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Implement SMP simulation for semu
In this commit, semu is able to simulate SMP architecture running on the Linux kernel. Before simulating SMP on SEMU, you need to enable SMP support in the Linux kernel. Please cross-compile the Linux kernel with the configuration file located at configs/linux.config. After recompiling the Linux kernel with SMP support enabled, simply execute `make check SMP=1` to simulate a quad-hart RISC-V core. ``` processor : 0 hart : 0 isa : rv32ima_zicntr_zicsr_zifencei_zihpm mmu : sv32 mvendorid : 0x12345678 marchid : 0x80000001 mimpid : 0x1 hart isa : rv32ima_zicntr_zicsr_zifencei_zihpm processor : 1 hart : 1 isa : rv32ima_zicntr_zicsr_zifencei_zihpm mmu : sv32 mvendorid : 0x12345678 marchid : 0x80000001 mimpid : 0x1 hart isa : rv32ima_zicntr_zicsr_zifencei_zihpm processor : 2 hart : 2 isa : rv32ima_zicntr_zicsr_zifencei_zihpm mmu : sv32 mvendorid : 0x12345678 marchid : 0x80000001 mimpid : 0x1 hart isa : rv32ima_zicntr_zicsr_zifencei_zihpm processor : 3 hart : 3 isa : rv32ima_zicntr_zicsr_zifencei_zihpm mmu : sv32 mvendorid : 0x12345678 marchid : 0x80000001 mimpid : 0x1 hart isa : rv32ima_zicntr_zicsr_zifencei_zihpm ```
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15 files changed

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-424
lines changed

15 files changed

+956
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lines changed

‎Makefile‎

Lines changed: 13 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -45,6 +45,7 @@ OBJS := \
4545
plic.o \
4646
uart.o \
4747
main.o \
48+
clint.o \
4849
$(OBJS_EXTRA)
4950

5051
deps := $(OBJS:%.o=.%.o.d)
@@ -73,16 +74,27 @@ minimal.dtb: minimal.dts
7374
$(subst ^,$S,$(filter -D^SEMU_FEATURE_%, $(subst -D$(S)SEMU_FEATURE,-D^SEMU_FEATURE,$(CFLAGS)))) $< \
7475
| $(DTC) - > $@
7576

77+
minimal-quad.dtb: minimal-quad.dts
78+
$(VECHO) " DTC\t$@\n"
79+
$(Q)$(CC) -nostdinc -E -P -x assembler-with-cpp -undef \
80+
$(subst ^,$S,$(filter -D^SEMU_FEATURE_%, $(subst -D$(S)SEMU_FEATURE,-D^SEMU_FEATURE,$(CFLAGS)))) $< \
81+
| $(DTC) - > $@
82+
7683
# Rules for downloading prebuilt Linux kernel image
7784
include mk/external.mk
7885

7986
ext4.img:
8087
$(Q)dd if=/dev/zero of=$@ bs=4k count=600
8188
$(Q)$(MKFS_EXT4) -F $@
8289

83-
check: $(BIN) minimal.dtb $(KERNEL_DATA) $(INITRD_DATA) $(DISKIMG_FILE)
90+
SMP ?= 0
91+
check: $(BIN) minimal.dtb minimal-quad.dtb $(KERNEL_DATA) $(INITRD_DATA) $(DISKIMG_FILE)
8492
@$(call notice, Ready to launch Linux kernel. Please be patient.)
93+
ifeq ($(SMP),1)
94+
$(Q)./$(BIN) -k $(KERNEL_DATA) -b minimal-quad.dtb -i $(INITRD_DATA) $(OPTS)
95+
else
8596
$(Q)./$(BIN) -k $(KERNEL_DATA) -b minimal.dtb -i $(INITRD_DATA) $(OPTS)
97+
endif
8698

8799
build-image:
88100
scripts/build-image.sh

‎clint.c‎

Lines changed: 87 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,87 @@
1+
#include <stdint.h>
2+
#include "device.h"
3+
#include "riscv.h"
4+
#include "riscv_private.h"
5+
6+
void clint_update_interrupts(hart_t *hart, clint_state_t *clint)
7+
{
8+
if (clint->mtime > clint->mtimecmp[hart->mhartid])
9+
hart->sip |= RV_INT_STI_BIT;
10+
else
11+
hart->sip &= ~RV_INT_STI_BIT;
12+
13+
if (clint->msip[hart->mhartid]) {
14+
hart->sip |= RV_INT_SSI_BIT;
15+
} else
16+
hart->sip &= ~RV_INT_SSI_BIT;
17+
}
18+
19+
static bool clint_reg_read(clint_state_t *clint, uint32_t addr, uint32_t *value)
20+
{
21+
if (addr < 0x4000) {
22+
*value = clint->msip[addr >> 2];
23+
return true;
24+
} else if (addr < 0xBFF8) {
25+
addr -= 0x4000;
26+
*value =
27+
(uint32_t) (clint->mtimecmp[addr >> 3] >> (32 & -!!(addr & 0b100)));
28+
return true;
29+
} else if (addr < 0xBFFF) {
30+
*value = clint->mtime >> (32 & -!!(addr & 0b100));
31+
return true;
32+
}
33+
return false;
34+
}
35+
36+
static bool clint_reg_write(clint_state_t *clint, uint32_t addr, uint32_t value)
37+
{
38+
if (addr < 0x4000) {
39+
clint->msip[addr >> 2] = value;
40+
return true;
41+
} else if (addr < 0xBFF8) {
42+
addr -= 0x4000;
43+
int32_t upper = clint->mtimecmp[addr >> 3] >> 32;
44+
int32_t lowwer = clint->mtimecmp[addr >> 3];
45+
if (addr & 0b100)
46+
upper = value;
47+
else
48+
lowwer = value;
49+
50+
clint->mtimecmp[addr >> 3] = (uint64_t) upper << 32 | lowwer;
51+
return true;
52+
} else if (addr < 0xBFFF) {
53+
int32_t upper = clint->mtime >> 32;
54+
int32_t lowwer = clint->mtime;
55+
if (addr & 0b100)
56+
upper = value;
57+
else
58+
lowwer = value;
59+
60+
clint->mtime = (uint64_t) upper << 32 | lowwer;
61+
return true;
62+
}
63+
return false;
64+
}
65+
66+
void clint_read(hart_t *hart,
67+
clint_state_t *clint,
68+
uint32_t addr,
69+
uint8_t width,
70+
uint32_t *value)
71+
{
72+
if (!clint_reg_read(clint, addr, value))
73+
hart_set_exception(hart, RV_EXC_LOAD_FAULT, hart->exc_val);
74+
*value = (*value) >> (RV_MEM_SW - width);
75+
return;
76+
}
77+
78+
void clint_write(hart_t *hart,
79+
clint_state_t *clint,
80+
uint32_t addr,
81+
uint8_t width,
82+
uint32_t value)
83+
{
84+
if (!clint_reg_write(clint, addr, value >> (RV_MEM_SW - width)))
85+
hart_set_exception(hart, RV_EXC_STORE_FAULT, hart->exc_val);
86+
return;
87+
}

‎configs/linux.config‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -223,7 +223,7 @@ CONFIG_ARCH_RV32I=y
223223
# CONFIG_CMODEL_MEDLOW is not set
224224
CONFIG_CMODEL_MEDANY=y
225225
CONFIG_MODULE_SECTIONS=y
226-
# CONFIG_SMP is not set
226+
CONFIG_SMP=y
227227
CONFIG_TUNE_GENERIC=y
228228
# CONFIG_RISCV_ISA_C is not set
229229
CONFIG_TOOLCHAIN_HAS_ZICBOM=y

‎device.h‎

Lines changed: 33 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -9,13 +9,13 @@
99
#define DTB_SIZE (1 * 1024 * 1024)
1010
#define INITRD_SIZE (8 * 1024 * 1024)
1111

12-
void ram_read(vm_t *core,
12+
void ram_read(hart_t *core,
1313
uint32_t *mem,
1414
const uint32_t addr,
1515
const uint8_t width,
1616
uint32_t *value);
1717

18-
void ram_write(vm_t *core,
18+
void ram_write(hart_t *core,
1919
uint32_t *mem,
2020
const uint32_t addr,
2121
const uint8_t width,
@@ -25,19 +25,19 @@ void ram_write(vm_t *core,
2525

2626
typedef struct {
2727
uint32_t masked;
28-
uint32_t ip;
29-
uint32_t ie;
28+
uint32_t ip; /* support 32 interrupt sources only */
29+
uint32_t ie[32]; /* support 32 sources to 32 contexts only */
3030
/* state of input interrupt lines (level-triggered), set by environment */
3131
uint32_t active;
3232
} plic_state_t;
3333

34-
void plic_update_interrupts(vm_t *core, plic_state_t *plic);
35-
void plic_read(vm_t *core,
34+
void plic_update_interrupts(vm_t *vm, plic_state_t *plic);
35+
void plic_read(hart_t *core,
3636
plic_state_t *plic,
3737
uint32_t addr,
3838
uint8_t width,
3939
uint32_t *value);
40-
void plic_write(vm_t *core,
40+
void plic_write(hart_t *core,
4141
plic_state_t *plic,
4242
uint32_t addr,
4343
uint8_t width,
@@ -60,12 +60,12 @@ typedef struct {
6060
} u8250_state_t;
6161

6262
void u8250_update_interrupts(u8250_state_t *uart);
63-
void u8250_read(vm_t *core,
63+
void u8250_read(hart_t *core,
6464
u8250_state_t *uart,
6565
uint32_t addr,
6666
uint8_t width,
6767
uint32_t *value);
68-
void u8250_write(vm_t *core,
68+
void u8250_write(hart_t *core,
6969
u8250_state_t *uart,
7070
uint32_t addr,
7171
uint8_t width,
@@ -107,12 +107,12 @@ typedef struct {
107107
void *priv;
108108
} virtio_net_state_t;
109109

110-
void virtio_net_read(vm_t *core,
110+
void virtio_net_read(hart_t *core,
111111
virtio_net_state_t *vnet,
112112
uint32_t addr,
113113
uint8_t width,
114114
uint32_t *value);
115-
void virtio_net_write(vm_t *core,
115+
void virtio_net_write(hart_t *core,
116116
virtio_net_state_t *vnet,
117117
uint32_t addr,
118118
uint8_t width,
@@ -156,13 +156,13 @@ typedef struct {
156156
void *priv;
157157
} virtio_blk_state_t;
158158

159-
void virtio_blk_read(vm_t *vm,
159+
void virtio_blk_read(hart_t *hart,
160160
virtio_blk_state_t *vblk,
161161
uint32_t addr,
162162
uint8_t width,
163163
uint32_t *value);
164164

165-
void virtio_blk_write(vm_t *vm,
165+
void virtio_blk_write(hart_t *hart,
166166
virtio_blk_state_t *vblk,
167167
uint32_t addr,
168168
uint8_t width,
@@ -171,6 +171,25 @@ void virtio_blk_write(vm_t *vm,
171171
uint32_t *virtio_blk_init(virtio_blk_state_t *vblk, char *disk_file);
172172
#endif /* SEMU_HAS(VIRTIOBLK) */
173173

174+
/* clint */
175+
typedef struct {
176+
uint32_t msip[4096];
177+
uint64_t mtimecmp[4095];
178+
uint64_t mtime;
179+
} clint_state_t;
180+
181+
void clint_update_interrupts(hart_t *hart, clint_state_t *clint);
182+
void clint_read(hart_t *hart,
183+
clint_state_t *clint,
184+
uint32_t addr,
185+
uint8_t width,
186+
uint32_t *value);
187+
void clint_write(hart_t *hart,
188+
clint_state_t *clint,
189+
uint32_t addr,
190+
uint8_t width,
191+
uint32_t value);
192+
174193
/* memory mapping */
175194

176195
typedef struct {
@@ -185,5 +204,5 @@ typedef struct {
185204
#if SEMU_HAS(VIRTIOBLK)
186205
virtio_blk_state_t vblk;
187206
#endif
188-
uint64_t timer;
207+
clint_state_t clint;
189208
} emu_state_t;

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