From a0540658f66feb32c1abe71d9d7589b854e9aaa5 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Sun, 30 Jun 2024 23:51:40 -0400
Subject: kernel/amd64: proc: Add stack init func for exec

Add stack initialization code for exec functions. This new code
initializes values on the stack, including argc, argv, and the
auxiliary vector.

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/include/sys/exec.h | 16 ++++++++++++++++
 sys/include/sys/proc.h |  5 +++++
 2 files changed, 21 insertions(+)

(limited to 'sys/include')

diff --git a/sys/include/sys/exec.h b/sys/include/sys/exec.h
index 4910ff2..73eae01 100644
--- a/sys/include/sys/exec.h
+++ b/sys/include/sys/exec.h
@@ -34,7 +34,23 @@
 
 #if defined(_KERNEL)
 
+/* Danger: Do not change these !! */
+#define AT_NULL 0
+#define AT_ENTRY 1
+#define AT_PHDR 2
+#define AT_PHENT 3
+#define AT_PHNUM 4
+#define AT_EXECPATH 5
+#define AT_SECURE 6
+#define AT_RANDOM 7
+#define AT_EXECFN 8
+#define AT_PAGESIZE 9
+
 #define MAX_PHDRS 32
+#define STACK_PUSH(PTR, VAL) *(--(PTR)) = VAL
+#define AUXVAL(PTR, TAG, VAL)   \
+    STACK_PUSH(PTR, VAL);       \
+    STACK_PUSH(PTR, TAG);
 
 struct exec_range {
     uintptr_t start;
diff --git a/sys/include/sys/proc.h b/sys/include/sys/proc.h
index 5303072..0c3cd33 100644
--- a/sys/include/sys/proc.h
+++ b/sys/include/sys/proc.h
@@ -43,6 +43,8 @@
 #define PROC_STACK_PAGES 8
 #define PROC_STACK_SIZE  (PROC_STACK_PAGES * DEFAULT_PAGESIZE)
 
+struct exec_prog;
+
 struct proc {
     pid_t pid;
     struct trapframe tf;
@@ -57,6 +59,9 @@ struct proc {
 
 struct proc *this_td(void);
 int md_fork(struct proc *p, struct proc *parent, uintptr_t ip);
+
+void md_td_stackinit(struct proc *td, void *stack_top, struct exec_prog *prog);
+
 int fork1(struct proc *cur, int flags, void(*ip)(void), struct proc **newprocp);
 int exit1(struct proc *td);
 
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