451 lines
12 KiB
C
451 lines
12 KiB
C
/*
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* Copyright (C) 2002- 2004 Jeff Dike (jdike@addtoit.com)
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* Licensed under the GPL
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <signal.h>
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#include <setjmp.h>
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#include <sched.h>
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#include <sys/wait.h>
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#include <sys/mman.h>
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#include <sys/user.h>
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#include <asm/unistd.h>
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#include <asm/types.h>
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#include "user.h"
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#include "ptrace_user.h"
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#include "time_user.h"
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#include "sysdep/ptrace.h"
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#include "user_util.h"
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#include "kern_util.h"
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#include "skas.h"
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#include "mm_id.h"
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#include "sysdep/sigcontext.h"
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#include "sysdep/stub.h"
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#include "os.h"
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#include "proc_mm.h"
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#include "skas_ptrace.h"
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#include "chan_user.h"
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#include "signal_user.h"
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#include "registers.h"
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#include "mem.h"
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#include "uml-config.h"
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#include "process.h"
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int is_skas_winch(int pid, int fd, void *data)
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{
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if(pid != os_getpgrp())
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return(0);
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register_winch_irq(-1, fd, -1, data);
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return(1);
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}
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void wait_stub_done(int pid, int sig, char * fname)
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{
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int n, status, err;
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do {
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if ( sig != -1 ) {
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err = ptrace(PTRACE_CONT, pid, 0, sig);
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if(err)
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panic("%s : continue failed, errno = %d\n",
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fname, errno);
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}
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sig = 0;
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CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
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} while((n >= 0) && WIFSTOPPED(status) &&
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(WSTOPSIG(status) == SIGVTALRM));
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if((n < 0) || !WIFSTOPPED(status) ||
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(WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status != SIGTRAP))){
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panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
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"pid = %d, n = %d, errno = %d, status = 0x%x\n",
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fname, pid, n, errno, status);
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}
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}
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void get_skas_faultinfo(int pid, struct faultinfo * fi)
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{
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int err;
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if(ptrace_faultinfo){
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err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
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if(err)
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panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
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"errno = %d\n", errno);
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/* Special handling for i386, which has different structs */
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if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
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memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
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sizeof(struct faultinfo) -
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sizeof(struct ptrace_faultinfo));
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}
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else {
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wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
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/* faultinfo is prepared by the stub-segv-handler at start of
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* the stub stack page. We just have to copy it.
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*/
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memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
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}
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}
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static void handle_segv(int pid, union uml_pt_regs * regs)
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{
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get_skas_faultinfo(pid, ®s->skas.faultinfo);
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segv(regs->skas.faultinfo, 0, 1, NULL);
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}
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/*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
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static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
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{
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int err, status;
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/* Mark this as a syscall */
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UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
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if (!local_using_sysemu)
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{
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err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
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if(err < 0)
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panic("handle_trap - nullifying syscall failed errno = %d\n",
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errno);
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err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
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if(err < 0)
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panic("handle_trap - continuing to end of syscall failed, "
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"errno = %d\n", errno);
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CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
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if((err < 0) || !WIFSTOPPED(status) ||
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(WSTOPSIG(status) != SIGTRAP + 0x80))
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panic("handle_trap - failed to wait at end of syscall, "
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"errno = %d, status = %d\n", errno, status);
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}
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handle_syscall(regs);
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}
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extern int __syscall_stub_start;
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static int userspace_tramp(void *stack)
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{
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void *addr;
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ptrace(PTRACE_TRACEME, 0, 0, 0);
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init_new_thread_signals(1);
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enable_timer();
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if(!proc_mm){
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/* This has a pte, but it can't be mapped in with the usual
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* tlb_flush mechanism because this is part of that mechanism
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*/
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int fd;
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__u64 offset;
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fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
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addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(),
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PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
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if(addr == MAP_FAILED){
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printk("mapping mmap stub failed, errno = %d\n",
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errno);
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exit(1);
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}
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if(stack != NULL){
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fd = phys_mapping(to_phys(stack), &offset);
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addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(),
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PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_SHARED, fd, offset);
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if(addr == MAP_FAILED){
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printk("mapping segfault stack failed, "
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"errno = %d\n", errno);
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exit(1);
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}
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}
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}
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if(!ptrace_faultinfo && (stack != NULL)){
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unsigned long v = UML_CONFIG_STUB_CODE +
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(unsigned long) stub_segv_handler -
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(unsigned long) &__syscall_stub_start;
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set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
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set_handler(SIGSEGV, (void *) v, SA_ONSTACK,
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SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
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SIGUSR1, -1);
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}
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os_stop_process(os_getpid());
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return(0);
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}
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/* Each element set once, and only accessed by a single processor anyway */
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#undef NR_CPUS
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#define NR_CPUS 1
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int userspace_pid[NR_CPUS];
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int start_userspace(unsigned long stub_stack)
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{
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void *stack;
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unsigned long sp;
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int pid, status, n, flags;
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stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if(stack == MAP_FAILED)
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panic("start_userspace : mmap failed, errno = %d", errno);
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sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
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flags = CLONE_FILES | SIGCHLD;
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if(proc_mm) flags |= CLONE_VM;
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pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
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if(pid < 0)
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panic("start_userspace : clone failed, errno = %d", errno);
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do {
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CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
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if(n < 0)
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panic("start_userspace : wait failed, errno = %d",
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errno);
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} while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
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if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
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panic("start_userspace : expected SIGSTOP, got status = %d",
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status);
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if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0)
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panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n",
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errno);
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if(munmap(stack, PAGE_SIZE) < 0)
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panic("start_userspace : munmap failed, errno = %d\n", errno);
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return(pid);
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}
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void userspace(union uml_pt_regs *regs)
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{
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int err, status, op, pid = userspace_pid[0];
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int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
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while(1){
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restore_registers(pid, regs);
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/* Now we set local_using_sysemu to be used for one loop */
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local_using_sysemu = get_using_sysemu();
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op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL));
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err = ptrace(op, pid, 0, 0);
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if(err)
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panic("userspace - could not resume userspace process, "
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"pid=%d, ptrace operation = %d, errno = %d\n",
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op, errno);
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CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
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if(err < 0)
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panic("userspace - waitpid failed, errno = %d\n",
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errno);
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regs->skas.is_user = 1;
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save_registers(pid, regs);
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UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
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if(WIFSTOPPED(status)){
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switch(WSTOPSIG(status)){
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case SIGSEGV:
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if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
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user_signal(SIGSEGV, regs, pid);
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else handle_segv(pid, regs);
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break;
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case SIGTRAP + 0x80:
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handle_trap(pid, regs, local_using_sysemu);
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break;
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case SIGTRAP:
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relay_signal(SIGTRAP, regs);
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break;
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case SIGIO:
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case SIGVTALRM:
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case SIGILL:
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case SIGBUS:
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case SIGFPE:
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case SIGWINCH:
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user_signal(WSTOPSIG(status), regs, pid);
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break;
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default:
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printk("userspace - child stopped with signal "
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"%d\n", WSTOPSIG(status));
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}
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pid = userspace_pid[0];
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interrupt_end();
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/* Avoid -ERESTARTSYS handling in host */
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PT_SYSCALL_NR(regs->skas.regs) = -1;
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}
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}
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}
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#define INIT_JMP_NEW_THREAD 0
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#define INIT_JMP_REMOVE_SIGSTACK 1
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#define INIT_JMP_CALLBACK 2
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#define INIT_JMP_HALT 3
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#define INIT_JMP_REBOOT 4
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void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
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void (*handler)(int))
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{
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unsigned long flags;
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sigjmp_buf switch_buf, fork_buf;
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*switch_buf_ptr = &switch_buf;
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*fork_buf_ptr = &fork_buf;
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/* Somewhat subtle - siglongjmp restores the signal mask before doing
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* the longjmp. This means that when jumping from one stack to another
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* when the target stack has interrupts enabled, an interrupt may occur
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* on the source stack. This is bad when starting up a process because
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* it's not supposed to get timer ticks until it has been scheduled.
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* So, we disable interrupts around the sigsetjmp to ensure that
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* they can't happen until we get back here where they are safe.
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*/
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flags = get_signals();
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block_signals();
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if(sigsetjmp(fork_buf, 1) == 0)
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new_thread_proc(stack, handler);
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remove_sigstack();
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set_signals(flags);
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}
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void thread_wait(void *sw, void *fb)
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{
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sigjmp_buf buf, **switch_buf = sw, *fork_buf;
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*switch_buf = &buf;
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fork_buf = fb;
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if(sigsetjmp(buf, 1) == 0)
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siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK);
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}
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void switch_threads(void *me, void *next)
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{
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sigjmp_buf my_buf, **me_ptr = me, *next_buf = next;
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*me_ptr = &my_buf;
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if(sigsetjmp(my_buf, 1) == 0)
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siglongjmp(*next_buf, 1);
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}
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static sigjmp_buf initial_jmpbuf;
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/* XXX Make these percpu */
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static void (*cb_proc)(void *arg);
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static void *cb_arg;
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static sigjmp_buf *cb_back;
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int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr)
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{
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sigjmp_buf **switch_buf = switch_buf_ptr;
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int n;
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set_handler(SIGWINCH, (__sighandler_t) sig_handler,
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SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
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SIGVTALRM, -1);
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*fork_buf_ptr = &initial_jmpbuf;
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n = sigsetjmp(initial_jmpbuf, 1);
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switch(n){
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case INIT_JMP_NEW_THREAD:
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new_thread_proc((void *) stack, new_thread_handler);
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break;
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case INIT_JMP_REMOVE_SIGSTACK:
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remove_sigstack();
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break;
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case INIT_JMP_CALLBACK:
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(*cb_proc)(cb_arg);
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siglongjmp(*cb_back, 1);
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break;
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case INIT_JMP_HALT:
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kmalloc_ok = 0;
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return(0);
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case INIT_JMP_REBOOT:
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kmalloc_ok = 0;
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return(1);
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default:
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panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
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}
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siglongjmp(**switch_buf, 1);
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}
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void remove_sigstack(void)
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{
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stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE,
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.ss_sp = NULL,
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.ss_size = 0 });
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if(sigaltstack(&stack, NULL) != 0)
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panic("disabling signal stack failed, errno = %d\n", errno);
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}
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void initial_thread_cb_skas(void (*proc)(void *), void *arg)
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{
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sigjmp_buf here;
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cb_proc = proc;
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cb_arg = arg;
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cb_back = &here;
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block_signals();
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if(sigsetjmp(here, 1) == 0)
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siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK);
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unblock_signals();
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cb_proc = NULL;
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cb_arg = NULL;
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cb_back = NULL;
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}
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void halt_skas(void)
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{
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block_signals();
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siglongjmp(initial_jmpbuf, INIT_JMP_HALT);
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}
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void reboot_skas(void)
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{
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block_signals();
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siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT);
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}
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void switch_mm_skas(struct mm_id *mm_idp)
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{
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int err;
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#warning need cpu pid in switch_mm_skas
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if(proc_mm){
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err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
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mm_idp->u.mm_fd);
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if(err)
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panic("switch_mm_skas - PTRACE_SWITCH_MM failed, "
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"errno = %d\n", errno);
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}
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else userspace_pid[0] = mm_idp->u.pid;
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}
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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