From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Date: Thu, 8 Oct 2015 09:08:18 +0000 (+0100)
Subject: Protect against overlapping with the 32-bit kernel
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=5933e49b6f45fa18dd1e32d14372bb60837ff954;p=people%2Fjulieng%2Fboot-wrapper-aarch64.git

Protect against overlapping with the 32-bit kernel

This patch adds a guard in the linker script to abort the build when the
bootloader code overflows the 12k limit. Indeed, 32-bit Linux with LPAE
enabled puts its initial page tables between 0x80003000 and 0x80007fff.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
---

diff --git a/Makefile.am b/Makefile.am
index 0e2b92a..5cc7d0b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -71,9 +71,11 @@ endif
 if KERNEL_32
 MBOX_OFFSET	:= 0x7ff8
 KERNEL_OFFSET	:= 0x8000
+TEXT_LIMIT	:= 0x80003000
 else
 MBOX_OFFSET	:= 0xfff8
 KERNEL_OFFSET	:= 0x80000
+TEXT_LIMIT	:= 0x80080000
 endif
 
 LD_SCRIPT	:= model.lds.S
@@ -123,7 +125,7 @@ $(IMAGE): $(OFILES) model.lds fdt.dtb $(KERNEL_IMAGE) $(FILESYSTEM)
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(DEFINES) -c -o $@ $<
 
 model.lds: $(LD_SCRIPT) Makefile
-	$(CPP) $(CPPFLAGS) -ansi -DPHYS_OFFSET=$(PHYS_OFFSET) -DMBOX_OFFSET=$(MBOX_OFFSET) -DKERNEL_OFFSET=$(KERNEL_OFFSET) -DFDT_OFFSET=$(FDT_OFFSET) -DFS_OFFSET=$(FS_OFFSET) -DKERNEL=$(KERNEL_IMAGE) -DFILESYSTEM=$(FILESYSTEM) -P -C -o $@ $<
+	$(CPP) $(CPPFLAGS) -ansi -DPHYS_OFFSET=$(PHYS_OFFSET) -DMBOX_OFFSET=$(MBOX_OFFSET) -DKERNEL_OFFSET=$(KERNEL_OFFSET) -DFDT_OFFSET=$(FDT_OFFSET) -DFS_OFFSET=$(FS_OFFSET) -DKERNEL=$(KERNEL_IMAGE) -DFILESYSTEM=$(FILESYSTEM) -DTEXT_LIMIT=$(TEXT_LIMIT) -P -C -o $@ $<
 
 fdt.dtb: $(KERNEL_DTB) Makefile gen-cpu-nodes.sh
 	( $(DTC) -O dts -I dtb $(KERNEL_DTB) ; echo "/ { $(CHOSEN_NODE) $(PSCI_NODE) $(CPUS_NODE) };" ) | $(DTC) -O dtb -o $@ -
diff --git a/model.lds.S b/model.lds.S
index c906d0c..f1902e1 100644
--- a/model.lds.S
+++ b/model.lds.S
@@ -49,10 +49,13 @@ SECTIONS
 		*(.text* .data* .rodata* .bss* COMMON)
 		*(.vectors)
 		*(.stack)
+		PROVIDE(etext = .);
 	}
 
 	.mbox (PHYS_OFFSET + MBOX_OFFSET): {
 		mbox = .;
 		QUAD(0x0)
 	}
+
+	ASSERT(etext <= TEXT_LIMIT, ".text overflow!")
 }