# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1461614209 -7200
# Node ID a1f3027033f2725e10f61d5395e1cc9bd10b445f
# Parent  bdbe5b78ca43783f5c1b36dcdaa0eb63bec127da
Attempt to provide memory mapping to the lower memory object table.

diff -r bdbe5b78ca43 -r a1f3027033f2 stage2/entry.S
--- a/stage2/entry.S	Mon Apr 25 17:19:53 2016 +0200
+++ b/stage2/entry.S	Mon Apr 25 21:56:49 2016 +0200
@@ -21,6 +21,7 @@
 .extern interrupt_handler
 .extern current_registers
 .extern current_stack_pointer
+.extern _payload_end
 .globl _tlb_entry
 .globl _exc_entry
 .globl _irq_entry
@@ -42,13 +43,15 @@
 	beqz $k1, _tlb_entry_direct
 	nop
 
-	/* For addresses over 0x00080000... */
+	/* For addresses beyond the relocated global object table... */
 
-	li $k1, 0xfff80000
-	and $k1, $k0, $k1
+	lui $k1, %hi(_payload_end - 0x80000000)
+	ori $k1, $k1, %lo(_payload_end - 0x80000000)
+	sltu $k1, $k1, $k0
 	bnez $k1, _tlb_entry_direct
 	nop
 
+_tlb_entry_table:
 	/* Otherwise, load the page table entries. */
 
 	andi $k1, $k0, 0xff			/* ASID */
diff -r bdbe5b78ca43 -r a1f3027033f2 stage2/stage2.ld
--- a/stage2/stage2.ld	Mon Apr 25 17:19:53 2016 +0200
+++ b/stage2/stage2.ld	Mon Apr 25 21:56:49 2016 +0200
@@ -6,6 +6,10 @@
 	/* Program memory section. */
 
 	. = 0x81c00000;
+
+	_payload_start = ABSOLUTE(.);
+	_shared_start = ABSOLUTE(.);
+
 	.text2 : { *(.text*) }
 
 	. = ALIGN(4);
@@ -17,21 +21,33 @@
 	. = ALIGN(4);
 	.data : { *(.data*) *(.scommon*) *(.reginfo*) }
 
-	_gp = ALIGN(16);
-
-	_got_start = ABSOLUTE(.);	
-	.got : { *(.got*) }
-	_got_end = ABSOLUTE(.);	
-
-	_gp_copy = ALIGN(16);
-
-	_got_copy_start = ABSOLUTE(.);
-	. += _got_end - _got_start;
-	_got_copy_end = ABSOLUTE(.);
+	_shared_end = ABSOLUTE(.);
 
 	. = ALIGN(4);
+
+	_bss_start = ABSOLUTE(.);
+
 	.sbss : { *(.sbss*) }
 	.bss : { *(.bss*) }
 	. = ALIGN (4);
+
+	_bss_end = ABSOLUTE(.);
+
+	/* The global object table. */
+
+	.got : ALIGN(4096) {
+		_gp = ALIGN(16);
+		_got_start = ABSOLUTE(.);	
+		 *(.got*)
+	}
+	_got_end = ABSOLUTE(.);	
+
+	/* The relocated copy of the global object table. */
+
+	.got_copy : ALIGN(4096) {
+		_got_copy_start = ABSOLUTE(.);
+		. += _got_end - _got_start - 1;
+	}
+	_got_copy_end = ABSOLUTE(.);
+	_payload_end = ABSOLUTE(.);
 }
-
diff -r bdbe5b78ca43 -r a1f3027033f2 stage2/tasks.c
--- a/stage2/tasks.c	Mon Apr 25 17:19:53 2016 +0200
+++ b/stage2/tasks.c	Mon Apr 25 21:56:49 2016 +0200
@@ -36,9 +36,16 @@
 const u32 stack_size = 0x00002000;
 const u32 pagesize = 4 * 1024;
 
-/* A reference to the unrelocated symbol table location. */
+/*
+References to the unrelocated symbol table and to the relocated version, both in
+their original locations.
+*/
 
-extern u32 _got_copy_start;
+extern u32 _got_start, _got_copy_start;
+
+/* Regions to be mapped directly. */
+
+extern u32 _shared_start, _shared_end;
 
 /* Task management functions. */
 
@@ -56,7 +63,7 @@
 
 void start_task(unsigned short task, void (*function)(), u32 args[], u8 nargs)
 {
-	u32 virtual, physical;
+	u32 virtual, physical, address;
 
 	/*
 	Each task employs a stack at a multiple of the given start address in
@@ -68,6 +75,18 @@
 
 	init_page_table(page_table_start, virtual - pagesize * 2, physical - pagesize * 2, pagesize, 0x1e, task);
 
+	/* Map shared pages. */
+
+	for (address = (u32) &_shared_start; address < (u32) &_shared_end; address += pagesize * 2)
+	{
+		address = address & 0x7fffffff;
+		init_page_table(page_table_start, address, address, pagesize, 0x1e, task);
+	}
+
+	/* Map the task's global object table to the relocated version. */
+
+	init_page_table(page_table_start, (u32) &_got_start & 0x7fffffff, (u32) &_got_copy_start & 0x7fffffff, pagesize, 0x1e, task);
+
 	/*
 	Subtract from the stack pointer to prevent the called function from
 	reaching into unmapped memory.
@@ -80,7 +99,7 @@
 	return address.
 	*/
 
-	init_registers(registers[task], (u32) &_got_copy_start, function, args, nargs);
+	init_registers(registers[task], (u32) &_got_start, function, args, nargs);
 }
 
 void start_task_now()