Workaround for Neoverse N1 erratum 1073348

Neoverse N1 erratum 1073348 is a Cat B erratum [1],
present in older revisions of the Neoverse N1 processor core.
The workaround is to set a bit in the implementation defined
CPUACTLR_EL1 system register, which disables static prediction.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.pjdoc-466751330-10325/index.html

Change-Id: I674126c0af6e068eecb379a190bcf7c75dcbca8e
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>

diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 6b524c24cd1396eb4131e1fc34876844574117db..55109dc7de6ab273b24675fd680e7a067d3a7b72 100644 (file)
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -226,6 +226,11 @@ For Cortex-A76, the following errata build flags are defined :
 -  ``ERRATA_A76_1275112``: This applies errata 1275112 workaround to Cortex-A76
    CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
 
+For Neoverse N1, the following errata build flags are defined :
+
+-  ``ERRATA_N1_1073348``: This applies errata 1073348 workaround to Neoverse-N1
+   CPU. This needs to be enabled only for revision r0p0 and r1p0 of the CPU.
+
 -  ``ERRATA_N1_1315703``: This applies errata 1315703 workaround to Neoverse-N1
    CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
 

diff --git a/include/lib/cpus/aarch64/neoverse_n1.h b/include/lib/cpus/aarch64/neoverse_n1.h
index b66aeb8a02be37e788e2ef58034c4ce87f2fbc6e..9048f4372814bdb9f9fb1aa536671c2085cd1dbf 100644 (file)
--- a/include/lib/cpus/aarch64/neoverse_n1.h
+++ b/include/lib/cpus/aarch64/neoverse_n1.h
@@ -33,6 +33,10 @@
 /*******************************************************************************
  * CPU Auxiliary Control register specific definitions.
  ******************************************************************************/
+#define NEOVERSE_N1_CPUACTLR_EL1       S3_0_C15_C1_0
+
+#define NEOVERSE_N1_CPUACTLR_EL1_BIT_6 (ULL(1) << 6)
+
 #define NEOVERSE_N1_CPUACTLR2_EL1      S3_0_C15_C1_1
 
 #define NEOVERSE_N1_CPUACTLR2_EL1_BIT_2                (ULL(1) << 2)

diff --git a/lib/cpus/aarch64/neoverse_n1.S b/lib/cpus/aarch64/neoverse_n1.S
index 8afc4a2833ff5d8f136d9fbeb7286af34de7cc24..2d427b608a188c68f82c7fc1c54b9b1c1dd92fc1 100644 (file)
--- a/lib/cpus/aarch64/neoverse_n1.S
+++ b/lib/cpus/aarch64/neoverse_n1.S
@@ -75,6 +75,33 @@ func neoverse_n1_disable_speculative_loads
        ret
 endfunc neoverse_n1_disable_speculative_loads
 
+/* --------------------------------------------------
+ * Errata Workaround for Neoverse N1 Errata #1073348
+ * This applies to revision r0p0 and r1p0 of Neoverse N1.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_n1_1073348_wa
+       /* Compare x0 against revision r1p0 */
+       mov     x17, x30
+       bl      check_errata_1073348
+       cbz     x0, 1f
+       mrs     x1, NEOVERSE_N1_CPUACTLR_EL1
+       orr     x1, x1, NEOVERSE_N1_CPUACTLR_EL1_BIT_6
+       msr     NEOVERSE_N1_CPUACTLR_EL1, x1
+       isb
+1:
+       ret     x17
+endfunc errata_n1_1073348_wa
+
+func check_errata_1073348
+       /* Applies to r0p0 and r1p0 */
+       mov     x1, #0x10
+       b       cpu_rev_var_ls
+endfunc check_errata_1073348
+
 /* --------------------------------------------------
  * Errata Workaround for Neoverse N1 Erratum 1315703.
  * This applies to revision <= r3p0 of Neoverse N1.
@@ -123,6 +150,11 @@ func neoverse_n1_reset_func
        bl      errata_n1_1043202_wa
 #endif
 
+#if ERRATA_N1_1073348
+       mov     x0, x18
+       bl      errata_n1_1073348_wa
+#endif
+
 #if ERRATA_N1_1315703
        mov     x0, x18
        bl      errata_n1_1315703_wa
@@ -185,6 +217,7 @@ func neoverse_n1_errata_report
         * checking functions of each errata.
         */
        report_errata ERRATA_N1_1043202, neoverse_n1, 1043202
+       report_errata ERRATA_N1_1073348, neoverse_n1, 1073348
        report_errata ERRATA_N1_1315703, neoverse_n1, 1315703
        report_errata ERRATA_DSU_936184, neoverse_n1, dsu_936184
 

diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index db4537528968c6b01b59bdb0772ac317b59662cb..0d00d0adc904ef33d8890be7432ce190fdee2080 100644 (file)
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -238,6 +238,10 @@ ERRATA_A76_1286807 ?=0
 # only to r0p0 and r1p0 of the Neoverse N1 cpu.
 ERRATA_N1_1043202      ?=1
 
+# Flag to apply erratum 1073348 workaround during reset. This erratum applies
+# only to revision r0p0 and r1p0 of the Neoverse N1 cpu.
+ERRATA_N1_1073348      ?=0
+
 # Flag to apply erratum 1315703 workaround during reset. This erratum applies
 # to revisions before r3p1 of the Neoverse N1 cpu.
 ERRATA_N1_1315703      ?=1
@@ -431,6 +435,10 @@ $(eval $(call add_define,ERRATA_A76_1286807))
 $(eval $(call assert_boolean,ERRATA_N1_1043202))
 $(eval $(call add_define,ERRATA_N1_1043202))
 
+# Process ERRATA_N1_1073348 flag
+$(eval $(call assert_boolean,ERRATA_N1_1073348))
+$(eval $(call add_define,ERRATA_N1_1073348))
+
 # Process ERRATA_N1_1315703 flag
 $(eval $(call assert_boolean,ERRATA_N1_1315703))
 $(eval $(call add_define,ERRATA_N1_1315703))