From cbe2690cd5d1b290633c466ebb4df7b64b09b037 Mon Sep 17 00:00:00 2001
From: Danny Holman <dholman@gymli.org>
Date: Thu, 28 Mar 2024 21:30:12 -0500
Subject: arch: i386: kernel: add mostly finished PFA and paging system

Add the mostly finished physical memory allocator and expose its
functions to the paging system.

Signed-off-by: Danny Holman <dholman@gymli.org>
---
 arch/i386/include/kernel/asm.h    | 24 +++++++++++++++++++++---
 arch/i386/include/kernel/paging.h |  5 +++--
 arch/i386/include/kernel/pmem.h   | 28 ++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 5 deletions(-)
 create mode 100644 arch/i386/include/kernel/pmem.h

(limited to 'arch/i386/include/kernel')

diff --git a/arch/i386/include/kernel/asm.h b/arch/i386/include/kernel/asm.h
index 615da74..cf394e1 100644
--- a/arch/i386/include/kernel/asm.h
+++ b/arch/i386/include/kernel/asm.h
@@ -3,6 +3,23 @@
 
 #include <stdint.h>
 
+extern uintptr_t _kernel_start;
+extern uintptr_t _kernel_end;
+#define KSTART          ((uintptr_t)&_kernel_start)
+#define KEND            ((uintptr_t)&_kernel_end - 0xC0000000)
+
+#define HIMEM_START     0x00100000
+#define PAGE_SIZE       4096
+
+struct thread_block {
+        uint32_t esp;
+        uint32_t cr3;
+        unsigned int tid;
+        unsigned int tgid;
+        unsigned int state;
+        struct thread_block *next;
+};
+
 struct regs {
         uint32_t cr4;
         uint32_t cr3;
@@ -87,17 +104,18 @@ static inline uint8_t inb(uint16_t port) {
 
 static inline void enable_ints(void) {
         __asm__ volatile("sti");
-        return;
 }
 
 static inline void disable_ints(void) {
         __asm__ volatile("cli");
-        return;
 }
 
 static inline void flush_tss(void) {
         __asm__ volatile("movw $0x28, %ax; ltr %ax");
-        return;
+}
+
+static inline void invlpg(void *addr) {
+        __asm__ volatile("invlpg (%0)" : : "b"(addr) : "memory");
 }
 
 #endif
diff --git a/arch/i386/include/kernel/paging.h b/arch/i386/include/kernel/paging.h
index 7f820e8..e949e32 100644
--- a/arch/i386/include/kernel/paging.h
+++ b/arch/i386/include/kernel/paging.h
@@ -23,9 +23,10 @@
 #define ERR_RESERVED    0x8
 #define ERR_INST        0x10
 
-#define PAGE_SIZE       4096
+#define PGROUNDUP(size) (((size)+PAGE_SIZE-1) & ~(PAGE_SIZE-1))
+#define PGROUNDDN(size) (((size)) & ~(PAGE_SIZE-1))
 
-uint32_t* init_page_table(uint32_t flags);
+int init_page_directory(uintptr_t *pd, int user);
 void enable_paging(uintptr_t pd_addr);
 
 void paging_init(void);
diff --git a/arch/i386/include/kernel/pmem.h b/arch/i386/include/kernel/pmem.h
new file mode 100644
index 0000000..ddd9c8b
--- /dev/null
+++ b/arch/i386/include/kernel/pmem.h
@@ -0,0 +1,28 @@
+#ifndef I386_PMEM_H
+#define I386_PMEM_H
+
+#include <kernel/multiboot.h>
+#include <stdint.h>
+
+#define PFA_BLOCK_FREE  1
+#define PFA_BLOCK_ALLOC 3
+
+#define PFA_ALLOC_ERR   0xFFFFFFFF
+
+struct pfa_page {
+        struct pfa_page *next;
+};
+
+struct pfa_zone {
+        uintptr_t start;
+        uintptr_t size;
+        struct pfa_page *freelist;
+};
+
+int pfa_init(struct mboot_info *header);
+
+uintptr_t pfa_alloc(void);
+void pfa_free(struct pfa_zone *zone, uintptr_t paddr);
+void pfa_free_range(struct pfa_zone *zone, uintptr_t pstart, uintptr_t pend);
+
+#endif
-- 
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