QTechOS/kernel/kernel.cpp

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#include <stdarg.h>
#include <inttypes.h>
#include <dtb/dtb.h>
#include <opensbi/opensbi.h>
#include <opensbi/extensions/legacy.h>
#include <opensbi/extensions/base.h>
#include <opensbi/extensions/timer.h>
#include <opensbi/extensions/ipi.h>
#include <opensbi/extensions/rfence.h>
#include <opensbi/extensions/hsm.h>
#include <opensbi/extensions/srst.h>
#include <opensbi/extensions/pmu.h>
#define read_csr(csr) \
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({ \
unsigned long __v; \
asm volatile ("csrr %0, " csr : "=r"(__v) : : "memory");\
__v;\
})
#define write_csr(csr, v) \
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({ \
unsigned long __v = (v); \
asm volatile ("csrw " csr ", %0" : : "r"(__v) : "memory");\
})
#define set_csr_bits(csr, bits) \
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({ \
unsigned long __v = (bits); \
asm volatile ("csrs " csr ", %0" : : "r"(__v) : "memory");\
})
#define clear_csr_bits(csr, bits) \
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({ \
unsigned long __v = (bits); \
asm volatile ("csrc " csr ", %0" : : "r"(__v) : "memory");\
})
typedef unsigned long sbi_word;
void fmt(const char *f, ...) {
namespace legacy = drivers::opensbi::legacy;
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va_list va;
va_start(va, f);
while(*f) {
if(*f != '{') {
legacy::console_putchar(*(f++));
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continue;
}
f++;
while(*f != '}') {
if(!(*f))
return;
f++;
}
f++;
unsigned long v = va_arg(va, unsigned long);
for(int i = 0; i < 16; ++i) {
const char *digits = "0123456789abcdef";
int d = (v >> (60 - i * 4)) & 0xF;
legacy::console_putchar(digits[d]);
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}
}
va_end(va);
}
enum {
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pte_valid = 1 << 0,
pte_r = 1 << 1,
pte_w = 1 << 2,
pte_x = 1 << 3,
pte_user = 1 << 4,
pte_access = 1 << 6,
pte_dirty = 1 << 7,
};
enum {
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pte_ppn_shift = 10
};
struct pt_t {
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unsigned long ptes[512];
} __attribute__((aligned(4096)));
enum {
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satp_sv48 = 9UL << 60
};
const char *exception_strings[] = {
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"instruction misaligned",
"instruction access fault",
"illegal instruction",
"breakpoint",
"load misaligned",
"load access fault",
"store misaligned",
"store access fault",
"u-mode ecall",
"s-mode ecall",
"reserved (10)",
"reserved (11)",
"instruction page fault",
"load page fault",
"reserved (14)",
"store page fault",
};
enum {
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sie_s_software = (1 << 1),
sie_s_timer = (1 << 5)
};
enum {
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sstatus_sie = (1 << 1)
};
void cli() {
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clear_csr_bits("sstatus", sstatus_sie);
}
void sti() {
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set_csr_bits("sstatus", sstatus_sie);
}
typedef struct {
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void *sp;
} continuation_t;
struct task_t;
struct isr_frame_t {
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task_t *task;
isr_frame_t *next;
unsigned long ra; // Offset 0x10.
unsigned long a[8]; // Offset 0x18.
unsigned long t[7]; // Offset 0x58.
unsigned long s1; // Offset 0x90.
unsigned long sstatus; // Offset 0x98.
unsigned long sepc; // Offset 0xA0.
};
enum {
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kernel_stack_size = 0x10000
};
struct task_t {
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continuation_t cont;
isr_frame_t isr_frames[2];
isr_frame_t *next_isr;
char kernel_stack[kernel_stack_size];
};
task_t task1;
task_t task2;
task_t *current_task;
continuation_t prepare_stack(void *s_top, void (*mainfn)(continuation_t)) {
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void *sp = (void *)((uintptr_t)s_top - 0x78);
*((uint64_t *)((uintptr_t)sp + 0x70)) = (uint64_t)mainfn;
return (continuation_t){.sp = sp};
}
extern "C" void save_stack(void (*f)(void *, continuation_t), void *ctx);
extern "C" void restore_stack(continuation_t c);
void create_task(task_t *task, void (*mainfn)(continuation_t)) {
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task->isr_frames[0].task = task;
task->isr_frames[1].task = task;
task->isr_frames[0].next = &task->isr_frames[1];
task->isr_frames[1].next = 0;
task->next_isr = &task->isr_frames[0];
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task->cont = prepare_stack((void *)(task->kernel_stack + kernel_stack_size), mainfn);
}
void switch_task(void *ctx, continuation_t c) {
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task_t *task = (task_t *)ctx;
if(task) {
task->next_isr = (isr_frame_t *)read_csr("sscratch");
task->cont = c;
}
task_t *next;
if(task == &task1) {
next = &task2;
}else{
next = &task1;
}
current_task = next;
write_csr("sscratch", (unsigned long)next->next_isr);
restore_stack(next->cont);
}
extern "C" void isr();
extern "C" void handle_isr(isr_frame_t *frame) {
namespace legacy = drivers::opensbi::legacy;
namespace timer = drivers::opensbi::timer;
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unsigned long cause = read_csr("scause");
unsigned long code = cause & ~(1UL << 63);
if(cause & (1UL << 63)) {
if(code == 1) {
fmt("it's an IPI\n");
clear_csr_bits("sip", sie_s_software);
}else if(code == 5) { // Timer interrupt.
//clear_csr_bits("sie", sie_s_timer);
unsigned long time = read_csr("time");
//drivers::opensbi::ecall(0x54494D45, 0, time + 100000);
timer::set_timer(time + 10000000);
//set_timer(time + 100000);
//save_stack(switch_task, current_task);
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}else{
fmt("it's an unhandled interrupt, code: {}\n", code);
}
}else{
if(code == 8) { // Syscall.
legacy::console_putchar(frame->a[0]);
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}else{
unsigned long sepc = read_csr("sepc");
fmt("it's an exception at {}\n", sepc);
const char *s = exception_strings[cause];
while(*s)
legacy::console_putchar(*(s++));
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while(1)
;
}
}
}
extern "C" void isr_frame_overflow() {
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fmt("isr frame overflow\n");
while(1)
;
}
pt_t pml4;
extern "C" void enter_umode(void *entry);
void syscall(int n, unsigned long arg0) {
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register sbi_word rArg0 asm("a0") = arg0;
register sbi_word rN asm("a7") = n;
asm volatile("ecall" : "+r"(rArg0) : "r"(rN) : "memory");
if(rArg0)
__builtin_trap();
}
void task1_umode() {
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while(1)
syscall(0, '!');
}
void task1_main(continuation_t c) {
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fmt("hello from task1\n");
sti();
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//syscall(0, '!');
//enter_umode((void *)task1_umode);
}
void task2_main(continuation_t c) {
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fmt("hello from task2\n");
sti();
//while(1)
//fmt(".");
}
isr_frame_t global_isr_frames[2];
extern "C" void kmain(unsigned long hart, void *dtb) {
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(void)hart;
(void)dtb;
// D1 doesnt give me dtb ptr?
// dtb = (void *)0x5fb38580;
dtb::DeviceTree dt;
int res = dtb::validate_and_parse_header(dt, dtb);
if(!res) {
fmt("validate_and_parse_header: {}\n", res);
fmt("magic: {}\n", dt.meta.base);
dtb::print_reserved_regions(dt);
dtb::print_structure_block(dt);
}
namespace legacy = drivers::opensbi::legacy;
namespace base = drivers::opensbi::base;
namespace timer = drivers::opensbi::timer;
namespace ipi = drivers::opensbi::ipi;
fmt("test\n");
auto ret = base::get_spec_version();
if(ret.error) {
fmt("get_spec_version failed\n");
} else {
fmt("spec version: {}\n", ret.value);
}
ret = base::get_impl_id();
if(ret.error) {
fmt("get_impl_id failed\n");
} else {
fmt("impl id: {}\n", ret.value);
}
ret = base::get_impl_version();
if(ret.error) {
fmt("get_impl_version failed\n");
} else {
fmt("impl version: {}\n", ret.value);
}
ret = base::get_mvendor_id();
if(ret.error) {
fmt("get_mvendor_id failed\n");
} else {
fmt("vendor id: {}\n", ret.value);
}
ret = base::get_march_id();
if(ret.error) {
fmt("get_march_id failed\n");
} else {
fmt("arch id: {}\n", ret.value);
}
ret = base::get_mimp_id();
if(ret.error) {
fmt("get_mimp_id failed\n");
} else {
fmt("imp id: {}\n", ret.value);
}
fmt("uintmax: {} bits\n", sizeof(uintmax_t) * 8);
fmt("HART: {}, DTB: {}\n", hart, dtb);
volatile uint32_t *cfg = (uint32_t *)0x2000060;
volatile uint32_t *dat = (uint32_t *)0x2000070;
*cfg = 0x10;
*dat = 0xFF;
//while(1);
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cli();
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global_isr_frames[0].next = &global_isr_frames[1];
write_csr("sscratch", (unsigned long)&global_isr_frames[0]);
write_csr("stvec", ((unsigned long)&isr));
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const char *s;
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set_csr_bits("sie", sie_s_software | sie_s_timer);
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// Self-IPI.
ipi::send_ipi({ 1UL << hart, 0 });
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sti();
unsigned long timea = read_csr("time");
ret = timer::set_timer(timea + 100000);
drivers::opensbi::rfence::remote_fence_i({0, 0});
//ret = drivers::opensbi::hsm::hart_stop();
using drivers::opensbi::srst::ResetType;
using drivers::opensbi::srst::ResetReason;
// ret = drivers::opensbi::srst::system_reset(ResetType::WARM_REBOOT, ResetReason::SYSTEM_FAILURE);
namespace pmu = drivers::opensbi::pmu;
ret = pmu::num_counters();
fmt("Number of counters: {}\n", ret.value);
for(int i = 0; i < ret.value; i++) {
ret = pmu::counter_get_info(i);
fmt("{} err: {}\n", i, ret.error);
fmt("{} val: {}\n", i, ret.value);
}
while(1);
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cli();
unsigned long time;
//volatile uint32_t *meme = (uint32_t *)0x6011010;
//while(true) {
time = read_csr("time");
fmt("hello world {}\n", time);
//*meme = *meme | (0xA57 << 1) | (1 << 0);
//}
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// Identity map the first 512GiB.
pml4.ptes[0] = ((0UL >> 12) << pte_ppn_shift) | pte_valid
| pte_r | pte_w | pte_x | pte_access | pte_dirty | pte_user;
// Map 512GiB -> 0.
pml4.ptes[1] = ((0UL >> 12) << pte_ppn_shift) | pte_valid
| pte_r | pte_w | pte_x | pte_access | pte_dirty | pte_user;
fmt("Writing paging memes\n");
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unsigned long pml4p = (unsigned long)&pml4;
fmt("pml4p @ {}\n", pml4p);
fmt("Setting SStatus\n");
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set_csr_bits("sstatus", 1 << 18);
fmt("Setting Satp\n");
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write_csr("satp", (pml4p >> 12) | satp_sv48);
fmt("Paging might work?...\n");
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s = "paging works!\n";
s += 512UL * 1024 * 1024 * 1024;
while(*s)
legacy::console_putchar(*(s++));
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create_task(&task1, task1_main);
create_task(&task2, task2_main);
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time = read_csr("time");
//set_timer(time + 100000);
//drivers::opensbi::ecall(0x54494D45, 0, time + 100000);
//timer::set_timer(time + 100000);
//save_stack(switch_task, 0);
namespace hsm = drivers::opensbi::hsm;
hsm::hart_stop();
// drivers::opensbi::ecall(8, 0, 0);
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while(1);
}