xref: /openbmc/qemu/linux-user/qemu.h (revision de799beb)
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       start_brk;
33         abi_ulong       brk;
34         abi_ulong       reserve_brk;
35         abi_ulong       start_mmap;
36         abi_ulong       start_stack;
37         abi_ulong       stack_limit;
38         abi_ulong       entry;
39         abi_ulong       code_offset;
40         abi_ulong       data_offset;
41         abi_ulong       saved_auxv;
42         abi_ulong       auxv_len;
43         abi_ulong       argc;
44         abi_ulong       argv;
45         abi_ulong       envc;
46         abi_ulong       envp;
47         abi_ulong       file_string;
48         uint32_t        elf_flags;
49         int             personality;
50         abi_ulong       alignment;
51 
52         /* Generic semihosting knows about these pointers. */
53         abi_ulong       arg_strings;   /* strings for argv */
54         abi_ulong       env_strings;   /* strings for envp; ends arg_strings */
55 
56         /* The fields below are used in FDPIC mode.  */
57         abi_ulong       loadmap_addr;
58         uint16_t        nsegs;
59         void            *loadsegs;
60         abi_ulong       pt_dynamic_addr;
61         abi_ulong       interpreter_loadmap_addr;
62         abi_ulong       interpreter_pt_dynamic_addr;
63         struct image_info *other_info;
64 
65         /* For target-specific processing of NT_GNU_PROPERTY_TYPE_0. */
66         uint32_t        note_flags;
67 
68 #ifdef TARGET_MIPS
69         int             fp_abi;
70         int             interp_fp_abi;
71 #endif
72 };
73 
74 #ifdef TARGET_I386
75 /* Information about the current linux thread */
76 struct vm86_saved_state {
77     uint32_t eax; /* return code */
78     uint32_t ebx;
79     uint32_t ecx;
80     uint32_t edx;
81     uint32_t esi;
82     uint32_t edi;
83     uint32_t ebp;
84     uint32_t esp;
85     uint32_t eflags;
86     uint32_t eip;
87     uint16_t cs, ss, ds, es, fs, gs;
88 };
89 #endif
90 
91 #if defined(TARGET_ARM) && defined(TARGET_ABI32)
92 /* FPU emulator */
93 #include "nwfpe/fpa11.h"
94 #endif
95 
96 struct emulated_sigtable {
97     int pending; /* true if signal is pending */
98     target_siginfo_t info;
99 };
100 
101 typedef struct TaskState {
102     pid_t ts_tid;     /* tid (or pid) of this task */
103 #ifdef TARGET_ARM
104 # ifdef TARGET_ABI32
105     /* FPA state */
106     FPA11 fpa;
107 # endif
108 #endif
109 #if defined(TARGET_ARM) || defined(TARGET_RISCV)
110     int swi_errno;
111 #endif
112 #if defined(TARGET_I386) && !defined(TARGET_X86_64)
113     abi_ulong target_v86;
114     struct vm86_saved_state vm86_saved_regs;
115     struct target_vm86plus_struct vm86plus;
116     uint32_t v86flags;
117     uint32_t v86mask;
118 #endif
119     abi_ulong child_tidptr;
120 #ifdef TARGET_M68K
121     abi_ulong tp_value;
122 #endif
123 #if defined(TARGET_ARM) || defined(TARGET_M68K) || defined(TARGET_RISCV)
124     /* Extra fields for semihosted binaries.  */
125     abi_ulong heap_base;
126     abi_ulong heap_limit;
127 #endif
128     abi_ulong stack_base;
129     int used; /* non zero if used */
130     struct image_info *info;
131     struct linux_binprm *bprm;
132 
133     struct emulated_sigtable sync_signal;
134     struct emulated_sigtable sigtab[TARGET_NSIG];
135     /*
136      * This thread's signal mask, as requested by the guest program.
137      * The actual signal mask of this thread may differ:
138      *  + we don't let SIGSEGV and SIGBUS be blocked while running guest code
139      *  + sometimes we block all signals to avoid races
140      */
141     sigset_t signal_mask;
142     /*
143      * The signal mask imposed by a guest sigsuspend syscall, if we are
144      * currently in the middle of such a syscall
145      */
146     sigset_t sigsuspend_mask;
147     /* Nonzero if we're leaving a sigsuspend and sigsuspend_mask is valid. */
148     int in_sigsuspend;
149 
150     /*
151      * Nonzero if process_pending_signals() needs to do something (either
152      * handle a pending signal or unblock signals).
153      * This flag is written from a signal handler so should be accessed via
154      * the qatomic_read() and qatomic_set() functions. (It is not accessed
155      * from multiple threads.)
156      */
157     int signal_pending;
158 
159     /* This thread's sigaltstack, if it has one */
160     struct target_sigaltstack sigaltstack_used;
161 
162     /* Start time of task after system boot in clock ticks */
163     uint64_t start_boottime;
164 } TaskState;
165 
166 abi_long do_brk(abi_ulong new_brk);
167 
168 /* user access */
169 
170 #define VERIFY_READ  PAGE_READ
171 #define VERIFY_WRITE (PAGE_READ | PAGE_WRITE)
172 
173 static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
174 {
175     if (size == 0
176         ? !guest_addr_valid_untagged(addr)
177         : !guest_range_valid_untagged(addr, size)) {
178         return false;
179     }
180     return page_check_range((target_ulong)addr, size, type) == 0;
181 }
182 
183 static inline bool access_ok(CPUState *cpu, int type,
184                              abi_ulong addr, abi_ulong size)
185 {
186     return access_ok_untagged(type, cpu_untagged_addr(cpu, addr), size);
187 }
188 
189 /* NOTE __get_user and __put_user use host pointers and don't check access.
190    These are usually used to access struct data members once the struct has
191    been locked - usually with lock_user_struct.  */
192 
193 /*
194  * Tricky points:
195  * - Use __builtin_choose_expr to avoid type promotion from ?:,
196  * - Invalid sizes result in a compile time error stemming from
197  *   the fact that abort has no parameters.
198  * - It's easier to use the endian-specific unaligned load/store
199  *   functions than host-endian unaligned load/store plus tswapN.
200  * - The pragmas are necessary only to silence a clang false-positive
201  *   warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
202  * - gcc has bugs in its _Pragma() support in some versions, eg
203  *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
204  *   include the warning-suppression pragmas for clang
205  */
206 #if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
207 #define PRAGMA_DISABLE_PACKED_WARNING                                   \
208     _Pragma("GCC diagnostic push");                                     \
209     _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
210 
211 #define PRAGMA_REENABLE_PACKED_WARNING          \
212     _Pragma("GCC diagnostic pop")
213 
214 #else
215 #define PRAGMA_DISABLE_PACKED_WARNING
216 #define PRAGMA_REENABLE_PACKED_WARNING
217 #endif
218 
219 #define __put_user_e(x, hptr, e)                                            \
220     do {                                                                    \
221         PRAGMA_DISABLE_PACKED_WARNING;                                      \
222         (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p,                 \
223         __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p,            \
224         __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p,            \
225         __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort))))  \
226             ((hptr), (x)), (void)0);                                        \
227         PRAGMA_REENABLE_PACKED_WARNING;                                     \
228     } while (0)
229 
230 #define __get_user_e(x, hptr, e)                                            \
231     do {                                                                    \
232         PRAGMA_DISABLE_PACKED_WARNING;                                      \
233         ((x) = (typeof(*hptr))(                                             \
234         __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p,                 \
235         __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p,           \
236         __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p,            \
237         __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort))))  \
238             (hptr)), (void)0);                                              \
239         PRAGMA_REENABLE_PACKED_WARNING;                                     \
240     } while (0)
241 
242 
243 #if TARGET_BIG_ENDIAN
244 # define __put_user(x, hptr)  __put_user_e(x, hptr, be)
245 # define __get_user(x, hptr)  __get_user_e(x, hptr, be)
246 #else
247 # define __put_user(x, hptr)  __put_user_e(x, hptr, le)
248 # define __get_user(x, hptr)  __get_user_e(x, hptr, le)
249 #endif
250 
251 /* put_user()/get_user() take a guest address and check access */
252 /* These are usually used to access an atomic data type, such as an int,
253  * that has been passed by address.  These internally perform locking
254  * and unlocking on the data type.
255  */
256 #define put_user(x, gaddr, target_type)					\
257 ({									\
258     abi_ulong __gaddr = (gaddr);					\
259     target_type *__hptr;						\
260     abi_long __ret = 0;							\
261     if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \
262         __put_user((x), __hptr);				\
263         unlock_user(__hptr, __gaddr, sizeof(target_type));		\
264     } else								\
265         __ret = -TARGET_EFAULT;						\
266     __ret;								\
267 })
268 
269 #define get_user(x, gaddr, target_type)					\
270 ({									\
271     abi_ulong __gaddr = (gaddr);					\
272     target_type *__hptr;						\
273     abi_long __ret = 0;							\
274     if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \
275         __get_user((x), __hptr);				\
276         unlock_user(__hptr, __gaddr, 0);				\
277     } else {								\
278         /* avoid warning */						\
279         (x) = 0;							\
280         __ret = -TARGET_EFAULT;						\
281     }									\
282     __ret;								\
283 })
284 
285 #define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong)
286 #define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long)
287 #define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t)
288 #define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t)
289 #define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t)
290 #define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t)
291 #define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t)
292 #define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t)
293 #define put_user_u8(x, gaddr)  put_user((x), (gaddr), uint8_t)
294 #define put_user_s8(x, gaddr)  put_user((x), (gaddr), int8_t)
295 
296 #define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong)
297 #define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long)
298 #define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t)
299 #define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t)
300 #define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t)
301 #define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t)
302 #define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t)
303 #define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t)
304 #define get_user_u8(x, gaddr)  get_user((x), (gaddr), uint8_t)
305 #define get_user_s8(x, gaddr)  get_user((x), (gaddr), int8_t)
306 
307 /* copy_from_user() and copy_to_user() are usually used to copy data
308  * buffers between the target and host.  These internally perform
309  * locking/unlocking of the memory.
310  */
311 int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
312 int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len);
313 
314 /* Functions for accessing guest memory.  The tget and tput functions
315    read/write single values, byteswapping as necessary.  The lock_user function
316    gets a pointer to a contiguous area of guest memory, but does not perform
317    any byteswapping.  lock_user may return either a pointer to the guest
318    memory, or a temporary buffer.  */
319 
320 /* Lock an area of guest memory into the host.  If copy is true then the
321    host area will have the same contents as the guest.  */
322 void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy);
323 
324 /* Unlock an area of guest memory.  The first LEN bytes must be
325    flushed back to guest memory. host_ptr = NULL is explicitly
326    allowed and does nothing. */
327 #ifndef DEBUG_REMAP
328 static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
329                                ssize_t len)
330 {
331     /* no-op */
332 }
333 #else
334 void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len);
335 #endif
336 
337 /* Return the length of a string in target memory or -TARGET_EFAULT if
338    access error. */
339 ssize_t target_strlen(abi_ulong gaddr);
340 
341 /* Like lock_user but for null terminated strings.  */
342 void *lock_user_string(abi_ulong guest_addr);
343 
344 /* Helper macros for locking/unlocking a target struct.  */
345 #define lock_user_struct(type, host_ptr, guest_addr, copy)	\
346     (host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy))
347 #define unlock_user_struct(host_ptr, guest_addr, copy)		\
348     unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
349 
350 #endif /* QEMU_H */
351