build system and some other stuff

20 files changed, 337 insertions, 34 deletions

diff --git a/Makefile b/Makefile
index 3c2a981..e683c86 100644
--- a/Makefile
+++ b/Makefile
@@ -1,30 +1,22 @@
 TARGET?=virt
 CROSS_COMPILE?=riscv64-unknown-elf- 
+GDB_PORT?=1234
+CFLAGS=-nostdlib -ffreestanding -mcmodel=medany -nostdinc -I${.CURDIR}/include 
+.export
 
-BUILDDIR=build/${TARGET}
-TARGETDIR=mainboard/${TARGET}
+sys: ${SRC} lib/build/libc.a
+	@echo "building kernel"
+	(${MAKE} -C sys -e) 
 
-CFLAGS=-nostdlib -ffreestanding -mcmodel=medany
+lib/build/libc.a: 
+	@echo "building libc"
+	(${MAKE} -C lib -e)
 
-.if !exists(${TARGETDIR}/conf/mainboard.mk)
-.error 'ERROR: invalid target "${TARGET}"'
-.else
-.include <${TARGETDIR}/conf/mainboard.mk>
-.endif
-
-all: ${BUILDDIR}/kernel.elf 
+debug: sys
+	(${MAKE} -C sys -e debug) 
 
 clean:
-	rm -rf ${BUILDDIR}
-
-${BUILDDIR}/kernel.elf: ${SRC}
-	mkdir -p ${BUILDDIR}
-	${CROSS_COMPILE}gcc ${SRC} \
-		-Wl,--defsym=LOAD_ADDR=${LOAD_ADDR}\
-		-Wl,--defsym=PAGE_SIZE=${PAGE_SIZE}\
-		-Wl,--defsym=NPROC=${NPROC}\
-		-DPAGE_SIZE=${PAGE_SIZE}\
-		${CFLAGS} -T kernel/lds/kernel.ld ${LDFLAGS}\
-		-o $@
+	(${MAKE} -C sys -e clean)
+	(${MAKE} -C lib -e clean)
 
-.PHONY: all clean
+.PHONY: sys debug all clean
diff --git a/include/endian.h b/include/endian.h
new file mode 100644
index 0000000..79b4c93
--- /dev/null
+++ b/include/endian.h
@@ -0,0 +1,17 @@
+#ifndef _ENDIAN_H
+#define _ENDIAN_H
+
+#include <stdint.h>
+
+#define LITTLE_ENDIAN 1234
+#define BIG_ENDIAN	4321
+#define BYTE_ORDER __BYTE_ORDER__
+
+static inline uint32_t
+__bswap32(uint32_t x)
+{
+        uint8_t *p = (uint8_t*)&x;
+        return ((p[0] << 030) | (p[1] << 020) | (p[2] << 010) | p[3]);
+}
+
+#endif /* _ENDIAN_H */
diff --git a/include/stddef.h b/include/stddef.h
new file mode 100644
index 0000000..998f53d
--- /dev/null
+++ b/include/stddef.h
@@ -0,0 +1,7 @@
+#ifndef _STDDEF_H
+#define _STDDEF_H
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+
+#endif /* _STDDEF_H_ */
diff --git a/include/stdint.h b/include/stdint.h
new file mode 100644
index 0000000..4afd32d
--- /dev/null
+++ b/include/stdint.h
@@ -0,0 +1,19 @@
+#ifndef _STDINT_H
+#define _STDINT_H
+
+
+typedef unsigned char	uint8_t;
+typedef unsigned short 	uint16_t;
+typedef unsigned int	uint32_t;
+typedef unsigned long	uint64_t;
+
+
+typedef char	int8_t;
+typedef short 	int16_t;
+typedef int	int32_t;
+typedef long	int64_t;
+
+
+#endif /* _STDINT_H */
+  
+  
diff --git a/include/string.h b/include/string.h
new file mode 100644
index 0000000..a8edd63
--- /dev/null
+++ b/include/string.h
@@ -0,0 +1,8 @@
+#ifndef _STRING_H
+#define _STRING_H
+
+#include <stddef.h>
+
+void *memset(void *s, int c, size_t n);
+
+#endif /* _STRING_H */
diff --git a/lib/Makefile b/lib/Makefile
new file mode 100644
index 0000000..b44c1f6
--- /dev/null
+++ b/lib/Makefile
@@ -0,0 +1,21 @@
+BUILDDIR=build/${TARGET}
+TARGETDIR=../mainboard/${TARGET}
+
+.if !exists(${TARGETDIR}/conf/mainboard.conf)
+.error 'ERROR: invalid target "${TARGET}"'
+.else
+.include <${TARGETDIR}/conf/mainboard.conf>
+.endif
+
+SRC=\
+    string/memset.c
+
+
+${BUILDDIR}/libc.a: ${SRC}
+	mkdir -p ${BUILDDIR}
+	cd ${BUILDDIR} && ${CROSS_COMPILE}gcc -c ${CFLAGS} ${SRC:%=../../%}
+	cd ${BUILDDIR} && ${CROSS_COMPILE}ar -rcs ${@:T} ${SRC:T:%.c=%.o}
+
+
+clean:
+	rm -rf ${BUILDDIR}
diff --git a/lib/build/memset.o b/lib/build/memset.o
new file mode 100644
index 0000000..a5c0c8c
--- /dev/null
+++ b/lib/build/memset.o
diff --git a/lib/string/memset.c b/lib/string/memset.c
new file mode 100644
index 0000000..59e3bea
--- /dev/null
+++ b/lib/string/memset.c
@@ -0,0 +1,14 @@
+#include <stddef.h>
+#include <string.h>
+
+void *
+memset(void *s, int c, size_t n)
+{
+	char *xs = s;
+
+	while (n--)
+		*xs++ = c;
+
+	return s;
+}
+
diff --git a/mainboard/virt/conf/mainboard.conf b/mainboard/virt/conf/mainboard.conf
new file mode 100644
index 0000000..77e8e2a
--- /dev/null
+++ b/mainboard/virt/conf/mainboard.conf
@@ -0,0 +1,4 @@
+LOAD_ADDR=0x80200000
+PAGE_SIZE=4096
+NPROC=1
+DEBUG=qemu-system-riscv64 -nographic -machine virt -smp ${NPROC} -m 128M -bios default -gdb tcp::${GDB_PORT} -kernel
diff --git a/sys/Makefile b/sys/Makefile
new file mode 100644
index 0000000..865a5a3
--- /dev/null
+++ b/sys/Makefile
@@ -0,0 +1,36 @@
+BUILDDIR=build/${TARGET}
+TARGETDIR=../mainboard/${TARGET}
+
+.if !exists(${TARGETDIR}/conf/mainboard.conf)
+.error 'ERROR: invalid target "${TARGET}"'
+.else
+.include <${TARGETDIR}/conf/mainboard.conf>
+.endif
+
+SRC=\
+    kern/entry.S\
+    kern/init.c\
+    kern/kernel_earlyprintf.c\
+    kern/mm/kalloc.c\
+    dev/sbi.c
+
+${BUILDDIR}/kernel.elf: ${SRC}
+	mkdir -p ${BUILDDIR}
+	${CROSS_COMPILE}gcc ${SRC} \
+		-Wl,--defsym=LOAD_ADDR=${LOAD_ADDR}\
+		-Wl,--defsym=PAGE_SIZE=${PAGE_SIZE}\
+		-Wl,--defsym=NPROC=${NPROC}\
+		-DPAGE_SIZE=${PAGE_SIZE}\
+		-I ./include\
+		${CFLAGS} -T kern/kernel.lds ${LDFLAGS}\
+		-L../lib/${BUILDDIR}/\
+		-l:libc.a\
+		-o $@
+
+debug: ${BUILDDIR}/kernel.elf
+	${DEBUG} ${BUILDDIR}/kernel.elf
+
+clean:
+	rm -rf ${BUILDDIR}
+
+.PHONY: debug clean
diff --git a/sys/dev/sbi.c b/sys/dev/sbi.c
new file mode 100644
index 0000000..0c9e3f2
--- /dev/null
+++ b/sys/dev/sbi.c
@@ -0,0 +1,39 @@
+#include <sbi.h>
+
+struct sbiret 
+sbi_ecall(int ext, int fid, unsigned long arg0,
+                        unsigned long arg1, unsigned long arg2,
+                        unsigned long arg3, unsigned long arg4,
+                        unsigned long arg5)
+{
+        struct sbiret ret;
+
+        register unsigned long a0 asm ("a0") = (unsigned long)(arg0);
+        register unsigned long a1 asm ("a1") = (unsigned long)(arg1);
+        register unsigned long a2 asm ("a2") = (unsigned long)(arg2);
+        register unsigned long a3 asm ("a3") = (unsigned long)(arg3);
+        register unsigned long a4 asm ("a4") = (unsigned long)(arg4);
+        register unsigned long a5 asm ("a5") = (unsigned long)(arg5);
+        register unsigned long a6 asm ("a6") = (unsigned long)(fid);
+        register unsigned long a7 asm ("a7") = (unsigned long)(ext);
+        asm volatile ("ecall"
+                      : "+r" (a0), "+r" (a1)
+                      : "r" (a2), "r" (a3), "r" (a4), "r" (a5), "r" (a6), "r" (a7)
+                      : "memory");
+        ret.err = a0;
+        ret.val = a1;
+
+        return ret;
+}
+
+void
+sbi_console_putchar(int c)
+{
+	sbi_ecall(1, 0, c, 0, 0, 0, 0, 0);
+}
+
+void
+sbi_shutdown(void)
+{
+	sbi_ecall(8, 0, 0, 0, 0, 0, 0, 0);
+}
diff --git a/sys/include/fdt.h b/sys/include/fdt.h
new file mode 100644
index 0000000..92e5695
--- /dev/null
+++ b/sys/include/fdt.h
@@ -0,0 +1,37 @@
+#include <stdint.h>
+#include <endian.h>
+
+#ifndef _FDT_H
+#define _FDT_H
+
+#define FDT_HEADER_MAGIC        0xd00dfeed
+
+static inline uint32_t
+fdt_uint32(uint32_t x)
+{
+#if BYTE_ORDER == LITTLE_ENDIAN
+return __bswap32(x);
+#else
+return x;
+#endif
+}
+
+struct fdt_header {
+        uint32_t magic;                 /* FDT_HEADER_MAGIC */
+        uint32_t totalsize;             /* size of the whole device tree, in bytes */
+        uint32_t off_dt_struct;         /* offset to structure block */
+        uint32_t off_dt_strings;        /* offset to strings block */
+        uint32_t off_mem_rsvmap;        /* offset to memory reservation block */
+        uint32_t version;               /* dt spec version */
+        uint32_t last_comp_version;     /* last compatible version. spec says this needs to be 16 */
+        uint32_t boot_cpuid_phys;       /* physical id of the systems boot cpu */
+        uint32_t size_dt_strings;       /* size of strings block */
+        uint32_t size_dt_struct;        /* size of structure block */
+};
+
+struct fdt_reserve_entry {
+        uint64_t address;
+        uint64_t size;
+};
+
+#endif /* _FDT_H */
diff --git a/sys/include/kernel_earlyprintf.h b/sys/include/kernel_earlyprintf.h
new file mode 100644
index 0000000..051d7e5
--- /dev/null
+++ b/sys/include/kernel_earlyprintf.h
@@ -0,0 +1,6 @@
+#ifndef _KPRINTF_H
+#define _KPRINTF_H
+
+int kernel_earlyputs(const char *); 
+
+#endif /* _KPRINTF_H */
diff --git a/sys/include/mm/kalloc.h b/sys/include/mm/kalloc.h
new file mode 100644
index 0000000..e99d624
--- /dev/null
+++ b/sys/include/mm/kalloc.h
@@ -0,0 +1,11 @@
+#ifndef _KALLOC_H
+#define _KALLOC_H
+
+void *kalloc(void);
+
+void *kzalloc(void);
+
+void kfree(void *);
+
+#endif /* _KALLOC_H */
+
diff --git a/sys/include/sbi.h b/sys/include/sbi.h
new file mode 100644
index 0000000..0dbcd02
--- /dev/null
+++ b/sys/include/sbi.h
@@ -0,0 +1,16 @@
+#ifndef _SBICALL_H
+#define _SBICALL_H
+
+struct sbiret {
+        long err;
+        long val;
+};
+
+struct sbiret 	sbi_ecall(int _eid, int _fid, unsigned long _a0, unsigned long _a1, 
+               		unsigned long _a2, unsigned long _a3, unsigned long _a4, unsigned long _a5);
+
+void    sbi_console_putchar(int c);
+void    sbi_shutdown(void);
+
+#endif /* _SBICALL_H */
+
diff --git a/kernel/boot/entry.S b/sys/kern/entry.S
index 4c977a3..5ad0490 100644
--- a/kernel/boot/entry.S
+++ b/sys/kern/entry.S
@@ -1,4 +1,4 @@
-.section .text.init
+.section ".text.init"
 
 .globl _start
 _start:
@@ -12,25 +12,28 @@ _start:
         .option pop
 
         la         sp, __stack_start
-        mv         t0, a0
         li         t1, PAGE_SIZE 
-        mul        t0, t0, t1
-        add        sp, sp, t0
+        mul        t1, t1, a0
+        add        sp, sp, t1
 
         li         a2, 1
         lla        a3, _boot_hart
-        amoswap.w, a3, a2, (a3)
-        bnez a3,   mp_entry 
+        amoswap.w  a3, a2, (a3)
+        bnez a3,   _spin
 
         la         a2, __bss_start
         la         a3, __bss_end
 1:
-        sd         zero, (a2)
+        sd	   zero, (a2)
         addi       a2, a2, __SIZEOF_POINTER__
         blt        a2, a3, 1b 
         
-        call       boot
+        call       init
 
-_boot_hart:
-        .dword 0
 
+_spin:
+	wfi
+	j _spin
+
+.section ".data"
+_boot_hart: .word 0
diff --git a/sys/kern/init.c b/sys/kern/init.c
new file mode 100644
index 0000000..a49c304
--- /dev/null
+++ b/sys/kern/init.c
@@ -0,0 +1,11 @@
+#include <fdt.h>
+#include <kernel_earlyprintf.h>
+
+void 
+init(unsigned long hartid, struct fdt_header *fdt)
+{
+	kernel_earlyputs("booting...\n");
+	if (fdt_uint32(fdt->magic) == FDT_HEADER_MAGIC) 
+		kernel_earlyputs("found flattened device tree!\n");
+
+}
diff --git a/kernel/lds/kernel.ld b/sys/kern/kernel.lds
index 052aa32..2e2fe29 100644
--- a/kernel/lds/kernel.ld
+++ b/sys/kern/kernel.lds
@@ -8,13 +8,13 @@ SECTIONS
 
         .text :
         {
-                provide(__text_start = .);
+                PROVIDE(__text_start = .);
                 *(.text.init)
                 *(.text .text.*)
                 . = ALIGN(8);
                 PROVIDE(__text_end = .);
         }
-        .  = ALIGN(PAGE_SIZE);
+        . = ALIGN(PAGE_SIZE);
 
         PROVIDE(__global_pointer$ = .);
 
@@ -41,6 +41,17 @@ SECTIONS
 
         . = ALIGN(PAGE_SIZE); 
 
+	.bss :
+	{
+		PROVIDE(__bss_start = .);
+		*(.sbss .sbss.*)
+		*(.bss .bss.*)
+		. = ALIGN(8);
+		PROVIDE(__bss_end = .);
+	}
+
+	. = ALIGN(PAGE_SIZE);
+
         PROVIDE(__stack_start = .);
         PROVIDE(__stack_end = __stack_start + (PAGE_SIZE * NPROC));
         PROVIDE(__heap_start = __stack_end);
diff --git a/sys/kern/kernel_earlyprintf.c b/sys/kern/kernel_earlyprintf.c
new file mode 100644
index 0000000..e6c85c4
--- /dev/null
+++ b/sys/kern/kernel_earlyprintf.c
@@ -0,0 +1,11 @@
+#include <kernel_earlyprintf.h>
+#include <sbi.h>
+
+int
+kernel_earlyputs(const char *str)
+{
+	do {
+		sbi_console_putchar(*str);
+	} while (*(str++) != '\0');
+}
+
diff --git a/sys/kern/mm/kalloc.c b/sys/kern/mm/kalloc.c
new file mode 100644
index 0000000..b17d432
--- /dev/null
+++ b/sys/kern/mm/kalloc.c
@@ -0,0 +1,40 @@
+#include <stddef.h>
+#include <string.h>
+#include <mm/kalloc.h>
+
+typedef struct freenode {
+	struct freenode *next;
+} freenode_t;
+
+freenode_t *head = NULL;
+
+void *
+kalloc(void) 
+{
+	freenode_t *p = head;
+
+	if (p == NULL)
+		return NULL;
+
+	head = p->next;
+	return p;
+}
+
+void *
+kzalloc(void)
+{
+	freenode_t *p = kalloc();
+	memset(p, 0, PAGE_SIZE);
+	return p;
+}
+
+void
+kfree(void *p)
+{
+	if (p == NULL || (unsigned long)p % PAGE_SIZE)
+		return;
+
+	freenode_t *tmp = head;
+	head = p;
+	head->next = tmp;
+}