diff options
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/entry.S | 28 | ||||
| -rw-r--r-- | sys/kern/init.c | 34 | ||||
| -rw-r--r-- | sys/kern/printf.c | 18 | ||||
| -rw-r--r-- | sys/kern/spinlock.c | 33 |
4 files changed, 92 insertions, 21 deletions
diff --git a/sys/kern/entry.S b/sys/kern/entry.S index 03ff76c..9bf72ea 100644 --- a/sys/kern/entry.S +++ b/sys/kern/entry.S @@ -1,8 +1,14 @@ .section ".text.init" +// entrypoint for boot hart(s). a0: hartid, a1: *fdt .globl _start -_start: - /* disable interrupts and poging */ + + +// entrypoint for other harts. a0: hartid, a1: unused for now +.global _mpentry + +_start: + /* disable interrupts and paging */ csrw satp, zero csrw sie, zero csrw sip, zero @@ -12,7 +18,9 @@ _start: la gp, __global_pointer$ .option pop - /* setup stack */ + /* setup stack. + * stack grows toward lower address so sp will mark end of frame. + */ addi t0, a0, 1 li t1, PAGE_SIZE la sp, __stack_start @@ -22,11 +30,11 @@ _start: /* setup thread pointer */ mv tp, a0 - /* the label _boot_hart is shared between threads. only one hart will branch before it is no longer 0 */ + /* the label _boot_hart is shared between threads. after the first atomic swap, all other harts will branch to mpentry */ li a2, 1 lla a3, _boot_hart amoswap.w a3, a2, (a3) - bnez a3, 2f + bnez a3, _mpentry /* clear the bss section */ la a2, __bss_start @@ -39,9 +47,16 @@ _start: call init j _spin +_mpentry: + /* satp = 0, sstatus.sie = 0, a0 = hartid, a1 = opaque */ + + call mpinit + /* shouldn't reach this point */ + j _spin + _spin: wfi - j _spin + j _spin .section ".data" _boot_hart: @@ -51,3 +66,4 @@ _boot_hart: /* linker imports */ .globl HEAP_START HEAP_START: .dword __heap_start + diff --git a/sys/kern/init.c b/sys/kern/init.c index 208df6d..a58d3bc 100644 --- a/sys/kern/init.c +++ b/sys/kern/init.c @@ -1,12 +1,17 @@ #include <fdt.h> #include <mm/kalloc.h> #include <printf.h> -#include <stdint.h> #include <spinlock.h> +#include <sbi.h> +#include <stdint.h> extern uint64_t HEAP_START; -void +#define HLT()\ + for (;;)\ + asm("wfi") + +void init(unsigned long hartid, struct fdt_header *fdt) { @@ -22,14 +27,25 @@ init(unsigned long hartid, struct fdt_header *fdt) kalloc_init(); printf("done!\n"); // printf("printing free pages:\n"); - //walkfree(); + ///walkfree(); + printf("bringing up other harts...\n"); + // todo: detect harts from device tree can also be used for more conservative stack allocation + for (int i = 0; i < NPROC; ++i) { + if (i == hartid) { + printf("skipping hart #%d\n", i); + continue; + } + printf("starting hart #%d\n", i); + struct sbiret r = _start_hart(i, (unsigned long)LOAD_ADDR); + if (r.err != SBI_SUCCESS) + printf("ERROR"); + } } -/* non boot harts enter here */ -void -mpinit(unsigned long hartid, struct fdt_header *fdt) +void +mpinit(unsigned long hartid) { - unsigned char *uart = (unsigned char*)0x10000000; - *uart = hartid + '0'; - *(uart + 1) = '\n'; + printf("mpinit: %d", hartid); + HLT(); } + diff --git a/sys/kern/printf.c b/sys/kern/printf.c index dfd0657..89add9e 100644 --- a/sys/kern/printf.c +++ b/sys/kern/printf.c @@ -1,10 +1,14 @@ #include <printf.h> #include <stdint.h> +#include <spinlock.h> #include <sbi.h> #include <stdarg.h> static char digits[] = "0123456789abcdef"; +struct spinlock mutex; +int locked = 0; + int puts(const char *str) { @@ -52,9 +56,13 @@ void printf(const char *fmt, ...) { va_list ap; - int i, c; + int i, c, _locked; char *s; + _locked = locked; + if (_locked) + acquire(&mutex); + va_start(ap, fmt); for (i = 0; (c = fmt[i] & 0xff) != 0; i++) { @@ -82,4 +90,12 @@ printf(const char *fmt, ...) break; } } + if (_locked) + release(&mutex); +} + +void printf_init(void) +{ + initlock(&mutex); + locked = 1; } diff --git a/sys/kern/spinlock.c b/sys/kern/spinlock.c index a35b8ce..ade270f 100644 --- a/sys/kern/spinlock.c +++ b/sys/kern/spinlock.c @@ -1,15 +1,38 @@ +#include <asm.h> #include <spinlock.h> void -init_locklock(struct spinlock *l, const char *_name) +initlock(struct spinlock *l) { - l->name = _name; l->locked = 0; - l->cpu = 0; } void -acquire_lock(struct spinlock *l) +acquire(struct spinlock *l) { - asm volatile("csrr sie, zero"); + sie_disable(); + + if (l->locked) + return; + + while (__sync_lock_test_and_set(&l->locked, 1)) + ; + + __sync_synchronize(); +} + +void +release(struct spinlock *l) +{ + sie_disable(); // avoid deadlock + + if (l->locked) + return; // interrupts are still disabled, what to do here? + + /* fence */ + __sync_synchronize(); + + __sync_lock_release(&l->locked); + + sie_enable(); } |