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/* This file is allowed to be undocumented as it is only temporarily in this
* tree. At some point in the (hopefully) near future, I intend to move the
* kernel code and initrd generation stuff into separate repositories, to make
* things easier for myself. For now though, this is good enough.
*/
/* compile with riscv64-unknown-elf-gcc -ffreestanding -nostdlib */
/* create initrd with echo init | cpio -H newc -o > initrd */
#include <stdint.h>
#include "../../../include/apos/syscalls.h"
#define ecall() do { asm volatile ("ecall" \
: \
: \
: "a0", "a1", "a2", "a3", "a4", "a5", \
"memory"); \
} while (0)
static void sys_noop()
{
long register a0 asm ("a0") = SYS_NOOP;
ecall();
}
static void sys_putch(char c)
{
long register a0 asm ("a0") = SYS_PUTCH;
long register a1 asm ("a1") = c;
ecall();
}
static uint64_t sys_timebase()
{
long register a0 asm ("a0") = SYS_TIMEBASE;
long register a1 asm ("a1") = 0;
long register a2 asm ("a2") = 0;
ecall();
#if defined(_LP64)
return a1;
#else
uint64_t t = a1;
t <<= 32;
return t + a2;
#endif
}
static uint64_t sys_ticks()
{
long register a0 asm ("a0") = SYS_TICKS;
long register a1 asm ("a1") = 0;
long register a2 asm ("a2") = 0;
ecall();
#if defined(_LP64)
return a1;
#else
uint64_t t = a1;
t <<= 32;
return t + a2;
#endif
}
static void puts(const char *s)
{
while (*s)
sys_putch(*s++);
}
static void _print_number(uint64_t v)
{
if (v == 0)
return;
_print_number(v / 10);
sys_putch((v % 10) + '0');
}
static void print_number(uint64_t v)
{
if (v == 0) {
sys_putch('0');
return;
}
_print_number(v);
}
static void print_value(const char *s, uint64_t v)
{
puts(s);
puts(": ");
print_number(v);
sys_putch('\n');
}
static uint64_t sys_fork()
{
long register a0 asm ("a0") = SYS_FORK;
long register a1 asm ("a1") = 0;
ecall();
if (a0 != 0)
print_value("fork() failed with error ", a0);
return a1;
}
static uint64_t sys_swap(long tid)
{
long register a0 asm ("a0") = SYS_SWAP;
long register a1 asm ("a1") = tid;
ecall();
if (a0 != 0)
print_value("swap() failed with error ", a0);
return a0;
}
static void sys_ipc_server(void *f)
{
long register a0 asm ("a0") = SYS_IPC_SERVER;
long register a1 asm ("a1") = (long)f;
ecall();
if (a0 != 0)
print_value("ipc_server() failed with error ", a0);
}
static uint64_t sys_ipc_req(long tid, long *d0, long *d1, long *d2, long *d3)
{
long register a0 asm ("a0") = SYS_IPC_REQ;
long register a1 asm ("a1") = tid;
long register a2 asm ("a2") = *d0;
long register a3 asm ("a3") = *d1;
long register a4 asm ("a4") = *d2;
long register a5 asm ("a5") = *d3;
ecall();
if (a0)
print_value("ipc_req() failed with error ", a0);
*d0 = a2;
*d1 = a3;
*d2 = a4;
*d3 = a5;
return a0;
}
static void sys_ipc_resp(long d0, long d1, long d2, long d3)
{
long register a0 asm ("a0") = SYS_IPC_RESP;
long register a1 asm ("a1") = d0;
long register a2 asm ("a2") = d1;
long register a3 asm ("a3") = d2;
long register a4 asm ("a4") = d3;
ecall();
}
static void sys_poweroff(long type)
{
long register a0 asm ("a0") = SYS_POWEROFF;
long register a1 asm ("a1") = type;
ecall();
}
void callback(long status, long tid, long d0, long d1, long d2, long d3)
{
sys_ipc_resp(d0, d1, d2, d3);
}
#define CSR_TIME "0xc01"
#define csr_read(csr, \
res) __asm__ volatile ("csrr %0, " csr : "=r" (res) :: "memory")
void _start()
{
sys_noop();
puts("Hello, world!\n");
uint64_t second = sys_timebase();
print_value("Timebase", second);
uint64_t n = 0, i, start;
start = i = sys_ticks();
print_value("Start ticks", start);
while (i < start + second) {
i = sys_ticks();
n++;
}
print_value("End ticks", i);
print_value("Syscalls per second", n);
puts("Setting callback...");
sys_ipc_server(callback);
puts("Starting fork():\n");
long pid = sys_fork();
if (pid != 0) {
print_value("Child pid", pid);
puts("Swapping to child...\n");
while(1) sys_swap(pid);
}
puts("Hello from child!\n");
puts("Doing swaps...\n");
csr_read(CSR_TIME, i);
start = i; n = 0;
while (i < start + second) {
sys_swap(1);
csr_read(CSR_TIME, i);
n++;
}
print_value("Swaps (both ways) per second", n);
puts("Doing ipc requests...\n");
long d0, d1, d2, d3;
csr_read(CSR_TIME, i);
start = i; n = 0;
while (i < start + second) {
sys_ipc_req(1, &d0, &d1, &d2, &d3);
csr_read(CSR_TIME, i);
n++;
}
print_value("IPC requests per second", n);
sys_poweroff(0);
}
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