[IA64] Proper handling of TLB errors from duplicate itr.d dropins

Jack Steiner noticed that duplicate TLB DTC entries do not cause a
linux panic.  See discussion:

http://www.gelato.unsw.edu.au/archives/linux-ia64/0307/6108.html

The current TLB recovery code is recovering from the duplicate itr.d
dropins, masking the underlying problem.  This change modifies
the MCA recovery code to look for the TLB check signature of the
duplicate TLB entry and panic in that case.

Signed-off-by: Russ Anderson (rja@sgi.com)
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/arch/ia64/kernel/mca_drv.c b/arch/ia64/kernel/mca_drv.c
index afc1403799c9..5e2d18fbce40 100644
--- a/arch/ia64/kernel/mca_drv.c
+++ b/arch/ia64/kernel/mca_drv.c
@@ -607,6 +607,33 @@ recover_from_platform_error(slidx_table_t *slidx, peidx_table_t *peidx,
         return status;
 }
 
+/*
+ * recover_from_tlb_check
+ * @peidx:      pointer of index of processor error section
+ *
+ * Return value:
+ *      1 on Success / 0 on Failure
+ */
+static int
+recover_from_tlb_check(peidx_table_t *peidx)
+{
+        sal_log_mod_error_info_t *smei;
+        pal_tlb_check_info_t *ptci;
+
+        smei = (sal_log_mod_error_info_t *)peidx_tlb_check(peidx, 0);
+        ptci = (pal_tlb_check_info_t *)&(smei->check_info);
+
+        /*
+         * Look for signature of a duplicate TLB DTC entry, which is
+         * a SW bug and always fatal.
+         */
+        if (ptci->op == PAL_TLB_CHECK_OP_PURGE
+            && !(ptci->itr || ptci->dtc || ptci->itc))
+                return fatal_mca("Duplicate TLB entry");
+
+        return mca_recovered("TLB check recovered");
+}
+
 /**
  * recover_from_processor_error
  * @platform:   whether there are some platform error section or not
@@ -652,6 +679,12 @@ recover_from_processor_error(int platform, slidx_table_t *slidx,
                 return fatal_mca("error not contained");
 
         /*
+         * Look for recoverable TLB check
+         */
+        if (psp->tc && !(psp->cc || psp->bc || psp->rc || psp->uc))
+                return recover_from_tlb_check(peidx);
+
+        /*
          * The cache check and bus check bits have four possible states
          *   cc bc
          *    0  0      Weird record, not recovered