Ninja-based buildsystem now building a running kernel!

generate_build.py

@@ -5,7 +5,7 @@ from collections import namedtuple
 library = namedtuple('library', ['path', 'deps'])
 program = namedtuple('program', ['path', 'deps', 'output', 'targets'])
 source = namedtuple('source', ['name', 'input', 'output', 'action'])
-version = namedtuple('version', ['major', 'minor', 'patch', 'sha'])
+version = namedtuple('version', ['major', 'minor', 'patch', 'sha', 'dirty'])
 
 MODULES = {
     "elf":       library('src/libraries/elf', ['kutil']),
@@ -45,7 +45,7 @@ def get_sources(path, srcroot):
                 source(
                     relpath(name, srcroot),
                     abspath(name),
-                    f + ".o",
+                    relpath(abspath(name), path) + ".o",
                     actions[ext]))
 
     return sources
@@ -53,18 +53,24 @@ def get_sources(path, srcroot):
 
 def get_git_version():
     from subprocess import run
-    cp = run(['git', 'describe', '--always'],
+    cp = run(['git', 'describe', '--dirty', '--abbrev=7'],
             check=True, capture_output=True)
     full_version = cp.stdout.decode('utf-8').strip()
 
+    dirty = False
     parts1 = full_version.split('-')
+    if parts1[-1] == "dirty":
+        dirty = True
+        parts1 = parts1[:-1]
+
     parts2 = parts1[0].split('.')
 
     return version(
         parts2[0],
         parts2[1],
         parts2[2],
-        parts1[-1])
+        parts1[-1][1:],
+        dirty)
 
 
 def main(buildroot):

qemu.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+build=${1:-"$(dirname $0)/build"}
+ninja -C $build
+
+kvm=""
+if [[ -f /dev/kvm ]]; then
+	kvm="--enable-kvm"
+fi
+
+exec qemu-system-x86_64 \
+	-drive "if=pflash,format=raw,file=${build}/flash.img" \
+	-drive "format=raw,file=${build}/popcorn.img" \
+	-smp 1 \
+	-m 512 \
+	-d mmu,int,guest_errors \
+	-D popcorn.log \
+	-cpu Broadwell \
+	-M q35 \
+	-no-reboot \
+	-nographic \
+	$kvm

scripts/templates/build.ninja.j2

@@ -31,15 +31,16 @@ ccflags = $
     -DVERSION_MAJOR={{ version.major }} $
     -DVERSION_MINOR={{ version.minor }} $
     -DVERSION_PATCH={{ version.patch }} $
-    -DVERSION_GITSHA=\"{{ version.sha }}\" $
+    -DVERSION_GITSHA=0x{% if version.dirty %}1{% else %}0{% endif %}{{ version.sha }} $
     -DGIT_VERSION=\"{{ version.major }}.{{ version.minor }}.{{ version.patch }}-{{ version.sha }}\" $
+    -DGIT_VERSION_WIDE=L\"{{ version.major }}.{{ version.minor }}.{{ version.patch }}-{{ version.sha }}\" $
     $warnflags
 
 asflags = $
     -DVERSION_MAJOR={{ version.major }} $
     -DVERSION_MINOR={{ version.minor }} $
     -DVERSION_PATCH={{ version.patch }} $
-    -DVERSION_GITSHA=\"{{ version.sha }}\"
+    -DVERSION_GITSHA=0x{% if version.dirty %}1{% else %}0{% endif %}{{ version.sha }}
 
 cflags = -std=c11
 cxxflags = -std=c++14
@@ -121,9 +122,6 @@ build $
 build $builddir/flash.img : cp $srcroot/assets/ovmf/x64/OVMF.fd
     name = flash.img
 
-build $builddir/popcorn.fat : cp $srcroot/assets/ovmf/x64/OVMF.fd
-    name = flash.img
-
 build $builddir/fatroot/popcorn.elf : cp $builddir/host/popcorn.elf
     name = kernel to FAT image
 

scripts/templates/target.host.ninja.j2

@@ -11,30 +11,32 @@ objcopy = ${srcroot}/sysroot/bin/x86_64-elf-objcopy
 {% block variables %}
 
 ccflags = $ccflags $
-    -D__ELF__ $
-    -D__POPCORN__ $
-    -nodefaultlibs $
-    -nostdinc $
     -nostdlib $
     -ffreestanding $
+    -nodefaultlibs $
+    -fno-builtin $
     -mno-sse $
     -fno-omit-frame-pointer $
     -mno-red-zone $
+    -g $
     -mcmodel=large $
+    -D__ELF__ $
+    -D__POPCORN__ $
     -isystem${srcroot}/sysroot/include $
     --sysroot="${srcroot}/sysroot"
 
 cxxflags = $cxxflags $
-    -nostdlibinc $
-    -isystem${srcroot}/sysroot/include/c++/v1 $
     -fno-exceptions $
-    -fno-rtti
+    -fno-rtti $
+    -isystem${srcroot}/sysroot/include/c++/v1
 
 ldflags = $ldflags $
     -g $
     -nostdlib $
-    -nostartfiles $
     -znocombreloc $
-    -nostartfiles
+    -Bsymbolic $
+    -nostartfiles $
+    -Bstatic
 
 {% endblock %}
+# vim: et ts=4 sts=4 sw=4

src/arch/x86_64/kernel.ld

@@ -27,7 +27,7 @@ SECTIONS
 		*(.note.*)
 	}
 
-	.bss ALIGN(0x1000) : {
+	.bss ALIGN(16) : {
 		__bss_start = .;
 		*(.bss)
 		__bss_end = .;

src/boot/loader.c

@@ -87,6 +87,8 @@ loader_load_elf(
 {
 	EFI_STATUS status;
 
+	con_debug(L"Opening kernel file %s\r\n", (CHAR16 *)kernel_name);
+
 	EFI_FILE_PROTOCOL *file = NULL;
 	status = root->Open(root, &file, (CHAR16 *)kernel_name, EFI_FILE_MODE_READ,
 						EFI_FILE_READ_ONLY | EFI_FILE_HIDDEN | EFI_FILE_SYSTEM);
@@ -107,6 +109,8 @@ loader_load_elf(
 	status = file->Read(file, &length, &header);
 	CHECK_EFI_STATUS_OR_RETURN(status, L"Reading ELF header");
 
+	con_debug(L"Read %u bytes of ELF header\r\n", length);
+
 	if (length < sizeof(struct elf_header))
 		CHECK_EFI_STATUS_OR_RETURN(EFI_LOAD_ERROR, L"Incomplete read of ELF header");
 
@@ -131,10 +135,14 @@ loader_load_elf(
 		header.machine != 0x3e)
 		CHECK_EFI_STATUS_OR_RETURN(EFI_LOAD_ERROR, L"ELF load error: wrong machine architecture");
 
+	con_debug(L"ELF is valid, entrypoint %lu\r\n", header.entrypoint);
+
 	data->kernel_entry = (void *)header.entrypoint;
 
 	struct elf_program_header prog_header;
 	for (int i = 0; i < header.ph_num; ++i) {
+		con_debug(L"Reading ELF program header %d\r\n", i);
+
 		status = file->SetPosition(file, header.ph_offset + i * header.ph_entsize);
 		CHECK_EFI_STATUS_OR_RETURN(status, L"Setting ELF file position");
 
@@ -156,6 +164,8 @@ loader_load_elf(
 
 	struct elf_section_header sec_header;
 	for (int i = 0; i < header.sh_num; ++i) {
+		con_debug(L"Reading ELF section header %d ", i);
+
 		status = file->SetPosition(file, header.sh_offset + i * header.sh_entsize);
 		CHECK_EFI_STATUS_OR_RETURN(status, L"Setting ELF file position");
 
@@ -163,11 +173,15 @@ loader_load_elf(
 		status = file->Read(file, &length, &sec_header);
 		CHECK_EFI_STATUS_OR_RETURN(status, L"Reading ELF section header");
 
-		if ((sec_header.flags & ELF_SHF_ALLOC) == 0) continue;
+		if ((sec_header.flags & ELF_SHF_ALLOC) == 0) {
+			con_debug(L"SHF_ALLOC section\r\n");
+			continue;
+		}
 
 		void *addr = (void *)(sec_header.addr - KERNEL_VIRT_ADDRESS);
 
 		if (sec_header.type == ELF_ST_PROGBITS) {
+			con_debug(L"PROGBITS section\r\n");
 			status = file->SetPosition(file, sec_header.offset);
 			CHECK_EFI_STATUS_OR_RETURN(status, L"Setting ELF file position");
 
@@ -175,7 +189,10 @@ loader_load_elf(
 			status = file->Read(file, &length, addr);
 			CHECK_EFI_STATUS_OR_RETURN(status, L"Reading file");
 		} else if (sec_header.type == ELF_ST_NOBITS) {
+			con_debug(L"NOBITS section\r\n");
 			bootsvc->SetMem(addr, sec_header.size, 0);
+		} else {
+			con_debug(L"other section\r\n");
 		}
 	}
 

src/boot/utility.h

@@ -32,3 +32,9 @@ const CHAR16 *util_error_message(EFI_STATUS status);
 			: "r"((uint64_t)s), "r"((uint64_t)d), "r"((uint64_t)__LINE__) \
 			: "rax", "rdx", "r8", "r9", "r10"); \
 	}
+
+#ifdef BOOTLOADER_DEBUG
+#define con_debug(...) con_printf(L"DEBUG: " __VA_ARGS__)
+#else
+#define con_debug(...)
+#endif

src/kernel/gdt.s

@@ -3,17 +3,17 @@ extern g_gdtr
 
 global idt_write
 idt_write:
-	lidt [g_idtr]
+	lidt [rel g_idtr]
 	ret
 
 global idt_load
 idt_load:
-	sidt [g_idtr]
+	sidt [rel g_idtr]
 	ret
 
 global gdt_write
 gdt_write:
-	lgdt [g_gdtr]
+	lgdt [rel g_gdtr]
 	mov ax, si ; second arg is data segment
 	mov ds, ax
 	mov es, ax
@@ -30,6 +30,6 @@ gdt_write:
 
 global gdt_load
 gdt_load:
-	sgdt [g_gdtr]
+	sgdt [rel g_gdtr]
 	ret