#ifndef QEMU_H #define QEMU_H #include "hostdep.h" #include "cpu.h" #include "exec/exec-all.h" #include "exec/cpu_ldst.h" #undef DEBUG_REMAP #ifdef DEBUG_REMAP #endif /* DEBUG_REMAP */ #include "exec/user/abitypes.h" #include "exec/user/thunk.h" #include "syscall_defs.h" #include "target_syscall.h" #include "exec/gdbstub.h" /* This is the size of the host kernel's sigset_t, needed where we make * direct system calls that take a sigset_t pointer and a size. */ #define SIGSET_T_SIZE (_NSIG / 8) /* This struct is used to hold certain information about the image. * Basically, it replicates in user space what would be certain * task_struct fields in the kernel */ struct image_info { abi_ulong load_bias; abi_ulong load_addr; abi_ulong start_code; abi_ulong end_code; abi_ulong start_data; abi_ulong end_data; abi_ulong start_brk; abi_ulong brk; abi_ulong start_mmap; abi_ulong start_stack; abi_ulong stack_limit; abi_ulong entry; abi_ulong code_offset; abi_ulong data_offset; abi_ulong saved_auxv; abi_ulong auxv_len; abi_ulong arg_start; abi_ulong arg_end; abi_ulong arg_strings; abi_ulong env_strings; abi_ulong file_string; uint32_t elf_flags; int personality; abi_ulong alignment; /* The fields below are used in FDPIC mode. */ abi_ulong loadmap_addr; uint16_t nsegs; void *loadsegs; abi_ulong pt_dynamic_addr; abi_ulong interpreter_loadmap_addr; abi_ulong interpreter_pt_dynamic_addr; struct image_info *other_info; #ifdef TARGET_MIPS int fp_abi; int interp_fp_abi; #endif }; #ifdef TARGET_I386 /* Information about the current linux thread */ struct vm86_saved_state { uint32_t eax; /* return code */ uint32_t ebx; uint32_t ecx; uint32_t edx; uint32_t esi; uint32_t edi; uint32_t ebp; uint32_t esp; uint32_t eflags; uint32_t eip; uint16_t cs, ss, ds, es, fs, gs; }; #endif #if defined(TARGET_ARM) && defined(TARGET_ABI32) /* FPU emulator */ #include "nwfpe/fpa11.h" #endif #define MAX_SIGQUEUE_SIZE 1024 struct emulated_sigtable { int pending; /* true if signal is pending */ target_siginfo_t info; }; /* NOTE: we force a big alignment so that the stack stored after is aligned too */ typedef struct TaskState { pid_t ts_tid; /* tid (or pid) of this task */ #ifdef TARGET_ARM # ifdef TARGET_ABI32 /* FPA state */ FPA11 fpa; # endif int swi_errno; #endif #if defined(TARGET_I386) && !defined(TARGET_X86_64) abi_ulong target_v86; struct vm86_saved_state vm86_saved_regs; struct target_vm86plus_struct vm86plus; uint32_t v86flags; uint32_t v86mask; #endif abi_ulong child_tidptr; #ifdef TARGET_M68K abi_ulong tp_value; #endif #if defined(TARGET_ARM) || defined(TARGET_M68K) /* Extra fields for semihosted binaries. */ abi_ulong heap_base; abi_ulong heap_limit; #endif abi_ulong stack_base; int used; /* non zero if used */ struct image_info *info; struct linux_binprm *bprm; struct emulated_sigtable sync_signal; struct emulated_sigtable sigtab[TARGET_NSIG]; /* This thread's signal mask, as requested by the guest program. * The actual signal mask of this thread may differ: * + we don't let SIGSEGV and SIGBUS be blocked while running guest code * + sometimes we block all signals to avoid races */ sigset_t signal_mask; /* The signal mask imposed by a guest sigsuspend syscall, if we are * currently in the middle of such a syscall */ sigset_t sigsuspend_mask; /* Nonzero if we're leaving a sigsuspend and sigsuspend_mask is valid. */ int in_sigsuspend; /* Nonzero if process_pending_signals() needs to do something (either * handle a pending signal or unblock signals). * This flag is written from a signal handler so should be accessed via * the atomic_read() and atomic_set() functions. (It is not accessed * from multiple threads.) */ int signal_pending; /* This thread's sigaltstack, if it has one */ struct target_sigaltstack sigaltstack_used; } __attribute__((aligned(16))) TaskState; extern char *exec_path; void init_task_state(TaskState *ts); void task_settid(TaskState *); void stop_all_tasks(void); extern const char *qemu_uname_release; extern unsigned long mmap_min_addr; /* ??? See if we can avoid exposing so much of the loader internals. */ /* Read a good amount of data initially, to hopefully get all the program headers loaded. */ #define BPRM_BUF_SIZE 1024 /* * This structure is used to hold the arguments that are * used when loading binaries. */ struct linux_binprm { char buf[BPRM_BUF_SIZE] __attribute__((aligned)); abi_ulong p; int fd; int e_uid, e_gid; int argc, envc; char **argv; char **envp; char * filename; /* Name of binary */ int (*core_dump)(int, const CPUArchState *); /* coredump routine */ }; void do_init_thread(struct target_pt_regs *regs, struct image_info *infop); abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp, abi_ulong stringp, int push_ptr); int loader_exec(int fdexec, const char *filename, char **argv, char **envp, struct target_pt_regs * regs, struct image_info *infop, struct linux_binprm *); /* Returns true if the image uses the FDPIC ABI. If this is the case, * we have to provide some information (loadmap, pt_dynamic_info) such * that the program can be relocated adequately. This is also useful * when handling signals. */ int info_is_fdpic(struct image_info *info); uint32_t get_elf_eflags(int fd); int load_elf_binary(struct linux_binprm *bprm, struct image_info *info); int load_flt_binary(struct linux_binprm *bprm, struct image_info *info); abi_long memcpy_to_target(abi_ulong dest, const void *src, unsigned long len); void target_set_brk(abi_ulong new_brk); abi_long do_brk(abi_ulong new_brk); void syscall_init(void); abi_long do_syscall(void *cpu_env, int num, abi_long arg1, abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, abi_long arg6, abi_long arg7, abi_long arg8); void gemu_log(const char *fmt, ...) GCC_FMT_ATTR(1, 2); extern __thread CPUState *thread_cpu; void cpu_loop(CPUArchState *env); const char *target_strerror(int err); int get_osversion(void); void init_qemu_uname_release(void); void fork_start(void); void fork_end(int child); /* Creates the initial guest address space in the host memory space using * the given host start address hint and size. The guest_start parameter * specifies the start address of the guest space. guest_base will be the * difference between the host start address computed by this function and * guest_start. If fixed is specified, then the mapped address space must * start at host_start. The real start address of the mapped memory space is * returned or -1 if there was an error. */ unsigned long init_guest_space(unsigned long host_start, unsigned long host_size, unsigned long guest_start, bool fixed); #include "qemu/log.h" /* safe_syscall.S */ /** * safe_syscall: * @int number: number of system call to make * ...: arguments to the system call * * Call a system call if guest signal not pending. * This has the same API as the libc syscall() function, except that it * may return -1 with errno == TARGET_ERESTARTSYS if a signal was pending. * * Returns: the system call result, or -1 with an error code in errno * (Errnos are host errnos; we rely on TARGET_ERESTARTSYS not clashing * with any of the host errno values.) */ /* A guide to using safe_syscall() to handle interactions between guest * syscalls and guest signals: * * Guest syscalls come in two flavours: * * (1) Non-interruptible syscalls * * These are guest syscalls that never get interrupted by signals and * so never return EINTR. They can be implemented straightforwardly in * QEMU: just make sure that if the implementation code has to make any * blocking calls that those calls are retried if they return EINTR. * It's also OK to implement these with safe_syscall, though it will be * a little less efficient if a signal is delivered at the 'wrong' moment. * * Some non-interruptible syscalls need to be handled using block_signals() * to block signals for the duration of the syscall. This mainly applies * to code which needs to modify the data structures used by the * host_signal_handler() function and the functions it calls, including * all syscalls which change the thread's signal mask. * * (2) Interruptible syscalls * * These are guest syscalls that can be interrupted by signals and * for which we need to either return EINTR or arrange for the guest * syscall to be restarted. This category includes both syscalls which * always restart (and in the kernel return -ERESTARTNOINTR), ones * which only restart if there is no handler (kernel returns -ERESTARTNOHAND * or -ERESTART_RESTARTBLOCK), and the most common kind which restart * if the handler was registered with SA_RESTART (kernel returns * -ERESTARTSYS). System calls which are only interruptible in some * situations (like 'open') also need to be handled this way. * * Here it is important that the host syscall is made * via this safe_syscall() function, and *not* via the host libc. * If the host libc is used then the implementation will appear to work * most of the time, but there will be a race condition where a * signal could arrive just before we make the host syscall inside libc, * and then then guest syscall will not correctly be interrupted. * Instead the implementation of the guest syscall can use the safe_syscall * function but otherwise just return the result or errno in the usual * way; the main loop code will take care of restarting the syscall * if appropriate. * * (If the implementation needs to make multiple host syscalls this is * OK; any which might really block must be via safe_syscall(); for those * which are only technically blocking (ie which we know in practice won't * stay in the host kernel indefinitely) it's OK to use libc if necessary. * You must be able to cope with backing out correctly if some safe_syscall * you make in the implementation returns either -TARGET_ERESTARTSYS or * EINTR though.) * * block_signals() cannot be used for interruptible syscalls. * * * How and why the safe_syscall implementation works: * * The basic setup is that we make the host syscall via a known * section of host native assembly. If a signal occurs, our signal * handler checks the interrupted host PC against the addresse of that * known section. If the PC is before or at the address of the syscall * instruction then we change the PC to point at a "return * -TARGET_ERESTARTSYS" code path instead, and then exit the signal handler * (causing the safe_syscall() call to immediately return that value). * Then in the main.c loop if we see this magic return value we adjust * the guest PC to wind it back to before the system call, and invoke * the guest signal handler as usual. * * This winding-back will happen in two cases: * (1) signal came in just before we took the host syscall (a race); * in this case we'll take the guest signal and have another go * at the syscall afterwards, and this is indistinguishable for the * guest from the timing having been different such that the guest * signal really did win the race * (2) signal came in while the host syscall was blocking, and the * host kernel decided the syscall should be restarted; * in this case we want to restart the guest syscall also, and so * rewinding is the right thing. (Note that "restart" semantics mean * "first call the signal handler, then reattempt the syscall".) * The other situation to consider is when a signal came in while the * host syscall was blocking, and the host kernel decided that the syscall * should not be restarted; in this case QEMU's host signal handler will * be invoked with the PC pointing just after the syscall instruction, * with registers indicating an EINTR return; the special code in the * handler will not kick in, and we will return EINTR to the guest as * we should. * * Notice that we can leave the host kernel to make the decision for * us about whether to do a restart of the syscall or not; we do not * need to check SA_RESTART flags in QEMU or distinguish the various * kinds of restartability. */ #ifdef HAVE_SAFE_SYSCALL /* The core part of this function is implemented in assembly */ extern long safe_syscall_base(int *pending, long number, ...); #define safe_syscall(...) \ ({ \ long ret_; \ int *psp_ = &((TaskState *)thread_cpu->opaque)->signal_pending; \ ret_ = safe_syscall_base(psp_, __VA_ARGS__); \ if (is_error(ret_)) { \ errno = -ret_; \ ret_ = -1; \ } \ ret_; \ }) #else /* Fallback for architectures which don't yet provide a safe-syscall assembly * fragment; note that this is racy! * This should go away when all host architectures have been updated. */ #define safe_syscall syscall #endif /* syscall.c */ int host_to_target_waitstatus(int status); /* strace.c */ void print_syscall(int num, abi_long arg1, abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, abi_long arg6); void print_syscall_ret(int num, abi_long arg1); /** * print_taken_signal: * @target_signum: target signal being taken * @tinfo: target_siginfo_t which will be passed to the guest for the signal * * Print strace output indicating that this signal is being taken by the guest, * in a format similar to: * --- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} --- */ void print_taken_signal(int target_signum, const target_siginfo_t *tinfo); extern int do_strace; /* signal.c */ void process_pending_signals(CPUArchState *cpu_env); void signal_init(void); int queue_signal(CPUArchState *env, int sig, int si_type, target_siginfo_t *info); void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info); void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo); int target_to_host_signal(int sig); int host_to_target_signal(int sig); long do_sigreturn(CPUArchState *env); long do_rt_sigreturn(CPUArchState *env); abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp); int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset); abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx, abi_ulong unew_ctx, abi_long ctx_size); /** * block_signals: block all signals while handling this guest syscall * * Block all signals, and arrange that the signal mask is returned to * its correct value for the guest before we resume execution of guest code. * If this function returns non-zero, then the caller should immediately * return -TARGET_ERESTARTSYS to the main loop, which will take the pending * signal and restart execution of the syscall. * If block_signals() returns zero, then the caller can continue with * emulation of the system call knowing that no signals can be taken * (and therefore that no race conditions will result). * This should only be called once, because if it is called a second time * it will always return non-zero. (Think of it like a mutex that can't * be recursively locked.) * Signals will be unblocked again by process_pending_signals(). * * Return value: non-zero if there was a pending signal, zero if not. */ int block_signals(void); /* Returns non zero if signal pending */ #ifdef TARGET_I386 /* vm86.c */ void save_v86_state(CPUX86State *env); void handle_vm86_trap(CPUX86State *env, int trapno); void handle_vm86_fault(CPUX86State *env); int do_vm86(CPUX86State *env, long subfunction, abi_ulong v86_addr); #elif defined(TARGET_SPARC64) void sparc64_set_context(CPUSPARCState *env); void sparc64_get_context(CPUSPARCState *env); #endif /* mmap.c */ int target_mprotect(abi_ulong start, abi_ulong len, int prot); abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, int flags, int fd, abi_ulong offset); int target_munmap(abi_ulong start, abi_ulong len); abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size, abi_ulong new_size, unsigned long flags, abi_ulong new_addr); extern unsigned long last_brk; extern abi_ulong mmap_next_start; abi_ulong mmap_find_vma(abi_ulong, abi_ulong, abi_ulong); void mmap_fork_start(void); void mmap_fork_end(int child); /* main.c */ extern unsigned long guest_stack_size; /* user access */ #define VERIFY_READ 0 #define VERIFY_WRITE 1 /* implies read access */ static inline int access_ok(int type, abi_ulong addr, abi_ulong size) { return guest_addr_valid(addr) && (size == 0 || guest_addr_valid(addr + size - 1)) && page_check_range((target_ulong)addr, size, (type == VERIFY_READ) ? PAGE_READ : (PAGE_READ | PAGE_WRITE)) == 0; } /* NOTE __get_user and __put_user use host pointers and don't check access. These are usually used to access struct data members once the struct has been locked - usually with lock_user_struct. */ /* * Tricky points: * - Use __builtin_choose_expr to avoid type promotion from ?:, * - Invalid sizes result in a compile time error stemming from * the fact that abort has no parameters. * - It's easier to use the endian-specific unaligned load/store * functions than host-endian unaligned load/store plus tswapN. * - The pragmas are necessary only to silence a clang false-positive * warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 . * - gcc has bugs in its _Pragma() support in some versions, eg * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only * include the warning-suppression pragmas for clang */ #if defined(__clang__) && __has_warning("-Waddress-of-packed-member") #define PRAGMA_DISABLE_PACKED_WARNING \ _Pragma("GCC diagnostic push"); \ _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"") #define PRAGMA_REENABLE_PACKED_WARNING \ _Pragma("GCC diagnostic pop") #else #define PRAGMA_DISABLE_PACKED_WARNING #define PRAGMA_REENABLE_PACKED_WARNING #endif #define __put_user_e(x, hptr, e) \ do { \ PRAGMA_DISABLE_PACKED_WARNING; \ (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p, \ __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p, \ __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p, \ __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort)))) \ ((hptr), (x)), (void)0); \ PRAGMA_REENABLE_PACKED_WARNING; \ } while (0) #define __get_user_e(x, hptr, e) \ do { \ PRAGMA_DISABLE_PACKED_WARNING; \ ((x) = (typeof(*hptr))( \ __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p, \ __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p, \ __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p, \ __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort)))) \ (hptr)), (void)0); \ PRAGMA_REENABLE_PACKED_WARNING; \ } while (0) #ifdef TARGET_WORDS_BIGENDIAN # define __put_user(x, hptr) __put_user_e(x, hptr, be) # define __get_user(x, hptr) __get_user_e(x, hptr, be) #else # define __put_user(x, hptr) __put_user_e(x, hptr, le) # define __get_user(x, hptr) __get_user_e(x, hptr, le) #endif /* put_user()/get_user() take a guest address and check access */ /* These are usually used to access an atomic data type, such as an int, * that has been passed by address. These internally perform locking * and unlocking on the data type. */ #define put_user(x, gaddr, target_type) \ ({ \ abi_ulong __gaddr = (gaddr); \ target_type *__hptr; \ abi_long __ret = 0; \ if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \ __put_user((x), __hptr); \ unlock_user(__hptr, __gaddr, sizeof(target_type)); \ } else \ __ret = -TARGET_EFAULT; \ __ret; \ }) #define get_user(x, gaddr, target_type) \ ({ \ abi_ulong __gaddr = (gaddr); \ target_type *__hptr; \ abi_long __ret = 0; \ if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \ __get_user((x), __hptr); \ unlock_user(__hptr, __gaddr, 0); \ } else { \ /* avoid warning */ \ (x) = 0; \ __ret = -TARGET_EFAULT; \ } \ __ret; \ }) #define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong) #define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long) #define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t) #define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t) #define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t) #define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t) #define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t) #define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t) #define put_user_u8(x, gaddr) put_user((x), (gaddr), uint8_t) #define put_user_s8(x, gaddr) put_user((x), (gaddr), int8_t) #define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong) #define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long) #define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t) #define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t) #define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t) #define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t) #define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t) #define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t) #define get_user_u8(x, gaddr) get_user((x), (gaddr), uint8_t) #define get_user_s8(x, gaddr) get_user((x), (gaddr), int8_t) /* copy_from_user() and copy_to_user() are usually used to copy data * buffers between the target and host. These internally perform * locking/unlocking of the memory. */ abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len); abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len); /* Functions for accessing guest memory. The tget and tput functions read/write single values, byteswapping as necessary. The lock_user function gets a pointer to a contiguous area of guest memory, but does not perform any byteswapping. lock_user may return either a pointer to the guest memory, or a temporary buffer. */ /* Lock an area of guest memory into the host. If copy is true then the host area will have the same contents as the guest. */ static inline void *lock_user(int type, abi_ulong guest_addr, long len, int copy) { if (!access_ok(type, guest_addr, len)) return NULL; #ifdef DEBUG_REMAP { void *addr; addr = g_malloc(len); if (copy) memcpy(addr, g2h(guest_addr), len); else memset(addr, 0, len); return addr; } #else return g2h(guest_addr); #endif } /* Unlock an area of guest memory. The first LEN bytes must be flushed back to guest memory. host_ptr = NULL is explicitly allowed and does nothing. */ static inline void unlock_user(void *host_ptr, abi_ulong guest_addr, long len) { #ifdef DEBUG_REMAP if (!host_ptr) return; if (host_ptr == g2h(guest_addr)) return; if (len > 0) memcpy(g2h(guest_addr), host_ptr, len); g_free(host_ptr); #endif } /* Return the length of a string in target memory or -TARGET_EFAULT if access error. */ abi_long target_strlen(abi_ulong gaddr); /* Like lock_user but for null terminated strings. */ static inline void *lock_user_string(abi_ulong guest_addr) { abi_long len; len = target_strlen(guest_addr); if (len < 0) return NULL; return lock_user(VERIFY_READ, guest_addr, (long)(len + 1), 1); } /* Helper macros for locking/unlocking a target struct. */ #define lock_user_struct(type, host_ptr, guest_addr, copy) \ (host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy)) #define unlock_user_struct(host_ptr, guest_addr, copy) \ unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0) #include <pthread.h> static inline int is_error(abi_long ret) { return (abi_ulong)ret >= (abi_ulong)(-4096); } /** * preexit_cleanup: housekeeping before the guest exits * * env: the CPU state * code: the exit code */ void preexit_cleanup(CPUArchState *env, int code); /* Include target-specific struct and function definitions; * they may need access to the target-independent structures * above, so include them last. */ #include "target_cpu.h" #include "target_structs.h" #endif /* QEMU_H */