| /* |
| * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) |
| * 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/wait.h> |
| #include <asm/unistd.h> |
| #include <as-layout.h> |
| #include <init.h> |
| #include <kern_util.h> |
| #include <mem.h> |
| #include <os.h> |
| #include <ptrace_user.h> |
| #include <registers.h> |
| #include <skas.h> |
| #include <sysdep/stub.h> |
| |
| int is_skas_winch(int pid, int fd, void *data) |
| { |
| return pid == getpgrp(); |
| } |
| |
| 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 << SIGALRM) | (1 << SIGWINCH)) |
| |
| /* 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) { |
| printk(UM_KERN_ERR "wait_stub_done : continue failed, " |
| "errno = %d\n", errno); |
| fatal_sigsegv(); |
| } |
| } |
| |
| 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); |
| printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, " |
| "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno, |
| status); |
| fatal_sigsegv(); |
| } |
| |
| extern unsigned long current_stub_stack(void); |
| |
| static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs) |
| { |
| int err; |
| |
| err = get_fp_registers(pid, aux_fp_regs); |
| if (err < 0) { |
| printk(UM_KERN_ERR "save_fp_registers returned %d\n", |
| err); |
| fatal_sigsegv(); |
| } |
| err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV); |
| if (err) { |
| printk(UM_KERN_ERR "Failed to continue stub, pid = %d, " |
| "errno = %d\n", pid, errno); |
| fatal_sigsegv(); |
| } |
| 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)); |
| |
| err = put_fp_registers(pid, aux_fp_regs); |
| if (err < 0) { |
| printk(UM_KERN_ERR "put_fp_registers returned %d\n", |
| err); |
| fatal_sigsegv(); |
| } |
| } |
| |
| static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs) |
| { |
| get_skas_faultinfo(pid, ®s->faultinfo, aux_fp_regs); |
| 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; |
| |
| if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END)) |
| fatal_sigsegv(); |
| |
| if (!local_using_sysemu) |
| { |
| err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, |
| __NR_getpid); |
| if (err < 0) { |
| printk(UM_KERN_ERR "handle_trap - nullifying syscall " |
| "failed, errno = %d\n", errno); |
| fatal_sigsegv(); |
| } |
| |
| err = ptrace(PTRACE_SYSCALL, pid, 0, 0); |
| if (err < 0) { |
| printk(UM_KERN_ERR "handle_trap - continuing to end of " |
| "syscall failed, errno = %d\n", errno); |
| fatal_sigsegv(); |
| } |
| |
| 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); |
| printk(UM_KERN_ERR "handle_trap - failed to wait at " |
| "end of syscall, errno = %d, status = %d\n", |
| errno, status); |
| fatal_sigsegv(); |
| } |
| } |
| |
| handle_syscall(regs); |
| } |
| |
| extern char __syscall_stub_start[]; |
| |
| static int userspace_tramp(void *stack) |
| { |
| void *addr; |
| int fd; |
| unsigned long long offset; |
| |
| ptrace(PTRACE_TRACEME, 0, 0, 0); |
| |
| signal(SIGTERM, SIG_DFL); |
| signal(SIGWINCH, SIG_IGN); |
| |
| /* |
| * This has a pte, but it can't be mapped in with the usual |
| * tlb_flush mechanism because this is part of that mechanism |
| */ |
| 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 (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_SIGINFO; |
| sa.sa_sigaction = (void *) v; |
| sa.sa_restorer = NULL; |
| if (sigaction(SIGSEGV, &sa, NULL) < 0) { |
| printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV " |
| "handler failed - errno = %d\n", errno); |
| exit(1); |
| } |
| } |
| |
| 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, err; |
| |
| stack = mmap(NULL, UM_KERN_PAGE_SIZE, |
| PROT_READ | PROT_WRITE | PROT_EXEC, |
| MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| if (stack == MAP_FAILED) { |
| err = -errno; |
| printk(UM_KERN_ERR "start_userspace : mmap failed, " |
| "errno = %d\n", errno); |
| return err; |
| } |
| |
| sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *); |
| |
| flags = CLONE_FILES | SIGCHLD; |
| |
| pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); |
| if (pid < 0) { |
| err = -errno; |
| printk(UM_KERN_ERR "start_userspace : clone failed, " |
| "errno = %d\n", errno); |
| return err; |
| } |
| |
| do { |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL)); |
| if (n < 0) { |
| err = -errno; |
| printk(UM_KERN_ERR "start_userspace : wait failed, " |
| "errno = %d\n", errno); |
| goto out_kill; |
| } |
| } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGALRM)); |
| |
| if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) { |
| err = -EINVAL; |
| printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got " |
| "status = %d\n", status); |
| goto out_kill; |
| } |
| |
| if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, |
| (void *) PTRACE_O_TRACESYSGOOD) < 0) { |
| err = -errno; |
| printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS " |
| "failed, errno = %d\n", errno); |
| goto out_kill; |
| } |
| |
| if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) { |
| err = -errno; |
| printk(UM_KERN_ERR "start_userspace : munmap failed, " |
| "errno = %d\n", errno); |
| goto out_kill; |
| } |
| |
| return pid; |
| |
| out_kill: |
| os_kill_ptraced_process(pid, 1); |
| return err; |
| } |
| |
| void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs) |
| { |
| int err, status, op, pid = userspace_pid[0]; |
| /* To prevent races if using_sysemu changes under us.*/ |
| int local_using_sysemu; |
| siginfo_t si; |
| |
| /* Handle any immediate reschedules or signals */ |
| interrupt_end(); |
| |
| while (1) { |
| |
| /* |
| * This can legitimately fail if the process loads a |
| * bogus value into a segment register. It will |
| * segfault and PTRACE_GETREGS will read that value |
| * out of the process. However, PTRACE_SETREGS will |
| * fail. In this case, there is nothing to do but |
| * just kill the process. |
| */ |
| if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp)) |
| fatal_sigsegv(); |
| |
| if (put_fp_registers(pid, regs->fp)) |
| fatal_sigsegv(); |
| |
| /* 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)); |
| |
| if (ptrace(op, pid, 0, 0)) { |
| printk(UM_KERN_ERR "userspace - ptrace continue " |
| "failed, op = %d, errno = %d\n", op, errno); |
| fatal_sigsegv(); |
| } |
| |
| CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL)); |
| if (err < 0) { |
| printk(UM_KERN_ERR "userspace - wait failed, " |
| "errno = %d\n", errno); |
| fatal_sigsegv(); |
| } |
| |
| regs->is_user = 1; |
| if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) { |
| printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, " |
| "errno = %d\n", errno); |
| fatal_sigsegv(); |
| } |
| |
| if (get_fp_registers(pid, regs->fp)) { |
| printk(UM_KERN_ERR "userspace - get_fp_registers failed, " |
| "errno = %d\n", errno); |
| fatal_sigsegv(); |
| } |
| |
| UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ |
| |
| if (WIFSTOPPED(status)) { |
| int sig = WSTOPSIG(status); |
| |
| ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si); |
| |
| switch (sig) { |
| case SIGSEGV: |
| if (PTRACE_FULL_FAULTINFO) { |
| get_skas_faultinfo(pid, |
| ®s->faultinfo, aux_fp_regs); |
| (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si, |
| regs); |
| } |
| else handle_segv(pid, regs, aux_fp_regs); |
| break; |
| case SIGTRAP + 0x80: |
| handle_trap(pid, regs, local_using_sysemu); |
| break; |
| case SIGTRAP: |
| relay_signal(SIGTRAP, (struct siginfo *)&si, regs); |
| break; |
| case SIGALRM: |
| break; |
| case SIGIO: |
| case SIGILL: |
| case SIGBUS: |
| case SIGFPE: |
| case SIGWINCH: |
| block_signals(); |
| (*sig_info[sig])(sig, (struct siginfo *)&si, regs); |
| unblock_signals(); |
| break; |
| default: |
| printk(UM_KERN_ERR "userspace - child stopped " |
| "with signal %d\n", sig); |
| fatal_sigsegv(); |
| } |
| 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 unsigned long thread_fp_regs[FP_SIZE]; |
| |
| static int __init init_thread_regs(void) |
| { |
| get_safe_registers(thread_regs, thread_fp_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) |
| { |
| 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 |
| }); |
| |
| err = ptrace_setregs(pid, thread_regs); |
| if (err < 0) { |
| err = -errno; |
| printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS " |
| "failed, pid = %d, errno = %d\n", pid, -err); |
| return err; |
| } |
| |
| err = put_fp_registers(pid, thread_fp_regs); |
| if (err < 0) { |
| printk(UM_KERN_ERR "copy_context_skas0 : put_fp_registers " |
| "failed, pid = %d, err = %d\n", pid, err); |
| return 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) { |
| err = -errno; |
| printk(UM_KERN_ERR "Failed to continue new process, pid = %d, " |
| "errno = %d\n", pid, errno); |
| return err; |
| } |
| |
| wait_stub_done(pid); |
| |
| pid = data->err; |
| if (pid < 0) { |
| printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports " |
| "error %d\n", -pid); |
| return 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) { |
| printk(UM_KERN_ERR "copy_context_skas0 - stub-child reports " |
| "error %ld\n", child_data->err); |
| err = child_data->err; |
| goto out_kill; |
| } |
| |
| if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, |
| (void *)PTRACE_O_TRACESYSGOOD) < 0) { |
| err = -errno; |
| printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS " |
| "failed, errno = %d\n", errno); |
| goto out_kill; |
| } |
| |
| return pid; |
| |
| out_kill: |
| os_kill_ptraced_process(pid, 1); |
| return err; |
| } |
| |
| 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); |
| |
| /* |
| * 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) uml_finishsetup; |
| (*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: |
| printk(UM_KERN_ERR "Bad sigsetjmp return in " |
| "start_idle_thread - %d\n", n); |
| fatal_sigsegv(); |
| } |
| longjmp(*switch_buf, 1); |
| |
| /* unreachable */ |
| printk(UM_KERN_ERR "impossible long jump!"); |
| fatal_sigsegv(); |
| return 0; |
| } |
| |
| 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) |
| { |
| userspace_pid[0] = mm_idp->u.pid; |
| } |