xref: /openbmc/qemu/linux-user/qemu.h (revision b91a0fa7)
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       arg_start;
44         abi_ulong       arg_end;
45         abi_ulong       arg_strings;
46         abi_ulong       env_strings;
47         abi_ulong       file_string;
48         uint32_t        elf_flags;
49         int             personality;
50         abi_ulong       alignment;
51 
52         /* The fields below are used in FDPIC mode.  */
53         abi_ulong       loadmap_addr;
54         uint16_t        nsegs;
55         void            *loadsegs;
56         abi_ulong       pt_dynamic_addr;
57         abi_ulong       interpreter_loadmap_addr;
58         abi_ulong       interpreter_pt_dynamic_addr;
59         struct image_info *other_info;
60 
61         /* For target-specific processing of NT_GNU_PROPERTY_TYPE_0. */
62         uint32_t        note_flags;
63 
64 #ifdef TARGET_MIPS
65         int             fp_abi;
66         int             interp_fp_abi;
67 #endif
68 };
69 
70 #ifdef TARGET_I386
71 /* Information about the current linux thread */
72 struct vm86_saved_state {
73     uint32_t eax; /* return code */
74     uint32_t ebx;
75     uint32_t ecx;
76     uint32_t edx;
77     uint32_t esi;
78     uint32_t edi;
79     uint32_t ebp;
80     uint32_t esp;
81     uint32_t eflags;
82     uint32_t eip;
83     uint16_t cs, ss, ds, es, fs, gs;
84 };
85 #endif
86 
87 #if defined(TARGET_ARM) && defined(TARGET_ABI32)
88 /* FPU emulator */
89 #include "nwfpe/fpa11.h"
90 #endif
91 
92 struct emulated_sigtable {
93     int pending; /* true if signal is pending */
94     target_siginfo_t info;
95 };
96 
97 /*
98  * NOTE: we force a big alignment so that the stack stored after is
99  * aligned too
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 } __attribute__((aligned(16))) TaskState;
162 
163 abi_long do_brk(abi_ulong new_brk);
164 
165 /* user access */
166 
167 #define VERIFY_READ  PAGE_READ
168 #define VERIFY_WRITE (PAGE_READ | PAGE_WRITE)
169 
170 static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
171 {
172     if (size == 0
173         ? !guest_addr_valid_untagged(addr)
174         : !guest_range_valid_untagged(addr, size)) {
175         return false;
176     }
177     return page_check_range((target_ulong)addr, size, type) == 0;
178 }
179 
180 static inline bool access_ok(CPUState *cpu, int type,
181                              abi_ulong addr, abi_ulong size)
182 {
183     return access_ok_untagged(type, cpu_untagged_addr(cpu, addr), size);
184 }
185 
186 /* NOTE __get_user and __put_user use host pointers and don't check access.
187    These are usually used to access struct data members once the struct has
188    been locked - usually with lock_user_struct.  */
189 
190 /*
191  * Tricky points:
192  * - Use __builtin_choose_expr to avoid type promotion from ?:,
193  * - Invalid sizes result in a compile time error stemming from
194  *   the fact that abort has no parameters.
195  * - It's easier to use the endian-specific unaligned load/store
196  *   functions than host-endian unaligned load/store plus tswapN.
197  * - The pragmas are necessary only to silence a clang false-positive
198  *   warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
199  * - gcc has bugs in its _Pragma() support in some versions, eg
200  *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
201  *   include the warning-suppression pragmas for clang
202  */
203 #if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
204 #define PRAGMA_DISABLE_PACKED_WARNING                                   \
205     _Pragma("GCC diagnostic push");                                     \
206     _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
207 
208 #define PRAGMA_REENABLE_PACKED_WARNING          \
209     _Pragma("GCC diagnostic pop")
210 
211 #else
212 #define PRAGMA_DISABLE_PACKED_WARNING
213 #define PRAGMA_REENABLE_PACKED_WARNING
214 #endif
215 
216 #define __put_user_e(x, hptr, e)                                            \
217     do {                                                                    \
218         PRAGMA_DISABLE_PACKED_WARNING;                                      \
219         (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p,                 \
220         __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p,            \
221         __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p,            \
222         __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort))))  \
223             ((hptr), (x)), (void)0);                                        \
224         PRAGMA_REENABLE_PACKED_WARNING;                                     \
225     } while (0)
226 
227 #define __get_user_e(x, hptr, e)                                            \
228     do {                                                                    \
229         PRAGMA_DISABLE_PACKED_WARNING;                                      \
230         ((x) = (typeof(*hptr))(                                             \
231         __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p,                 \
232         __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p,           \
233         __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p,            \
234         __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort))))  \
235             (hptr)), (void)0);                                              \
236         PRAGMA_REENABLE_PACKED_WARNING;                                     \
237     } while (0)
238 
239 
240 #ifdef TARGET_WORDS_BIGENDIAN
241 # define __put_user(x, hptr)  __put_user_e(x, hptr, be)
242 # define __get_user(x, hptr)  __get_user_e(x, hptr, be)
243 #else
244 # define __put_user(x, hptr)  __put_user_e(x, hptr, le)
245 # define __get_user(x, hptr)  __get_user_e(x, hptr, le)
246 #endif
247 
248 /* put_user()/get_user() take a guest address and check access */
249 /* These are usually used to access an atomic data type, such as an int,
250  * that has been passed by address.  These internally perform locking
251  * and unlocking on the data type.
252  */
253 #define put_user(x, gaddr, target_type)					\
254 ({									\
255     abi_ulong __gaddr = (gaddr);					\
256     target_type *__hptr;						\
257     abi_long __ret = 0;							\
258     if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \
259         __put_user((x), __hptr);				\
260         unlock_user(__hptr, __gaddr, sizeof(target_type));		\
261     } else								\
262         __ret = -TARGET_EFAULT;						\
263     __ret;								\
264 })
265 
266 #define get_user(x, gaddr, target_type)					\
267 ({									\
268     abi_ulong __gaddr = (gaddr);					\
269     target_type *__hptr;						\
270     abi_long __ret = 0;							\
271     if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \
272         __get_user((x), __hptr);				\
273         unlock_user(__hptr, __gaddr, 0);				\
274     } else {								\
275         /* avoid warning */						\
276         (x) = 0;							\
277         __ret = -TARGET_EFAULT;						\
278     }									\
279     __ret;								\
280 })
281 
282 #define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong)
283 #define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long)
284 #define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t)
285 #define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t)
286 #define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t)
287 #define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t)
288 #define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t)
289 #define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t)
290 #define put_user_u8(x, gaddr)  put_user((x), (gaddr), uint8_t)
291 #define put_user_s8(x, gaddr)  put_user((x), (gaddr), int8_t)
292 
293 #define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong)
294 #define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long)
295 #define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t)
296 #define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t)
297 #define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t)
298 #define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t)
299 #define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t)
300 #define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t)
301 #define get_user_u8(x, gaddr)  get_user((x), (gaddr), uint8_t)
302 #define get_user_s8(x, gaddr)  get_user((x), (gaddr), int8_t)
303 
304 /* copy_from_user() and copy_to_user() are usually used to copy data
305  * buffers between the target and host.  These internally perform
306  * locking/unlocking of the memory.
307  */
308 int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
309 int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len);
310 
311 /* Functions for accessing guest memory.  The tget and tput functions
312    read/write single values, byteswapping as necessary.  The lock_user function
313    gets a pointer to a contiguous area of guest memory, but does not perform
314    any byteswapping.  lock_user may return either a pointer to the guest
315    memory, or a temporary buffer.  */
316 
317 /* Lock an area of guest memory into the host.  If copy is true then the
318    host area will have the same contents as the guest.  */
319 void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy);
320 
321 /* Unlock an area of guest memory.  The first LEN bytes must be
322    flushed back to guest memory. host_ptr = NULL is explicitly
323    allowed and does nothing. */
324 #ifndef DEBUG_REMAP
325 static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
326                                ssize_t len)
327 {
328     /* no-op */
329 }
330 #else
331 void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len);
332 #endif
333 
334 /* Return the length of a string in target memory or -TARGET_EFAULT if
335    access error. */
336 ssize_t target_strlen(abi_ulong gaddr);
337 
338 /* Like lock_user but for null terminated strings.  */
339 void *lock_user_string(abi_ulong guest_addr);
340 
341 /* Helper macros for locking/unlocking a target struct.  */
342 #define lock_user_struct(type, host_ptr, guest_addr, copy)	\
343     (host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy))
344 #define unlock_user_struct(host_ptr, guest_addr, copy)		\
345     unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
346 
347 #endif /* QEMU_H */
348