powerpc: Rename and flesh out the facility unavailable exception handler

commit 021424a1fce335e05807fd770eb8e1da30a63eea upstream.

The exception at 0xf60 is not the TM (Transactional Memory) unavailable
exception, it is the "Facility Unavailable Exception", rename it as
such.

Flesh out the handler to acknowledge the fact that it can be called for
many reasons, one of which is TM being unavailable.

Use STD_EXCEPTION_COMMON() for the exception body, for some reason we
had it open-coded, I've checked the generated code is identical.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 32 insertions, 22 deletions

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 6bd676391a6d..d55a63c3559a 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -341,10 +341,11 @@ vsx_unavailable_pSeries_1:
         EXCEPTION_PROLOG_0(PACA_EXGEN)
         b       vsx_unavailable_pSeries
 
+facility_unavailable_trampoline:
         . = 0xf60
         SET_SCRATCH0(r13)
         EXCEPTION_PROLOG_0(PACA_EXGEN)
-        b       tm_unavailable_pSeries
+        b       facility_unavailable_pSeries
 
 #ifdef CONFIG_CBE_RAS
         STD_EXCEPTION_HV(0x1200, 0x1202, cbe_system_error)
@@ -522,7 +523,7 @@ denorm_done:
         KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0xf20)
         STD_EXCEPTION_PSERIES_OOL(0xf40, vsx_unavailable)
         KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0xf40)
-        STD_EXCEPTION_PSERIES_OOL(0xf60, tm_unavailable)
+        STD_EXCEPTION_PSERIES_OOL(0xf60, facility_unavailable)
         KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0xf60)
 
 /*
@@ -829,11 +830,11 @@ vsx_unavailable_relon_pSeries_1:
         EXCEPTION_PROLOG_0(PACA_EXGEN)
         b       vsx_unavailable_relon_pSeries
 
-tm_unavailable_relon_pSeries_1:
+facility_unavailable_relon_trampoline:
         . = 0x4f60
         SET_SCRATCH0(r13)
         EXCEPTION_PROLOG_0(PACA_EXGEN)
-        b       tm_unavailable_relon_pSeries
+        b       facility_unavailable_relon_pSeries
 
         STD_RELON_EXCEPTION_PSERIES(0x5300, 0x1300, instruction_breakpoint)
 #ifdef CONFIG_PPC_DENORMALISATION
@@ -1159,15 +1160,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
         bl      .vsx_unavailable_exception
         b       .ret_from_except
 
-        .align  7
-        .globl tm_unavailable_common
-tm_unavailable_common:
-        EXCEPTION_PROLOG_COMMON(0xf60, PACA_EXGEN)
-        bl      .save_nvgprs
-        DISABLE_INTS
-        addi    r3,r1,STACK_FRAME_OVERHEAD
-        bl      .tm_unavailable_exception
-        b       .ret_from_except
+        STD_EXCEPTION_COMMON(0xf60, facility_unavailable, .facility_unavailable_exception)
 
         .align  7
         .globl  __end_handlers
@@ -1180,7 +1173,7 @@ __end_handlers:
         STD_RELON_EXCEPTION_PSERIES_OOL(0xf00, performance_monitor)
         STD_RELON_EXCEPTION_PSERIES_OOL(0xf20, altivec_unavailable)
         STD_RELON_EXCEPTION_PSERIES_OOL(0xf40, vsx_unavailable)
-        STD_RELON_EXCEPTION_PSERIES_OOL(0xf60, tm_unavailable)
+        STD_RELON_EXCEPTION_PSERIES_OOL(0xf60, facility_unavailable)
 
 #if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
 /*
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index c0e5caf8ccc7..2053bbd26a06 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1282,25 +1282,42 @@ void vsx_unavailable_exception(struct pt_regs *regs)
         die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
 }
 
-void tm_unavailable_exception(struct pt_regs *regs)
+void facility_unavailable_exception(struct pt_regs *regs)
 {
+        static char *facility_strings[] = {
+                "FPU",
+                "VMX/VSX",
+                "DSCR",
+                "PMU SPRs",
+                "BHRB",
+                "TM",
+                "AT",
+                "EBB",
+                "TAR",
+        };
+        char *facility;
+        u64 value;
+
+        value = mfspr(SPRN_FSCR) >> 56;
+
         /* We restore the interrupt state now */
         if (!arch_irq_disabled_regs(regs))
                 local_irq_enable();
 
-        /* Currently we never expect a TMU exception.  Catch
-         * this and kill the process!
-         */
-        printk(KERN_EMERG "Unexpected TM unavailable exception at %lx "
-               "(msr %lx)\n",
-               regs->nip, regs->msr);
+        if (value < ARRAY_SIZE(facility_strings))
+                facility = facility_strings[value];
+        else
+                facility = "unknown";
+
+        pr_err("Facility '%s' unavailable, exception at 0x%lx, MSR=%lx\n",
+                facility, regs->nip, regs->msr);
 
         if (user_mode(regs)) {
                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
                 return;
         }
 
-        die("Unexpected TM unavailable exception", regs, SIGABRT);
+        die("Unexpected facility unavailable exception", regs, SIGABRT);
 }
 
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM