From 335b3c79c79dcfc04e9776ce2e21c3b16aa6febf Mon Sep 17 00:00:00 2001 From: lauwal01 Date: Mon, 24 Jun 2019 11:42:02 -0500 Subject: Workaround for Neoverse N1 erratum 1257314 Neoverse N1 erratum 1257314 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 CPUACTLR3_EL1 system register, which prevents parallel execution of divide and square root instructions. [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.pjdoc-466751330-10325/index.html Change-Id: I54f0f40ff9043efee40d51e796b92ed85b394cbb Signed-off-by: Lauren Wehrmeister --- docs/design/cpu-specific-build-macros.rst | 3 +++ include/lib/cpus/aarch64/neoverse_n1.h | 3 +++ lib/cpus/aarch64/neoverse_n1.S | 33 +++++++++++++++++++++++++++++++ lib/cpus/cpu-ops.mk | 8 ++++++++ 4 files changed, 47 insertions(+) diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst index ee8da176..14dfe958 100644 --- a/docs/design/cpu-specific-build-macros.rst +++ b/docs/design/cpu-specific-build-macros.rst @@ -243,6 +243,9 @@ For Neoverse N1, the following errata build flags are defined : - ``ERRATA_N1_1220197``: This applies errata 1220197 workaround to Neoverse-N1 CPU. This needs to be enabled only for revision <= r2p0 of the CPU. +- ``ERRATA_N1_1257314``: This applies errata 1257314 workaround to Neoverse-N1 + CPU. This needs to be enabled only for revision <= r3p0 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 952ae6eb..0e9ddb8f 100644 --- a/include/lib/cpus/aarch64/neoverse_n1.h +++ b/include/lib/cpus/aarch64/neoverse_n1.h @@ -48,6 +48,9 @@ #define NEOVERSE_N1_CPUACTLR2_EL1_BIT_16 (ULL(1) << 16) #define NEOVERSE_N1_CPUACTLR2_EL1_BIT_59 (ULL(1) << 59) +#define NEOVERSE_N1_CPUACTLR3_EL1 S3_0_C15_C1_2 + +#define NEOVERSE_N1_CPUACTLR3_EL1_BIT_10 (ULL(1) << 10) /* Instruction patching registers */ #define CPUPSELR_EL3 S3_6_C15_C8_0 diff --git a/lib/cpus/aarch64/neoverse_n1.S b/lib/cpus/aarch64/neoverse_n1.S index 0e7b8e8c..19b21a57 100644 --- a/lib/cpus/aarch64/neoverse_n1.S +++ b/lib/cpus/aarch64/neoverse_n1.S @@ -211,6 +211,33 @@ func check_errata_1220197 b cpu_rev_var_ls endfunc check_errata_1220197 +/* -------------------------------------------------- + * Errata Workaround for Neoverse N1 Errata #1257314 + * This applies to revision <=r3p0 of Neoverse N1. + * Inputs: + * x0: variant[4:7] and revision[0:3] of current cpu. + * Shall clobber: x0-x17 + * -------------------------------------------------- + */ +func errata_n1_1257314_wa + /* Compare x0 against revision r3p0 */ + mov x17, x30 + bl check_errata_1257314 + cbz x0, 1f + mrs x1, NEOVERSE_N1_CPUACTLR3_EL1 + orr x1, x1, NEOVERSE_N1_CPUACTLR3_EL1_BIT_10 + msr NEOVERSE_N1_CPUACTLR3_EL1, x1 + isb +1: + ret x17 +endfunc errata_n1_1257314_wa + +func check_errata_1257314 + /* Applies to <=r3p0 */ + mov x1, #0x30 + b cpu_rev_var_ls +endfunc check_errata_1257314 + /* -------------------------------------------------- * Errata Workaround for Neoverse N1 Erratum 1315703. * This applies to revision <= r3p0 of Neoverse N1. @@ -284,6 +311,11 @@ func neoverse_n1_reset_func bl errata_n1_1220197_wa #endif +#if ERRATA_N1_1257314 + mov x0, x18 + bl errata_n1_1257314_wa +#endif + #if ERRATA_N1_1315703 mov x0, x18 bl errata_n1_1315703_wa @@ -351,6 +383,7 @@ func neoverse_n1_errata_report report_errata ERRATA_N1_1165347, neoverse_n1, 1165347 report_errata ERRATA_N1_1207823, neoverse_n1, 1207823 report_errata ERRATA_N1_1220197, neoverse_n1, 1220197 + report_errata ERRATA_N1_1257314, neoverse_n1, 1257314 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 bb53dad0..c4769d9e 100644 --- a/lib/cpus/cpu-ops.mk +++ b/lib/cpus/cpu-ops.mk @@ -258,6 +258,10 @@ ERRATA_N1_1207823 ?=0 # only to revision <= r2p0 of the Neoverse N1 cpu. ERRATA_N1_1220197 ?=0 +# Flag to apply erratum 1257314 workaround during reset. This erratum applies +# only to revision <= r3p0 of the Neoverse N1 cpu. +ERRATA_N1_1257314 ?=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 @@ -471,6 +475,10 @@ $(eval $(call add_define,ERRATA_N1_1207823)) $(eval $(call assert_boolean,ERRATA_N1_1220197)) $(eval $(call add_define,ERRATA_N1_1220197)) +# Process ERRATA_N1_1257314 flag +$(eval $(call assert_boolean,ERRATA_N1_1257314)) +$(eval $(call add_define,ERRATA_N1_1257314)) + # Process ERRATA_N1_1315703 flag $(eval $(call assert_boolean,ERRATA_N1_1315703)) $(eval $(call add_define,ERRATA_N1_1315703)) -- cgit v1.2.3