From 3a2710dcab0dc6dc625f0a4956a44bace1788618 Mon Sep 17 00:00:00 2001 From: johpow01 Date: Wed, 7 Oct 2020 15:08:01 -0500 Subject: [PATCH] Workaround for Cortex A78 erratum 1951500 Cortex A78 erratum 1951500 is a Cat B erratum that applies to revisions r0p0, r1p0, and r1p1. The workaround is to insert a DMB ST before acquire atomic instructions without release semantics. This workaround works on revisions r1p0 and r1p1, in r0p0 there is no workaround. SDEN can be found here: https://documentation-service.arm.com/static/5fb66157ca04df4095c1cc2e Signed-off-by: John Powell Change-Id: I47610cee75af6a127ea65edc4d5cffc7e6a2d0a3 --- docs/design/cpu-specific-build-macros.rst | 4 ++ include/lib/cpus/errata_report.h | 3 ++ lib/cpus/aarch64/cortex_a78.S | 60 +++++++++++++++++++++++ lib/cpus/cpu-ops.mk | 9 ++++ 4 files changed, 76 insertions(+) diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst index 09aa3017f..be7096cd3 100644 --- a/docs/design/cpu-specific-build-macros.rst +++ b/docs/design/cpu-specific-build-macros.rst @@ -268,6 +268,10 @@ For Cortex-A78, the following errata build flags are defined : - ``ERRATA_A78_1941498``: This applies errata 1941498 workaround to Cortex-A78 CPU. This needs to be enabled for revisions r0p0, r1p0, and r1p1 of the CPU. +- ``ERRATA_A78_1951500``: This applies errata 1951500 workaround to Cortex-A78 + CPU. This needs to be enabled for revisions r1p0 and r1p1, r0p0 has the same + issue but there is no workaround for that revision. + For Neoverse N1, the following errata build flags are defined : - ``ERRATA_N1_1073348``: This applies errata 1073348 workaround to Neoverse-N1 diff --git a/include/lib/cpus/errata_report.h b/include/lib/cpus/errata_report.h index 7cac77ebe..efdedf0aa 100644 --- a/include/lib/cpus/errata_report.h +++ b/include/lib/cpus/errata_report.h @@ -30,4 +30,7 @@ int errata_needs_reporting(spinlock_t *lock, uint32_t *reported); #define ERRATA_APPLIES 1 #define ERRATA_MISSING 2 +/* Macro to get CPU revision code for checking errata version compatibility. */ +#define CPU_REV(r, p) ((r << 4) | p) + #endif /* ERRATA_REPORT_H */ diff --git a/lib/cpus/aarch64/cortex_a78.S b/lib/cpus/aarch64/cortex_a78.S index ef760ed8a..f61726b46 100644 --- a/lib/cpus/aarch64/cortex_a78.S +++ b/lib/cpus/aarch64/cortex_a78.S @@ -72,6 +72,60 @@ func check_errata_1941498 b cpu_rev_var_ls endfunc check_errata_1941498 + /* -------------------------------------------------- + * Errata Workaround for A78 Erratum 1951500. + * This applies to revisions r1p0 and r1p1 of A78. + * The issue also exists in r0p0 but there is no fix + * in that revision. + * Inputs: + * x0: variant[4:7] and revision[0:3] of current cpu. + * Shall clobber: x0-x17 + * -------------------------------------------------- + */ +func errata_a78_1951500_wa + /* Compare x0 against revisions r1p0 - r1p1 */ + mov x17, x30 + bl check_errata_1951500 + cbz x0, 1f + + msr S3_6_c15_c8_0, xzr + ldr x0, =0x10E3900002 + msr S3_6_c15_c8_2, x0 + ldr x0, =0x10FFF00083 + msr S3_6_c15_c8_3, x0 + ldr x0, =0x2001003FF + msr S3_6_c15_c8_1, x0 + + mov x0, #1 + msr S3_6_c15_c8_0, x0 + ldr x0, =0x10E3800082 + msr S3_6_c15_c8_2, x0 + ldr x0, =0x10FFF00083 + msr S3_6_c15_c8_3, x0 + ldr x0, =0x2001003FF + msr S3_6_c15_c8_1, x0 + + mov x0, #2 + msr S3_6_c15_c8_0, x0 + ldr x0, =0x10E3800200 + msr S3_6_c15_c8_2, x0 + ldr x0, =0x10FFF003E0 + msr S3_6_c15_c8_3, x0 + ldr x0, =0x2001003FF + msr S3_6_c15_c8_1, x0 + + isb +1: + ret x17 +endfunc errata_a78_1951500_wa + +func check_errata_1951500 + /* Applies to revisions r1p0 and r1p1. */ + mov x1, #CPU_REV(1, 0) + mov x2, #CPU_REV(1, 1) + b cpu_rev_var_range +endfunc check_errata_1951500 + /* ------------------------------------------------- * The CPU Ops reset function for Cortex-A78 * ------------------------------------------------- @@ -91,6 +145,11 @@ func cortex_a78_reset_func bl errata_a78_1941498_wa #endif +#if ERRATA_A78_1951500 + mov x0, x18 + bl errata_a78_1951500_wa +#endif + #if ENABLE_AMU /* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */ mrs x0, actlr_el3 @@ -147,6 +206,7 @@ func cortex_a78_errata_report */ report_errata ERRATA_A78_1688305, cortex_a78, 1688305 report_errata ERRATA_A78_1941498, cortex_a78, 1941498 + report_errata ERRATA_A78_1951500, cortex_a78, 1951500 ldp x8, x30, [sp], #16 ret diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk index b7dec0b77..93b538c58 100644 --- a/lib/cpus/cpu-ops.mk +++ b/lib/cpus/cpu-ops.mk @@ -298,6 +298,11 @@ ERRATA_A78_1688305 ?=0 # to revisions r0p0, r1p0, and r1p1 of the A78 cpu. ERRATA_A78_1941498 ?=0 +# Flag to apply erratum 1951500 workaround during reset. This erratum applies +# to revisions r1p0 and r1p1 of the A78 cpu. The issue is present in r0p0 as +# well but there is no workaround for that revision. +ERRATA_A78_1951500 ?=0 + # Flag to apply T32 CLREX workaround during reset. This erratum applies # only to r0p0 and r1p0 of the Neoverse N1 cpu. ERRATA_N1_1043202 ?=0 @@ -583,6 +588,10 @@ $(eval $(call add_define,ERRATA_A78_1688305)) $(eval $(call assert_boolean,ERRATA_A78_1941498)) $(eval $(call add_define,ERRATA_A78_1941498)) +# Process ERRATA_A78_1951500 flag +$(eval $(call assert_boolean,ERRATA_A78_1951500)) +$(eval $(call add_define,ERRATA_A78_1951500)) + # Process ERRATA_N1_1043202 flag $(eval $(call assert_boolean,ERRATA_N1_1043202)) $(eval $(call add_define,ERRATA_N1_1043202)) -- 2.39.5