On Mon, 26 Nov 2007 12:17:46 +0000, linux-mips@xxxxxxxxxxxxxx wrote: > Author: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Sat Nov 3 02:05:43 2007 +0000 > Commit: 75c0de3513644f9868a14f74b0c4dfec1eb4ffd5 > Gitweb: http://www.linux-mips.org/g/linux/75c0de35 > Branch: master > > Sibyte SOCs only have 32-bit PCI. Due to the sparse use of the address > space only the first 1GB of memory is mapped at physical addresses > below 1GB. If a system has more than 1GB of memory 32-bit DMA will > not be able to reach all of it. > > For now this patch is good enough to keep Sibyte users happy but it seems > eventually something like swiotlb will be needed for Sibyte. This commit breaks platforms which have real prom_free_prom_memory(). You can reproduce the problem with this patch. diff --git a/arch/mips/qemu/q-mem.c b/arch/mips/qemu/q-mem.c index dae39b5..84cbee2 100644 --- a/arch/mips/qemu/q-mem.c +++ b/arch/mips/qemu/q-mem.c @@ -1,5 +1,9 @@ #include <linux/init.h> +#include <asm/bootinfo.h> +#include <asm/sections.h> +#include <asm/page.h> void __init prom_free_prom_memory(void) { + free_init_pages("prom memory", PAGE_SIZE, __pa_symbol(&_text)); } With this patch, qemu kernel crashes on boot as this: Bad page state in process 'swapper' page:81000020 flags:0x00000000 mapping:00000000 mapcount:1 count:0 Trying to fix it up, but a reboot is needed Backtrace: Call Trace: [<8001691c>] dump_stack+0x8/0x34 [<8005a758>] bad_page+0x6c/0xa4 [<8005af7c>] free_hot_cold_page+0x98/0x1d4 [<80019e44>] free_init_pages+0x94/0xf8 [<80164b3c>] free_initmem+0x10/0x40 [<80010428>] init_post+0x10/0xe8 [<801b988c>] kernel_init+0x2f8/0x328 [<80013220>] kernel_thread_helper+0x10/0x18 If I reverted the commit, this crash does not happen. How I can fix this? --- Atsushi Nemoto
