MIPS: Don't read GCRs when a CM is not present

Commit 3885c2b463f6 ("MIPS: CM: Add support for reporting CM cache
errors") leads to Malta boards unconditionally reading CM GCRs upon bus
errors, regardless of whether a CM is present. This is incorrect & will
lead to further exceptions. Fix by moving the GCR reads to after the
check for whether a CM is present.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11186/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/mips-cm.c b/arch/mips/kernel/mips-cm.c
index b8ceee576cdfce2e22e1b2d8ffab6f90bf69f6b8..10524ce769ae891af4c36994f2b12e408d563cf5 100644 (file)
--- a/arch/mips/kernel/mips-cm.c
+++ b/arch/mips/kernel/mips-cm.c
@@ -252,7 +252,6 @@ int mips_cm_probe(void)
 
 void mips_cm_error_report(void)
 {
-       unsigned long revision = mips_cm_revision();
        /*
         * CM3 has a 64-bit Error cause register with 0:57 containing the error
         * info and 63:58 the error type. For old CMs, everything is contained
@@ -260,17 +259,21 @@ void mips_cm_error_report(void)
         * though the cm_error is u64, we will simply ignore the upper word
         * for CM2.
         */
-       u64 cm_error = read_gcr_error_cause();
-       int cm_error_cause_sft = CM_GCR_ERROR_CAUSE_ERRTYPE_SHF +
-                                ((revision >= CM_REV_CM3) ? 31 : 0);
-       unsigned long cm_addr = read_gcr_error_addr();
-       unsigned long cm_other = read_gcr_error_mult();
-       int ocause, cause;
+       u64 cm_error;
+       unsigned long revision, cm_addr, cm_other;
+       int ocause, cause, cm_error_cause_sft;
        char buf[256];
 
        if (!mips_cm_present())
                return;
 
+       revision = mips_cm_revision();
+       cm_error = read_gcr_error_cause();
+       cm_addr = read_gcr_error_addr();
+       cm_other = read_gcr_error_mult();
+
+       cm_error_cause_sft = CM_GCR_ERROR_CAUSE_ERRTYPE_SHF +
+                                ((revision >= CM_REV_CM3) ? 31 : 0);
        cause = cm_error >> cm_error_cause_sft;
 
        if (!cause)