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Improve syscall definitions

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- Allow constant id specification
- Define function signature in SYSCALL macro
- Move implementation into src/kernel/syscalls/*.cpp
This commit is contained in:
Justin C. Miller
2019-04-02 23:14:52 -07:00
parent 11a53e792f
commit 8375870af6
13 changed files with 173 additions and 97 deletions
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2
src/drivers/nulldrv/main.cpp
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@@ -6,6 +6,7 @@ extern "C" {
int32_t fork();
void sleep(uint64_t til);
void debug();
void message(const char *msg);
int main(int, const char **);
}
@@ -15,6 +16,7 @@ int
main(int argc, const char **argv)
{
int32_t pid = getpid();
message("hello from nulldrv!");
//int32_t child = fork();
//debug();
for (int i = 1; i < 5; ++i)

24
src/drivers/nulldrv/main.s
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@@ -11,8 +11,8 @@ getpid:
push rbp
mov rbp, rsp
mov rax, 3 ; getpid syscall
syscall ; pid is now already in rax, so just return
mov rax, 0x02 ; getpid syscall
syscall ; pid is now already in rax, so just return
pop rbp
ret
@@ -22,7 +22,7 @@ debug:
push rbp
mov rbp, rsp
mov rax, 0 ; debug syscall
mov rax, 0x00 ; debug syscall
syscall
pop rbp
@@ -33,7 +33,7 @@ sleep:
push rbp
mov rbp, rsp
mov rax, 6 ; sleep syscall
mov rax, 0x21 ; sleep syscall
syscall
pop rbp
@@ -44,14 +44,26 @@ fork:
push rbp
mov rbp, rsp
mov rax, 0
mov rax, 0x00
syscall ; pid left in rax
pop rbp
ret
global message
message:
push rbp
mov rbp, rsp
; message should already be in rdi
mov rax, 0x10
syscall
pop rbp
ret
global _start
_start:
xor rbp, rbp ; Sentinel rbp

100
src/kernel/syscall.cpp
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@@ -8,89 +8,42 @@
#include "syscall.h"
extern "C" {
void _halt();
void syscall_invalid(uint64_t call);
void syscall_handler_prelude();
}
namespace syscalls {
void
noop()
{
auto &s = scheduler::get();
auto *p = s.current();
log::debug(logs::syscall, "Process %d called noop syscall.", p->pid);
}
void
exit(int64_t status)
{
auto &s = scheduler::get();
auto *p = s.current();
log::debug(logs::syscall, "Process %d exiting with code %d", p->pid, status);
p->exit(status);
s.schedule();
}
pid_t
getpid()
{
auto &s = scheduler::get();
auto *p = s.current();
return p->pid;
}
pid_t fork() { return 0; }
void
message(const char *message)
{
auto &s = scheduler::get();
auto *p = s.current();
log::info(logs::syscall, "Message[%d]: %s", p->pid, message);
}
void
pause()
{
auto &s = scheduler::get();
auto *p = s.current();
p->wait_on_signal(-1ull);
s.schedule();
}
void
sleep(uint64_t til)
{
auto &s = scheduler::get();
auto *p = s.current();
log::debug(logs::syscall, "Process %d sleeping until %d", p->pid, til);
p->wait_on_time(til);
s.schedule();
}
void send() {}
void receive() {}
} // namespace syscalls
struct syscall_handler_info
{
unsigned nargs;
const char *name;
};
uintptr_t syscall_registry[static_cast<unsigned>(syscall::COUNT)];
syscall_handler_info syscall_info_registry[static_cast<unsigned>(syscall::COUNT)];
uintptr_t syscall_registry[static_cast<unsigned>(syscall::MAX)];
const char * syscall_names[static_cast<unsigned>(syscall::MAX)];
void
syscall_invalid(uint64_t call)
{
console *cons = console::get();
cons->set_color(9);
cons->printf("\nReceived unknown syscall: %d\n", call);
cons->printf("\nReceived unknown syscall: %02x\n", call);
const unsigned num_calls =
static_cast<unsigned>(syscall::MAX);
cons->printf(" Known syscalls:\n");
cons->printf(" invalid %016lx\n", syscall_invalid);
for (unsigned i = 0; i < num_calls; ++i) {
const char *name = syscall_names[i];
uintptr_t handler = syscall_registry[i];
if (name)
cons->printf(" %02x %10s %016lx\n", i, name, handler);
}
cons->set_color();
_halt();
}
@@ -190,11 +143,18 @@ syscall_enable()
// IA32_FMASK - FLAGS mask inside syscall
wrmsr(msr::ia32_fmask, 0x200);
#define SYSCALL(name, nargs) \
syscall_registry[static_cast<unsigned>(syscall::name)] = \
reinterpret_cast<uintptr_t>(syscalls::name); \
syscall_info_registry[static_cast<unsigned>(syscall::name)] = { \
nargs, #name };
static constexpr unsigned num_calls =
static_cast<unsigned>(syscall::MAX);
for (unsigned i = 0; i < num_calls; ++i) {
syscall_registry[i] = reinterpret_cast<uintptr_t>(syscall_invalid);
syscall_names[i] = nullptr;
}
#define SYSCALL(id, name, result, ...) \
syscall_registry[id] = reinterpret_cast<uintptr_t>(syscalls::name); \
syscall_names[id] = #name; \
static_assert( id <= num_calls, "Syscall " #name " has id > syscall::MAX" );
#include "syscalls.inc"
#undef SYSCALL
}

14
src/kernel/syscall.h
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@@ -6,12 +6,20 @@ struct cpu_state;
enum class syscall : uint64_t
{
#define SYSCALL(name, nargs) name ,
#define SYSCALL(id, name, result, ...) name = id,
#include "syscalls.inc"
#undef SYSCALL
COUNT
// Maximum syscall id. If you change this, also change
// MAX_SYSCALLS in syscall.s
MAX = 64
};
void syscall_enable();
extern "C" void syscall_invalid(uint64_t call);
namespace syscalls
{
#define SYSCALL(id, name, result, ...) result name (__VA_ARGS__);
#include "syscalls.inc"
#undef SYSCALL
}

14
src/kernel/syscall.s
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@@ -1,13 +1,9 @@
%include "push_all.inc"
%include "tasking.inc"
%define SYSCALL(name, nargs) resb 1
struc SYSCALLS
%include "syscalls.inc"
.count:
endstruc
; Make sure to keep MAX_SYSCALLS in sync with
; syscall::MAX in syscall.h
MAX_SYSCALLS equ 64
extern __counter_syscall_enter
extern __counter_syscall_sysret
@@ -28,8 +24,8 @@ syscall_handler_prelude:
inc qword [rel __counter_syscall_enter]
cmp rax, SYSCALLS.count
jl .ok_syscall
cmp rax, MAX_SYSCALLS
jle .ok_syscall
mov rdi, rax
call syscall_invalid

18
src/kernel/syscalls.inc
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@@ -1,12 +1,12 @@
SYSCALL(noop, 0)
SYSCALL(exit, 1)
SYSCALL(getpid, 0)
SYSCALL(fork, 0)
SYSCALL(0x00, noop, void)
SYSCALL(0x01, exit, void, int64_t)
SYSCALL(0x02, getpid, pid_t)
SYSCALL(0x03, fork, pid_t)
SYSCALL(message, 1)
SYSCALL(0x10, message, void, const char *)
SYSCALL(pause, 0)
SYSCALL(sleep, 1)
SYSCALL(0x20, pause, void)
SYSCALL(0x21, sleep, void, uint64_t)
SYSCALL(send, 2)
SYSCALL(receive, 2)
SYSCALL(0x30, send, void)
SYSCALL(0x31, receive, void)

17
src/kernel/syscalls/exit.cpp Normal file
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@@ -0,0 +1,17 @@
#include "log.h"
#include "scheduler.h"
namespace syscalls {
void
exit(int64_t status)
{
auto &s = scheduler::get();
auto *p = s.current();
log::debug(logs::syscall, "Process %d exiting with code %d", p->pid, status);
p->exit(status);
s.schedule();
}
} // namespace syscalls

14
src/kernel/syscalls/getpid.cpp Normal file
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@@ -0,0 +1,14 @@
#include "log.h"
#include "scheduler.h"
namespace syscalls {
pid_t
getpid()
{
auto &s = scheduler::get();
auto *p = s.current();
return p->pid;
}
} // namespace syscalls

14
src/kernel/syscalls/message.cpp Normal file
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@@ -0,0 +1,14 @@
#include "log.h"
#include "scheduler.h"
namespace syscalls {
void
message(const char *message)
{
auto &s = scheduler::get();
auto *p = s.current();
log::info(logs::syscall, "Message[%d]: %s", p->pid, message);
}
} // namespace syscalls

14
src/kernel/syscalls/noop.cpp Normal file
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@@ -0,0 +1,14 @@
#include "log.h"
#include "scheduler.h"
namespace syscalls {
void
noop()
{
auto &s = scheduler::get();
auto *p = s.current();
log::debug(logs::syscall, "Process %d called noop syscall.", p->pid);
}
} // namespace syscalls

15
src/kernel/syscalls/pause.cpp Normal file
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@@ -0,0 +1,15 @@
#include "log.h"
#include "scheduler.h"
namespace syscalls {
void
pause()
{
auto &s = scheduler::get();
auto *p = s.current();
p->wait_on_signal(-1ull);
s.schedule();
}
} // namespace syscalls

17
src/kernel/syscalls/sleep.cpp Normal file
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@@ -0,0 +1,17 @@
#include "log.h"
#include "scheduler.h"
namespace syscalls {
void
sleep(uint64_t til)
{
auto &s = scheduler::get();
auto *p = s.current();
log::debug(logs::syscall, "Process %d sleeping until %d", p->pid, til);
p->wait_on_time(til);
s.schedule();
}
} // namespace syscalls