From c948185c973c13df36c62c4bcb50e22b14d6e06a Mon Sep 17 00:00:00 2001 From: nayanpatel-arm Date: Wed, 20 Oct 2021 18:28:58 -0700 Subject: [PATCH] fix(errata): workaround for Neoverse-N2 erratum 2138958 Neoverse-N2 erratum 2138958 is a Cat B erratum that applies to revision r0p0 of CPU. It is still open. The workaround is to set CPUACTLR5_EL1[13] to 1'b1. SDEN can be found here: https://developer.arm.com/documentation/SDEN1982442/latest Signed-off-by: nayanpatel-arm Change-Id: I5247f8f8eef08d38c169aad6d2c5501ac387c720 --- docs/design/cpu-specific-build-macros.rst | 3 ++ include/lib/cpus/aarch64/neoverse_n2.h | 1 + lib/cpus/aarch64/neoverse_n2.S | 34 +++++++++++++++++++++++ lib/cpus/cpu-ops.mk | 8 ++++++ 4 files changed, 46 insertions(+) diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst index b19c534cb..cd4d0fdca 100644 --- a/docs/design/cpu-specific-build-macros.rst +++ b/docs/design/cpu-specific-build-macros.rst @@ -423,6 +423,9 @@ For Neoverse N2, the following errata build flags are defined : - ``ERRATA_N2_2242415``: This applies errata 2242415 workaround to Neoverse-N2 CPU. This needs to be enabled for revision r0p0 of the CPU and is still open. +- ``ERRATA_N2_2138958``: This applies errata 2138958 workaround to Neoverse-N2 + CPU. This needs to be enabled for revision r0p0 of the CPU and is still open. + DSU Errata Workarounds ---------------------- diff --git a/include/lib/cpus/aarch64/neoverse_n2.h b/include/lib/cpus/aarch64/neoverse_n2.h index 8ba62a3f7..a457f2a54 100644 --- a/include/lib/cpus/aarch64/neoverse_n2.h +++ b/include/lib/cpus/aarch64/neoverse_n2.h @@ -41,6 +41,7 @@ ******************************************************************************/ #define NEOVERSE_N2_CPUACTLR5_EL1 S3_0_C15_C8_0 #define NEOVERSE_N2_CPUACTLR5_EL1_BIT_44 (ULL(1) << 44) +#define NEOVERSE_N2_CPUACTLR5_EL1_BIT_13 (ULL(1) << 13) /******************************************************************************* * CPU Auxiliary Control register specific definitions. diff --git a/lib/cpus/aarch64/neoverse_n2.S b/lib/cpus/aarch64/neoverse_n2.S index c197590ba..ff569fb23 100644 --- a/lib/cpus/aarch64/neoverse_n2.S +++ b/lib/cpus/aarch64/neoverse_n2.S @@ -240,6 +240,34 @@ func check_errata_2138953 b cpu_rev_var_ls endfunc check_errata_2138953 +/* -------------------------------------------------- + * Errata Workaround for Neoverse N2 Erratum 2138958. + * This applies to revision r0p0 of Neoverse N2. it is still open. + * Inputs: + * x0: variant[4:7] and revision[0:3] of current cpu. + * Shall clobber: x0-x1, x17 + * -------------------------------------------------- + */ +func errata_n2_2138958_wa + /* Check revision. */ + mov x17, x30 + bl check_errata_2138958 + cbz x0, 1f + + /* Apply instruction patching sequence */ + mrs x1, NEOVERSE_N2_CPUACTLR5_EL1 + orr x1, x1, NEOVERSE_N2_CPUACTLR5_EL1_BIT_13 + msr NEOVERSE_N2_CPUACTLR5_EL1, x1 +1: + ret x17 +endfunc errata_n2_2138958_wa + +func check_errata_2138958 + /* Applies to r0p0 */ + mov x1, #0x00 + b cpu_rev_var_ls +endfunc check_errata_2138958 + /* ------------------------------------------- * The CPU Ops reset function for Neoverse N2. * ------------------------------------------- @@ -291,6 +319,11 @@ func neoverse_n2_reset_func bl errata_n2_2242415_wa #endif +#if ERRATA_N2_2138958 + mov x0, x18 + bl errata_n2_2138958_wa +#endif + #if ENABLE_AMU /* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */ mrs x0, cptr_el3 @@ -358,6 +391,7 @@ func neoverse_n2_errata_report report_errata ERRATA_N2_2138956, neoverse_n2, 2138956 report_errata ERRATA_N2_2138953, neoverse_n2, 2138953 report_errata ERRATA_N2_2242415, neoverse_n2, 2242415 + report_errata ERRATA_N2_2138958, neoverse_n2, 2138958 ldp x8, x30, [sp], #16 ret diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk index 4224fcc65..b676987d7 100644 --- a/lib/cpus/cpu-ops.mk +++ b/lib/cpus/cpu-ops.mk @@ -465,6 +465,10 @@ ERRATA_N2_2138953 ?=0 # to revision r0p0 of the Neoverse N2 cpu and is still open. ERRATA_N2_2242415 ?=0 +# Flag to apply erratum 2138958 workaround during reset. This erratum applies +# to revision r0p0 of the Neoverse N2 cpu and is still open. +ERRATA_N2_2138958 ?=0 + # Flag to apply erratum 2055002 workaround during reset. This erratum applies # to revision r1p0, r2p0 of the Cortex-A710 cpu and is still open. ERRATA_A710_2055002 ?=0 @@ -870,6 +874,10 @@ $(eval $(call add_define,ERRATA_N2_2138953)) $(eval $(call assert_boolean,ERRATA_N2_2242415)) $(eval $(call add_define,ERRATA_N2_2242415)) +# Process ERRATA_N2_2138958 flag +$(eval $(call assert_boolean,ERRATA_N2_2138958)) +$(eval $(call add_define,ERRATA_N2_2138958)) + # Process ERRATA_A710_2055002 flag $(eval $(call assert_boolean,ERRATA_A710_2055002)) $(eval $(call add_define,ERRATA_A710_2055002))