[kernel] Create system_map_mmio syscall

Create a syscall for drivers to be able to ask the kernel for a VMA that
maps a MMIO area. Also expose vm_flags via j6 table style include file
and new flags.h header.

src/include/j6/flags.h

@@ -0,0 +1,10 @@
+#pragma once
+/// \file flags.h
+/// Enums used as flags for syscalls
+
+enum j6_vm_flags {
+#define VM_FLAG(name, v) j6_vm_flag_ ## name = v,
+#include "j6/tables/vm_flags.inc"
+#undef VM_FLAG
+	j6_vm_flags_MAX
+};

src/include/j6/tables/syscalls.inc

@@ -2,6 +2,7 @@ SYSCALL(0x00, system_log,        const char *)
 SYSCALL(0x01, system_noop,       void)
 SYSCALL(0x02, system_get_log,    j6_handle_t, char *, size_t *)
 SYSCALL(0x03, system_bind_irq,   j6_handle_t, j6_handle_t, unsigned)
+SYSCALL(0x04, system_map_mmio,   j6_handle_t, j6_handle_t *, uintptr_t, size_t, uint32_t)
 
 SYSCALL(0x08, object_koid,       j6_handle_t, j6_koid_t *)
 SYSCALL(0x09, object_wait,       j6_handle_t, j6_signal_t, j6_signal_t *)

src/include/j6/tables/vm_flags.inc

@@ -0,0 +1,9 @@
+VM_FLAG( none,            0x00000000)
+VM_FLAG( write,           0x00000001)
+VM_FLAG( exec,            0x00000002)
+VM_FLAG( zero,            0x00000010)
+VM_FLAG( contiguous,      0x00000020)
+VM_FLAG( large_pages,     0x00000100)
+VM_FLAG( huge_pages,      0x00000200)
+VM_FLAG( write_combine,   0x00001000)
+VM_FLAG( mmio,            0x00010000)

src/kernel/objects/vm_area.h

@@ -17,20 +17,9 @@ class vm_space;
 
 enum class vm_flags : uint32_t
 {
-	none            = 0x00000000,
-
-	write           = 0x00000001,
-	exec            = 0x00000002,
-
-	zero            = 0x00000010, 
-	contiguous      = 0x00000020,
-
-	large_pages     = 0x00000100,
-	huge_pages      = 0x00000200,
-
-	mmio            = 0x00010000,
-	write_combine   = 0x00020000,
-
+#define VM_FLAG(name, v) name = v,
+#include "j6/tables/vm_flags.inc"
+#undef VM_FLAG
 	user_mask       = 0x0000ffff  ///< flags allowed via syscall
 };
 

src/kernel/syscalls/system.cpp

@@ -6,6 +6,7 @@
 #include "objects/endpoint.h"
 #include "objects/thread.h"
 #include "objects/system.h"
+#include "objects/vm_area.h"
 #include "syscalls/helpers.h"
 
 extern log::logger &g_logger;
@@ -58,4 +59,16 @@ system_bind_irq(j6_handle_t sys, j6_handle_t endp, unsigned irq)
 	return j6_err_invalid_arg;
 }
 
+j6_status_t
+system_map_mmio(j6_handle_t sys, j6_handle_t *vma_handle, uintptr_t phys_addr, size_t size, uint32_t flags)
+{
+	// TODO: check capabilities on sys handle
+	if (!vma_handle) return j6_err_invalid_arg;
+
+	vm_flags vmf = vm_flags::mmio | (static_cast<vm_flags>(flags) & vm_flags::user_mask);
+	construct_handle<vm_area_fixed>(vma_handle, phys_addr, size, vmf);
+
+	return j6_status_ok;
+}
+
 } // namespace syscalls