Signals kinda work!

include/sys/amd64/sys/thread.h

@@ -5,10 +5,16 @@
 
 struct thread;
 struct amd64_thread {
-    uintptr_t rsp0;
+    uintptr_t rsp0, rsp0s;
+    // Normal context
     uintptr_t stack0_base;
     uintptr_t stack0_size;
 
+    // Signal handling context
+    uintptr_t stack0s_base;
+    uintptr_t stack0s_size;
+
+    // User stack
     uintptr_t stack3_base;
     uintptr_t stack3_size;
 
@@ -16,3 +22,5 @@ struct amd64_thread {
 };
 
 void amd64_thread_set_ip(struct thread *t, uintptr_t ip);
+void amd64_thread_sigenter(struct thread *t, int signum);
+void amd64_thread_sigret(struct thread *t);

include/sys/sched.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "sys/thread.h"
 
+struct thread *sched_find(int pid);
 void sched_set_cpu_count(size_t ncpus);
 void sched_add(struct thread *t);
 void sched_init(void);

include/sys/signum.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#define SIGINT      2
+#define SIGQUIT     3
+#define SIGILL      4
+#define SIGABRT     6
+#define SIGFPE      8
+#define SIGKILL     9
+#define SIGSEGV     11
+
+#define SIGUSR1     16
+#define SIGUSR2     17
+

include/sys/syscall.h

@@ -8,6 +8,9 @@
 #define SYSCALL_NR_READDIR  89
 
 #define SYSCALL_NR_BRK      12
+#define SYSCALL_NRX_SIGNAL  48
 #define SYSCALL_NR_FORK     57
 #define SYSCALL_NR_EXECVE   59
 #define SYSCALL_NR_EXIT     60
+#define SYSCALL_NR_KILL     62
+#define SYSCALL_NRX_SIGRET  119

include/sys/thread.h

@@ -5,6 +5,7 @@
 #define THREAD_KERNEL       (1 << 31)
 #define THREAD_CTX_ONLY     (1 << 30)
 #define THREAD_STOPPED      (1 << 2)
+#define THREAD_SIGRET       (1 << 29)
 
 #if defined(ARCH_AMD64)
 typedef uint64_t *mm_space_t;
@@ -28,6 +29,13 @@ struct thread {
     struct vfs_ioctx ioctx;
     struct ofile fds[4];
 
+    // Signal processing queue
+    int sigqueue[8];
+    size_t sigqsz;
+    // Signal handler stack and entry
+    uintptr_t sigentry;
+    uintptr_t sigstack;
+
     mm_space_t space;
 
     // TODO: maybe __sched_thread
@@ -46,3 +54,5 @@ int thread_init(struct thread *t,
                 uint32_t flags,
                 void *arg);
 void thread_cleanup(struct thread *t);
+
+void thread_signal(struct thread *t, int signum);