xref: /openbmc/qemu/linux-user/qemu.h (revision 2f44bea9)
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 #define MAX_SIGQUEUE_SIZE 1024
93 
94 struct emulated_sigtable {
95     int pending; /* true if signal is pending */
96     target_siginfo_t info;
97 };
98 
99 /*
100  * NOTE: we force a big alignment so that the stack stored after is
101  * aligned too
102  */
103 typedef struct TaskState {
104     pid_t ts_tid;     /* tid (or pid) of this task */
105 #ifdef TARGET_ARM
106 # ifdef TARGET_ABI32
107     /* FPA state */
108     FPA11 fpa;
109 # endif
110 #endif
111 #if defined(TARGET_ARM) || defined(TARGET_RISCV)
112     int swi_errno;
113 #endif
114 #if defined(TARGET_I386) && !defined(TARGET_X86_64)
115     abi_ulong target_v86;
116     struct vm86_saved_state vm86_saved_regs;
117     struct target_vm86plus_struct vm86plus;
118     uint32_t v86flags;
119     uint32_t v86mask;
120 #endif
121     abi_ulong child_tidptr;
122 #ifdef TARGET_M68K
123     abi_ulong tp_value;
124 #endif
125 #if defined(TARGET_ARM) || defined(TARGET_M68K) || defined(TARGET_RISCV)
126     /* Extra fields for semihosted binaries.  */
127     abi_ulong heap_base;
128     abi_ulong heap_limit;
129 #endif
130     abi_ulong stack_base;
131     int used; /* non zero if used */
132     struct image_info *info;
133     struct linux_binprm *bprm;
134 
135     struct emulated_sigtable sync_signal;
136     struct emulated_sigtable sigtab[TARGET_NSIG];
137     /*
138      * This thread's signal mask, as requested by the guest program.
139      * The actual signal mask of this thread may differ:
140      *  + we don't let SIGSEGV and SIGBUS be blocked while running guest code
141      *  + sometimes we block all signals to avoid races
142      */
143     sigset_t signal_mask;
144     /*
145      * The signal mask imposed by a guest sigsuspend syscall, if we are
146      * currently in the middle of such a syscall
147      */
148     sigset_t sigsuspend_mask;
149     /* Nonzero if we're leaving a sigsuspend and sigsuspend_mask is valid. */
150     int in_sigsuspend;
151 
152     /*
153      * Nonzero if process_pending_signals() needs to do something (either
154      * handle a pending signal or unblock signals).
155      * This flag is written from a signal handler so should be accessed via
156      * the qatomic_read() and qatomic_set() functions. (It is not accessed
157      * from multiple threads.)
158      */
159     int signal_pending;
160 
161     /* This thread's sigaltstack, if it has one */
162     struct target_sigaltstack sigaltstack_used;
163 } __attribute__((aligned(16))) TaskState;
164 
165 abi_long do_brk(abi_ulong new_brk);
166 
167 /* user access */
168 
169 #define VERIFY_READ  PAGE_READ
170 #define VERIFY_WRITE (PAGE_READ | PAGE_WRITE)
171 
172 static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
173 {
174     if (size == 0
175         ? !guest_addr_valid_untagged(addr)
176         : !guest_range_valid_untagged(addr, size)) {
177         return false;
178     }
179     return page_check_range((target_ulong)addr, size, type) == 0;
180 }
181 
182 static inline bool access_ok(CPUState *cpu, int type,
183                              abi_ulong addr, abi_ulong size)
184 {
185     return access_ok_untagged(type, cpu_untagged_addr(cpu, addr), size);
186 }
187 
188 /* NOTE __get_user and __put_user use host pointers and don't check access.
189    These are usually used to access struct data members once the struct has
190    been locked - usually with lock_user_struct.  */
191 
192 /*
193  * Tricky points:
194  * - Use __builtin_choose_expr to avoid type promotion from ?:,
195  * - Invalid sizes result in a compile time error stemming from
196  *   the fact that abort has no parameters.
197  * - It's easier to use the endian-specific unaligned load/store
198  *   functions than host-endian unaligned load/store plus tswapN.
199  * - The pragmas are necessary only to silence a clang false-positive
200  *   warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
201  * - gcc has bugs in its _Pragma() support in some versions, eg
202  *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
203  *   include the warning-suppression pragmas for clang
204  */
205 #if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
206 #define PRAGMA_DISABLE_PACKED_WARNING                                   \
207     _Pragma("GCC diagnostic push");                                     \
208     _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
209 
210 #define PRAGMA_REENABLE_PACKED_WARNING          \
211     _Pragma("GCC diagnostic pop")
212 
213 #else
214 #define PRAGMA_DISABLE_PACKED_WARNING
215 #define PRAGMA_REENABLE_PACKED_WARNING
216 #endif
217 
218 #define __put_user_e(x, hptr, e)                                            \
219     do {                                                                    \
220         PRAGMA_DISABLE_PACKED_WARNING;                                      \
221         (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p,                 \
222         __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p,            \
223         __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p,            \
224         __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort))))  \
225             ((hptr), (x)), (void)0);                                        \
226         PRAGMA_REENABLE_PACKED_WARNING;                                     \
227     } while (0)
228 
229 #define __get_user_e(x, hptr, e)                                            \
230     do {                                                                    \
231         PRAGMA_DISABLE_PACKED_WARNING;                                      \
232         ((x) = (typeof(*hptr))(                                             \
233         __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p,                 \
234         __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p,           \
235         __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p,            \
236         __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort))))  \
237             (hptr)), (void)0);                                              \
238         PRAGMA_REENABLE_PACKED_WARNING;                                     \
239     } while (0)
240 
241 
242 #ifdef TARGET_WORDS_BIGENDIAN
243 # define __put_user(x, hptr)  __put_user_e(x, hptr, be)
244 # define __get_user(x, hptr)  __get_user_e(x, hptr, be)
245 #else
246 # define __put_user(x, hptr)  __put_user_e(x, hptr, le)
247 # define __get_user(x, hptr)  __get_user_e(x, hptr, le)
248 #endif
249 
250 /* put_user()/get_user() take a guest address and check access */
251 /* These are usually used to access an atomic data type, such as an int,
252  * that has been passed by address.  These internally perform locking
253  * and unlocking on the data type.
254  */
255 #define put_user(x, gaddr, target_type)					\
256 ({									\
257     abi_ulong __gaddr = (gaddr);					\
258     target_type *__hptr;						\
259     abi_long __ret = 0;							\
260     if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \
261         __put_user((x), __hptr);				\
262         unlock_user(__hptr, __gaddr, sizeof(target_type));		\
263     } else								\
264         __ret = -TARGET_EFAULT;						\
265     __ret;								\
266 })
267 
268 #define get_user(x, gaddr, target_type)					\
269 ({									\
270     abi_ulong __gaddr = (gaddr);					\
271     target_type *__hptr;						\
272     abi_long __ret = 0;							\
273     if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \
274         __get_user((x), __hptr);				\
275         unlock_user(__hptr, __gaddr, 0);				\
276     } else {								\
277         /* avoid warning */						\
278         (x) = 0;							\
279         __ret = -TARGET_EFAULT;						\
280     }									\
281     __ret;								\
282 })
283 
284 #define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong)
285 #define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long)
286 #define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t)
287 #define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t)
288 #define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t)
289 #define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t)
290 #define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t)
291 #define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t)
292 #define put_user_u8(x, gaddr)  put_user((x), (gaddr), uint8_t)
293 #define put_user_s8(x, gaddr)  put_user((x), (gaddr), int8_t)
294 
295 #define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong)
296 #define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long)
297 #define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t)
298 #define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t)
299 #define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t)
300 #define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t)
301 #define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t)
302 #define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t)
303 #define get_user_u8(x, gaddr)  get_user((x), (gaddr), uint8_t)
304 #define get_user_s8(x, gaddr)  get_user((x), (gaddr), int8_t)
305 
306 /* copy_from_user() and copy_to_user() are usually used to copy data
307  * buffers between the target and host.  These internally perform
308  * locking/unlocking of the memory.
309  */
310 int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
311 int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len);
312 
313 /* Functions for accessing guest memory.  The tget and tput functions
314    read/write single values, byteswapping as necessary.  The lock_user function
315    gets a pointer to a contiguous area of guest memory, but does not perform
316    any byteswapping.  lock_user may return either a pointer to the guest
317    memory, or a temporary buffer.  */
318 
319 /* Lock an area of guest memory into the host.  If copy is true then the
320    host area will have the same contents as the guest.  */
321 void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy);
322 
323 /* Unlock an area of guest memory.  The first LEN bytes must be
324    flushed back to guest memory. host_ptr = NULL is explicitly
325    allowed and does nothing. */
326 #ifndef DEBUG_REMAP
327 static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
328                                ssize_t len)
329 {
330     /* no-op */
331 }
332 #else
333 void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len);
334 #endif
335 
336 /* Return the length of a string in target memory or -TARGET_EFAULT if
337    access error. */
338 ssize_t target_strlen(abi_ulong gaddr);
339 
340 /* Like lock_user but for null terminated strings.  */
341 void *lock_user_string(abi_ulong guest_addr);
342 
343 /* Helper macros for locking/unlocking a target struct.  */
344 #define lock_user_struct(type, host_ptr, guest_addr, copy)	\
345     (host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy))
346 #define unlock_user_struct(host_ptr, guest_addr, copy)		\
347     unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
348 
349 #endif /* QEMU_H */
350