xref: /openbmc/qemu/linux-user/qemu.h (revision 259ebed4)
1 #ifndef QEMU_H
2 #define QEMU_H
3 
4 #include "cpu.h"
5 #include "exec/cpu_ldst.h"
6 
7 #undef DEBUG_REMAP
8 
9 #include "exec/user/abitypes.h"
10 
11 #include "syscall_defs.h"
12 #include "target_syscall.h"
13 
14 /*
15  * This is the size of the host kernel's sigset_t, needed where we make
16  * direct system calls that take a sigset_t pointer and a size.
17  */
18 #define SIGSET_T_SIZE (_NSIG / 8)
19 
20 /*
21  * This struct is used to hold certain information about the image.
22  * Basically, it replicates in user space what would be certain
23  * task_struct fields in the kernel
24  */
25 struct image_info {
26         abi_ulong       load_bias;
27         abi_ulong       load_addr;
28         abi_ulong       start_code;
29         abi_ulong       end_code;
30         abi_ulong       start_data;
31         abi_ulong       end_data;
32         abi_ulong       brk;
33         abi_ulong       start_stack;
34         abi_ulong       stack_limit;
35         abi_ulong       vdso;
36         abi_ulong       entry;
37         abi_ulong       code_offset;
38         abi_ulong       data_offset;
39         abi_ulong       saved_auxv;
40         abi_ulong       auxv_len;
41         abi_ulong       argc;
42         abi_ulong       argv;
43         abi_ulong       envc;
44         abi_ulong       envp;
45         abi_ulong       file_string;
46         uint32_t        elf_flags;
47         int             personality;
48         abi_ulong       alignment;
49         bool            exec_stack;
50 
51         /* Generic semihosting knows about these pointers. */
52         abi_ulong       arg_strings;   /* strings for argv */
53         abi_ulong       env_strings;   /* strings for envp; ends arg_strings */
54 
55         /* The fields below are used in FDPIC mode.  */
56         abi_ulong       loadmap_addr;
57         uint16_t        nsegs;
58         void            *loadsegs;
59         abi_ulong       pt_dynamic_addr;
60         abi_ulong       interpreter_loadmap_addr;
61         abi_ulong       interpreter_pt_dynamic_addr;
62         struct image_info *other_info;
63 
64         /* For target-specific processing of NT_GNU_PROPERTY_TYPE_0. */
65         uint32_t        note_flags;
66 
67 #ifdef TARGET_MIPS
68         int             fp_abi;
69         int             interp_fp_abi;
70 #endif
71 };
72 
73 #ifdef TARGET_I386
74 /* Information about the current linux thread */
75 struct vm86_saved_state {
76     uint32_t eax; /* return code */
77     uint32_t ebx;
78     uint32_t ecx;
79     uint32_t edx;
80     uint32_t esi;
81     uint32_t edi;
82     uint32_t ebp;
83     uint32_t esp;
84     uint32_t eflags;
85     uint32_t eip;
86     uint16_t cs, ss, ds, es, fs, gs;
87 };
88 #endif
89 
90 #if defined(TARGET_ARM) && defined(TARGET_ABI32)
91 /* FPU emulator */
92 #include "nwfpe/fpa11.h"
93 #endif
94 
95 struct emulated_sigtable {
96     int pending; /* true if signal is pending */
97     target_siginfo_t info;
98 };
99 
100 typedef struct TaskState {
101     pid_t ts_tid;     /* tid (or pid) of this task */
102 #ifdef TARGET_ARM
103 # ifdef TARGET_ABI32
104     /* FPA state */
105     FPA11 fpa;
106 # endif
107 #endif
108 #if defined(TARGET_ARM) || defined(TARGET_RISCV)
109     int swi_errno;
110 #endif
111 #if defined(TARGET_I386) && !defined(TARGET_X86_64)
112     abi_ulong target_v86;
113     struct vm86_saved_state vm86_saved_regs;
114     struct target_vm86plus_struct vm86plus;
115     uint32_t v86flags;
116     uint32_t v86mask;
117 #endif
118     abi_ulong child_tidptr;
119 #ifdef TARGET_M68K
120     abi_ulong tp_value;
121 #endif
122 #if defined(TARGET_ARM) || defined(TARGET_M68K) || defined(TARGET_RISCV)
123     /* Extra fields for semihosted binaries.  */
124     abi_ulong heap_base;
125     abi_ulong heap_limit;
126 #endif
127     abi_ulong stack_base;
128     int used; /* non zero if used */
129     struct image_info *info;
130     struct linux_binprm *bprm;
131 
132     struct emulated_sigtable sync_signal;
133     struct emulated_sigtable sigtab[TARGET_NSIG];
134     /*
135      * This thread's signal mask, as requested by the guest program.
136      * The actual signal mask of this thread may differ:
137      *  + we don't let SIGSEGV and SIGBUS be blocked while running guest code
138      *  + sometimes we block all signals to avoid races
139      */
140     sigset_t signal_mask;
141     /*
142      * The signal mask imposed by a guest sigsuspend syscall, if we are
143      * currently in the middle of such a syscall
144      */
145     sigset_t sigsuspend_mask;
146     /* Nonzero if we're leaving a sigsuspend and sigsuspend_mask is valid. */
147     int in_sigsuspend;
148 
149     /*
150      * Nonzero if process_pending_signals() needs to do something (either
151      * handle a pending signal or unblock signals).
152      * This flag is written from a signal handler so should be accessed via
153      * the qatomic_read() and qatomic_set() functions. (It is not accessed
154      * from multiple threads.)
155      */
156     int signal_pending;
157 
158     /* This thread's sigaltstack, if it has one */
159     struct target_sigaltstack sigaltstack_used;
160 
161     /* Start time of task after system boot in clock ticks */
162     uint64_t start_boottime;
163 } TaskState;
164 
165 abi_long do_brk(abi_ulong new_brk);
166 int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname,
167                     int flags, mode_t mode, bool safe);
168 ssize_t do_guest_readlink(const char *pathname, char *buf, size_t bufsiz);
169 
170 /* user access */
171 
172 #define VERIFY_NONE  0
173 #define VERIFY_READ  PAGE_READ
174 #define VERIFY_WRITE (PAGE_READ | PAGE_WRITE)
175 
176 static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
177 {
178     if (size == 0
179         ? !guest_addr_valid_untagged(addr)
180         : !guest_range_valid_untagged(addr, size)) {
181         return false;
182     }
183     return page_check_range((target_ulong)addr, size, type);
184 }
185 
186 static inline bool access_ok(CPUState *cpu, int type,
187                              abi_ulong addr, abi_ulong size)
188 {
189     return access_ok_untagged(type, cpu_untagged_addr(cpu, addr), size);
190 }
191 
192 /* NOTE __get_user and __put_user use host pointers and don't check access.
193    These are usually used to access struct data members once the struct has
194    been locked - usually with lock_user_struct.  */
195 
196 /*
197  * Tricky points:
198  * - Use __builtin_choose_expr to avoid type promotion from ?:,
199  * - Invalid sizes result in a compile time error stemming from
200  *   the fact that abort has no parameters.
201  * - It's easier to use the endian-specific unaligned load/store
202  *   functions than host-endian unaligned load/store plus tswapN.
203  * - The pragmas are necessary only to silence a clang false-positive
204  *   warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
205  * - gcc has bugs in its _Pragma() support in some versions, eg
206  *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
207  *   include the warning-suppression pragmas for clang
208  */
209 #if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
210 #define PRAGMA_DISABLE_PACKED_WARNING                                   \
211     _Pragma("GCC diagnostic push");                                     \
212     _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
213 
214 #define PRAGMA_REENABLE_PACKED_WARNING          \
215     _Pragma("GCC diagnostic pop")
216 
217 #else
218 #define PRAGMA_DISABLE_PACKED_WARNING
219 #define PRAGMA_REENABLE_PACKED_WARNING
220 #endif
221 
222 #define __put_user_e(x, hptr, e)                                            \
223     do {                                                                    \
224         PRAGMA_DISABLE_PACKED_WARNING;                                      \
225         (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p,                 \
226         __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p,            \
227         __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p,            \
228         __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort))))  \
229             ((hptr), (x)), (void)0);                                        \
230         PRAGMA_REENABLE_PACKED_WARNING;                                     \
231     } while (0)
232 
233 #define __get_user_e(x, hptr, e)                                            \
234     do {                                                                    \
235         PRAGMA_DISABLE_PACKED_WARNING;                                      \
236         ((x) = (typeof(*hptr))(                                             \
237         __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p,                 \
238         __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p,           \
239         __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p,            \
240         __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort))))  \
241             (hptr)), (void)0);                                              \
242         PRAGMA_REENABLE_PACKED_WARNING;                                     \
243     } while (0)
244 
245 
246 #if TARGET_BIG_ENDIAN
247 # define __put_user(x, hptr)  __put_user_e(x, hptr, be)
248 # define __get_user(x, hptr)  __get_user_e(x, hptr, be)
249 #else
250 # define __put_user(x, hptr)  __put_user_e(x, hptr, le)
251 # define __get_user(x, hptr)  __get_user_e(x, hptr, le)
252 #endif
253 
254 /* put_user()/get_user() take a guest address and check access */
255 /* These are usually used to access an atomic data type, such as an int,
256  * that has been passed by address.  These internally perform locking
257  * and unlocking on the data type.
258  */
259 #define put_user(x, gaddr, target_type)					\
260 ({									\
261     abi_ulong __gaddr = (gaddr);					\
262     target_type *__hptr;						\
263     abi_long __ret = 0;							\
264     if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \
265         __put_user((x), __hptr);				\
266         unlock_user(__hptr, __gaddr, sizeof(target_type));		\
267     } else								\
268         __ret = -TARGET_EFAULT;						\
269     __ret;								\
270 })
271 
272 #define get_user(x, gaddr, target_type)					\
273 ({									\
274     abi_ulong __gaddr = (gaddr);					\
275     target_type *__hptr;						\
276     abi_long __ret = 0;							\
277     if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \
278         __get_user((x), __hptr);				\
279         unlock_user(__hptr, __gaddr, 0);				\
280     } else {								\
281         /* avoid warning */						\
282         (x) = 0;							\
283         __ret = -TARGET_EFAULT;						\
284     }									\
285     __ret;								\
286 })
287 
288 #define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong)
289 #define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long)
290 #define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t)
291 #define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t)
292 #define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t)
293 #define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t)
294 #define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t)
295 #define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t)
296 #define put_user_u8(x, gaddr)  put_user((x), (gaddr), uint8_t)
297 #define put_user_s8(x, gaddr)  put_user((x), (gaddr), int8_t)
298 
299 #define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong)
300 #define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long)
301 #define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t)
302 #define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t)
303 #define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t)
304 #define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t)
305 #define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t)
306 #define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t)
307 #define get_user_u8(x, gaddr)  get_user((x), (gaddr), uint8_t)
308 #define get_user_s8(x, gaddr)  get_user((x), (gaddr), int8_t)
309 
310 /* copy_from_user() and copy_to_user() are usually used to copy data
311  * buffers between the target and host.  These internally perform
312  * locking/unlocking of the memory.
313  */
314 int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
315 int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len);
316 
317 /* Functions for accessing guest memory.  The tget and tput functions
318    read/write single values, byteswapping as necessary.  The lock_user function
319    gets a pointer to a contiguous area of guest memory, but does not perform
320    any byteswapping.  lock_user may return either a pointer to the guest
321    memory, or a temporary buffer.  */
322 
323 /* Lock an area of guest memory into the host.  If copy is true then the
324    host area will have the same contents as the guest.  */
325 void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy);
326 
327 /* Unlock an area of guest memory.  The first LEN bytes must be
328    flushed back to guest memory. host_ptr = NULL is explicitly
329    allowed and does nothing. */
330 #ifndef DEBUG_REMAP
331 static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
332                                ssize_t len)
333 {
334     /* no-op */
335 }
336 #else
337 void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len);
338 #endif
339 
340 /* Return the length of a string in target memory or -TARGET_EFAULT if
341    access error. */
342 ssize_t target_strlen(abi_ulong gaddr);
343 
344 /* Like lock_user but for null terminated strings.  */
345 void *lock_user_string(abi_ulong guest_addr);
346 
347 /* Helper macros for locking/unlocking a target struct.  */
348 #define lock_user_struct(type, host_ptr, guest_addr, copy)	\
349     (host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy))
350 #define unlock_user_struct(host_ptr, guest_addr, copy)		\
351     unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
352 
353 #endif /* QEMU_H */
354