diff options
| -rw-r--r-- | .gitignore | 1 | ||||
| -rw-r--r-- | bsp/env/start.S | 51 | ||||
| -rw-r--r-- | software/smp/Makefile | 6 | ||||
| -rw-r--r-- | software/smp/atomic.h | 29 | ||||
| -rw-r--r-- | software/smp/smp.c | 40 |
5 files changed, 126 insertions, 1 deletions
@@ -13,3 +13,4 @@ software/hello/hello software/led_fade/led_fade software/local_interrupts/local_interrupts software/performance_counters/performance_counters +software/smp/smp diff --git a/bsp/env/start.S b/bsp/env/start.S index e86105b..4e9f665 100644 --- a/bsp/env/start.S +++ b/bsp/env/start.S @@ -1,18 +1,27 @@ // See LICENSE for license details. +#include <sifive/smp.h> -// See LICENSE for license details. +/* This is defined in sifive/platform.h, but that can't be included from + * assembly. */ +#define CLINT_CTRL_ADDR 0x02000000 .section .init .globl _start .type _start,@function _start: + .cfi_startproc + .cfi_undefined ra .option push .option norelax la gp, __global_pointer$ .option pop la sp, _sp +#if defined(ENABLE_SMP) + smp_pause(t0, t1) +#endif + /* Load data section */ la a0, _data_lma la a1, _data @@ -52,11 +61,51 @@ _start: 1: #endif +#if defined(ENABLE_SMP) + smp_resume(t0, t1) + + csrr a0, mhartid + bnez a0, 2f +#endif + + auipc ra, 0 + addi sp, sp, -16 +#if __riscv_xlen == 32 + sw ra, 8(sp) +#else + sd ra, 8(sp) +#endif + /* argc = argv = 0 */ li a0, 0 li a1, 0 call main tail exit +1: + j 1b + +#if defined(ENABLE_SMP) +2: + la t0, trap_entry + csrw mtvec, t0 + + csrr a0, mhartid + la t1, _sp + slli t0, a0, 10 + sub sp, t1, t0 + + auipc ra, 0 + addi sp, sp, -16 +#if __riscv_xlen == 32 + sw ra, 8(sp) +#else + sd ra, 8(sp) +#endif + + call secondary_main + tail exit 1: j 1b +#endif + .cfi_endproc diff --git a/software/smp/Makefile b/software/smp/Makefile new file mode 100644 index 0000000..4131ffc --- /dev/null +++ b/software/smp/Makefile @@ -0,0 +1,6 @@ +TARGET = smp +C_SRCS += smp.c +CFLAGS += -O2 -fno-builtin-printf -DENABLE_SMP + +BSP_BASE = ../../bsp +include $(BSP_BASE)/env/common.mk diff --git a/software/smp/atomic.h b/software/smp/atomic.h new file mode 100644 index 0000000..074c6a2 --- /dev/null +++ b/software/smp/atomic.h @@ -0,0 +1,29 @@ +#ifndef SIFIVE_ATOMIC_H +#define SIFIVE_ATOMIC_H + +#define ATOMIC_INIT(x) \ + { \ + .counter = (x), \ + } + +typedef struct { + int counter; +} atomic_t; + +static inline int atomic_xchg(atomic_t *v, int n) +{ + register int c; + + __asm__ __volatile__ ( + "amoswap.w.aqrl %0, %2, %1" + : "=r" (c), "+A" (v->counter) + : "r" (n)); + return c; +} + +static inline void mb(void) +{ + __asm__ __volatile__ ("fence"); +} + +#endif diff --git a/software/smp/smp.c b/software/smp/smp.c new file mode 100644 index 0000000..36c9db9 --- /dev/null +++ b/software/smp/smp.c @@ -0,0 +1,40 @@ +#include <stdio.h> +#include <unistd.h> +#include "atomic.h" +void write_hex(int, unsigned long); + +atomic_t tty_lock = ATOMIC_INIT(0); + +void get_lock(atomic_t *lock) +{ + while (atomic_xchg(lock, 1) == 1); + mb(); +} + +void put_lock(atomic_t *lock) +{ + mb(); + atomic_xchg(lock, 0); +} + +int secondary_main(int hartid) +{ + volatile int counter; + + while (1) { + get_lock(&tty_lock); + write(1, "hello world from hart ", 22); + char s[] = {'0', '\n', '\0'}; + s[0] += hartid; + write(1, s, 2); + put_lock(&tty_lock); + + for (counter = 0; counter < 10000 + 100*hartid; ++counter) + mb(); + } +} + +int main() +{ + return secondary_main(0); +} |