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Implement syscalls, hello world from userspace

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This commit is contained in:
Kamil Kowalczyk
2025-09-02 23:51:14 +02:00
parent 920de10025
commit 8a12f23b69
24 changed files with 313 additions and 44 deletions
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1
kernel/Makefile
View File

@ -57,6 +57,7 @@ SRCFILES += $(call GRABSRC, \
std \
flanterm/src \
flanterm/src/flanterm_backends \
syscall \
)
ifeq ($(ARCH),x86_64)

7
kernel/compiler/attr.h
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@ -1,8 +1,9 @@
#ifndef COMPILER_ATTR_H_
#define COMPILER_ATTR_H_
#define PACKED __attribute__((packed))
#define ALIGNED(x) __attribute__((aligned((x))))
#define NORETURN __attribute__((noreturn))
#define PACKED __attribute__((packed))
#define ALIGNED(x) __attribute__((aligned((x))))
#define NORETURN __attribute__((noreturn))
#define UNUSED __attribute__((unused))
#endif // COMPILER_ATTR_H_

19
kernel/errors.h
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@ -1,13 +1,16 @@
#ifndef ERRORS_H_
#define ERRORS_H_
#define E_OK 0
#define E_NOMEMORY -1
#define E_UNKNOWN_FSTYPE -2
#define E_NOENTRY -3
#define E_OUTOFBOUNDS -4
#define E_UNKNOWN_SDTYPE -5
#define E_TODO -6
#define E_BADIO -7
enum {
E_OK = 0,
E_NOMEMORY = -1,
E_UNKNOWN_FSTYPE = -2,
E_NOENTRY = -3,
E_OUTOFBOUNDS = -4,
E_UNKNOWN_SDTYPE = -5,
E_TODO = -6,
E_BADIO = -7,
E_BADSYSCALL = -8,
};
#endif // ERRORS_H_

20
kernel/hal/x86_64/cpu.c
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@ -1,14 +1,28 @@
#include <stdint.h>
#include <stddef.h>
#include "cpu.h"
#include "vmm.h"
#include "pmm/pmm.h"
#include "hal/hal.h"
#include "bootinfo/bootinfo.h"
LocalCpuData HAL_CPUS[HAL_CPUS_MAX];
uint64_t hal_cpu_rdmsr(uint32_t id) {
uint32_t lo, hi;
asm volatile("rdmsr" : "=m"(lo), "=d"(hi) : "c"(id));
asm volatile("rdmsr" : "=a"(lo), "=d"(hi) : "c"(id));
return ((uint64_t)lo) | ((uint64_t)hi << 32);
}
uint64_t hal_cpu_wrmsr(uint32_t id, uint64_t val) {
uint32_t lo = val & 0xffffffff, hi = (val >> 32) & 0xffffffff;
asm volatile("wrmsr" :: "a"(lo), "d"(hi), "c"(id) : "memory");
uint32_t lo = val & 0xFFFFFFFF;
uint32_t hi = val >> 32;
asm volatile("wrmsr" :: "c"(id), "a"(lo), "d"(hi));
return val;
}
void hal_cpu_init(uint32_t cpu) {
void *addr = pmm_alloc(16) + (16 * HAL_PAGE_SIZE);
HAL_CPUS[cpu].syscall_kstack = (uint64_t *)VIRT(addr);
HAL_CPUS[cpu].kcr3 = hal_vmm_current_cr3();
}

25
kernel/hal/x86_64/cpu.h
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@ -1,11 +1,36 @@
#ifndef HAL_CPU_H_
#define HAL_CPU_H_
#include <stdint.h>
#include "compiler/attr.h"
#include "vmm.h"
#include "intr.h"
#define HAL_CPUS_MAX 0xff
#define HAL_CPU_EFER 0xC0000080
#define HAL_CPU_STAR 0xC0000081
#define HAL_CPU_LSTAR 0xC0000082
#define HAL_CPU_CSTAR 0xC0000083
#define HAL_CPU_SFMASK 0xC0000084
#define HAL_CPU_FSBASE 0xC0000100
#define HAL_CPU_GSBASE 0xC0000101
#define HAL_CPU_KGSBASE 0xC0000102
typedef struct {
uint64_t *syscall_kstack;
uint64_t *syscall_ustack;
PgTable *kcr3;
PgTable *pcr3;
IntrStackFrame *frame;
} PACKED LocalCpuData;
uint64_t hal_cpu_rdmsr(uint32_t id);
uint64_t hal_cpu_wrmsr(uint32_t id, uint64_t val);
void hal_cpu_init(uint32_t cpu);
extern LocalCpuData HAL_CPUS[HAL_CPUS_MAX];
#endif // HAL_CPU_H_

2
kernel/hal/x86_64/hal.c
View File

@ -9,6 +9,7 @@
#include "pic.h"
#include "apic.h"
#include "pit.h"
#include "syscall.h"
void hal_init(void) {
if (!serial_init()) {
@ -32,6 +33,7 @@ void hal_init_withmalloc(void) {
pit_init();
ioapic_setentry(IOAPIC, acpi_remapirq(0x00), INTR_TIMER);
hal_intr_disable();
hal_syscall_init();
}
void hal_wait(uint32_t ms) {

11
kernel/hal/x86_64/intr.c
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@ -133,7 +133,7 @@ void intr_dumpframe(IntrStackFrame *frame) {
asm volatile("mov %%cr3, %0" : "=r"(cr3));
uint64_t cr4;
asm volatile("mov %%cr4, %0" : "=r"(cr4));
kprintf_unsafe("rax=%016lx rcx=%016lx rdx=%016lx\n"
kprintf("rax=%016lx rcx=%016lx rdx=%016lx\n"
"rsi=%016lx rdi=%016lx r8 =%016lx\n"
"r9 =%016lx r10=%016lx r11=%016lx\n"
"rip=%016lx rfl=%016lx rsp=%016lx\n"
@ -150,9 +150,12 @@ void intr_dumpframe(IntrStackFrame *frame) {
}
void intr_handleintr(IntrStackFrame *frame) {
if (frame->trapnum >= 0 && frame->trapnum <= 31) {
// EXCEPTION
kprintf_unsafe("ERROR %s, 0x%lX\n", exceptions[frame->trapnum], frame->errnum);
if (frame->trapnum <= 31) {
if (frame->trapnum == 14 && frame->errnum & 0x4) {
proc_killself();
proc_sched((void *)frame);
}
kprintf("ERROR %s, 0x%lX\n", exceptions[frame->trapnum], frame->errnum);
intr_dumpframe(frame);
hal_hang();
} else if (frame->trapnum >= 32 && frame->trapnum <= 47) {

1
kernel/hal/x86_64/intr.h
View File

@ -17,6 +17,7 @@ typedef struct {
uint64_t r10;
uint64_t r9;
uint64_t r8;
uint64_t rbp;
uint64_t rdi;
uint64_t rsi;
uint64_t rdx;

1
kernel/hal/x86_64/intr0.S
View File

@ -215,4 +215,3 @@ intr_vec46:
intr_vec47:
_vecintr_plain_save 47
_vecintr_bodygen

2
kernel/hal/x86_64/regs.S
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@ -4,6 +4,7 @@
push %rdx
push %rsi
push %rdi
push %rbp
push %r8
push %r9
push %r10
@ -23,6 +24,7 @@
pop %r10
pop %r9
pop %r8
pop %rbp
pop %rdi
pop %rsi
pop %rdx

43
kernel/hal/x86_64/syscall.c Normal file
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@ -0,0 +1,43 @@
#include <stdint.h>
#include "syscall.h"
#include "cpu.h"
#include "intr.h"
#include "syscall/syscall.h"
#include "proc/proc.h"
#include "kprintf.h"
#include "errors.h"
extern void hal_enable_syscallentry(void);
extern void hal_syscallentry(void);
void hal_syscalldispatch(IntrStackFrame *frame) {
uint64_t sysnum = frame->regs.rax;
if (sysnum < SYSCALLS_MAX) {
SyscallFn fn = SYSCALL_TABLE[sysnum];
if (fn == NULL) {
frame->regs.rax = E_BADSYSCALL;
return;
}
int32_t ret = fn(frame->regs.rdi, frame->regs.rsi, frame->regs.rdx,
frame->regs.r10, frame->regs.r8, frame->regs.r9);
if (sysnum == SYS_QUITPROC) {
proc_sched((void *)frame);
}
frame->regs.rax = *(uint64_t *)&ret;
}
}
void hal_syscall_init(void) {
hal_cpu_init(0);
LocalCpuData *lcd = &HAL_CPUS[0];
hal_cpu_wrmsr(HAL_CPU_EFER, hal_cpu_rdmsr(HAL_CPU_EFER) | 0x1);
hal_enable_syscallentry();
hal_cpu_wrmsr(HAL_CPU_GSBASE, (uint64_t)lcd);
hal_cpu_wrmsr(HAL_CPU_KGSBASE, (uint64_t)lcd);
hal_cpu_wrmsr(HAL_CPU_SFMASK, (uint64_t)0);
hal_cpu_wrmsr(HAL_CPU_LSTAR, (uint64_t)&hal_syscallentry);
}

6
kernel/hal/x86_64/syscall.h Normal file
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@ -0,0 +1,6 @@
#ifndef HAL_SYSCALL_H_
#define HAL_SYSCALL_H_
void hal_syscall_init(void);
#endif // HAL_SYSCALL_H_

48
kernel/hal/x86_64/syscall0.S Normal file
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@ -0,0 +1,48 @@
#include "regs.S"
.extern hal_syscalldispatch
.global hal_enable_syscallentry
hal_enable_syscallentry:
movq $0xC0000080, %rcx
rdmsr
or $0x1, %eax
wrmsr
movq $0xC0000081, %rcx
rdmsr
movl $0x180008, %edx
wrmsr
ret
.global hal_syscallentry
hal_syscallentry:
cli
swapgs
movq %rsp, %gs:0x8
movq %gs:0x0, %rsp
pushq $0x23
pushq %gs:0x8
swapgs
pushq %r11
pushq $0x1b
pushq %rcx
_push_regs
mov %rsp, %rdi
mov $0x0, %rbp
call hal_syscalldispatch
cli
_pop_regs
popq %rcx
add $0x8, %rsp
popq %r11
popq %rsp
sysret

7
kernel/kprintf.h
View File

@ -6,13 +6,6 @@
#include "spinlock/spinlock.h"
#define kprintf(fmt, ...) \
do { \
spinlock_acquire(&TERM.spinlock); \
printf_(fmt, ##__VA_ARGS__); \
spinlock_release(&TERM.spinlock); \
} while(0)
#define kprintf_unsafe(fmt, ...) \
do { \
printf_(fmt, ##__VA_ARGS__); \
} while(0)

24
kernel/proc/proc.c
View File

@ -15,12 +15,6 @@
#define PROC_REAPER_FREQ 30
#define PROC_DIE() \
do { \
proc_killself(); \
for(;;); \
} while(0)
uint64_t pids = 0;
uint64_t sched_ticks = 0;
@ -161,8 +155,16 @@ void proc_register(Proc *proc) {
}
Proc *proc_nextready(void) {
Proc *next = PROCS.current->next;
Proc *proc = next == NULL ? PROCS.procs : next;
Proc *proc = PROCS.current->next;
for (;;) {
if (proc == NULL) {
proc = PROCS.procs;
}
if (proc->state != PROC_ZOMBIE) {
return proc;
}
proc = proc->next;
}
return proc;
}
@ -183,7 +185,7 @@ void proc_reaper(void) {
while (vashead) {
VasRange *tmp = vashead;
vashead = vashead->next;
hal_vmm_unmap_range(zombie->platformdata.cr3, tmp->virtstart, tmp->physstart, tmp->size);
hal_vmm_unmap_range(VIRT(zombie->platformdata.cr3), tmp->virtstart, tmp->physstart, tmp->size);
// first pmm mapping is for the elf itself
if (i == 0) {
pmm_free((uintptr_t)tmp->physstart, tmp->size / HAL_PAGE_SIZE);
@ -218,6 +220,7 @@ void proc_sched(void *cpustate) {
PROCS.current->state = PROC_RUNNING;
hal_cpu_wrmsr(HAL_CPU_FSBASE, PROCS.current->platformdata.fsbase);
HAL_CPUS[0].syscall_kstack = VIRT(PROCS.current->platformdata.kstack);
hal_switchproc(&PROCS.current->platformdata.trapframe, (void *)PROCS.current->platformdata.cr3);
}
@ -239,11 +242,12 @@ void proc_idle(void) {
}
void proc_status(void) {
static const char *statuses[] = {"ready", "running", "zombie", "waiting"};
for (;;) {
spinlock_acquire(&PROCS.spinlock);
Proc *head = PROCS.procs;
while (head) {
kprintf("%s %s\n", head->kern ? "kern" : "user", head->name);
kprintf("%s %s %s\n", head->kern ? "kern" : "user", statuses[head->state], head->name);
head = head->next;
}
kprintf("\n\n");

7
kernel/proc/proc.h
View File

@ -50,5 +50,12 @@ void proc_register(Proc *proc);
Proc *proc_spawnkern(void (*ent)(void), char *name);
Proc *proc_spawnuser(char *mountpoint, char *path);
void proc_sched(void *cpustate);
void proc_killself(void);
#define PROC_DIE() \
do { \
proc_killself(); \
for(;;); \
} while(0)
#endif // PROC_PROC_H_

27
kernel/syscall/syscall.c Normal file
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@ -0,0 +1,27 @@
#include <stdint.h>
#include "syscall.h"
#include "errors.h"
#include "dlmalloc/malloc.h"
#include "kprintf.h"
#include "proc/proc.h"
int32_t SYSCALL2(sys_debugprint, string1, len) {
char *buf = dlmalloc(len);
if (buf == NULL) {
return E_NOMEMORY;
}
ksnprintf(buf, len, "%s", string1);
kprintf("%s\n", buf);
dlfree(buf);
return E_OK;
}
int32_t SYSCALL0(sys_quitproc) {
proc_killself();
return E_OK;
}
SyscallFn SYSCALL_TABLE[SYSCALLS_MAX] = {
[SYS_DEBUGPRINT] = &sys_debugprint,
[SYS_QUITPROC] = &sys_quitproc,
};

81
kernel/syscall/syscall.h Normal file
View File

@ -0,0 +1,81 @@
#ifndef SYSCALL_SYSCALL_H_
#define SYSCALL_SYSCALL_H_
#include <stdint.h>
#include "compiler/attr.h"
#define SYSCALLS_MAX 0xff
#define SYSCALL0(name) \
name(UNUSED uint64_t _1, \
UNUSED uint64_t _2, \
UNUSED uint64_t _3, \
UNUSED uint64_t _4, \
UNUSED uint64_t _5, \
UNUSED uint64_t _6 \
)
#define SYSCALL1(name, arg1) \
name(uint64_t arg1, \
UNUSED uint64_t _2, \
UNUSED uint64_t _3, \
UNUSED uint64_t _4, \
UNUSED uint64_t _5, \
UNUSED uint64_t _6 \
)
#define SYSCALL2(name, arg1, arg2) \
name(uint64_t arg1, \
uint64_t arg2, \
UNUSED uint64_t _3, \
UNUSED uint64_t _4, \
UNUSED uint64_t _5, \
UNUSED uint64_t _6 \
)
#define SYSCALL3(name, arg1, arg2, arg3) \
name(uint64_t arg1, \
uint64_t arg2, \
uint64_t arg3, \
UNUSED uint64_t _4, \
UNUSED uint64_t _5, \
UNUSED uint64_t _6 \
)
#define SYSCALL4(name, arg1, arg2, arg3, arg4) \
name(uint64_t arg1, \
uint64_t arg2, \
uint64_t arg3, \
uint64_t arg4, \
UNUSED uint64_t _5, \
UNUSED uint64_t _6 \
)
#define SYSCALL5(name, arg1, arg2, arg3, arg4, arg5) \
name(uint64_t arg1, \
uint64_t arg2, \
uint64_t arg3, \
uint64_t arg4, \
uint64_t arg5, \
UNUSED uint64_t _6 \
)
#define SYSCALL6(name, arg1, arg2, arg3, arg4, arg5, arg6) \
name(uint64_t arg1, \
uint64_t arg2, \
uint64_t arg3, \
uint64_t arg4, \
uint64_t arg5, \
uint64_t arg6 \
)
enum {
SYS_DEBUGPRINT = 1,
SYS_QUITPROC = 2,
};
typedef int32_t (*SyscallFn)(uint64_t, uint64_t, uint64_t, uint64_t, uint64_t, uint64_t);
extern SyscallFn SYSCALL_TABLE[SYSCALLS_MAX];
#endif // SYSCALL_SYSCALL_H_

1
kernel/term/term.c
View File

@ -31,7 +31,6 @@ void term_doinit(void *addr) {
}
void term_init(void *addr) {
spinlock_init(&TERM.spinlock);
term_doinit(addr);
}

1
kernel/term/term.h
View File

@ -7,7 +7,6 @@
typedef struct {
struct flanterm_context *ftctx;
SpinLock spinlock;
} Term;
extern Term TERM;

2
run/qemu-x86_64.sh
View File

@ -2,4 +2,4 @@
set -x
qemu-system-x86_64 -cpu qemu64,+pdpe1gb -m 4G -cdrom mop2.iso -boot d -serial stdio $@
qemu-system-x86_64 -cpu IvyBridge -m 4G -cdrom mop2.iso -boot d -serial stdio $@

1
user/arch/x86_64/link.ld
View File

@ -1,7 +1,6 @@
ENTRY(_start)
SECTIONS {
/* . = 0xffff000000000000; */
. = 0x0000000000000000;
.rodata ALIGN(4K):

2
user/hello/Makefile
View File

@ -16,7 +16,7 @@ all: $(TARGET)
hello: $(OBJ)
$(LD) $^ $(LDFLAGS) -o $@
echo $(realpath $@) >> $(FILES)
echo $(realpath hello) >> $(FILES)
clean:
rm -f $(OBJ) $(TARGET)

16
user/hello/hello.s
View File

@ -1,6 +1,18 @@
.section .data
STRING:
.string "Hello World from userspace"
STRING_LEN:
.quad . - STRING
.section .text
.global _start
_start:
.spin:
jmp .spin
movq $1, %rax
lea STRING(%rip), %rdi
lea STRING_LEN(%rip), %rsi
syscall
movq $2, %rax
syscall