| /* |
| * Copyright (C) 2002- 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
| * Licensed under the GPL |
| */ |
| |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <sched.h> |
| #include <errno.h> |
| #include <string.h> |
| #include <sys/mman.h> |
| #include <sys/ptrace.h> |
| #include <sys/wait.h> |
| #include <asm/unistd.h> |
| #include "as-layout.h" |
| #include "chan_user.h" |
| #include "kern_constants.h" |
| #include "kern_util.h" |
| #include "mem.h" |
| #include "os.h" |
| #include "process.h" |
| #include "proc_mm.h" |
| #include "ptrace_user.h" |
| #include "registers.h" |
| #include "skas.h" |
| #include "skas_ptrace.h" |
| #include "user.h" |
| #include "sysdep/stub.h" |
| |
| int is_skas_winch(int pid, int fd, void *data) |
| { |
| if (pid != getpgrp()) |
| return 0; |
| |
| register_winch_irq(-1, fd, -1, data, 0); |
| return 1; |
| } |
| |
| static int ptrace_dump_regs(int pid) |
| { |
| unsigned long regs[MAX_REG_NR]; |
| int i; |
| |
| if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) |
| return -errno; |
| |
| printk(UM_KERN_ERR "Stub registers -\n"); |
| for (i = 0; i < ARRAY_SIZE(regs); i++) |
| printk(UM_KERN_ERR "\t%d - %lx\n", i, regs[i]); |
| |
| return 0; |
| } |
| |
| /* |
| * Signals that are OK to receive in the stub - we'll just continue it. |
| * SIGWINCH will happen when UML is inside a detached screen. |
| */ |
| #define STUB_SIG_MASK (1 << SIGVTALRM) |
| |
| /* Signals that the stub will finish with - anything else is an error */ |
| #define STUB_DONE_MASK (1 << SIGTRAP) |
| |
| void wait_stub_done(int pid) |
| { |
| int n, status, err; |
| |
| while (1) { |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL)); |
| if ((n < 0) || !WIFSTOPPED(status)) |
| goto bad_wait; |
| |
| if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0) |
| break; |
| |
| err = ptrace(PTRACE_CONT, pid, 0, 0); |
| if (err) |
| panic("wait_stub_done : continue failed, errno = %d\n", |
| errno); |
| } |
| |
| if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0) |
| return; |
| |
| bad_wait: |
| err = ptrace_dump_regs(pid); |
| if (err) |
| printk(UM_KERN_ERR "Failed to get registers from stub, " |
| "errno = %d\n", -err); |
| panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, " |
| "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status); |
| } |
| |
| extern unsigned long current_stub_stack(void); |
| |
| void get_skas_faultinfo(int pid, struct faultinfo * fi) |
| { |
| int err; |
| |
| if (ptrace_faultinfo) { |
| err = ptrace(PTRACE_FAULTINFO, pid, 0, fi); |
| if (err) |
| panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, " |
| "errno = %d\n", errno); |
| |
| /* Special handling for i386, which has different structs */ |
| if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo)) |
| memset((char *)fi + sizeof(struct ptrace_faultinfo), 0, |
| sizeof(struct faultinfo) - |
| sizeof(struct ptrace_faultinfo)); |
| } |
| else { |
| err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV); |
| if (err) |
| panic("Failed to continue stub, pid = %d, errno = %d\n", |
| pid, errno); |
| wait_stub_done(pid); |
| |
| /* |
| * faultinfo is prepared by the stub-segv-handler at start of |
| * the stub stack page. We just have to copy it. |
| */ |
| memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); |
| } |
| } |
| |
| static void handle_segv(int pid, struct uml_pt_regs * regs) |
| { |
| get_skas_faultinfo(pid, ®s->faultinfo); |
| segv(regs->faultinfo, 0, 1, NULL); |
| } |
| |
| /* |
| * To use the same value of using_sysemu as the caller, ask it that value |
| * (in local_using_sysemu |
| */ |
| static void handle_trap(int pid, struct uml_pt_regs *regs, |
| int local_using_sysemu) |
| { |
| int err, status; |
| |
| /* Mark this as a syscall */ |
| UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp); |
| |
| if (!local_using_sysemu) |
| { |
| err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, |
| __NR_getpid); |
| if (err < 0) |
| panic("handle_trap - nullifying syscall failed, " |
| "errno = %d\n", errno); |
| |
| err = ptrace(PTRACE_SYSCALL, pid, 0, 0); |
| if (err < 0) |
| panic("handle_trap - continuing to end of syscall " |
| "failed, errno = %d\n", errno); |
| |
| CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL)); |
| if ((err < 0) || !WIFSTOPPED(status) || |
| (WSTOPSIG(status) != SIGTRAP + 0x80)) { |
| err = ptrace_dump_regs(pid); |
| if (err) |
| printk(UM_KERN_ERR "Failed to get registers " |
| "from process, errno = %d\n", -err); |
| panic("handle_trap - failed to wait at end of syscall, " |
| "errno = %d, status = %d\n", errno, status); |
| } |
| } |
| |
| handle_syscall(regs); |
| } |
| |
| extern int __syscall_stub_start; |
| |
| static int userspace_tramp(void *stack) |
| { |
| void *addr; |
| int err; |
| |
| ptrace(PTRACE_TRACEME, 0, 0, 0); |
| |
| signal(SIGTERM, SIG_DFL); |
| signal(SIGWINCH, SIG_IGN); |
| err = set_interval(); |
| if (err) |
| panic("userspace_tramp - setting timer failed, errno = %d\n", |
| err); |
| |
| if (!proc_mm) { |
| /* |
| * This has a pte, but it can't be mapped in with the usual |
| * tlb_flush mechanism because this is part of that mechanism |
| */ |
| int fd; |
| unsigned long long offset; |
| fd = phys_mapping(to_phys(&__syscall_stub_start), &offset); |
| addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE, |
| PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset); |
| if (addr == MAP_FAILED) { |
| printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, " |
| "errno = %d\n", STUB_CODE, errno); |
| exit(1); |
| } |
| |
| if (stack != NULL) { |
| fd = phys_mapping(to_phys(stack), &offset); |
| addr = mmap((void *) STUB_DATA, |
| UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE, |
| MAP_FIXED | MAP_SHARED, fd, offset); |
| if (addr == MAP_FAILED) { |
| printk(UM_KERN_ERR "mapping segfault stack " |
| "at 0x%lx failed, errno = %d\n", |
| STUB_DATA, errno); |
| exit(1); |
| } |
| } |
| } |
| if (!ptrace_faultinfo && (stack != NULL)) { |
| struct sigaction sa; |
| |
| unsigned long v = STUB_CODE + |
| (unsigned long) stub_segv_handler - |
| (unsigned long) &__syscall_stub_start; |
| |
| set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE); |
| sigemptyset(&sa.sa_mask); |
| sa.sa_flags = SA_ONSTACK | SA_NODEFER; |
| sa.sa_handler = (void *) v; |
| sa.sa_restorer = NULL; |
| if (sigaction(SIGSEGV, &sa, NULL) < 0) |
| panic("userspace_tramp - setting SIGSEGV handler " |
| "failed - errno = %d\n", errno); |
| } |
| |
| kill(os_getpid(), SIGSTOP); |
| return 0; |
| } |
| |
| /* Each element set once, and only accessed by a single processor anyway */ |
| #undef NR_CPUS |
| #define NR_CPUS 1 |
| int userspace_pid[NR_CPUS]; |
| |
| int start_userspace(unsigned long stub_stack) |
| { |
| void *stack; |
| unsigned long sp; |
| int pid, status, n, flags; |
| |
| stack = mmap(NULL, UM_KERN_PAGE_SIZE, |
| PROT_READ | PROT_WRITE | PROT_EXEC, |
| MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| if (stack == MAP_FAILED) |
| panic("start_userspace : mmap failed, errno = %d", errno); |
| sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *); |
| |
| flags = CLONE_FILES; |
| if (proc_mm) |
| flags |= CLONE_VM; |
| else |
| flags |= SIGCHLD; |
| |
| pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); |
| if (pid < 0) |
| panic("start_userspace : clone failed, errno = %d", errno); |
| |
| do { |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL)); |
| if (n < 0) |
| panic("start_userspace : wait failed, errno = %d", |
| errno); |
| } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); |
| |
| if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) |
| panic("start_userspace : expected SIGSTOP, got status = %d", |
| status); |
| |
| if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, |
| (void *) PTRACE_O_TRACESYSGOOD) < 0) |
| panic("start_userspace : PTRACE_OLDSETOPTIONS failed, " |
| "errno = %d\n", errno); |
| |
| if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) |
| panic("start_userspace : munmap failed, errno = %d\n", errno); |
| |
| return pid; |
| } |
| |
| void userspace(struct uml_pt_regs *regs) |
| { |
| struct itimerval timer; |
| unsigned long long nsecs, now; |
| int err, status, op, pid = userspace_pid[0]; |
| /* To prevent races if using_sysemu changes under us.*/ |
| int local_using_sysemu; |
| |
| if (getitimer(ITIMER_VIRTUAL, &timer)) |
| printk("Failed to get itimer, errno = %d\n", errno); |
| nsecs = timer.it_value.tv_sec * UM_NSEC_PER_SEC + |
| timer.it_value.tv_usec * UM_NSEC_PER_USEC; |
| nsecs += os_nsecs(); |
| |
| while (1) { |
| restore_registers(pid, regs); |
| |
| /* Now we set local_using_sysemu to be used for one loop */ |
| local_using_sysemu = get_using_sysemu(); |
| |
| op = SELECT_PTRACE_OPERATION(local_using_sysemu, |
| singlestepping(NULL)); |
| |
| err = ptrace(op, pid, 0, 0); |
| if (err) |
| panic("userspace - could not resume userspace process, " |
| "pid=%d, ptrace operation = %d, errno = %d\n", |
| pid, op, errno); |
| |
| CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL)); |
| if (err < 0) |
| panic("userspace - waitpid failed, errno = %d\n", |
| errno); |
| |
| regs->is_user = 1; |
| save_registers(pid, regs); |
| UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ |
| |
| if (WIFSTOPPED(status)) { |
| int sig = WSTOPSIG(status); |
| switch(sig) { |
| case SIGSEGV: |
| if (PTRACE_FULL_FAULTINFO || |
| !ptrace_faultinfo) { |
| get_skas_faultinfo(pid, |
| ®s->faultinfo); |
| (*sig_info[SIGSEGV])(SIGSEGV, regs); |
| } |
| else handle_segv(pid, regs); |
| break; |
| case SIGTRAP + 0x80: |
| handle_trap(pid, regs, local_using_sysemu); |
| break; |
| case SIGTRAP: |
| relay_signal(SIGTRAP, regs); |
| break; |
| case SIGVTALRM: |
| now = os_nsecs(); |
| if(now < nsecs) |
| break; |
| block_signals(); |
| (*sig_info[sig])(sig, regs); |
| unblock_signals(); |
| nsecs = timer.it_value.tv_sec * |
| UM_NSEC_PER_SEC + |
| timer.it_value.tv_usec * |
| UM_NSEC_PER_USEC; |
| nsecs += os_nsecs(); |
| break; |
| case SIGIO: |
| case SIGILL: |
| case SIGBUS: |
| case SIGFPE: |
| case SIGWINCH: |
| block_signals(); |
| (*sig_info[sig])(sig, regs); |
| unblock_signals(); |
| break; |
| default: |
| printk(UM_KERN_ERR "userspace - child stopped " |
| "with signal %d\n", sig); |
| } |
| pid = userspace_pid[0]; |
| interrupt_end(); |
| |
| /* Avoid -ERESTARTSYS handling in host */ |
| if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET) |
| PT_SYSCALL_NR(regs->gp) = -1; |
| } |
| } |
| } |
| |
| static unsigned long thread_regs[MAX_REG_NR]; |
| |
| static int __init init_thread_regs(void) |
| { |
| get_safe_registers(thread_regs); |
| /* Set parent's instruction pointer to start of clone-stub */ |
| thread_regs[REGS_IP_INDEX] = STUB_CODE + |
| (unsigned long) stub_clone_handler - |
| (unsigned long) &__syscall_stub_start; |
| thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE - |
| sizeof(void *); |
| #ifdef __SIGNAL_FRAMESIZE |
| thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE; |
| #endif |
| return 0; |
| } |
| |
| __initcall(init_thread_regs); |
| |
| int copy_context_skas0(unsigned long new_stack, int pid) |
| { |
| struct timeval tv = { .tv_sec = 0, .tv_usec = UM_USEC_PER_SEC / UM_HZ }; |
| int err; |
| unsigned long current_stack = current_stub_stack(); |
| struct stub_data *data = (struct stub_data *) current_stack; |
| struct stub_data *child_data = (struct stub_data *) new_stack; |
| unsigned long long new_offset; |
| int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset); |
| |
| /* |
| * prepare offset and fd of child's stack as argument for parent's |
| * and child's mmap2 calls |
| */ |
| *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), |
| .fd = new_fd, |
| .timer = ((struct itimerval) |
| { .it_value = tv, |
| .it_interval = tv }) }); |
| |
| err = ptrace_setregs(pid, thread_regs); |
| if (err < 0) |
| panic("copy_context_skas0 : PTRACE_SETREGS failed, " |
| "pid = %d, errno = %d\n", pid, -err); |
| |
| /* set a well known return code for detection of child write failure */ |
| child_data->err = 12345678; |
| |
| /* |
| * Wait, until parent has finished its work: read child's pid from |
| * parent's stack, and check, if bad result. |
| */ |
| err = ptrace(PTRACE_CONT, pid, 0, 0); |
| if (err) |
| panic("Failed to continue new process, pid = %d, " |
| "errno = %d\n", pid, errno); |
| wait_stub_done(pid); |
| |
| pid = data->err; |
| if (pid < 0) |
| panic("copy_context_skas0 - stub-parent reports error %d\n", |
| -pid); |
| |
| /* |
| * Wait, until child has finished too: read child's result from |
| * child's stack and check it. |
| */ |
| wait_stub_done(pid); |
| if (child_data->err != STUB_DATA) |
| panic("copy_context_skas0 - stub-child reports error %ld\n", |
| child_data->err); |
| |
| if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, |
| (void *)PTRACE_O_TRACESYSGOOD) < 0) |
| panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, " |
| "errno = %d\n", errno); |
| |
| return pid; |
| } |
| |
| /* |
| * This is used only, if stub pages are needed, while proc_mm is |
| * available. Opening /proc/mm creates a new mm_context, which lacks |
| * the stub-pages. Thus, we map them using /proc/mm-fd |
| */ |
| void map_stub_pages(int fd, unsigned long code, |
| unsigned long data, unsigned long stack) |
| { |
| struct proc_mm_op mmop; |
| int n; |
| unsigned long long code_offset; |
| int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start), |
| &code_offset); |
| |
| mmop = ((struct proc_mm_op) { .op = MM_MMAP, |
| .u = |
| { .mmap = |
| { .addr = code, |
| .len = UM_KERN_PAGE_SIZE, |
| .prot = PROT_EXEC, |
| .flags = MAP_FIXED | MAP_PRIVATE, |
| .fd = code_fd, |
| .offset = code_offset |
| } } }); |
| CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop))); |
| if (n != sizeof(mmop)) { |
| n = errno; |
| printk(UM_KERN_ERR "mmap args - addr = 0x%lx, fd = %d, " |
| "offset = %llx\n", code, code_fd, |
| (unsigned long long) code_offset); |
| panic("map_stub_pages : /proc/mm map for code failed, " |
| "err = %d\n", n); |
| } |
| |
| if (stack) { |
| unsigned long long map_offset; |
| int map_fd = phys_mapping(to_phys((void *)stack), &map_offset); |
| mmop = ((struct proc_mm_op) |
| { .op = MM_MMAP, |
| .u = |
| { .mmap = |
| { .addr = data, |
| .len = UM_KERN_PAGE_SIZE, |
| .prot = PROT_READ | PROT_WRITE, |
| .flags = MAP_FIXED | MAP_SHARED, |
| .fd = map_fd, |
| .offset = map_offset |
| } } }); |
| CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop))); |
| if (n != sizeof(mmop)) |
| panic("map_stub_pages : /proc/mm map for data failed, " |
| "err = %d\n", errno); |
| } |
| } |
| |
| void new_thread(void *stack, jmp_buf *buf, void (*handler)(void)) |
| { |
| (*buf)[0].JB_IP = (unsigned long) handler; |
| (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE - |
| sizeof(void *); |
| } |
| |
| #define INIT_JMP_NEW_THREAD 0 |
| #define INIT_JMP_CALLBACK 1 |
| #define INIT_JMP_HALT 2 |
| #define INIT_JMP_REBOOT 3 |
| |
| void switch_threads(jmp_buf *me, jmp_buf *you) |
| { |
| if (UML_SETJMP(me) == 0) |
| UML_LONGJMP(you, 1); |
| } |
| |
| static jmp_buf initial_jmpbuf; |
| |
| /* XXX Make these percpu */ |
| static void (*cb_proc)(void *arg); |
| static void *cb_arg; |
| static jmp_buf *cb_back; |
| |
| int start_idle_thread(void *stack, jmp_buf *switch_buf) |
| { |
| int n; |
| |
| set_handler(SIGWINCH, (__sighandler_t) sig_handler, |
| SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGVTALRM, -1); |
| |
| /* |
| * Can't use UML_SETJMP or UML_LONGJMP here because they save |
| * and restore signals, with the possible side-effect of |
| * trying to handle any signals which came when they were |
| * blocked, which can't be done on this stack. |
| * Signals must be blocked when jumping back here and restored |
| * after returning to the jumper. |
| */ |
| n = setjmp(initial_jmpbuf); |
| switch(n) { |
| case INIT_JMP_NEW_THREAD: |
| (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler; |
| (*switch_buf)[0].JB_SP = (unsigned long) stack + |
| UM_THREAD_SIZE - sizeof(void *); |
| break; |
| case INIT_JMP_CALLBACK: |
| (*cb_proc)(cb_arg); |
| longjmp(*cb_back, 1); |
| break; |
| case INIT_JMP_HALT: |
| kmalloc_ok = 0; |
| return 0; |
| case INIT_JMP_REBOOT: |
| kmalloc_ok = 0; |
| return 1; |
| default: |
| panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); |
| } |
| longjmp(*switch_buf, 1); |
| } |
| |
| void initial_thread_cb_skas(void (*proc)(void *), void *arg) |
| { |
| jmp_buf here; |
| |
| cb_proc = proc; |
| cb_arg = arg; |
| cb_back = &here; |
| |
| block_signals(); |
| if (UML_SETJMP(&here) == 0) |
| UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK); |
| unblock_signals(); |
| |
| cb_proc = NULL; |
| cb_arg = NULL; |
| cb_back = NULL; |
| } |
| |
| void halt_skas(void) |
| { |
| block_signals(); |
| UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT); |
| } |
| |
| void reboot_skas(void) |
| { |
| block_signals(); |
| UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT); |
| } |
| |
| void __switch_mm(struct mm_id *mm_idp) |
| { |
| int err; |
| |
| /* FIXME: need cpu pid in __switch_mm */ |
| if (proc_mm) { |
| err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, |
| mm_idp->u.mm_fd); |
| if (err) |
| panic("__switch_mm - PTRACE_SWITCH_MM failed, " |
| "errno = %d\n", errno); |
| } |
| else userspace_pid[0] = mm_idp->u.pid; |
| } |