[PATCH 2.6.13-rc1 08/10] IOCHK interface for I/O error handling/detecting

Hidetoshi Seto
2005-07-06T06:49:34Z

[This is 8 of 10 patches, "iochk-08-mcadrv.patch"]

- Touching poisoned data become a MCA, so now it assumed as
a fatal error, directly will be a system down. But since
the MCA tells us a physical address - "where it happens",
we can do some action to survive.

If the address is present in resource of "check-in" device,
it is guaranteed that its driver will call iochk_read in
the very near future, and that now the driver have a
ability and responsibility of recovery from the error.

So if it was "check-in" address, what OS should do is mark
"check-in" devices and just restart usual works. Soon
the driver will notice the error and operate it properly.

Note:
We can identify a affected device, but because of SAL
behavior (mentioned at 6 of 10), we need to mark all
"check-in" devices. Fix in future, if possible.

Changes from previous one for 2.6.11.11:
- (non)

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>

---

arch/ia64/kernel/mca_drv.c | 84 ++++++++++++++++++++++++++++++++++++++++++++
arch/ia64/lib/iomap_check.c | 1
2 files changed, 85 insertions(+)

Index: linux-2.6.13-rc1/arch/ia64/lib/iomap_check.c
===================================================================
--- linux-2.6.13-rc1.orig/arch/ia64/lib/iomap_check.c
+++ linux-2.6.13-rc1/arch/ia64/lib/iomap_check.c
@@ -147,3 +147,4 @@ void clear_bridge_error(struct pci_dev *

EXPORT_SYMBOL(iochk_read);
EXPORT_SYMBOL(iochk_clear);
+EXPORT_SYMBOL(iochk_devices); /* for MCA driver */
Index: linux-2.6.13-rc1/arch/ia64/kernel/mca_drv.c
===================================================================
--- linux-2.6.13-rc1.orig/arch/ia64/kernel/mca_drv.c
+++ linux-2.6.13-rc1/arch/ia64/kernel/mca_drv.c
@@ -35,6 +35,12 @@

#include "mca_drv.h"

+#ifdef CONFIG_IOMAP_CHECK
+#include <linux/pci.h>
+#include <asm/io.h>
+extern struct list_head iochk_devices;
+#endif
+
/* max size of SAL error record (default) */
static int sal_rec_max = 10000;

@@ -377,6 +383,79 @@ is_mca_global(peidx_table_t *peidx, pal_
return MCA_IS_GLOBAL;
}

+#ifdef CONFIG_IOMAP_CHECK
+
+/**
+ * get_target_identifier - get address of target_identifier
+ * @peidx: pointer of index of processor error section
+ *
+ * Return value:
+ * addr if valid / 0 if not valid
+ */
+static u64 get_target_identifier(peidx_table_t *peidx)
+{
+ sal_log_mod_error_info_t *smei;
+
+ smei = peidx_bus_check(peidx, 0);
+ if (smei->valid.target_identifier)
+ return (smei->target_identifier);
+ return 0;
+}
+
+/**
+ * offending_addr_in_check - Check if the addr is in checking resource.
+ * @addr: address offending this MCA
+ *
+ * Return value:
+ * 1 if in / 0 if out
+ */
+static int offending_addr_in_check(u64 addr)
+{
+ int i;
+ struct pci_dev *tdev;
+ iocookie *cookie;
+
+ if (list_empty(&iochk_devices))
+ return 0;
+
+ list_for_each_entry(cookie, &iochk_devices, list) {
+ tdev = cookie->dev;
+ for (i = 0; i < PCI_ROM_RESOURCE; i++) {
+ if (tdev->resource[i].start <= addr
+ && addr <= tdev->resource[i].end)
+ return 1;
+ if ((tdev->resource[i].flags
+ & (PCI_BASE_ADDRESS_SPACE|PCI_BASE_ADDRESS_MEM_TYPE_MASK))
+ == (PCI_BASE_ADDRESS_SPACE_MEMORY|PCI_BASE_ADDRESS_MEM_TYPE_64))
+ i++;
+ }
+ }
+ return 0;
+}
+
+/**
+ * pci_error_recovery - Check if MCA occur on transaction in iochk.
+ * @peidx: pointer of index of processor error section
+ *
+ * Return value:
+ * 1 if error could be cought in driver / 0 if not
+ */
+static int pci_error_recovery(peidx_table_t *peidx)
+{
+ u64 addr;
+
+ addr = get_target_identifier(peidx);
+ if (!addr)
+ return 0;
+
+ if (offending_addr_in_check(addr))
+ return 1;
+
+ return 0;
+}
+
+#endif /* CONFIG_IOMAP_CHECK */
+
/**
* recover_from_read_error - Try to recover the errors which type are "read"s.
* @slidx: pointer of index of SAL error record
@@ -399,6 +478,11 @@ recover_from_read_error(slidx_table_t *s
if (!pbci->tv)
return 0;

+#ifdef CONFIG_IOMAP_CHECK
+ if (pci_error_recovery(peidx))
+ return 1;
+#endif
+
/*
* cpu read or memory-mapped io read
*