| From d7736ff5be31edaa4fe5ab62810c64529a24b149 Mon Sep 17 00:00:00 2001 |
| From: Michael Holzheu <holzheu@linux.vnet.ibm.com> |
| Date: Thu, 30 Jan 2014 16:14:02 +0100 |
| Subject: s390/dump: Fix dump memory detection |
| |
| From: Michael Holzheu <holzheu@linux.vnet.ibm.com> |
| |
| commit d7736ff5be31edaa4fe5ab62810c64529a24b149 upstream. |
| |
| Dumps created by kdump or zfcpdump can contain invalid memory holes when |
| dumping z/VM systems that have memory pressure. |
| |
| For example: |
| |
| # zgetdump -i /proc/vmcore. |
| Memory map: |
| 0000000000000000 - 0000000000bfffff (12 MB) |
| 0000000000e00000 - 00000000014fffff (7 MB) |
| 000000000bd00000 - 00000000f3bfffff (3711 MB) |
| |
| The memory detection function find_memory_chunks() issues tprot to |
| find valid memory chunks. In case of CMM it can happen that pages are |
| marked as unstable via set_page_unstable() in arch_free_page(). |
| If z/VM has released that pages, tprot returns -EFAULT and indicates |
| a memory hole. |
| |
| So fix this and switch off CMM in case of kdump or zfcpdump. |
| |
| Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> |
| Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/s390/mm/page-states.c | 10 ++++++++++ |
| 1 file changed, 10 insertions(+) |
| |
| --- a/arch/s390/mm/page-states.c |
| +++ b/arch/s390/mm/page-states.c |
| @@ -12,6 +12,8 @@ |
| #include <linux/mm.h> |
| #include <linux/gfp.h> |
| #include <linux/init.h> |
| +#include <asm/setup.h> |
| +#include <asm/ipl.h> |
| |
| #define ESSA_SET_STABLE 1 |
| #define ESSA_SET_UNUSED 2 |
| @@ -41,6 +43,14 @@ void __init cmma_init(void) |
| |
| if (!cmma_flag) |
| return; |
| + /* |
| + * Disable CMM for dump, otherwise the tprot based memory |
| + * detection can fail because of unstable pages. |
| + */ |
| + if (OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP) { |
| + cmma_flag = 0; |
| + return; |
| + } |
| asm volatile( |
| " .insn rrf,0xb9ab0000,%1,%1,0,0\n" |
| "0: la %0,0\n" |
