x86/mce: Move the mce_panic() call and 'kill_it' assignments to the right places

Right now, for local MCEs the machine calls panic(), if needed, right
after lmce is set. For MCE broadcasting, mce_reign() takes care of
calling mce_panic().

Hence:
- improve readability by moving the conditional evaluation of
tolerant up to when kill_it is set first;
- move the mce_panic() call up into the statement where mce_end()
fails.

 [ bp: Massage, remove comment in the mce_end() failure case because it
   is superfluous; use local ptr 'cfg' in both tests. ]

Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20201127161819.3106432-3-gabriele.paoloni@intel.com

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index f319bed1c59d22b4f66f69524ff0fab7992c332c..ebaa52a0c024748ed8ae24d4aebf598238fd47c6 100644 (file)
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1351,8 +1351,7 @@ noinstr void do_machine_check(struct pt_regs *regs)
         * severity is MCE_AR_SEVERITY we have other options.
         */
        if (!(m.mcgstatus & MCG_STATUS_RIPV))
-               kill_it = 1;
-
+               kill_it = (cfg->tolerant == 3) ? 0 : 1;
        /*
         * Check if this MCE is signaled to only this logical processor,
         * on Intel, Zhaoxin only.
@@ -1388,6 +1387,9 @@ noinstr void do_machine_check(struct pt_regs *regs)
                if (mce_end(order) < 0) {
                        if (!no_way_out)
                                no_way_out = worst >= MCE_PANIC_SEVERITY;
+
+                       if (no_way_out && cfg->tolerant < 3)
+                               mce_panic("Fatal machine check on current CPU", &m, msg);
                }
        } else {
                /*
@@ -1404,15 +1406,6 @@ noinstr void do_machine_check(struct pt_regs *regs)
                }
        }
 
-       /*
-        * If tolerant is at an insane level we drop requests to kill
-        * processes and continue even when there is no way out.
-        */
-       if (cfg->tolerant == 3)
-               kill_it = 0;
-       else if (no_way_out)
-               mce_panic("Fatal machine check on current CPU", &m, msg);
-
        if (worst > 0)
                irq_work_queue(&mce_irq_work);