xref: /openbmc/qemu/linux-user/qemu.h (revision 4921d0a7)
1 #ifndef QEMU_H
2 #define QEMU_H
3 
4 #include "cpu.h"
5 #include "exec/cpu_ldst.h"
6 
7 #include "exec/user/abitypes.h"
8 
9 #include "syscall_defs.h"
10 #include "target_syscall.h"
11 
12 /*
13  * This is the size of the host kernel's sigset_t, needed where we make
14  * direct system calls that take a sigset_t pointer and a size.
15  */
16 #define SIGSET_T_SIZE (_NSIG / 8)
17 
18 /*
19  * This struct is used to hold certain information about the image.
20  * Basically, it replicates in user space what would be certain
21  * task_struct fields in the kernel
22  */
23 struct image_info {
24         abi_ulong       load_bias;
25         abi_ulong       load_addr;
26         abi_ulong       start_code;
27         abi_ulong       end_code;
28         abi_ulong       start_data;
29         abi_ulong       end_data;
30         abi_ulong       brk;
31         abi_ulong       start_stack;
32         abi_ulong       stack_limit;
33         abi_ulong       vdso;
34         abi_ulong       entry;
35         abi_ulong       code_offset;
36         abi_ulong       data_offset;
37         abi_ulong       saved_auxv;
38         abi_ulong       auxv_len;
39         abi_ulong       argc;
40         abi_ulong       argv;
41         abi_ulong       envc;
42         abi_ulong       envp;
43         abi_ulong       file_string;
44         uint32_t        elf_flags;
45         int             personality;
46         abi_ulong       alignment;
47         bool            exec_stack;
48 
49         /* Generic semihosting knows about these pointers. */
50         abi_ulong       arg_strings;   /* strings for argv */
51         abi_ulong       env_strings;   /* strings for envp; ends arg_strings */
52 
53         /* The fields below are used in FDPIC mode.  */
54         abi_ulong       loadmap_addr;
55         uint16_t        nsegs;
56         void            *loadsegs;
57         abi_ulong       pt_dynamic_addr;
58         abi_ulong       interpreter_loadmap_addr;
59         abi_ulong       interpreter_pt_dynamic_addr;
60         struct image_info *other_info;
61 
62         /* For target-specific processing of NT_GNU_PROPERTY_TYPE_0. */
63         uint32_t        note_flags;
64 
65 #ifdef TARGET_MIPS
66         int             fp_abi;
67         int             interp_fp_abi;
68 #endif
69 };
70 
71 #ifdef TARGET_I386
72 /* Information about the current linux thread */
73 struct vm86_saved_state {
74     uint32_t eax; /* return code */
75     uint32_t ebx;
76     uint32_t ecx;
77     uint32_t edx;
78     uint32_t esi;
79     uint32_t edi;
80     uint32_t ebp;
81     uint32_t esp;
82     uint32_t eflags;
83     uint32_t eip;
84     uint16_t cs, ss, ds, es, fs, gs;
85 };
86 #endif
87 
88 #if defined(TARGET_ARM) && defined(TARGET_ABI32)
89 /* FPU emulator */
90 #include "nwfpe/fpa11.h"
91 #endif
92 
93 struct emulated_sigtable {
94     int pending; /* true if signal is pending */
95     target_siginfo_t info;
96 };
97 
98 typedef struct TaskState {
99     pid_t ts_tid;     /* tid (or pid) of this task */
100 #ifdef TARGET_ARM
101 # ifdef TARGET_ABI32
102     /* FPA state */
103     FPA11 fpa;
104 # endif
105 #endif
106 #if defined(TARGET_ARM) || defined(TARGET_RISCV)
107     int swi_errno;
108 #endif
109 #if defined(TARGET_I386) && !defined(TARGET_X86_64)
110     abi_ulong target_v86;
111     struct vm86_saved_state vm86_saved_regs;
112     struct target_vm86plus_struct vm86plus;
113     uint32_t v86flags;
114     uint32_t v86mask;
115 #endif
116     abi_ulong child_tidptr;
117 #ifdef TARGET_M68K
118     abi_ulong tp_value;
119 #endif
120 #if defined(TARGET_ARM) || defined(TARGET_M68K) || defined(TARGET_RISCV)
121     /* Extra fields for semihosted binaries.  */
122     abi_ulong heap_base;
123     abi_ulong heap_limit;
124 #endif
125     abi_ulong stack_base;
126     int used; /* non zero if used */
127     struct image_info *info;
128     struct linux_binprm *bprm;
129 
130     struct emulated_sigtable sync_signal;
131     struct emulated_sigtable sigtab[TARGET_NSIG];
132     /*
133      * This thread's signal mask, as requested by the guest program.
134      * The actual signal mask of this thread may differ:
135      *  + we don't let SIGSEGV and SIGBUS be blocked while running guest code
136      *  + sometimes we block all signals to avoid races
137      */
138     sigset_t signal_mask;
139     /*
140      * The signal mask imposed by a guest sigsuspend syscall, if we are
141      * currently in the middle of such a syscall
142      */
143     sigset_t sigsuspend_mask;
144     /* Nonzero if we're leaving a sigsuspend and sigsuspend_mask is valid. */
145     int in_sigsuspend;
146 
147     /*
148      * Nonzero if process_pending_signals() needs to do something (either
149      * handle a pending signal or unblock signals).
150      * This flag is written from a signal handler so should be accessed via
151      * the qatomic_read() and qatomic_set() functions. (It is not accessed
152      * from multiple threads.)
153      */
154     int signal_pending;
155 
156     /* This thread's sigaltstack, if it has one */
157     struct target_sigaltstack sigaltstack_used;
158 
159     /* Start time of task after system boot in clock ticks */
160     uint64_t start_boottime;
161 } TaskState;
162 
163 static inline TaskState *get_task_state(CPUState *cs)
164 {
165     return cs->opaque;
166 }
167 
168 abi_long do_brk(abi_ulong new_brk);
169 int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname,
170                     int flags, mode_t mode, bool safe);
171 ssize_t do_guest_readlink(const char *pathname, char *buf, size_t bufsiz);
172 
173 /* user access */
174 
175 #define VERIFY_NONE  0
176 #define VERIFY_READ  PAGE_READ
177 #define VERIFY_WRITE (PAGE_READ | PAGE_WRITE)
178 
179 static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
180 {
181     if (size == 0
182         ? !guest_addr_valid_untagged(addr)
183         : !guest_range_valid_untagged(addr, size)) {
184         return false;
185     }
186     return page_check_range((target_ulong)addr, size, type);
187 }
188 
189 static inline bool access_ok(CPUState *cpu, int type,
190                              abi_ulong addr, abi_ulong size)
191 {
192     return access_ok_untagged(type, cpu_untagged_addr(cpu, addr), size);
193 }
194 
195 /* NOTE __get_user and __put_user use host pointers and don't check access.
196    These are usually used to access struct data members once the struct has
197    been locked - usually with lock_user_struct.  */
198 
199 /*
200  * Tricky points:
201  * - Use __builtin_choose_expr to avoid type promotion from ?:,
202  * - Invalid sizes result in a compile time error stemming from
203  *   the fact that abort has no parameters.
204  * - It's easier to use the endian-specific unaligned load/store
205  *   functions than host-endian unaligned load/store plus tswapN.
206  * - The pragmas are necessary only to silence a clang false-positive
207  *   warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
208  * - gcc has bugs in its _Pragma() support in some versions, eg
209  *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
210  *   include the warning-suppression pragmas for clang
211  */
212 #if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
213 #define PRAGMA_DISABLE_PACKED_WARNING                                   \
214     _Pragma("GCC diagnostic push");                                     \
215     _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
216 
217 #define PRAGMA_REENABLE_PACKED_WARNING          \
218     _Pragma("GCC diagnostic pop")
219 
220 #else
221 #define PRAGMA_DISABLE_PACKED_WARNING
222 #define PRAGMA_REENABLE_PACKED_WARNING
223 #endif
224 
225 #define __put_user_e(x, hptr, e)                                            \
226     do {                                                                    \
227         PRAGMA_DISABLE_PACKED_WARNING;                                      \
228         (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p,                 \
229         __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p,            \
230         __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p,            \
231         __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort))))  \
232             ((hptr), (x)), (void)0);                                        \
233         PRAGMA_REENABLE_PACKED_WARNING;                                     \
234     } while (0)
235 
236 #define __get_user_e(x, hptr, e)                                            \
237     do {                                                                    \
238         PRAGMA_DISABLE_PACKED_WARNING;                                      \
239         ((x) = (typeof(*hptr))(                                             \
240         __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p,                 \
241         __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p,           \
242         __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p,            \
243         __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort))))  \
244             (hptr)), (void)0);                                              \
245         PRAGMA_REENABLE_PACKED_WARNING;                                     \
246     } while (0)
247 
248 
249 #if TARGET_BIG_ENDIAN
250 # define __put_user(x, hptr)  __put_user_e(x, hptr, be)
251 # define __get_user(x, hptr)  __get_user_e(x, hptr, be)
252 #else
253 # define __put_user(x, hptr)  __put_user_e(x, hptr, le)
254 # define __get_user(x, hptr)  __get_user_e(x, hptr, le)
255 #endif
256 
257 /* put_user()/get_user() take a guest address and check access */
258 /* These are usually used to access an atomic data type, such as an int,
259  * that has been passed by address.  These internally perform locking
260  * and unlocking on the data type.
261  */
262 #define put_user(x, gaddr, target_type)					\
263 ({									\
264     abi_ulong __gaddr = (gaddr);					\
265     target_type *__hptr;						\
266     abi_long __ret = 0;							\
267     if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \
268         __put_user((x), __hptr);				\
269         unlock_user(__hptr, __gaddr, sizeof(target_type));		\
270     } else								\
271         __ret = -TARGET_EFAULT;						\
272     __ret;								\
273 })
274 
275 #define get_user(x, gaddr, target_type)					\
276 ({									\
277     abi_ulong __gaddr = (gaddr);					\
278     target_type *__hptr;						\
279     abi_long __ret = 0;							\
280     if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \
281         __get_user((x), __hptr);				\
282         unlock_user(__hptr, __gaddr, 0);				\
283     } else {								\
284         /* avoid warning */						\
285         (x) = 0;							\
286         __ret = -TARGET_EFAULT;						\
287     }									\
288     __ret;								\
289 })
290 
291 #define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong)
292 #define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long)
293 #define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t)
294 #define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t)
295 #define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t)
296 #define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t)
297 #define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t)
298 #define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t)
299 #define put_user_u8(x, gaddr)  put_user((x), (gaddr), uint8_t)
300 #define put_user_s8(x, gaddr)  put_user((x), (gaddr), int8_t)
301 
302 #define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong)
303 #define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long)
304 #define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t)
305 #define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t)
306 #define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t)
307 #define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t)
308 #define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t)
309 #define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t)
310 #define get_user_u8(x, gaddr)  get_user((x), (gaddr), uint8_t)
311 #define get_user_s8(x, gaddr)  get_user((x), (gaddr), int8_t)
312 
313 /* copy_from_user() and copy_to_user() are usually used to copy data
314  * buffers between the target and host.  These internally perform
315  * locking/unlocking of the memory.
316  */
317 int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
318 int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len);
319 
320 /* Functions for accessing guest memory.  The tget and tput functions
321    read/write single values, byteswapping as necessary.  The lock_user function
322    gets a pointer to a contiguous area of guest memory, but does not perform
323    any byteswapping.  lock_user may return either a pointer to the guest
324    memory, or a temporary buffer.  */
325 
326 /* Lock an area of guest memory into the host.  If copy is true then the
327    host area will have the same contents as the guest.  */
328 void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy);
329 
330 /* Unlock an area of guest memory.  The first LEN bytes must be
331    flushed back to guest memory. host_ptr = NULL is explicitly
332    allowed and does nothing. */
333 #ifndef CONFIG_DEBUG_REMAP
334 static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
335                                ssize_t len)
336 {
337     /* no-op */
338 }
339 #else
340 void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len);
341 #endif
342 
343 /* Return the length of a string in target memory or -TARGET_EFAULT if
344    access error. */
345 ssize_t target_strlen(abi_ulong gaddr);
346 
347 /* Like lock_user but for null terminated strings.  */
348 void *lock_user_string(abi_ulong guest_addr);
349 
350 /* Helper macros for locking/unlocking a target struct.  */
351 #define lock_user_struct(type, host_ptr, guest_addr, copy)	\
352     (host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy))
353 #define unlock_user_struct(host_ptr, guest_addr, copy)		\
354     unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
355 
356 #endif /* QEMU_H */
357