path: root/linux-user/qemu.h

#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

#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       reserve_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;

        /* For target-specific processing of NT_GNU_PROPERTY_TYPE_0. */
        uint32_t        note_flags;

#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
#endif
#if defined(TARGET_ARM) || defined(TARGET_RISCV)
    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) || defined(TARGET_RISCV)
    /* 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 qatomic_read() and qatomic_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;

typedef struct IOCTLEntry IOCTLEntry;

typedef abi_long do_ioctl_fn(const IOCTLEntry *ie, uint8_t *buf_temp,
                             int fd, int cmd, abi_long arg);

struct IOCTLEntry {
    int target_cmd;
    unsigned int host_cmd;
    const char *name;
    int access;
    do_ioctl_fn *do_ioctl;
    const argtype arg_type[5];
};

extern IOCTLEntry ioctl_entries[];

#define IOC_R 0x0001
#define IOC_W 0x0002
#define IOC_RW (IOC_R | IOC_W)

/*
 * 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);

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);
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);

/**
 * probe_guest_base:
 * @image_name: the executable being loaded
 * @loaddr: the lowest fixed address in the executable
 * @hiaddr: the highest fixed address in the executable
 *
 * Creates the initial guest address space in the host memory space.
 *
 * If @loaddr == 0, then no address in the executable is fixed,
 * i.e. it is fully relocatable.  In that case @hiaddr is the size
 * of the executable.
 *
 * This function will not return if a valid value for guest_base
 * cannot be chosen.  On return, the executable loader can expect
 *
 *    target_mmap(loaddr, hiaddr - loaddr, ...)
 *
 * to succeed.
 */
void probe_guest_base(const char *image_name,
                      abi_ulong loaddr, abi_ulong hiaddr);

#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);

#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

/* user access */

#define VERIFY_READ  PAGE_READ
#define VERIFY_WRITE (PAGE_READ | PAGE_WRITE)

static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
{
    if (size == 0
        ? !guest_addr_valid_untagged(addr)
        : !guest_range_valid_untagged(addr, size)) {
        return false;
    }
    return page_check_range((target_ulong)addr, size, type) == 0;
}

static inline bool access_ok(CPUState *cpu, int type,
                             abi_ulong addr, abi_ulong size)
{
    return access_ok_untagged(type, cpu_untagged_addr(cpu, addr), size);
}

/* 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.
 */
int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
int copy_to_user(abi_ulong gaddr, void *hptr, ssize_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.  */
void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy);

/* 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. */
#ifndef DEBUG_REMAP
static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
                               ssize_t len)
{
    /* no-op */
}
#else
void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len);
#endif

/* Return the length of a string in target memory or -TARGET_EFAULT if
   access error. */
ssize_t target_strlen(abi_ulong gaddr);

/* Like lock_user but for null terminated strings.  */
void *lock_user_string(abi_ulong guest_addr);

/* 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);
}

#if TARGET_ABI_BITS == 32
static inline uint64_t target_offset64(uint32_t word0, uint32_t word1)
{
#ifdef TARGET_WORDS_BIGENDIAN
    return ((uint64_t)word0 << 32) | word1;
#else
    return ((uint64_t)word1 << 32) | word0;
#endif
}
#else /* TARGET_ABI_BITS == 32 */
static inline uint64_t target_offset64(uint64_t word0, uint64_t word1)
{
    return word0;
}
#endif /* TARGET_ABI_BITS != 32 */

void print_termios(void *arg);

/* ARM EABI and MIPS expect 64bit types aligned even on pairs or registers */
#ifdef TARGET_ARM
static inline int regpairs_aligned(void *cpu_env, int num)
{
    return ((((CPUARMState *)cpu_env)->eabi) == 1) ;
}
#elif defined(TARGET_MIPS) && (TARGET_ABI_BITS == 32)
static inline int regpairs_aligned(void *cpu_env, int num) { return 1; }
#elif defined(TARGET_PPC) && !defined(TARGET_PPC64)
/*
 * SysV AVI for PPC32 expects 64bit parameters to be passed on odd/even pairs
 * of registers which translates to the same as ARM/MIPS, because we start with
 * r3 as arg1
 */
static inline int regpairs_aligned(void *cpu_env, int num) { return 1; }
#elif defined(TARGET_SH4)
/* SH4 doesn't align register pairs, except for p{read,write}64 */
static inline int regpairs_aligned(void *cpu_env, int num)
{
    switch (num) {
    case TARGET_NR_pread64:
    case TARGET_NR_pwrite64:
        return 1;

    default:
        return 0;
    }
}
#elif defined(TARGET_XTENSA)
static inline int regpairs_aligned(void *cpu_env, int num) { return 1; }
#elif defined(TARGET_HEXAGON)
static inline int regpairs_aligned(void *cpu_env, int num) { return 1; }
#else
static inline int regpairs_aligned(void *cpu_env, int num) { return 0; }
#endif

/**
 * 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 */