From fba26da490b453f58b727954184650f9767fab94 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Wed, 8 Apr 2015 02:50:09 +0200
Subject: [PATCH] pc, pc64: extend initial memory map for qemu multiboot data

qemu puts multiboot data after the end of the kernel image, so
to be able to KADDR() that memory early, we extend the initial
identity mapping by 16K. right now we just got lucky with
the pc kernel as it rounds the map to 4MB pages.
---
 sys/src/9/pc/l.s   | 3 +++
 sys/src/9/pc64/l.s | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/sys/src/9/pc/l.s b/sys/src/9/pc/l.s
index 44071a634..0d28ab2f1 100644
--- a/sys/src/9/pc/l.s
+++ b/sys/src/9/pc/l.s
@@ -186,6 +186,9 @@ TEXT mode32bit(SB), $0
 
 	MOVL	$PADDR(CPU0PTE), AX		/* first page of page table */
 	MOVL	$end-KZERO(SB), CX
+
+	ADDL	$(16*1024), CX			/* qemu puts multiboot data after the kernel */
+
 	ADDL	$(BY2XPG-1), CX
 	ANDL	$~(BY2XPG-1), CX		/* round to 4MB */
 	MOVL	CX, MemMin-KZERO(SB)		/* see memory.c */
diff --git a/sys/src/9/pc64/l.s b/sys/src/9/pc64/l.s
index 94356a9fb..6736ec42b 100644
--- a/sys/src/9/pc64/l.s
+++ b/sys/src/9/pc64/l.s
@@ -149,6 +149,9 @@ TEXT _warp64<>(SB), 1, $-4
 	 */
 	ADDL	$PDO(KZERO), AX
 	MOVL	$end-KZERO(SB), CX
+
+	ADDL	$(16*1024), CX			/* qemu puts multiboot data after the kernel */
+
 	ADDL	$(PGLSZ(1)-1), CX
 	ANDL	$~(PGLSZ(1)-1), CX
 	MOVL	CX, MemMin-KZERO(SB)		/* see memory.c */