tree f9725aa273ebbfd40253a90b4d6ae1d5564e7a9f
parent 1c1734090ebcd31e479798b3af4c260ae09bf3a4
author Andi Kleen <[EMAIL PROTECTED]> Sun, 17 Apr 2005 05:25:09 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Sun, 17 Apr 2005 05:25:09 -0700

[PATCH] x86_64: Use the extended RIP MSR for machine check reporting if 
available.

They are rumoured to be much more reliable than the RIP in the stack frame on
P4s.

This is a borderline case because the code is very simple.  Please note there
are no plans to add support for all the MCE register MSRs.

Cc: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>

 x86_64/kernel/mce.c |   30 ++++++++++++++++++++++--------
 1 files changed, 22 insertions(+), 8 deletions(-)

Index: arch/x86_64/kernel/mce.c
===================================================================
--- de5f3374bfb56c0e5a4527b3b0127face20eca3f/arch/x86_64/kernel/mce.c  
(mode:100644 sha1:86f9fd85016a3cb2046fbfec058acbdd99903d17)
+++ f9725aa273ebbfd40253a90b4d6ae1d5564e7a9f/arch/x86_64/kernel/mce.c  
(mode:100644 sha1:6ca066424deed52ce3243d5398329647e86c13e2)
@@ -33,6 +33,7 @@
 static unsigned long bank[NR_BANKS] = { [0 ... NR_BANKS-1] = ~0UL };
 static unsigned long console_logged;
 static int notify_user;
+static int rip_msr;
 
 /*
  * Lockless MCE logging infrastructure.
@@ -124,6 +125,23 @@
               test_bit(X86_FEATURE_MCA, &c->x86_capability);
 }
 
+static inline void mce_get_rip(struct mce *m, struct pt_regs *regs)
+{
+       if (regs && (m->mcgstatus & MCG_STATUS_RIPV)) {
+               m->rip = regs->rip;
+               m->cs = regs->cs;
+       } else {
+               m->rip = 0;
+               m->cs = 0;
+       }
+       if (rip_msr) {
+               /* Assume the RIP in the MSR is exact. Is this true? */
+               m->mcgstatus |= MCG_STATUS_EIPV;
+               rdmsrl(rip_msr, m->rip);
+               m->cs = 0;
+       }
+}
+
 /* 
  * The actual machine check handler
  */
@@ -176,14 +194,7 @@
                if (m.status & MCI_STATUS_ADDRV)
                        rdmsrl(MSR_IA32_MC0_ADDR + i*4, m.addr);
 
-               if (regs && (m.mcgstatus & MCG_STATUS_RIPV)) {
-                       m.rip = regs->rip;
-                       m.cs = regs->cs;
-               } else {
-                       m.rip = 0;
-                       m.cs = 0;
-               }
-
+               mce_get_rip(&m, regs);
                if (error_code != -1)
                        rdtscll(m.tsc);
                wrmsrl(MSR_IA32_MC0_STATUS + i*4, 0);
@@ -296,6 +307,9 @@
                printk(KERN_INFO "MCE: warning: using only %d banks\n", banks);
                banks = NR_BANKS; 
        }
+       /* Use accurate RIP reporting if available. */
+       if ((cap & (1<<9)) && ((cap >> 16) & 0xff) >= 9)
+               rip_msr = MSR_IA32_MCG_EIP;
 
        /* Log the machine checks left over from the previous reset.
           This also clears all registers */
-
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