From b26098268eb443f1ed3dc50d902b2beee40c8342 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 16 Jul 2022 19:35:05 +0200
Subject: amd64: seemingly working syscalls (SYSCALL/SYSRET)

---
 src/user/app/main.c    |  1 +
 src/user/lib/syscall.s | 24 ++++--------------------
 2 files changed, 5 insertions(+), 20 deletions(-)

(limited to 'src/user')

diff --git a/src/user/app/main.c b/src/user/app/main.c
index ff47d4e..92aa56c 100644
--- a/src/user/app/main.c
+++ b/src/user/app/main.c
@@ -16,6 +16,7 @@ void read_file(const char *path, size_t len);
 
 __attribute__((section(".text.startup")))
 int main(void) {
+	_syscall(1, 2, 3, 4, 5);
 	// allocate bss
 	_syscall_memflag(&_bss_start, &_bss_end - &_bss_start, MEMFLAG_PRESENT);
 
diff --git a/src/user/lib/syscall.s b/src/user/lib/syscall.s
index 0f9e444..07f5631 100644
--- a/src/user/lib/syscall.s
+++ b/src/user/lib/syscall.s
@@ -2,24 +2,8 @@
 .global _syscall
 .type _syscall, @function
 _syscall:
-	push %rbx // preserve registers
-	push %rsi
-	push %rdi
-	push %rbp
-
-	// NOT the calling convention TODO you lazy fuck
-	mov 20(%rsp), %rax
-	mov 24(%rsp), %rbx
-	mov %rsp, %rcx
-	mov $_syscall_ret, %rdx
-	mov 28(%rsp), %rsi
-	mov 32(%rsp), %rdi
-	mov 36(%rsp), %rbp
-	sysenter
-
-_syscall_ret:
-	pop %rbp
-	pop %rdi
-	pop %rsi
-	pop %rbx
+	push %r10
+	mov %rcx, %r10
+	syscall
+	pop %r10
 	ret
-- 
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