Re: booting with BootX corrupts memory

On Wed, 2006-08-09 at 06:00 +0200, Niels Kristian Bech Jensen wrote:

 On Tue, Aug  1, Olaf Hering wrote:

quoted

Booting an old Mac with BootX corrupts memory, the kernel seldom gets
into init. Even the built-in initramfs archive gets corrupted. So far I
havent figured out where the corruption starts. The only data point so
far is that a passed initrd gets overwritten with stuff that looks like
part of the device-tree after the call to free_area_init_node() from
paging_init(). Perhaps the virtual/real address mapping isnt handled
correctly.

quoted

This is broken since at least 2.6.15, 2.6.14 dies very early, 2.6.13 was
still ok.

quoted

Symptoms differ, depending on used .config and wether an initrd is passed.

I think I've been hit by this bug on my beige G3 running Ubuntu Edgy.

When booting with initrd the boot process stops before any kernel output (CONFIG_BOOTX_TEXT is not enabled).
Booting without initrd works fine - at least until it cannot find the root filesystem driver. ;-)

Does this patch helps ?

Index: linux-work/arch/powerpc/platforms/powermac/bootx_init.c
===================================================================

--- linux-work.orig/arch/powerpc/platforms/powermac/bootx_init.c	2006-08-17 16:16:03.000000000 +1000
+++ linux-work/arch/powerpc/platforms/powermac/bootx_init.c	2006-08-18 14:01:36.000000000 +1000

@@ -411,8 +411,15 @@
 	DBG("End of boot params: %x\n", mem_end);
 	rsvmap[0] = mem_start;
 	rsvmap[1] = mem_end;
-	rsvmap[2] = 0;
-	rsvmap[3] = 0;
+	if (bootx_info->ramDisk) {
+		rsvmap[2] = ((unsigned long)bootx_info) + bootx_info->ramDisk;
+		rsvmap[3] = rsvmap[2] + bootx_info->ramDiskSize;
+		rsvmap[4] = 0;
+		rsvmap[5] = 0;
+	} else {
+		rsvmap[2] = 0;
+		rsvmap[3] = 0;
+	}
 
 	return (unsigned long)hdr;
 }

@@ -543,12 +550,12 @@
 	 */
 	if (bi->version < 5) {
 		space = bi->deviceTreeOffset + bi->deviceTreeSize;
-		if (bi->ramDisk)
+		if (bi->ramDisk >= space)
 			space = bi->ramDisk + bi->ramDiskSize;
 	} else
 		space = bi->totalParamsSize;
 
-	bootx_printf("Total space used by parameters & ramdisk: %x \n", space);
+	bootx_printf("Total space used by parameters & ramdisk: 0x%x \n", space);
 
 	/* New BootX will have flushed all TLBs and enters kernel with
 	 * MMU switched OFF, so this should not be useful anymore.