From a2f9ae9d4ab678fa66a2ec5d1072ea22a36a18a1 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Thu, 19 Jan 2023 23:36:11 +0100
Subject: kernel: user interrupts

---
 src/user/lib/_start2.c        |  4 ++++
 src/user/lib/include/unistd.h |  3 +++
 src/user/lib/intr.s           | 20 ++++++++++++++++++++
 src/user/lib/syscall.c        |  8 ++++++++
 src/user/lib/unistd.c         | 11 +++++++++++
 5 files changed, 46 insertions(+)
 create mode 100644 src/user/lib/intr.s

(limited to 'src/user/lib')

diff --git a/src/user/lib/_start2.c b/src/user/lib/_start2.c
index ba3b6b0..495f046 100644
--- a/src/user/lib/_start2.c
+++ b/src/user/lib/_start2.c
@@ -17,9 +17,13 @@ const char *shortname(const char *path) {
 	return path;
 }
 
+void intr_trampoline(void); /* intr.s */
+
 _Noreturn void _start2(struct execdata *ed) {
 	const char *progname;
 	elf_selfreloc();
+	_syscall_intr_set(intr_trampoline);
+	intr_set(intr_default);
 	__setinitialcwd(ed->cwd);
 
 	progname = shortname(ed->argv[0]);
diff --git a/src/user/lib/include/unistd.h b/src/user/lib/include/unistd.h
index f49c337..d13767b 100644
--- a/src/user/lib/include/unistd.h
+++ b/src/user/lib/include/unistd.h
@@ -26,3 +26,6 @@ size_t absolutepath(char *out, const char *in, size_t size);
 
 // TODO put in an internal libc header
 void __setinitialcwd(const char *c);
+
+void intr_set(void (*fn)(void));
+void intr_default(void);
diff --git a/src/user/lib/intr.s b/src/user/lib/intr.s
new file mode 100644
index 0000000..008387d
--- /dev/null
+++ b/src/user/lib/intr.s
@@ -0,0 +1,20 @@
+.section .text
+.global intr_trampoline
+.type intr_trampoline, @function
+intr_trampoline:
+	push %rax
+	push %rdx
+	call *_intr(%rip)
+	pop %rdx
+	pop %rax
+	pop tmprip(%rip)
+	pop %rsp
+	jmp *tmprip(%rip)
+
+.section .bss
+tmprip:
+	.skip 8
+
+.global _intr
+_intr:
+	.skip 8
diff --git a/src/user/lib/syscall.c b/src/user/lib/syscall.c
index d6ed0af..d42c2ee 100644
--- a/src/user/lib/syscall.c
+++ b/src/user/lib/syscall.c
@@ -74,6 +74,14 @@ void _syscall_filicide(void) {
 	return (void)_syscall(_SYSCALL_FILICIDE, 0, 0, 0, 0, 0);
 }
 
+void _syscall_intr(void) {
+	return (void)_syscall(_SYSCALL_INTR, 0, 0, 0, 0, 0);
+}
+
+void _syscall_intr_set(void __user *ip) {
+	return (void)_syscall(_SYSCALL_INTR_SET, (long)ip, 0, 0, 0, 0);
+}
+
 long _syscall_execbuf(void __user *buf, size_t len) {
 	return _syscall(_SYSCALL_EXECBUF, (long)buf, (long)len, 0, 0, 0);
 }
diff --git a/src/user/lib/unistd.c b/src/user/lib/unistd.c
index 01aa94f..cb862f8 100644
--- a/src/user/lib/unistd.c
+++ b/src/user/lib/unistd.c
@@ -161,3 +161,14 @@ size_t absolutepath(char *out, const char *in, size_t size) {
 void __setinitialcwd(const char *s) {
 	__initialcwd = s;
 }
+
+static void intr_null(void) { }
+
+extern void (*volatile _intr)(void);
+void intr_set(void (*fn)(void)) {
+	_intr = fn ? fn : intr_null;
+}
+
+void intr_default(void) {
+	exit(-1);
+}
-- 
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