From 69fd0dd9fda47aa52cccdbef6ca388cea38e693b Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Thu, 25 Jul 2024 22:17:27 +0200
Subject: kernel: pass more information to user on interrupt

This is meant to facilitate a syscall for returning from interrupts, which
will actually work in the general case as opposed to the current hack, which
only works if the interrupt occured during a syscall (which is correct... for
now).
---
 src/libc/_start2.c               |  2 +-
 src/libc/include/camellia/intr.h |  5 +++--
 src/libc/intr.c                  |  9 +++++----
 src/libc/intr.s                  | 13 +++----------
 4 files changed, 12 insertions(+), 17 deletions(-)

(limited to 'src/libc')

diff --git a/src/libc/_start2.c b/src/libc/_start2.c
index 2c6b64d..e6809b9 100644
--- a/src/libc/_start2.c
+++ b/src/libc/_start2.c
@@ -35,8 +35,8 @@ _Noreturn void _start2(struct execdata *ed) {
 
 	_klogf("_start2 %s %p", progname, __executable_start);
 
-	_sys_intr_set(intr_trampoline);
 	intr_set(intr_default);
+	_sys_intr_set(intr_trampoline); /* can cause queued interrupts to arrive */
 	__initialcwd = ed->cwd;
 
 	exit(main(ed->argc, ed->argv, ed->envp));
diff --git a/src/libc/include/camellia/intr.h b/src/libc/include/camellia/intr.h
index b9390fd..c6d0310 100644
--- a/src/libc/include/camellia/intr.h
+++ b/src/libc/include/camellia/intr.h
@@ -1,4 +1,5 @@
 #pragma once
+#include <camellia/types.h>
 
-void intr_set(void (*fn)(void));
-void intr_default(void);
+void intr_set(void (*fn)(struct intr_data *));
+void intr_default(struct intr_data *);
diff --git a/src/libc/intr.c b/src/libc/intr.c
index cdefc2f..c44a90e 100644
--- a/src/libc/intr.c
+++ b/src/libc/intr.c
@@ -1,13 +1,14 @@
 #include <camellia/intr.h>
+#include <stdio.h>
 #include <stdlib.h>
 
-static void intr_null(void) { }
+static void intr_null(struct intr_data *) { }
 
-extern void (*volatile _intr)(void);
-void intr_set(void (*fn)(void)) {
+extern void (*volatile _intr)(struct intr_data *);
+void intr_set(void (*fn)(struct intr_data *)) {
 	_intr = fn ? fn : intr_null;
 }
 
-void intr_default(void) {
+void intr_default(struct intr_data *intr) {
 	exit(-1);
 }
diff --git a/src/libc/intr.s b/src/libc/intr.s
index 008387d..dcc61fe 100644
--- a/src/libc/intr.s
+++ b/src/libc/intr.s
@@ -2,19 +2,12 @@
 .global intr_trampoline
 .type intr_trampoline, @function
 intr_trampoline:
-	push %rax
-	push %rdx
+	mov %rsp, %rdi /* pass intr_data as the argument */
+	and $~0xF, %rsp
 	call *_intr(%rip)
-	pop %rdx
-	pop %rax
-	pop tmprip(%rip)
-	pop %rsp
-	jmp *tmprip(%rip)
+	int3 /* you weren't supposed to return */
 
 .section .bss
-tmprip:
-	.skip 8
-
 .global _intr
 _intr:
 	.skip 8
-- 
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