From 6f8e5772d17d277842be3f6162ddd665a17e5be9 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Mon, 20 Dec 2021 14:53:44 +0200
Subject: More sensible init

+ Who knew some reservations were a good thing? (at least relativelyy
  speaking)
---
 arch/riscv/init/init.c | 42 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 8 deletions(-)

(limited to 'arch/riscv/init')

diff --git a/arch/riscv/init/init.c b/arch/riscv/init/init.c
index d9b32a0..728f8dd 100644
--- a/arch/riscv/init/init.c
+++ b/arch/riscv/init/init.c
@@ -1,5 +1,6 @@
 #include <apos/types.h>
 #include <apos/attrs.h>
+#include <apos/utils.h>
 #include <vmem.h>
 #include <csr.h>
 
@@ -8,22 +9,47 @@ struct __packed init_vmem {
 	int *leaf[512];
 };
 
-struct init_vmem root_branch;
+struct init_vmem *root_branch;
 
-/* assume Sv48 for now */
-void init_lowmem()
+/* assume Sv39 for now */
+void init_vmem()
 {
 	size_t flags = VM_V | VM_X | VM_R | VM_W;
+
+	extern char *__init_start;
+	root_branch = (struct init_vmem *)align_down((size_t)&__init_start - SZ_4K, SZ_4K);
 	for(size_t i = 0; i < 512; ++i)
-		root_branch.leaf[i] = (int *)((1UL << 37) * i | flags);
+		root_branch->leaf[i] = 0;
+
+	/* direct mapping (temp) */
+	for(size_t i = 0; i < 256; ++i)
+		root_branch->leaf[i] = (int *)((1UL << 28) * i | flags);
+
+	/* kernel (also sort of direct mapping) */
+	/* FIXME set up actually correct addressing retard */
+	for(size_t i = 256; i < 512; ++i)
+	root_branch->leaf[256] = (int *)(((RAM_BASE >> 12) << 10) | flags);
+
+	csr_write(CSR_SATP, SATP_MODE_Sv39 | ((size_t)root_branch >> 12));
+}
+
+void move_kernel()
+{
+	extern char *__init_end;
+	extern char *__kernel_size;
 
-	 csr_write(CSR_SATP, SATP_MODE_Sv48 | ((size_t)&root_branch >> 12));
+	size_t sz = (size_t)&__kernel_size;
+	char *src = (char *)&__init_end;
+	char *dst = (char *)VM_KERN;
+	for(size_t i = 0; i < sz; ++i)
+		dst[i] = src[i];
 }
 
-void __section(".init.start") main(void *fdt)
+void __init init(void *fdt)
 {
 	extern char *__init_end;
-	void (*kernel_main)(void *fdt) = (void (*)(void *))(VM_KERN + (size_t)&__init_end);
-	init_lowmem();
+	void (*kernel_main)(void *fdt) = (void (*)(void *))(VM_KERN);
+	init_vmem();
+	move_kernel();
 	kernel_main(fdt);
 }
-- 
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