xref: /openbmc/qemu/include/exec/cpu-defs.h (revision 438c78da)
1 /*
2  * common defines for all CPUs
3  *
4  * Copyright (c) 2003 Fabrice Bellard
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18  */
19 #ifndef CPU_DEFS_H
20 #define CPU_DEFS_H
21 
22 #ifndef NEED_CPU_H
23 #error cpu.h included from common code
24 #endif
25 
26 #include "qemu/host-utils.h"
27 #include "qemu/thread.h"
28 #include "qemu/queue.h"
29 #ifdef CONFIG_TCG
30 #include "tcg-target.h"
31 #endif
32 #ifndef CONFIG_USER_ONLY
33 #include "exec/hwaddr.h"
34 #endif
35 #include "exec/memattrs.h"
36 
37 #ifndef TARGET_LONG_BITS
38 #error TARGET_LONG_BITS must be defined before including this header
39 #endif
40 
41 #define TARGET_LONG_SIZE (TARGET_LONG_BITS / 8)
42 
43 /* target_ulong is the type of a virtual address */
44 #if TARGET_LONG_SIZE == 4
45 typedef int32_t target_long;
46 typedef uint32_t target_ulong;
47 #define TARGET_FMT_lx "%08x"
48 #define TARGET_FMT_ld "%d"
49 #define TARGET_FMT_lu "%u"
50 #elif TARGET_LONG_SIZE == 8
51 typedef int64_t target_long;
52 typedef uint64_t target_ulong;
53 #define TARGET_FMT_lx "%016" PRIx64
54 #define TARGET_FMT_ld "%" PRId64
55 #define TARGET_FMT_lu "%" PRIu64
56 #else
57 #error TARGET_LONG_SIZE undefined
58 #endif
59 
60 #if !defined(CONFIG_USER_ONLY) && defined(CONFIG_TCG)
61 /* use a fully associative victim tlb of 8 entries */
62 #define CPU_VTLB_SIZE 8
63 
64 #if HOST_LONG_BITS == 32 && TARGET_LONG_BITS == 32
65 #define CPU_TLB_ENTRY_BITS 4
66 #else
67 #define CPU_TLB_ENTRY_BITS 5
68 #endif
69 
70 /* TCG_TARGET_TLB_DISPLACEMENT_BITS is used in CPU_TLB_BITS to ensure that
71  * the TLB is not unnecessarily small, but still small enough for the
72  * TLB lookup instruction sequence used by the TCG target.
73  *
74  * TCG will have to generate an operand as large as the distance between
75  * env and the tlb_table[NB_MMU_MODES - 1][0].addend.  For simplicity,
76  * the TCG targets just round everything up to the next power of two, and
77  * count bits.  This works because: 1) the size of each TLB is a largish
78  * power of two, 2) and because the limit of the displacement is really close
79  * to a power of two, 3) the offset of tlb_table[0][0] inside env is smaller
80  * than the size of a TLB.
81  *
82  * For example, the maximum displacement 0xFFF0 on PPC and MIPS, but TCG
83  * just says "the displacement is 16 bits".  TCG_TARGET_TLB_DISPLACEMENT_BITS
84  * then ensures that tlb_table at least 0x8000 bytes large ("not unnecessarily
85  * small": 2^15).  The operand then will come up smaller than 0xFFF0 without
86  * any particular care, because the TLB for a single MMU mode is larger than
87  * 0x10000-0xFFF0=16 bytes.  In the end, the maximum value of the operand
88  * could be something like 0xC000 (the offset of the last TLB table) plus
89  * 0x18 (the offset of the addend field in each TLB entry) plus the offset
90  * of tlb_table inside env (which is non-trivial but not huge).
91  */
92 #define CPU_TLB_BITS                                             \
93     MIN(8,                                                       \
94         TCG_TARGET_TLB_DISPLACEMENT_BITS - CPU_TLB_ENTRY_BITS -  \
95         (NB_MMU_MODES <= 1 ? 0 :                                 \
96          NB_MMU_MODES <= 2 ? 1 :                                 \
97          NB_MMU_MODES <= 4 ? 2 :                                 \
98          NB_MMU_MODES <= 8 ? 3 : 4))
99 
100 #define CPU_TLB_SIZE (1 << CPU_TLB_BITS)
101 
102 typedef struct CPUTLBEntry {
103     /* bit TARGET_LONG_BITS to TARGET_PAGE_BITS : virtual address
104        bit TARGET_PAGE_BITS-1..4  : Nonzero for accesses that should not
105                                     go directly to ram.
106        bit 3                      : indicates that the entry is invalid
107        bit 2..0                   : zero
108     */
109     union {
110         struct {
111             target_ulong addr_read;
112             target_ulong addr_write;
113             target_ulong addr_code;
114             /* Addend to virtual address to get host address.  IO accesses
115                use the corresponding iotlb value.  */
116             uintptr_t addend;
117         };
118         /* padding to get a power of two size */
119         uint8_t dummy[1 << CPU_TLB_ENTRY_BITS];
120     };
121 } CPUTLBEntry;
122 
123 QEMU_BUILD_BUG_ON(sizeof(CPUTLBEntry) != (1 << CPU_TLB_ENTRY_BITS));
124 
125 /* The IOTLB is not accessed directly inline by generated TCG code,
126  * so the CPUIOTLBEntry layout is not as critical as that of the
127  * CPUTLBEntry. (This is also why we don't want to combine the two
128  * structs into one.)
129  */
130 typedef struct CPUIOTLBEntry {
131     /*
132      * @addr contains:
133      *  - in the lower TARGET_PAGE_BITS, a physical section number
134      *  - with the lower TARGET_PAGE_BITS masked off, an offset which
135      *    must be added to the virtual address to obtain:
136      *     + the ram_addr_t of the target RAM (if the physical section
137      *       number is PHYS_SECTION_NOTDIRTY or PHYS_SECTION_ROM)
138      *     + the offset within the target MemoryRegion (otherwise)
139      */
140     hwaddr addr;
141     MemTxAttrs attrs;
142 } CPUIOTLBEntry;
143 
144 typedef struct CPUTLBDesc {
145     /*
146      * Describe a region covering all of the large pages allocated
147      * into the tlb.  When any page within this region is flushed,
148      * we must flush the entire tlb.  The region is matched if
149      * (addr & large_page_mask) == large_page_addr.
150      */
151     target_ulong large_page_addr;
152     target_ulong large_page_mask;
153     /* The next index to use in the tlb victim table.  */
154     size_t vindex;
155 } CPUTLBDesc;
156 
157 /*
158  * Data elements that are shared between all MMU modes.
159  */
160 typedef struct CPUTLBCommon {
161     /* Serialize updates to tlb_table and tlb_v_table, and others as noted. */
162     QemuSpin lock;
163     /*
164      * Within dirty, for each bit N, modifications have been made to
165      * mmu_idx N since the last time that mmu_idx was flushed.
166      * Protected by tlb_c.lock.
167      */
168     uint16_t dirty;
169     /*
170      * Statistics.  These are not lock protected, but are read and
171      * written atomically.  This allows the monitor to print a snapshot
172      * of the stats without interfering with the cpu.
173      */
174     size_t full_flush_count;
175     size_t part_flush_count;
176     size_t elide_flush_count;
177 } CPUTLBCommon;
178 
179 /*
180  * The meaning of each of the MMU modes is defined in the target code.
181  * Note that NB_MMU_MODES is not yet defined; we can only reference it
182  * within preprocessor defines that will be expanded later.
183  */
184 #define CPU_COMMON_TLB \
185     CPUTLBCommon tlb_c;                                                 \
186     CPUTLBDesc tlb_d[NB_MMU_MODES];                                     \
187     CPUTLBEntry tlb_table[NB_MMU_MODES][CPU_TLB_SIZE];                  \
188     CPUTLBEntry tlb_v_table[NB_MMU_MODES][CPU_VTLB_SIZE];               \
189     CPUIOTLBEntry iotlb[NB_MMU_MODES][CPU_TLB_SIZE];                    \
190     CPUIOTLBEntry iotlb_v[NB_MMU_MODES][CPU_VTLB_SIZE];
191 
192 #else
193 
194 #define CPU_COMMON_TLB
195 
196 #endif
197 
198 
199 #define CPU_COMMON                                                      \
200     /* soft mmu support */                                              \
201     CPU_COMMON_TLB                                                      \
202 
203 #endif
204