/* $NetBSD: syscall.c,v 1.52 2026/05/10 23:51:37 tls Exp $ */ /*- * Copyright (c) 2001 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe and by Charles M. Hannum. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Copyright (c) 1988 University of Utah. * Copyright (c) 1992, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department and Ralph Campbell. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: Utah Hdr: trap.c 1.32 91/04/06 * * @(#)trap.c 8.5 (Berkeley) 1/11/94 */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: syscall.c,v 1.52 2026/05/10 23:51:37 tls Exp $"); #include <sys/param.h> #include <sys/cpu.h> #include <sys/endian.h> #include <sys/proc.h> #include <sys/signal.h> #include <sys/syscall.h> #include <sys/syscallvar.h> #include <sys/systm.h> #include <uvm/uvm_extern.h> #include <mips/locore.h> #include <mips/trap.h> #include <mips/reg.h> #include <mips/regnum.h> /* symbolic register indices */ #include <mips/userret.h> #ifndef EMULNAME #define EMULNAME(x) (x) #endif #ifndef SYSCALL_SHIFT #define SYSCALL_SHIFT 0 #endif void EMULNAME(syscall_intern)(struct proc *); static void EMULNAME(syscall)(struct lwp *, uint32_t, uint32_t, vaddr_t); void EMULNAME(syscall_intern)(struct proc *p) { p->p_md.md_syscall = EMULNAME(syscall); } /* * Process a system call. * * System calls are strange beasts. They are passed the syscall number * in v0, and the arguments in the registers (as normal). They return * an error flag in a3 (if a3 != 0 on return, the syscall had an error), * and the return value (if any) in v0 and possibly v1. */ void EMULNAME(syscall)(struct lwp *l, u_int status, u_int cause, vaddr_t pc) { struct proc *p = l->l_proc; struct trapframe *tf = l->l_md.md_utf; struct reg *reg = &tf->tf_registers; mips_reg_t *fargs = ®->r_regs[_R_A0]; register_t *args = NULL; register_t copyargs[2+SYS_MAXSYSARGS]; vaddr_t usp; size_t nargs; const struct sysent *callp; int code, error; #if defined(__mips_o32) const int abi = _MIPS_BSD_API_O32; KASSERTMSG(p->p_md.md_abi == abi, "pid %d(%p): md_abi(%d) != abi(%d)", p->p_pid, p, p->p_md.md_abi, abi); size_t nregs = 4; #else const int abi = p->p_md.md_abi; size_t nregs = _MIPS_SIM_NEWABI_P(abi) ? 8 : 4; size_t i; #endif curcpu()->ci_data.cpu_nsyscall++; if (cause & MIPS_CR_BR_DELAY) reg->r_regs[_R_PC] = mips_emul_branch(tf, pc, 0, false); else reg->r_regs[_R_PC] = pc + sizeof(uint32_t); callp = p->p_emul->e_sysent; const mips_reg_t saved_v0 = reg->r_regs[_R_V0]; code = saved_v0 - SYSCALL_SHIFT; if (code == SYS_syscall || (code == SYS___syscall && abi != _MIPS_BSD_API_O32)) { /* * Code is first argument, followed by actual args. */ code = *fargs++ - SYSCALL_SHIFT; nregs--; } else if (code == SYS___syscall) { /* * Like syscall, but code is a quad, so as to maintain * quad alignment for the rest of the arguments. */ code = fargs[_QUAD_LOWWORD] - SYSCALL_SHIFT; fargs += 2; nregs -= 2; } if (code >= p->p_emul->e_nsysent) callp += p->p_emul->e_nosys; else callp += code; nargs = callp->sy_narg; #if !defined(__mips_o32) if (abi != _MIPS_BSD_API_O32) { #endif CTASSERT(sizeof(copyargs[0]) == sizeof(fargs[0])); if (nargs <= nregs) { /* * Just use the trapframe for the source of arguments */ args = fargs; } else { const size_t nsaved = _MIPS_SIM_NEWABI_P(abi) ? 0 : 4; KASSERT(nargs <= __arraycount(copyargs)); args = copyargs; /* * Copy the arguments passed via register from the * trapframe to our argument array */ memcpy(copyargs, fargs, nregs * sizeof(register_t)); /* * Start copying args skipping the register slots * slots on the stack. */ usp = reg->r_regs[_R_SP] + nsaved * sizeof(register_t); error = copyin((register_t *)usp, ©args[nregs], (nargs - nregs) * sizeof(copyargs[0])); if (error) goto bad; } #if !defined(__mips_o32) } else do { /* * The only difference between O32 and N32 is the calling * sequence. If you make O32 */ int32_t copy32args[SYS_MAXSYSARGS]; int32_t *cargs = copy32args; unsigned int arg64mask = SYCALL_ARG_64_MASK(callp); bool doing_arg64; size_t narg64 = SYCALL_NARGS64(callp); /* * All arguments are 32bits wide and 64bit arguments use * two 32bit registers or stack slots. We need to remarshall * them into 64bit slots */ args = copyargs; CTASSERT(sizeof(copy32args[0]) != sizeof(fargs[0])); /* * If there are no 64bit arguments and all arguments were in * registers, just use the trapframe for the source of arguments */ if (nargs <= nregs && narg64 == 0) { args = fargs; break; } if (nregs <= nargs + narg64) { /* * Grab the non-register arguments from the stack * after skipping the slots for the 4 register passed * arguments. */ usp = reg->r_regs[_R_SP] + 4 * sizeof(int32_t); error = copyin((int32_t *)usp, copy32args, (nargs + narg64 - nregs) * sizeof(copy32args[0])); if (error) goto bad; } /* * Copy all the arguments to copyargs, starting with the ones * in registers. Using the hints in the 64bit argmask, * we marshall the passed 32bit values into 64bit slots. If we * encounter a 64 bit argument, we grab two adjacent 32bit * values and synthesize the 64bit argument. */ for (i = 0, doing_arg64 = false; i < nargs + narg64;) { register_t arg; if (nregs > 0) { arg = (int32_t) *fargs++; nregs--; } else { arg = *cargs++; } if (__predict_true((arg64mask & 1) == 0)) { /* * Just copy it with sign extension on */ copyargs[i++] = (int32_t) arg; arg64mask >>= 1; continue; } /* * 64bit arg. grab the low 32 bits, discard the high. */ arg = (uint32_t)arg; if (!doing_arg64) { /* * Pick up the 1st word of a 64bit arg. * If lowword == 1 then highword == 0, * so this is the highword and thus * shifted left by 32, otherwise * lowword == 0 and highword == 1 so * it isn't shifted at all. Remember * we still need another word. */ doing_arg64 = true; copyargs[i] = arg << (_QUAD_LOWWORD*32); narg64--; /* one less 64bit arg */ } else { /* * Pick up the 2nd word of a 64bit arg. * if highword == 1, it's shifted left * by 32, otherwise lowword == 1 and * highword == 0 so it isn't shifted at * all. And now head to the next argument. */ doing_arg64 = false; copyargs[i++] |= arg << (_QUAD_HIGHWORD*32); arg64mask >>= 1; } } } while (/*CONSTCOND*/ 0); /* avoid a goto */ #endif #ifdef MIPS_SYSCALL_DEBUG if (p->p_emul->e_syscallnames) printf("syscall %s:", p->p_emul->e_syscallnames[code]); else printf("syscall %u:", code); if (nargs == 0) printf(" <no args>"); else for (size_t j = 0; j < nargs; j++) { if (j == nregs) printf(" *"); printf(" [%s%zu]=%#"PRIxREGISTER, SYCALL_ARG_64_P(callp, j) ? "+" : "", j, args[j]); } printf("\n"); #endif error = sy_invoke(callp, l, args, ®->r_regs[_R_V0], code); switch (error) { case 0: #if !defined(__mips_o32) if (abi == _MIPS_BSD_API_O32 && SYCALL_RET_64_P(callp)) { /* * If this is from O32 and it's a 64bit quantity, * split it into 2 32bit values in adjacent registers. */ mips_reg_t tmp = reg->r_regs[_R_V0]; reg->r_regs[_R_V0 + _QUAD_LOWWORD] = (int32_t) tmp; reg->r_regs[_R_V0 + _QUAD_HIGHWORD] = tmp >> 32; } if (abi != _MIPS_BSD_API_O32 && !SYCALL_RET_WIDE_P(callp)) { /* * Sign-extend 32-bit syscall return values to 64 * bits, as required by ABI. Avoids corruption if * the returned value is spilled to and reloaded * from the stack in userspace. */ reg->r_regs[_R_V0] = (int32_t)(int64_t)reg->r_regs[_R_V0]; reg->r_regs[_R_V1] = (int32_t)(int64_t)reg->r_regs[_R_V1]; } #endif #ifdef MIPS_SYSCALL_DEBUG if (p->p_emul->e_syscallnames) printf("syscall %s:", p->p_emul->e_syscallnames[code]); else printf("syscall %u:", code); printf(" return v0=%#"PRIxREGISTER" v1=%#"PRIxREGISTER"\n", reg->r_regs[_R_V0], reg->r_regs[_R_V1]); #endif reg->r_regs[_R_A3] = 0; break; case ERESTART: reg->r_regs[_R_V0] = saved_v0; /* restore syscall code */ reg->r_regs[_R_PC] = pc; break; case EJUSTRETURN: break; /* nothing to do */ default: bad: if (p->p_emul->e_errno) error = p->p_emul->e_errno[error]; reg->r_regs[_R_V0] = error; reg->r_regs[_R_A3] = 1; #ifdef MIPS_SYSCALL_DEBUG if (p->p_emul->e_syscallnames) printf("syscall %s:", p->p_emul->e_syscallnames[code]); else printf("syscall %u:", code); printf(" return error=%d\n", error); #endif break; } KASSERT(l->l_blcnt == 0); KASSERT(curcpu()->ci_biglock_count == 0); userret(l); }
