Allow debug option to be communicated at boot

qemu.sh

@@ -1,13 +1,16 @@
 #!/usr/bin/env bash
 
 build="$(dirname $0)/build"
+assets="$(dirname $0)/assets"
 debug=""
+flash_name="ovmf.fd"
 gfx="-nographic"
 
 for arg in $@; do
 	case "${arg}" in
 		--debug)
 			debug="-s"
+			flash_name="ovmf_debug.fd"
 			;;
 		--gfx)
 			gfx=""
@@ -28,11 +31,16 @@ if ! ninja -C "${build}"; then
 fi
 
 if [[ -n $TMUX ]]; then
+	if [[ -n $debug ]]; then
+		tmux split-window "gdb ${build}/popcorn.elf" &
+	else
 		tmux split-window "sleep 1; telnet localhost 45454" &
+	fi
 fi
 
+touch "${build}/popd_table.data"
 exec qemu-system-x86_64 \
-	-drive "if=pflash,format=raw,file=${build}/flash.img" \
+	-drive "if=pflash,format=raw,file=${build}/${flash_name}" \
 	-drive "format=raw,file=${build}/popcorn.img" \
 	-monitor telnet:localhost:45454,server,nowait \
 	-smp 1 \

scripts/templates/build.ninja.j2

@@ -152,8 +152,11 @@ build $
     $modulefile $
     {{ generator }}
 
-build $builddir/flash.img : cp $srcroot/assets/ovmf/x64/OVMF.fd
+build $builddir/ovmf.fd : cp $srcroot/assets/ovmf/x64/ovmf.fd
-    name = flash.img
+    name = ovmf.fd
+
+build $builddir/ovmf_debug.fd : cp $srcroot/assets/ovmf/x64/ovmf_debug.fd
+    name = ovmf_debug.fd
 
 build $builddir/popcorn.elf | $builddir/popcorn.elf.debug : strip $builddir/host/popcorn.elf
     name = kernel
@@ -177,5 +180,5 @@ build $builddir/popcorn.img : makefat | $
     $builddir/fatroot/efi/boot/bootx64.efi
     name = popcorn.img
 
-# vim: et ts=4 sts=4 sw=4
+# vim: ft=ninja et ts=4 sts=4 sw=4
 

scripts/templates/exe.boot.j2

@@ -2,18 +2,13 @@
 {% block variables %}
 {{ super() }}
 
-ld = ld
-cc = clang
-cxx = clang++
-
 ccflags = $ccflags $
     -DKERNEL_FILENAME=L\"popcorn.elf\" $
     -DGNU_EFI_USE_MS_ABI $
     -DHAVE_USE_MS_ABI $
     -DEFI_DEBUG=0 $
     -DEFI_DEBUG_CLEAR_MEMORY=0 $
-	-DBOOTLOADER_DEBUG $
+    -DBOOTLOADER_DEBUG
-    -fPIC
 
 ldflags = $ldflags $
     -T ${srcroot}/src/arch/x86_64/boot.ld $
@@ -27,3 +22,6 @@ build $builddir/boot.efi : makeefi ${builddir}/{{ module.output }}
     name = boot.efi
 
 {% endblock %}
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/exe.default.j2

@@ -2,11 +2,7 @@
 {% block variables %}
 {{ super() }}
 
-libs = $
-    -L${builddir} $
-    {%- for dep in module.libdeps %}
-    -l{{ dep.name }} $
-    {%- endfor %}
-    $libs
-
 {% endblock %}
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/exe.kernel.j2

@@ -7,3 +7,6 @@ libs = $libs
 ldflags = $ldflags -T ${srcroot}/src/arch/x86_64/kernel.ld
 
 {% endblock %}
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/exe.tests.j2

@@ -5,3 +5,6 @@
 ccflags = $ccflags -ggdb
 
 {% endblock %}
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/lib.default.j2

@@ -1 +1,4 @@
 {% extends "module.base.j2" %}
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/target.boot.j2

@@ -1,10 +1,12 @@
 {% extends "target.default.j2" %}
 
 {% block binaries %}
-ld = ld
 cc = clang
 cxx = clang++
+ld = ld
+ar = ar
 nasm = nasm
+objcopy = objcopy
 {% endblock %}
 
 {% block variables %}
@@ -18,12 +20,13 @@ ccflags = $ccflags $
 	-mno-sse $
 	-fno-omit-frame-pointer $
 	-mno-red-zone $
-    -fshort-wchar
+	-fshort-wchar $
+	-D__ELF__ $
+	-fPIC
 
 cxxflags = $cxxflags $
-    -nostdlibinc $
 	-fno-exceptions $
-    -fno-rtti
+	-fno-rtti $
 
 ldflags = $ldflags $
 	-g $
@@ -33,3 +36,6 @@ ldflags = $ldflags $
 	-nostartfiles
 
 {% endblock %}
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/target.default.j2

@@ -22,3 +22,5 @@ build ${builddir}/cxx.defs : dump_cxx_defs | {{ buildfile }}
 build ${builddir}/cc.run : dump_cc_run | {{ buildfile }}
 build ${builddir}/cxx.run : dump_cxx_run | {{ buildfile }}
 
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/target.host.j2

@@ -40,4 +40,6 @@ ldflags = $ldflags $
     -Bstatic
 
 {% endblock %}
-# vim: et ts=4 sts=4 sw=4
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

scripts/templates/target.native.j2

@@ -5,4 +5,6 @@
 ccflags = $ccflags -g -ggdb
 
 {% endblock %}
-# vim: et ts=4 sts=4 sw=4
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

src/boot/guids.inc

@@ -6,4 +6,6 @@ GUID(0x964e5b22,0x6459,0x11d2,0x8e,0x39,0x00,0xa0,0xc9,0x69,0x72,0x3b, guid_simp
 GUID(0x09576e91,0x6d3f,0x11d2,0x8e,0x39,0x00,0xa0,0xc9,0x69,0x72,0x3b, guid_device_path);
 GUID(0x8b843e20,0x8132,0x4852,0x90,0xcc,0x55,0x1a,0x4e,0x4a,0x7f,0x1c, guid_device_path_to_text);
 
+GUID(0x10d0669c,0x9ec6,0x4268,0xbc,0x48,0xff,0x74,0x75,0x21,0xfe,0x07, guid_popcorn_vendor);
+
 // vim: ft=c

src/boot/loader.cpp

@@ -143,7 +143,7 @@ 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);
+	con_debug(L"ELF is valid, entrypoint %lx\r\n", header.entrypoint);
 
 	data->kernel_entry = (void *)header.entrypoint;
 

src/boot/main.cpp

@@ -5,7 +5,7 @@
 
 #include "console.h"
 #include "guids.h"
-#include "kernel_data.h"
+#include "kernel_args.h"
 #include "loader.h"
 #include "memory.h"
 #include "utility.h"
@@ -34,7 +34,51 @@ struct kernel_header {
 };
 #pragma pack(pop)
 
-using kernel_entry = void (*)(popcorn_data *);
+using kernel_entry = void (*)(kernel_args *);
+
+static void
+type_to_wchar(wchar_t *into, uint32_t type)
+{
+	for (int j=0; j<4; ++j)
+		into[j] = static_cast<wchar_t>(reinterpret_cast<char *>(&type)[j]);
+}
+
+EFI_STATUS
+detect_debug_mode(EFI_RUNTIME_SERVICES *run, kernel_args *header) {
+	wchar_t var_name[] = L"debug";
+
+	EFI_STATUS status;
+	uint8_t debug = 0;
+	UINTN var_size = sizeof(debug);
+
+#ifdef __POPCORN_SET_DEBUG_UEFI_VAR__
+	debug = __POPCORN_SET_DEBUG_UEFI_VAR__;
+	uint32_t attrs =
+		EFI_VARIABLE_NON_VOLATILE |
+		EFI_VARIABLE_BOOTSERVICE_ACCESS |
+		EFI_VARIABLE_RUNTIME_ACCESS;
+	status = run->SetVariable(
+			var_name,
+			&guid_popcorn_vendor,
+			attrs,
+			var_size,
+			&debug);
+	CHECK_EFI_STATUS_OR_RETURN(status, "detect_debug_mode::SetVariable");
+#endif
+
+	status = run->GetVariable(
+			var_name,
+			&guid_popcorn_vendor,
+			nullptr,
+			&var_size,
+			&debug);
+	CHECK_EFI_STATUS_OR_RETURN(status, "detect_debug_mode::GetVariable");
+
+	if (debug)
+		header->flags |= POPCORN_FLAG_DEBUG;
+
+	return EFI_SUCCESS;
+}
 
 extern "C" EFI_STATUS
 efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *system_table)
@@ -73,14 +117,13 @@ efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *system_table)
 	status = memory_get_map_length(bootsvc, &data_length);
 	CHECK_EFI_STATUS_OR_FAIL(status);
 
-	size_t header_size = sizeof(popcorn_data);
+	size_t header_size = sizeof(kernel_args);
-	const size_t header_align = alignof(popcorn_data);
+	const size_t header_align = alignof(kernel_args);
 	if (header_size % header_align)
 		header_size += header_align - (header_size % header_align);
 
 	data_length += header_size;
 
-
 	// Load the kernel image from disk and check it
 	//
 	console::print(L"Loading kernel into memory...\r\n");
@@ -111,12 +154,12 @@ efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *system_table)
 
 	// Set up the kernel data pages to pass to the kernel
 	//
-	struct popcorn_data *data_header = (struct popcorn_data *)load.data; 
+	struct kernel_args *data_header = (struct kernel_args *)load.data;
 	memory_mark_pointer_fixup((void **)&data_header);
 
 	data_header->magic = DATA_HEADER_MAGIC;
 	data_header->version = DATA_HEADER_VERSION;
-	data_header->length = sizeof(struct popcorn_data);
+	data_header->length = sizeof(struct kernel_args);
 
 	data_header->scratch_pages = SCRATCH_PAGES;
 	data_header->flags = 0;
@@ -168,6 +211,8 @@ efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE *system_table)
 	data_header->memory_map_length = map.length;
 	data_header->memory_map_desc_size = map.size;
 
+	detect_debug_mode(runsvc, data_header);
+
 	// bootsvc->Stall(5000000);
 
 	status = bootsvc->ExitBootServices(image_handle, map.key);

src/include/kernel_args.h

@@ -7,8 +7,10 @@
 #define DATA_HEADER_MAGIC     0x600dda7a
 #define DATA_HEADER_VERSION   1
 
+#define POPCORN_FLAG_DEBUG    0x00000001
+
 #pragma pack(push, 1)
-struct popcorn_data {
+struct kernel_args {
 	uint32_t magic;
 	uint16_t version;
 	uint16_t length;

src/kernel/assert.cpp

@@ -18,9 +18,3 @@ __kernel_assert(const char *file, unsigned line, const char *message)
 	__asm__ ( "int $0e7h" );
 	while (1) __asm__ ("hlt");
 }
-
-extern "C" [[noreturn]] void
-__assert_fail(const char *message, const char *file, unsigned int line, const char *function)
-{
-	__kernel_assert(file, line, message);
-}

src/kernel/main.cpp

@@ -11,7 +11,7 @@
 #include "gdt.h"
 #include "interrupts.h"
 #include "io.h"
-#include "kernel_data.h"
+#include "kernel_args.h"
 #include "log.h"
 #include "page_manager.h"
 #include "scheduler.h"
@@ -20,7 +20,7 @@
 #include "syscall.h"
 
 extern "C" {
-	void kernel_main(popcorn_data *header);
+	void kernel_main(kernel_args *header);
 	void *__bss_start, *__bss_end;
 }
 
@@ -39,28 +39,21 @@ init_console()
 
 	log::init(cons);
 	log::enable(logs::apic, log::level::info);
-	log::enable(logs::device, log::level::info);
+	log::enable(logs::device, log::level::debug);
+	log::enable(logs::paging, log::level::info);
 
 	log::enable(logs::driver, log::level::debug);
 	log::enable(logs::memory, log::level::debug);
 	log::enable(logs::fs, log::level::debug);
 	log::enable(logs::task, log::level::debug);
 	log::enable(logs::boot, log::level::debug);
-	log::enable(logs::paging, log::level::debug);
 }
 
 void
-kernel_main(popcorn_data *header)
+kernel_main(kernel_args *header)
 {
-#ifdef DEBUG
+	bool waiting = header && (header->flags && POPCORN_FLAG_DEBUG);
-	// Run `waf configure --debug` to enable compiling with DEBUG turned on.
-	// Then attach to QEMU's gdb server and `set waiting = false` to start
-	// the kernel. This compensates for GDB's poor handling of QEMU going
-	// through the x86 PC startup and switching to 64 bit mode when you
-	// attach to qemu with the -S option.
-	bool waiting = true;
 	while (waiting);
-#endif
 
 	kutil::assert_set_callback(__kernel_assert);
 

src/libraries/kutil/frame_allocator.cpp

@@ -1,5 +1,3 @@
-#include <algorithm>
-
 #include "kutil/frame_allocator.h"
 
 namespace kutil {
@@ -81,7 +79,7 @@ frame_allocator::allocate(size_t count, uintptr_t *address)
 
 	auto *first = m_free.front();
 
-	unsigned n = std::min(count, static_cast<size_t>(first->count));
+	unsigned n = count < first->count ? count : first->count;
 	*address = first->address;
 
 	if (count >= first->count) {