path: root/arch/ia64
diff options
authorTerry Loftin <terry.loftin@hp.com>2007-07-12 17:23:22 -0600
committerTony Luck <tony.luck@intel.com>2007-07-13 09:16:50 -0700
commit51b58e3e26ebfb8cd56825c4b396ed251f51dec9 (patch)
tree13e04ced4a61562a7c4a0ade7b453fa4e24a6753 /arch/ia64
parent773208946a132fb733ba273ee8562814f828cc28 (diff)
[IA64] use machvec=dig on hpzx1 platforms
On HP zx1 machines, the 'machvec=dig' parameter is needed for the kdump kernel to avoid problems with the HP sba iommu. The problem is that during the boot of the kdump kernel, the iommu is re-initialized, so in-flight DMA from improperly shutdown drivers causes an IOTLB miss which leads to an MCA. With kdump, the idea is to get into the kdump kernel with as little code as we can, so shutting down drivers properly is not an option. The workaround is to add 'machvec=dig' to the kdump kernel boot parameters. This makes the kdump kernel avoid using the sba iommu altogether, leaving the IOTLB intact. Any ongoing DMA falls harmlessly outside the kdump kernel. After the kdump kernel reboots, all devices will have been shutdown properly and DMA stopped. This patch pushes that functionality into the sba iommu initialization code, so that users won't have to find the obscure documentation telling them about 'machvec=dig'. This patch only affects HP platforms. It still includes one extern declaration in the file, because no applicable header file exists. Signed-off-by: Terry Loftin <terry.loftin@hp.com> Signed-off-by: Alex Williamson <alex.williamson@hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64')
1 files changed, 18 insertions, 2 deletions
diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
index c1dca226b47..cd4adf52f17 100644
--- a/arch/ia64/hp/common/sba_iommu.c
+++ b/arch/ia64/hp/common/sba_iommu.c
@@ -34,6 +34,7 @@
#include <linux/efi.h>
#include <linux/nodemask.h>
#include <linux/bitops.h> /* hweight64() */
+#include <linux/crash_dump.h>
#include <asm/delay.h> /* ia64_get_itc() */
#include <asm/io.h>
@@ -43,6 +44,8 @@
#include <asm/acpi-ext.h>
+extern int swiotlb_late_init_with_default_size (size_t size);
#define PFX "IOC: "
@@ -2026,11 +2029,24 @@ sba_init(void)
if (!ia64_platform_is("hpzx1") && !ia64_platform_is("hpzx1_swiotlb"))
return 0;
+#if defined(CONFIG_IA64_GENERIC) && defined(CONFIG_CRASH_DUMP)
+ /* If we are booting a kdump kernel, the sba_iommu will
+ * cause devices that were not shutdown properly to MCA
+ * as soon as they are turned back on. Our only option for
+ * a successful kdump kernel boot is to use the swiotlb.
+ */
+ if (elfcorehdr_addr < ELFCORE_ADDR_MAX) {
+ if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
+ panic("Unable to initialize software I/O TLB:"
+ " Try machvec=dig boot option");
+ machvec_init("dig");
+ return 0;
+ }
if (!ioc_list) {
- extern int swiotlb_late_init_with_default_size (size_t size);
* If we didn't find something sba_iommu can claim, we
* need to setup the swiotlb and switch to the dig machvec.