From eed73e2414f8112d0b647e5324d7b89d07f8809e Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Sat, 25 Feb 2023 17:58:23 +0000
Subject: [PATCH] build: add a "user" arch to allow the kernel to run as a
 program on the host machine

---
 Makefile                                 | 10 ++--
 arch/user/config.mk                      | 18 +++++++
 arch/user/cpu.c                          | 24 +++++++++
 arch/user/extra.mk                       | 13 +++++
 arch/user/hwlock.c                       | 27 ++++++++++
 arch/user/include/arch/stdcon.h          |  6 +++
 arch/user/include/socks/machine/cpu.h    | 15 ++++++
 arch/user/include/socks/machine/hwlock.h | 14 +++++
 arch/user/include/socks/machine/init.h   |  8 +++
 arch/user/include/socks/machine/irq.h    |  5 ++
 arch/user/include/socks/machine/pmap.h   |  9 ++++
 arch/user/include/socks/machine/vm.h     | 26 +++++++++
 arch/user/init.c                         | 68 ++++++++++++++++++++++++
 arch/user/stdcon.c                       | 27 ++++++++++
 arch/x86_64/config.mk                    | 12 ++++-
 arch/x86_64/extra.mk                     |  2 +-
 libc/include/socks/libc/string.h         |  6 +--
 libc/string/memchr.c                     |  4 +-
 libc/string/strcmp.c                     |  2 +-
 libc/string/strcpy.c                     |  6 +--
 tools/make/gcc-cross-compile.mk          | 10 ----
 21 files changed, 286 insertions(+), 26 deletions(-)
 create mode 100644 arch/user/config.mk
 create mode 100644 arch/user/cpu.c
 create mode 100644 arch/user/extra.mk
 create mode 100644 arch/user/hwlock.c
 create mode 100644 arch/user/include/arch/stdcon.h
 create mode 100644 arch/user/include/socks/machine/cpu.h
 create mode 100644 arch/user/include/socks/machine/hwlock.h
 create mode 100644 arch/user/include/socks/machine/init.h
 create mode 100644 arch/user/include/socks/machine/irq.h
 create mode 100644 arch/user/include/socks/machine/pmap.h
 create mode 100644 arch/user/include/socks/machine/vm.h
 create mode 100644 arch/user/init.c
 create mode 100644 arch/user/stdcon.c

diff --git a/Makefile b/Makefile
index ab3fd12..4cdc89b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 KERNEL_EXEC := socks_kernel
 
-ARCH := x86_64
+SOCKS_ARCH ?= x86_64
 
 MAKEFILE_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
 ROOT_DIR := $(patsubst %/,%,$(dir $(MAKEFILE_PATH)))
@@ -13,7 +13,7 @@ BUILD_DIR := build
 # Architecture-specific source files
 ####################################
 
-include arch/$(ARCH)/config.mk
+include arch/$(SOCKS_ARCH)/config.mk
 
 ####################################
 # Platform-independent kernel source files
@@ -31,10 +31,10 @@ LIBC_SRC_DIRS := stdio string ctype
 LIBC_C_FILES := $(foreach dir,$(LIBC_SRC_DIRS),$(wildcard libc/$(dir)/*.c))
 LIBC_OBJ := $(addprefix $(BUILD_DIR)/,$(LIBC_C_FILES:.c=.o))
 
-BUILD_ID := $(shell tools/generate_build_id.py --arch $(ARCH))
+BUILD_ID := $(shell tools/generate_build_id.py --arch $(SOCKS_ARCH))
 
 CFLAGS := $(CFLAGS) -DBUILD_ID=\"$(BUILD_ID)\" -g -Wall -Werror -pedantic \
-	-Iinclude -Iarch/$(ARCH)/include -Ilibc/include -Os
+	-Iinclude -Iarch/$(SOCKS_ARCH)/include -Ilibc/include -Os
 
 ASMFLAGS := $(ASMFLAGS) -DBUILD_ID=\"$(BUILD_ID)\"
 LDFLAGS := $(LDFLAGS) -g -Os
@@ -77,7 +77,7 @@ compile-db: $(BUILD_DIR)/compile_commands.json
 tools:
 	@$(MAKE) --no-print-directory -C tools
 
-include arch/$(ARCH)/extra.mk
+include arch/$(SOCKS_ARCH)/extra.mk
 
 .PHONY: all tools compile-db $(BUILD_DIR)/compile_commands.json
 
diff --git a/arch/user/config.mk b/arch/user/config.mk
new file mode 100644
index 0000000..b44f632
--- /dev/null
+++ b/arch/user/config.mk
@@ -0,0 +1,18 @@
+LD  := gcc
+CC  := gcc
+ASM := gcc
+OBJCOPY := objcopy
+STRIP := strip
+
+CFLAGS   :=
+ASMFLAGS := $(CFLAGS)
+LDFLAGS  :=
+
+ARCH_CFLAGS := -D_64BIT
+ARCH_LDFLAGS := 
+
+ARCH_DIR := arch/$(SOCKS_ARCH)
+
+ARCH_C_FILES := $(wildcard $(ARCH_DIR)/*.c) $(wildcard $(ARCH_DIR)/acpi/*.c)
+ARCH_ASM_FILES := $(wildcard $(ARCH_DIR)/*.S) $(wildcard $(ARCH_DIR)/acpi/*.S)
+ARCH_OBJ := $(addprefix $(BUILD_DIR)/,$(ARCH_C_FILES:.c=.o) $(ARCH_ASM_FILES:.S=.o))
diff --git a/arch/user/cpu.c b/arch/user/cpu.c
new file mode 100644
index 0000000..de3f477
--- /dev/null
+++ b/arch/user/cpu.c
@@ -0,0 +1,24 @@
+#include <unistd.h>
+#include <socks/machine/cpu.h>
+
+int ml_init_bootcpu(void)
+{
+	return 0;
+}
+
+int ml_cpu_block_init(ml_cpu_block *p)
+{
+	return 0;
+}
+
+int ml_cpu_block_use(ml_cpu_block *p)
+{
+	return 0;
+}
+
+void ml_halt_cpu(void)
+{
+	while (1) {
+		sleep(100);
+	}
+}
diff --git a/arch/user/extra.mk b/arch/user/extra.mk
new file mode 100644
index 0000000..3f37719
--- /dev/null
+++ b/arch/user/extra.mk
@@ -0,0 +1,13 @@
+run: $(BUILD_DIR)/$(KERNEL_EXEC)
+	@printf "    \033[1;93mEXEC\033[0m   $<\n"
+
+	@$(BUILD_DIR)/$(KERNEL_EXEC)
+
+debug: $(BUILD_DIR)/$(KERNEL_EXEC)
+	@if command -v gdb &> /dev/null; then \
+		gdb -tui $(BUILD_DIR)/$(KERNEL_EXEC) \
+	elif commad -v lldb &> /dev/null; then \
+		lldb -- $(BUILD_DIR)/$(KERNEL_EXEC) \
+	else \
+		printf "No debuggers available." \
+	endif
diff --git a/arch/user/hwlock.c b/arch/user/hwlock.c
new file mode 100644
index 0000000..26c0a34
--- /dev/null
+++ b/arch/user/hwlock.c
@@ -0,0 +1,27 @@
+#include <socks/machine/hwlock.h>
+#include <socks/compiler.h>
+
+void ml_hwlock_lock(ml_hwlock_t *lck)
+{
+	volatile int q = 0;
+	while (!__sync_bool_compare_and_swap(lck, 0, 1)) {
+		q++;
+	}
+}
+
+void ml_hwlock_unlock(ml_hwlock_t *lck)
+{
+	__sync_lock_release(lck);
+}
+
+void ml_hwlock_lock_irqsave(ml_hwlock_t *lck, unsigned long *flags)
+{
+	(void)flags;
+	ml_hwlock_lock(lck);
+}
+
+void ml_hwlock_unlock_irqrestore(ml_hwlock_t *lck, unsigned long flags)
+{
+	(void)flags;
+	ml_hwlock_unlock(lck);
+}
diff --git a/arch/user/include/arch/stdcon.h b/arch/user/include/arch/stdcon.h
new file mode 100644
index 0000000..b35d005
--- /dev/null
+++ b/arch/user/include/arch/stdcon.h
@@ -0,0 +1,6 @@
+#ifndef ARCH_STDCON_H_
+#define ARCH_STDCON_H_
+
+extern void stdcon_init(void);
+
+#endif
diff --git a/arch/user/include/socks/machine/cpu.h b/arch/user/include/socks/machine/cpu.h
new file mode 100644
index 0000000..36f90dc
--- /dev/null
+++ b/arch/user/include/socks/machine/cpu.h
@@ -0,0 +1,15 @@
+#ifndef SOCKS_USER_CPU_H_
+#define SOCKS_USER_CPU_H_
+
+typedef struct ml_cpu_block {
+	int cpu_reserved;
+} ml_cpu_block;
+
+extern int ml_init_bootcpu(void);
+
+extern int ml_cpu_block_init(ml_cpu_block *p);
+extern int ml_cpu_block_use(ml_cpu_block *p);
+
+extern void ml_halt_cpu(void);
+
+#endif
diff --git a/arch/user/include/socks/machine/hwlock.h b/arch/user/include/socks/machine/hwlock.h
new file mode 100644
index 0000000..6ba328b
--- /dev/null
+++ b/arch/user/include/socks/machine/hwlock.h
@@ -0,0 +1,14 @@
+#ifndef SOCKS_USER_HWLOCK_H_
+#define SOCKS_USER_HWLOCK_H_
+
+#define ML_HWLOCK_INIT (0)
+
+typedef int ml_hwlock_t;
+
+extern void ml_hwlock_lock(ml_hwlock_t *lck);
+extern void ml_hwlock_unlock(ml_hwlock_t *lck);
+
+extern void ml_hwlock_lock_irqsave(ml_hwlock_t *lck, unsigned long *flags);
+extern void ml_hwlock_unlock_irqrestore(ml_hwlock_t *lck, unsigned long flags);
+
+#endif
diff --git a/arch/user/include/socks/machine/init.h b/arch/user/include/socks/machine/init.h
new file mode 100644
index 0000000..6c594e6
--- /dev/null
+++ b/arch/user/include/socks/machine/init.h
@@ -0,0 +1,8 @@
+#ifndef SOCKS_X86_64_INIT_H_
+#define SOCKS_X86_64_INIT_H_
+
+#include <stdint.h>
+
+extern int ml_init(uintptr_t arg);
+
+#endif
diff --git a/arch/user/include/socks/machine/irq.h b/arch/user/include/socks/machine/irq.h
new file mode 100644
index 0000000..be06f01
--- /dev/null
+++ b/arch/user/include/socks/machine/irq.h
@@ -0,0 +1,5 @@
+#ifndef SOCKS_X86_64_IRQ_H_
+#define SOCKS_X86_64_IRQ_H_
+
+
+#endif
diff --git a/arch/user/include/socks/machine/pmap.h b/arch/user/include/socks/machine/pmap.h
new file mode 100644
index 0000000..85a1829
--- /dev/null
+++ b/arch/user/include/socks/machine/pmap.h
@@ -0,0 +1,9 @@
+#ifndef SOCKS_X86_64_PMAP_H_
+#define SOCKS_X86_64_PMAP_H_
+
+#include <arch/paging.h>
+
+typedef pml4t_ptr_t ml_pmap_t;
+typedef uint64_t ml_pfn_t;
+
+#endif
diff --git a/arch/user/include/socks/machine/vm.h b/arch/user/include/socks/machine/vm.h
new file mode 100644
index 0000000..d841b4c
--- /dev/null
+++ b/arch/user/include/socks/machine/vm.h
@@ -0,0 +1,26 @@
+#ifndef SOCKS_USER_VM_H_
+#define SOCKS_USER_VM_H_
+
+#include <stdint.h>
+
+extern uintptr_t __pagemap_base(void);
+extern uintptr_t __pagemap_limit(void);
+
+/* kernel higher-half base virtual address. */
+#define VM_KERNEL_VOFFSET (__pagemap_base())
+
+/* direct page-mapping region.
+   NOTE that these are the maximum bounds of this region.
+   the actual size depends on the amount of physical
+   memory present. */
+#define VM_PAGEMAP_BASE   (__pagemap_base())
+#define VM_PAGEMAP_LIMIT  (__pagemap_limit())
+
+#define VM_PAGE_SIZE  0x1000
+#define VM_PAGE_MASK  (VM_PAGE_SIZE-1)
+#define VM_PAGE_SHIFT 12
+
+#define VM_PAGE_MIN_ORDER VM_PAGE_4K
+#define VM_PAGE_MAX_ORDER VM_PAGE_8M
+
+#endif
diff --git a/arch/user/init.c b/arch/user/init.c
new file mode 100644
index 0000000..6436daa
--- /dev/null
+++ b/arch/user/init.c
@@ -0,0 +1,68 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <socks/init.h>
+#include <socks/memblock.h>
+#include <socks/vm.h>
+#include <socks/object.h>
+#include <socks/printk.h>
+#include <arch/stdcon.h>
+#include <sys/mman.h>
+
+#define PMEM_SIZE 0x2000000
+
+extern void kernel_init(uintptr_t arg);
+
+static void *pmem = NULL;
+
+static void early_vm_init(void)
+{
+	pmem = mmap(NULL, PMEM_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if (pmem == MAP_FAILED) {
+		fprintf(stderr, "arch: cannot map physical memory buffer.");
+		abort();
+	}
+	
+	uintptr_t alloc_start = (uintptr_t)pmem + VM_PAGE_SIZE;
+	uintptr_t alloc_end = alloc_start + PMEM_SIZE;
+
+	memblock_init(alloc_start, alloc_end, (uintptr_t)pmem);
+	printk("memblock: allocating from [0x%llx-0x%llx]", alloc_start, alloc_end);
+}
+
+uintptr_t __pagemap_base(void)
+{
+	return (uintptr_t)pmem;
+}
+
+uintptr_t __pagemap_limit(void)
+{
+	return (uintptr_t)pmem + PMEM_SIZE - 1;
+}
+
+int ml_init(uintptr_t arg)
+{
+	stdcon_init();
+	print_kernel_banner();
+	early_vm_init();
+
+	memblock_add(0, PMEM_SIZE);
+
+	vm_zone_descriptor_t vm_zones[] = {
+		{ .zd_id = VM_ZONE_DMA, .zd_node = 0, .zd_name = "dma", .zd_base = 0x00, .zd_limit = 0xffffff },
+		{ .zd_id = VM_ZONE_NORMAL, .zd_node = 0, .zd_name = "normal", .zd_base = 0x1000000, .zd_limit = UINTPTR_MAX },
+	};
+
+	vm_bootstrap(vm_zones, sizeof vm_zones / sizeof vm_zones[0]);
+
+	object_bootstrap();
+	return 0;
+}
+
+int main(int argc, const char **argv)
+{
+	kernel_init(0);
+
+	munmap(pmem, PMEM_SIZE);
+	return 0;
+}
diff --git a/arch/user/stdcon.c b/arch/user/stdcon.c
new file mode 100644
index 0000000..d71373e
--- /dev/null
+++ b/arch/user/stdcon.c
@@ -0,0 +1,27 @@
+#include <socks/libc/string.h>
+#include <socks/libc/ctype.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <socks/console.h>
+#include <socks/vm.h>
+#include <socks/printk.h>
+
+static void stdcon_write(console_t *con, const char *s, unsigned int len)
+{
+	for (unsigned int i = 0; i < len; i++) {
+		fputc(s[i], stdout);
+	}
+}
+
+static console_t stdcon = {
+	.c_name = "stdcon",
+	.c_flags = CON_BOOT,
+	.c_write = stdcon_write,
+	.c_lock = SPIN_LOCK_INIT,
+};
+
+void stdcon_init(void)
+{
+	console_register(&stdcon);
+	early_printk_init(&stdcon);
+}
diff --git a/arch/x86_64/config.mk b/arch/x86_64/config.mk
index 308c1a7..484fb9a 100644
--- a/arch/x86_64/config.mk
+++ b/arch/x86_64/config.mk
@@ -1,7 +1,17 @@
+LD  := $(SOCKS_ARCH)-elf-gcc
+CC  := $(SOCKS_ARCH)-elf-gcc
+ASM := $(SOCKS_ARCH)-elf-gcc
+OBJCOPY := $(SOCKS_ARCH)-elf-objcopy
+STRIP := $(SOCKS_ARCH)-elf-strip
+
+CFLAGS   := -ffreestanding -nostdlib
+ASMFLAGS := $(CFLAGS)
+LDFLAGS  := -nostdlib
+
 ARCH_CFLAGS := -z max-page-size=0x1000 -m64 -mcmodel=large -mno-red-zone -mno-mmx -mno-sse -mno-sse2 -D_64BIT -DBYTE_ORDER=1234
 ARCH_LDFLAGS := -z max-page-size=0x1000 -T arch/x86_64/layout.ld
 
-ARCH_DIR := arch/$(ARCH)
+ARCH_DIR := arch/$(SOCKS_ARCH)
 
 ARCH_C_FILES := $(wildcard $(ARCH_DIR)/*.c) $(wildcard $(ARCH_DIR)/acpi/*.c)
 ARCH_ASM_FILES := $(wildcard $(ARCH_DIR)/*.S) $(wildcard $(ARCH_DIR)/acpi/*.S)
diff --git a/arch/x86_64/extra.mk b/arch/x86_64/extra.mk
index 9153d85..5b47079 100644
--- a/arch/x86_64/extra.mk
+++ b/arch/x86_64/extra.mk
@@ -1,5 +1,5 @@
 QEMU := qemu-system-x86_64
-QEMU_FLAGS := -m 64M -smp 4 -cpu qemu64,pdpe1gb
+QEMU_FLAGS := -m 10M -smp 4 -cpu qemu64,pdpe1gb
 
 ARCH_TEMP_FILES := $(BUILD_DIR)/$(KERNEL_EXEC).elf32
 
diff --git a/libc/include/socks/libc/string.h b/libc/include/socks/libc/string.h
index 87c2c3f..a993d35 100644
--- a/libc/include/socks/libc/string.h
+++ b/libc/include/socks/libc/string.h
@@ -9,7 +9,7 @@ extern "C" {
 #endif
 
 extern char *strcpy(char *output, const char *input);
-extern char *strncpy(char *output, const char *input, unsigned int count);
+extern char *strncpy(char *output, const char *input, unsigned long count);
 extern char *strchrnul(const char *s, int c);
 extern char *strchr(const char *s, int c);
 extern size_t lfind(const char *str, const char accept);
@@ -19,7 +19,7 @@ extern char *strpbrk(const char *s, const char *b);
 extern size_t strlen(const char *str);
 extern char *strrchr(const char *str, int c);
 extern int strcmp(const char *s1, const char *s2);
-extern int strncmp(const char *s1, const char *s2, unsigned int n);
+extern int strncmp(const char *s1, const char *s2, unsigned long n);
 extern void *memcpy(void *str1, const void *str2, size_t n);
 extern int memcmp(const void *str1, const void *str2, size_t n);
 extern void *memset(void *str, int c, size_t n);
@@ -28,7 +28,7 @@ extern char *strdup(const char *src);
 extern char *strtok_r(char *str, const char *delim, char **saveptr);
 extern char *strcat(char *dest, const char *src);
 extern char *strncat(char *dest, const char *src, size_t num);
-extern void *memchr(const void *ptr, int value, size_t num);
+extern void *memchr(const void *ptr, int value, unsigned long num);
 
 #ifdef __cplusplus
 }
diff --git a/libc/string/memchr.c b/libc/string/memchr.c
index 9b4d9f1..7c47d65 100644
--- a/libc/string/memchr.c
+++ b/libc/string/memchr.c
@@ -1,10 +1,10 @@
 #include <stddef.h>
 
-const void *memchr(const void *ptr, int value, size_t num) {
+void *memchr(const void *ptr, int value, unsigned long num) {
     const unsigned char *buf = ptr;
     unsigned char val = value;
 
-    for (size_t i = 0; i < num; i++) {
+    for (unsigned long i = 0; i < num; i++) {
         if (buf[i] == val) {
             return (void *)(buf + i);
         }
diff --git a/libc/string/strcmp.c b/libc/string/strcmp.c
index 42aea66..f35df9b 100644
--- a/libc/string/strcmp.c
+++ b/libc/string/strcmp.c
@@ -8,7 +8,7 @@ int strcmp(const char *s1, const char *s2)
     return s1[i] - s2[i];
 }
 
-int strncmp(const char *s1, const char *s2, unsigned int n)
+int strncmp(const char *s1, const char *s2, unsigned long n)
 {
     for (; n > 0; s1++, s2++, --n)
         if (*s1 != *s2)
diff --git a/libc/string/strcpy.c b/libc/string/strcpy.c
index 7a816de..3056e02 100644
--- a/libc/string/strcpy.c
+++ b/libc/string/strcpy.c
@@ -11,10 +11,10 @@ char *strcpy(char *output, const char *input)
     return output;
 }
 
-char *strncpy(char *output, const char *input, unsigned int count)
+char *strncpy(char *output, const char *input, unsigned long count)
 {
-    unsigned int size = count;
-    unsigned int i;
+    unsigned long size = count;
+    unsigned long i;
     for (i = 0; i < size; i++) {
         output[i] = input[i];
 
diff --git a/tools/make/gcc-cross-compile.mk b/tools/make/gcc-cross-compile.mk
index d24eba1..e69de29 100644
--- a/tools/make/gcc-cross-compile.mk
+++ b/tools/make/gcc-cross-compile.mk
@@ -1,10 +0,0 @@
-LD  := $(ARCH)-elf-gcc
-CC  := $(ARCH)-elf-gcc
-ASM := $(ARCH)-elf-gcc
-OBJCOPY := $(ARCH)-elf-objcopy
-STRIP := $(ARCH)-elf-strip
-
-CFLAGS   := -ffreestanding -nostdlib
-ASMFLAGS := $(CFLAGS)
-LDFLAGS  := -nostdlib
-