Change initrd 'executable' bool to type enum.

Not actually integrating with the kernel yet.

assets/initrd.toml

@@ -8,6 +8,11 @@
 #                               # initial application for the kernel to execute
 #                               # on startup
 
+[[files]]
+dest = "vdso.so"
+source = "host/libvdso.so"
+type = "vdso"
+
 [[files]]
 dest = "screenfont.psf"
 source = "../assets/fonts/tamsyn8x16r.psf"
@@ -15,9 +20,9 @@ source = "../assets/fonts/tamsyn8x16r.psf"
 [[files]]
 dest = "nulldrv1"
 source = "user/nulldrv"
-executable = true
+type = "executable"
 
 [[files]]
 dest = "nulldrv2"
 source = "user/nulldrv"
-executable = true
+type = "executable"

modules.yaml

@@ -9,6 +9,7 @@ modules:
             - elf
             - initrd
             - kutil
+            - vdso
         includes:
             - src/kernel
         source:
@@ -64,6 +65,16 @@ modules:
             - src/boot/reloc.cpp
             - src/boot/utility.cpp
 
+    vdso:
+        kind: exe
+        target: host
+        output: libvdso.so
+        extra:
+            - src/arch/x86_64/vdso.ld
+        source:
+            - src/vdso/syscalls.cpp
+            - src/vdso/overrides.cpp
+
     nulldrv:
         kind: exe
         target: user

scripts/templates/build.ninja.j2

@@ -43,6 +43,7 @@ ccflags = $
     $warnflags
 
 asflags = $
+    -I${srcroot}/src/include $
     -DVERSION_MAJOR={{ version_major }} $
     -DVERSION_MINOR={{ version_minor }} $
     -DVERSION_PATCH={{ version_patch }} $
@@ -186,6 +187,7 @@ build $builddir/fatroot/efi/boot/bootx64.efi : cp $builddir/boot/boot.efi
     name = bootloader to FAT image
 
 build $builddir/fatroot/initrd.img : makerd ${srcroot}/assets/initrd.toml | $
+    ${builddir}/host/libvdso.so $
     ${builddir}/native/makerd $
     ${builddir}/user/nulldrv
 

scripts/templates/exe.vdso.j2

@@ -0,0 +1,9 @@
+{% extends "exe.default.j2" %}
+{% block variables %}
+{{ super() }}
+ccflags = $ccflags -fPIC -mcmodel=large
+ldflags = $ldflags -shared -znotext -T ${srcroot}/src/arch/x86_64/vdso.ld
+{% endblock %}
+
+# vim: ft=ninja et ts=4 sts=4 sw=4
+

src/arch/x86_64/vdso.ld

@@ -0,0 +1,73 @@
+PHDRS {
+	headers PT_PHDR FLAGS(4) FILEHDR PHDRS ;
+	rodata PT_LOAD FLAGS(4) ;
+	text PT_LOAD FLAGS(5) ;
+	dynamic PT_DYNAMIC FLAGS(4) ;
+	note PT_NOTE ;
+	eh_frame PT_GNU_EH_FRAME ;
+}
+
+SECTIONS {
+	. = SIZEOF_HEADERS;
+
+	/DISCARD/ : {
+		*(.got*)
+		*(.plt*)
+		*(.note.*)
+		*(.hash*)
+		*(.debug*)
+	}
+
+	.illegal.relocations : {
+		*(.rel*)
+	}
+
+	.illegal.writeable : {
+		*(.data*)
+		*(.bss*)
+	}
+
+	.rodata : {
+		*(.rodata*)
+	} :rodata
+
+	.dynamic : {
+		*(.dynamic)
+	} :dynamic
+
+	.dynsym : {
+		*(.dynsym*)
+	} :rodata :dynamic
+
+	.dynstr : {
+		*(.dynstr*)
+	} :rodata :dynamic
+
+	.gnu.hash : {
+		*(.gnu.hash*)
+	} :rodata
+
+	.eh_frame_hdr : {
+		__eh_frame_start = .;
+		KEEP(*(.eh_frame))
+		__eh_frame_end = .;
+
+		KEEP(*(.eh_frame_hdr))
+	} :eh_frame
+
+	.shstrtab : {
+		*(.shstrtab)
+	}
+
+	.text ALIGN(0x1000) : {
+		*(.text*)
+		*(.init*)
+		*(.fini*)
+		. = ALIGN(0x1000);
+	} :text
+
+	ASSERT(SIZEOF(.illegal.relocations) == 0,
+			"Code has introduced relocations into the VDSO")
+	ASSERT(SIZEOF(.illegal.writeable) == 0,
+			"Code has introduced writeable data into the VDSO")
+}

src/include/syscalls.inc

@@ -2,8 +2,8 @@ SYSCALL(0x00, object_noop,      void)
 SYSCALL(0x01, object_wait,      j6_handle_t, j6_signal_t, j6_signal_t *)
 
 SYSCALL(0x11, process_exit,     int64_t)
-SYSCALL(0x12, process_fork,     pid_t*)
-SYSCALL(0x13, process_getpid,   pid_t*)
+//SYSCALL(0x12, process_fork,     j6_koid_t*)
+//SYSCALL(0x13, process_getpid,   j6_koid_t*)
 SYSCALL(0x14, process_log,      const char *)
 SYSCALL(0x15, process_pause,    void)
 SYSCALL(0x16, process_sleep,    uint64_t)

src/kernel/main.cpp

@@ -108,7 +108,11 @@ kernel_main(kernel_args *header)
 	initrd::disk ird(header->initrd, heap);
 	log::info(logs::boot, "initrd loaded with %d files.", ird.files().count());
 	for (auto &f : ird.files())
-		log::info(logs::boot, "  %s%s (%d bytes).", f.executable() ? "*" : "", f.name(), f.size());
+		log::info(logs::boot, "  %s%s (%d bytes).",
+				f.type() == initrd::file_type::executable ? "*" :
+					f.type() == initrd::file_type::vdso ? "^" : "",
+				f.name(),
+				f.size());
 
 	/*
 	   page_manager::get()->dump_pml4(nullptr, 0);
@@ -163,7 +167,7 @@ kernel_main(kernel_args *header)
 	sched->create_kernel_task(-1, logger_task);
 
 	for (auto &f : ird.files()) {
-		if (f.executable())
+		if (f.type() == initrd::file_type::executable)
 			sched->load_process(f.name(), f.data(), f.size());
 	}
 

src/libraries/initrd/include/initrd/file_type.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <stdint.h>
+
+namespace initrd {
+
+enum class file_type : uint8_t
+{
+	unknown,
+	executable,
+	vdso
+};
+
+} // namespace initrd

src/libraries/initrd/include/initrd/headers.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <stdint.h>
 #include "kutil/enum_bitfields.h"
+#include "initrd/file_type.h"
 
 namespace initrd {
 
@@ -18,10 +19,8 @@ struct disk_header
 	uint8_t reserved[3];
 } __attribute__ ((packed));
 
-
-enum class file_flags : uint16_t
+enum class file_flags : uint8_t
 {
-	executable = 0x01
 };
 
 struct file_header
@@ -29,10 +28,10 @@ struct file_header
 	uint32_t offset;
 	uint32_t length;
 	uint16_t name_offset;
+	file_type type;
 	file_flags flags;
 } __attribute__ ((packed));
 
 } // namepsace initrd
 
 IS_BITFIELD(initrd::disk_flags);
-IS_BITFIELD(initrd::file_flags);

src/libraries/initrd/include/initrd/initrd.h

@@ -5,6 +5,7 @@
 
 #include <stdint.h>
 #include "kutil/vector.h"
+#include "initrd/file_type.h"
 
 // File format:
 // 1x disk_header
@@ -33,8 +34,8 @@ public:
 	/// Get a pointer to the file data
 	const void * data() const;
 
-	/// Whether this file is an executable
-	bool executable() const;
+	/// Type of file
+	file_type type() const;
 
 private:
 	const file_header *m_header;

src/libraries/initrd/initrd.cpp

@@ -16,11 +16,7 @@ file::file(const file_header *header, const void *start) :
 const char * file::name() const { return m_name; }
 const size_t file::size() const { return m_header->length; }
 const void * file::data() const { return m_data; }
-
-bool
-file::executable() const {
-	return bitfield_has(m_header->flags, file_flags::executable);
-}
+file_type file::type() const { return m_header->type; }
 
 
 disk::disk(const void *start, kutil::allocator &alloc) :

src/tools/makerd/entry.cpp

@@ -1,10 +1,10 @@
 #include "entry.h"
 
-entry::entry(const std::string &in, const std::string &out, bool executable) :
+entry::entry(const std::string &in, const std::string &out, initrd::file_type type) :
 	m_in(in),
 	m_out(out),
 	m_file(in, std::ios_base::binary),
-	m_exec(executable)
+	m_type(type)
 {
 	m_file.seekg(0, std::ios_base::end);
 	m_size = m_file.tellg();

src/tools/makerd/entry.h

@@ -1,17 +1,18 @@
 #pragma once
 #include <string>
 #include <fstream>
+#include "initrd/headers.h"
 
 class entry
 {
 public:
-	entry(const std::string &in, const std::string &out, bool executable = false);
+	entry(const std::string &in, const std::string &out, initrd::file_type type);
 
 	inline const std::string & in() const { return m_in; }
 	inline const std::string & out() const { return m_out; }
 	inline const std::ifstream & file() const { return m_file; }
 
-	inline bool executable() const { return m_exec; }
+	inline initrd::file_type type() const { return m_type; }
 	inline size_t size() const { return m_size; }
 	inline bool good() const { return m_file.good(); }
 
@@ -20,6 +21,6 @@ private:
 	std::string m_out;
 	std::ifstream m_file;
 	size_t m_size;
-	bool m_exec;
+	initrd::file_type m_type;
 };
 

src/tools/makerd/main.cpp

@@ -43,9 +43,15 @@ int main(int argc, char **argv)
 			return 1;
 		}
 
-		auto exec = file->get_as<bool>("executable").value_or(false);
+		auto type_name = file->get_as<std::string>("type").value_or("unknown");
+		initrd::file_type type = initrd::file_type::unknown;
+		if (type_name == "executable") {
+			type = initrd::file_type::executable;
+		} else if (type_name == "vdso") {
+			type = initrd::file_type::vdso;
+		}
 
-		entries.emplace_back(*source, *dest, exec);
+		entries.emplace_back(*source, *dest, type);
 		const entry &e = entries.back();
 
 		if (!e.good()) {
@@ -92,9 +98,7 @@ int main(int argc, char **argv)
 		fheader.offset = file_offset;
 		fheader.length = e.size();
 		fheader.name_offset = name_offset;
-
-		if (e.executable())
-			fheader.flags |= initrd::file_flags::executable;
+		fheader.type = e.type();
 
 		out.write(
 			reinterpret_cast<const char *>(&fheader),

src/vdso/overrides.cpp

@@ -0,0 +1,17 @@
+#include <j6/errors.h>
+#include <j6/types.h>
+#include "vdso_internal.h"
+
+extern "C" {
+
+j6_status_t j6_object_noop() {
+	// Skip the kernel
+	return j6_status_ok;
+}
+
+// An example of overriding a weak default symbol with a custom function
+j6_status_t j6_object_wait(j6_handle_t target, j6_signal_t signals, j6_signal_t *triggered) {
+	return __sys_j6_object_wait(target, signals, triggered);
+}
+
+}

src/vdso/syscalls.cpp

@@ -0,0 +1,17 @@
+#include <j6/errors.h>
+#include <j6/types.h>
+#include "vdso_internal.h"
+
+#define SYSCALL(num, name, ...) \
+	j6_status_t __sys_j6_##name (__VA_ARGS__) { \
+		j6_status_t result = 0; \
+		__asm__ __volatile__ ( "syscall" : "=a"(result) : "a"(num) ); \
+		return result; \
+	} \
+	j6_status_t j6_ ## name(__VA_ARGS__) __weak_alias("__sys_j6_" #name);
+
+extern "C" {
+#include "syscalls.inc"
+}
+
+#undef SYSCALL

src/vdso/vdso_internal.h

@@ -0,0 +1,16 @@
+#pragma once
+/// \file vdso_internal.h
+/// VDSO syscall forward-declares and linker utils
+
+#define __weak_alias(name) __attribute__((weak, alias(name)));
+#define __local __attribute__((__visibility__("hidden")))
+
+#define SYSCALL(num, name, ...) \
+	j6_status_t __sys_j6_ ## name (__VA_ARGS__) __local; \
+
+extern "C" {
+#include "syscalls.inc"
+}
+
+#undef SYSCALL
+