FreeBSD/Linux Kernel Cross Reference
sys/mips/mips/pm_machdep.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1992 Terrence R. Lambert.
      * Copyright (c) 1982, 1987, 1990 The Regents of the University of California.
      * All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * William Jolitz.
     *
     * 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: @(#)machdep.c     7.4 (Berkeley) 6/3/91
     *      from: src/sys/i386/i386/machdep.c,v 1.385.2.3 2000/05/10 02:04:46 obrien
     *      JNPR: pm_machdep.c,v 1.9.2.1 2007/08/16 15:59:10 girish
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/12.0/sys/mips/mips/pm_machdep.c 333076 2018-04-27 21:22:32Z jhb $");
    
    #include <sys/types.h>
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/sysent.h>
    #include <sys/proc.h>
    #include <sys/signalvar.h>
    #include <sys/exec.h>
    #include <sys/imgact.h>
    #include <sys/ucontext.h>
    #include <sys/lock.h>
    #include <sys/syscallsubr.h>
    #include <sys/sysproto.h>
    #include <sys/ptrace.h>
    #include <sys/syslog.h>
    #include <vm/vm.h>
    #include <vm/pmap.h>
    #include <vm/vm_map.h>
    #include <vm/vm_extern.h>
    #include <sys/user.h>
    #include <sys/uio.h>
    #include <machine/abi.h>
    #include <machine/cpuinfo.h>
    #include <machine/reg.h>
    #include <machine/md_var.h>
    #include <machine/sigframe.h>
    #include <machine/tls.h>
    #include <machine/vmparam.h>
    #include <sys/vnode.h>
    #include <fs/pseudofs/pseudofs.h>
    #include <fs/procfs/procfs.h>
    
    #define UCONTEXT_MAGIC  0xACEDBADE
    
    /*
     * Send an interrupt to process.
     *
     * Stack is set up to allow sigcode stored
     * at top to call routine, followed by kcall
     * to sigreturn routine below.  After sigreturn
     * resets the signal mask, the stack, and the
     * frame pointer, it returns to the user
     * specified pc, psl.
     */
    void
    sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
    {
            struct proc *p;
            struct thread *td;
            struct trapframe *regs;
            struct sigacts *psp;
            struct sigframe sf, *sfp;
            int sig;
            int oonstack;
    
            td = curthread;
            p = td->td_proc;
            PROC_LOCK_ASSERT(p, MA_OWNED);
           sig = ksi->ksi_signo;
           psp = p->p_sigacts;
           mtx_assert(&psp->ps_mtx, MA_OWNED);
   
           regs = td->td_frame;
           oonstack = sigonstack(regs->sp);
   
           /* save user context */
           bzero(&sf, sizeof(struct sigframe));
           sf.sf_uc.uc_sigmask = *mask;
           sf.sf_uc.uc_stack = td->td_sigstk;
           sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
           sf.sf_uc.uc_mcontext.mc_pc = regs->pc;
           sf.sf_uc.uc_mcontext.mullo = regs->mullo;
           sf.sf_uc.uc_mcontext.mulhi = regs->mulhi;
           sf.sf_uc.uc_mcontext.mc_tls = td->td_md.md_tls;
           sf.sf_uc.uc_mcontext.mc_regs[0] = UCONTEXT_MAGIC;  /* magic number */
           bcopy((void *)&regs->ast, (void *)&sf.sf_uc.uc_mcontext.mc_regs[1],
               sizeof(sf.sf_uc.uc_mcontext.mc_regs) - sizeof(register_t));
           sf.sf_uc.uc_mcontext.mc_fpused = td->td_md.md_flags & MDTD_FPUSED;
           if (sf.sf_uc.uc_mcontext.mc_fpused) {
                   /* if FPU has current state, save it first */
                   if (td == PCPU_GET(fpcurthread))
                           MipsSaveCurFPState(td);
                   bcopy((void *)&td->td_frame->f0,
                       (void *)sf.sf_uc.uc_mcontext.mc_fpregs,
                       sizeof(sf.sf_uc.uc_mcontext.mc_fpregs));
           }
   
           /* Allocate and validate space for the signal handler context. */
           if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
               SIGISMEMBER(psp->ps_sigonstack, sig)) {
                   sfp = (struct sigframe *)(((uintptr_t)td->td_sigstk.ss_sp +
                       td->td_sigstk.ss_size - sizeof(struct sigframe))
                       & ~(STACK_ALIGN - 1));
           } else
                   sfp = (struct sigframe *)((vm_offset_t)(regs->sp - 
                       sizeof(struct sigframe)) & ~(STACK_ALIGN - 1));
   
           /* Build the argument list for the signal handler. */
           regs->a0 = sig;
           regs->a2 = (register_t)(intptr_t)&sfp->sf_uc;
           if (SIGISMEMBER(psp->ps_siginfo, sig)) {
                   /* Signal handler installed with SA_SIGINFO. */
                   regs->a1 = (register_t)(intptr_t)&sfp->sf_si;
                   /* sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher; */
   
                   /* fill siginfo structure */
                   sf.sf_si = ksi->ksi_info;
                   sf.sf_si.si_signo = sig;
                   sf.sf_si.si_code = ksi->ksi_code;
                   sf.sf_si.si_addr = (void*)(intptr_t)regs->badvaddr;
           } else {
                   /* Old FreeBSD-style arguments. */
                   regs->a1 = ksi->ksi_code;
                   regs->a3 = regs->badvaddr;
                   /* sf.sf_ahu.sf_handler = catcher; */
           }
   
           mtx_unlock(&psp->ps_mtx);
           PROC_UNLOCK(p);
   
           /*
            * Copy the sigframe out to the user's stack.
            */
           if (copyout(&sf, sfp, sizeof(struct sigframe)) != 0) {
                   /*
                    * Something is wrong with the stack pointer.
                    * ...Kill the process.
                    */
                   PROC_LOCK(p);
                   sigexit(td, SIGILL);
           }
   
           regs->pc = (register_t)(intptr_t)catcher;
           regs->t9 = (register_t)(intptr_t)catcher;
           regs->sp = (register_t)(intptr_t)sfp;
           /*
            * Signal trampoline code is at base of user stack.
            */
           regs->ra = (register_t)(intptr_t)PS_STRINGS - *(p->p_sysent->sv_szsigcode);
           PROC_LOCK(p);
           mtx_lock(&psp->ps_mtx);
   }
   
   /*
    * System call to cleanup state after a signal
    * has been taken.  Reset signal mask and
    * stack state from context left by sendsig (above).
    * Return to previous pc as specified by
    * context left by sendsig.
    */
   int
   sys_sigreturn(struct thread *td, struct sigreturn_args *uap)
   {
           ucontext_t uc;
           int error;
   
           error = copyin(uap->sigcntxp, &uc, sizeof(uc));
           if (error != 0)
               return (error);
   
           error = set_mcontext(td, &uc.uc_mcontext);
           if (error != 0)
                   return (error);
   
           kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
   
           return (EJUSTRETURN);
   }
   
   int
   ptrace_set_pc(struct thread *td, unsigned long addr)
   {
           td->td_frame->pc = (register_t) addr;
           return 0;
   }
   
   static int
   ptrace_read_int(struct thread *td, uintptr_t addr, int *v)
   {
   
           if (proc_readmem(td, td->td_proc, addr, v, sizeof(*v)) != sizeof(*v))
                   return (EFAULT);
           return (0);
   }
   
   static int
   ptrace_write_int(struct thread *td, uintptr_t addr, int v)
   {
   
           if (proc_writemem(td, td->td_proc, addr, &v, sizeof(v)) != sizeof(v))
                   return (EFAULT);
           return (0);
   }
   
   int
   ptrace_single_step(struct thread *td)
   {
           uintptr_t va;
           struct trapframe *locr0 = td->td_frame;
           int error;
           int bpinstr = MIPS_BREAK_SSTEP;
           int curinstr;
           struct proc *p;
   
           p = td->td_proc;
           PROC_UNLOCK(p);
           /*
            * Fetch what's at the current location.
            */
           error = ptrace_read_int(td, locr0->pc, &curinstr);
           if (error)
                   goto out;
   
           CTR3(KTR_PTRACE,
               "ptrace_single_step: tid %d, current instr at %#lx: %#08x",
               td->td_tid, locr0->pc, curinstr);
   
           /* compute next address after current location */
           if (locr0->cause & MIPS_CR_BR_DELAY) {
                   va = MipsEmulateBranch(locr0, locr0->pc, locr0->fsr,
                       (uintptr_t)&curinstr);
           } else {
                   va = locr0->pc + 4;
           }
           if (td->td_md.md_ss_addr) {
                   printf("SS %s (%d): breakpoint already set at %p (va %p)\n",
                       p->p_comm, p->p_pid, (void *)td->td_md.md_ss_addr,
                       (void *)va); /* XXX */
                   error = EFAULT;
                   goto out;
           }
           td->td_md.md_ss_addr = va;
           /*
            * Fetch what's at the current location.
            */
           error = ptrace_read_int(td, (off_t)va, &td->td_md.md_ss_instr);
           if (error)
                   goto out;
   
           /*
            * Store breakpoint instruction at the "next" location now.
            */
           error = ptrace_write_int(td, va, bpinstr);
   
           /*
            * The sync'ing of I & D caches is done by proc_rwmem()
            * through proc_writemem().
            */
   
   out:
           PROC_LOCK(p);
           if (error == 0)
                   CTR3(KTR_PTRACE,
                       "ptrace_single_step: tid %d, break set at %#lx: (%#08x)",
                       td->td_tid, va, td->td_md.md_ss_instr); 
           return (error);
   }
   
   
   void
   makectx(struct trapframe *tf, struct pcb *pcb)
   {
   
           pcb->pcb_context[PCB_REG_RA] = tf->ra;
           pcb->pcb_context[PCB_REG_PC] = tf->pc;
           pcb->pcb_context[PCB_REG_SP] = tf->sp;
   }
   
   int
   fill_regs(struct thread *td, struct reg *regs)
   {
           memcpy(regs, td->td_frame, sizeof(struct reg));
           return (0);
   }
   
   int
   set_regs(struct thread *td, struct reg *regs)
   {
           struct trapframe *f;
           register_t sr;
   
           f = (struct trapframe *) td->td_frame;
           /*
            * Don't allow the user to change SR
            */
           sr = f->sr;
           memcpy(td->td_frame, regs, sizeof(struct reg));
           f->sr = sr;
           return (0);
   }
   
   int
   get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
   {
           struct trapframe *tp;
   
           tp = td->td_frame;
           PROC_LOCK(curthread->td_proc);
           mcp->mc_onstack = sigonstack(tp->sp);
           PROC_UNLOCK(curthread->td_proc);
           bcopy((void *)&td->td_frame->zero, (void *)&mcp->mc_regs,
               sizeof(mcp->mc_regs));
   
           mcp->mc_fpused = td->td_md.md_flags & MDTD_FPUSED;
           if (mcp->mc_fpused) {
                   bcopy((void *)&td->td_frame->f0, (void *)&mcp->mc_fpregs,
                       sizeof(mcp->mc_fpregs));
           }
           if (flags & GET_MC_CLEAR_RET) {
                   mcp->mc_regs[V0] = 0;
                   mcp->mc_regs[V1] = 0;
                   mcp->mc_regs[A3] = 0;
           }
   
           mcp->mc_pc = td->td_frame->pc;
           mcp->mullo = td->td_frame->mullo;
           mcp->mulhi = td->td_frame->mulhi;
           mcp->mc_tls = td->td_md.md_tls;
           return (0);
   }
   
   int
   set_mcontext(struct thread *td, mcontext_t *mcp)
   {
           struct trapframe *tp;
   
           tp = td->td_frame;
           bcopy((void *)&mcp->mc_regs, (void *)&td->td_frame->zero,
               sizeof(mcp->mc_regs));
   
           td->td_md.md_flags = mcp->mc_fpused & MDTD_FPUSED;
           if (mcp->mc_fpused) {
                   bcopy((void *)&mcp->mc_fpregs, (void *)&td->td_frame->f0,
                       sizeof(mcp->mc_fpregs));
           }
           td->td_frame->pc = mcp->mc_pc;
           td->td_frame->mullo = mcp->mullo;
           td->td_frame->mulhi = mcp->mulhi;
           td->td_md.md_tls = mcp->mc_tls;
           /* Dont let user to set any bits in status and cause registers. */
   
           return (0);
   }
   
   int
   fill_fpregs(struct thread *td, struct fpreg *fpregs)
   {
           if (td == PCPU_GET(fpcurthread))
                   MipsSaveCurFPState(td);
           memcpy(fpregs, &td->td_frame->f0, sizeof(struct fpreg));
           fpregs->r_regs[FIR_NUM] = cpuinfo.fpu_id;
           return 0;
   }
   
   int
   set_fpregs(struct thread *td, struct fpreg *fpregs)
   {
           if (PCPU_GET(fpcurthread) == td)
                   PCPU_SET(fpcurthread, (struct thread *)0);
           memcpy(&td->td_frame->f0, fpregs, sizeof(struct fpreg));
           return 0;
   }
   
   
   /*
    * Clear registers on exec
    * $sp is set to the stack pointer passed in.  $pc is set to the entry
    * point given by the exec_package passed in, as is $t9 (used for PIC
    * code by the MIPS elf abi).
    */
   void
   exec_setregs(struct thread *td, struct image_params *imgp, u_long stack)
   {
   
           bzero((caddr_t)td->td_frame, sizeof(struct trapframe));
   
           td->td_frame->sp = ((register_t)stack) & ~(STACK_ALIGN - 1);
   
           /*
            * If we're running o32 or n32 programs but have 64-bit registers,
            * GCC may use stack-relative addressing near the top of user
            * address space that, due to sign extension, will yield an
            * invalid address.  For instance, if sp is 0x7fffff00 then GCC
            * might do something like this to load a word from 0x7ffffff0:
            *
            *      addu    sp, sp, 32768
            *      lw      t0, -32528(sp)
            *
            * On systems with 64-bit registers, sp is sign-extended to
            * 0xffffffff80007f00 and the load is instead done from
            * 0xffffffff7ffffff0.
            *
            * To prevent this, we subtract 64K from the stack pointer here
            * for processes with 32-bit pointers.
            */
   #if defined(__mips_n32) || defined(__mips_n64)
           if (!SV_PROC_FLAG(td->td_proc, SV_LP64))
                   td->td_frame->sp -= 65536;
   #endif
   
           td->td_frame->pc = imgp->entry_addr & ~3;
           td->td_frame->t9 = imgp->entry_addr & ~3; /* abicall req */
           td->td_frame->sr = MIPS_SR_KSU_USER | MIPS_SR_EXL | MIPS_SR_INT_IE |
               (mips_rd_status() & MIPS_SR_INT_MASK);
   #if defined(__mips_n32) 
           td->td_frame->sr |= MIPS_SR_PX;
   #elif  defined(__mips_n64)
           td->td_frame->sr |= MIPS_SR_PX | MIPS_SR_UX | MIPS_SR_KX;
   #endif
           /*
            * FREEBSD_DEVELOPERS_FIXME:
            * Setup any other CPU-Specific registers (Not MIPS Standard)
            * and/or bits in other standard MIPS registers (if CPU-Specific)
            *  that are needed.
            */
   
           /*
            * Set up arguments for the rtld-capable crt0:
            *      a0      stack pointer
            *      a1      rtld cleanup (filled in by dynamic loader)
            *      a2      rtld object (filled in by dynamic loader)
            *      a3      ps_strings
            */
           td->td_frame->a0 = (register_t) stack;
           td->td_frame->a1 = 0;
           td->td_frame->a2 = 0;
           td->td_frame->a3 = (register_t)imgp->ps_strings;
   
           td->td_md.md_flags &= ~MDTD_FPUSED;
           if (PCPU_GET(fpcurthread) == td)
               PCPU_SET(fpcurthread, (struct thread *)0);
           td->td_md.md_ss_addr = 0;
   
           td->td_md.md_tls_tcb_offset = TLS_TP_OFFSET + TLS_TCB_SIZE;
   }
   
   int
   ptrace_clear_single_step(struct thread *td)
   {
           struct proc *p;
           int error;
   
           p = td->td_proc;
           PROC_LOCK_ASSERT(p, MA_OWNED);
           if (!td->td_md.md_ss_addr)
                   return EINVAL;
   
           /*
            * Restore original instruction and clear BP
            */
           PROC_UNLOCK(p);
           CTR3(KTR_PTRACE,
               "ptrace_clear_single_step: tid %d, restore instr at %#lx: %#08x",
               td->td_tid, td->td_md.md_ss_addr, td->td_md.md_ss_instr);
           error = ptrace_write_int(td, td->td_md.md_ss_addr,
               td->td_md.md_ss_instr);
           PROC_LOCK(p);
   
           /* The sync'ing of I & D caches is done by proc_rwmem(). */
   
           if (error != 0) {
                   log(LOG_ERR,
                       "SS %s %d: can't restore instruction at %p: %x\n",
                       p->p_comm, p->p_pid, (void *)td->td_md.md_ss_addr,
                       td->td_md.md_ss_instr);
           }
           td->td_md.md_ss_addr = 0;
           return 0;
   }

Cache object: 4e8e4fdcf3e97bb1ff03bc17aa35a0e1