = parm4; parms[5] = parm5; sysname = sfnames[syscallnr]; if (strncmp(sysname, "sys_", 4) == 0) sysname = sysname + 4; printk("\017SYSCALL:I:%x:%d:%s %s(", regs->pc, current->pid, current->comm, sysname); for (i = 0; i < nargs; i++) printk((i>0) ? ", %#lx" : "%#lx", parms[i]); printk(")\n"); #endif res = syscall((void *)parm0, parm1, parm2, parm3, parm4, parm5); #if DEBUG printk("\017SYSCALL:O:%d:%s %s(",current->pid, current->comm, sysname); for (i = 0; i < nargs; i++) printk((i>0) ? ", %#lx" : "%#lx", parms[i]); if (res < 4096) printk(") = %d\n", res); else printk(") = %#x\n", res); #endif /* DEBUG */ regs->areg[2] = res; do_syscall_trace(); } /* * Do a system call from kernel instead of calling sys_execve so we * end up with proper pt_regs. */ int kernel_execve(const char *filename, char *const argv[], char *const envp[]) { long __res; asm volatile ( " mov a5, %2 \n" " mov a4, %4 \n" " mov a3, %3 \n" " movi a2, %1 \n" " syscall \n" " mov %0, a2 \n" : "=a" (__res) : "i" (__NR_execve), "a" (filename), "a" (argv), "a" (envp) : "a2", "a3", "a4", "a5"); return __res; }