build system and some other stuff

11 files changed, 304 insertions, 0 deletions

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/sys/kern/entry.S b/sys/kern/entry.S
new file mode 100644
index 0000000..5ad0490
--- /dev/null
+++ b/sys/kern/entry.S
@@ -0,0 +1,39 @@
+.section ".text.init"
+
+.globl _start
+_start:
+        csrw       satp, zero
+        csrw       sie, zero
+        csrw       sip, zero
+
+        .option push
+        .option norelax
+        la         gp, __global_pointer$
+        .option pop
+
+        la         sp, __stack_start
+        li         t1, PAGE_SIZE 
+        mul        t1, t1, a0
+        add        sp, sp, t1
+
+        li         a2, 1
+        lla        a3, _boot_hart
+        amoswap.w  a3, a2, (a3)
+        bnez a3,   _spin
+
+        la         a2, __bss_start
+        la         a3, __bss_end
+1:
+        sd	   zero, (a2)
+        addi       a2, a2, __SIZEOF_POINTER__
+        blt        a2, a3, 1b 
+        
+        call       init
+
+
+_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/sys/kern/kernel.lds b/sys/kern/kernel.lds
new file mode 100644
index 0000000..2e2fe29
--- /dev/null
+++ b/sys/kern/kernel.lds
@@ -0,0 +1,58 @@
+OUTPUT_ARCH(riscv)
+ENTRY(_start)
+
+SECTIONS
+{
+        . = LOAD_ADDR;
+        . = ALIGN(PAGE_SIZE);
+
+        .text :
+        {
+                PROVIDE(__text_start = .);
+                *(.text.init)
+                *(.text .text.*)
+                . = ALIGN(8);
+                PROVIDE(__text_end = .);
+        }
+        . = ALIGN(PAGE_SIZE);
+
+        PROVIDE(__global_pointer$ = .);
+
+        .rodata :
+        {
+                PROVIDE(__rodata_start = .);
+                *(.rodata .rodata.*)
+                . = ALIGN(8);
+                PROVIDE(__rodata_end = .); 
+        }
+
+        . = ALIGN(PAGE_SIZE);
+
+        .data : 
+        {
+                PROVIDE(__data_start = .);
+                *(.sdata .sdata.*) 
+                *(.data .data.*)
+                *(.readmostly.data)
+                *(*.data)
+                . = ALIGN(8);
+                PROVIDE(__data_end = .);
+        }
+
+        . = 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;
+}