fix(cpus): workaround for Cortex-A77 erratum 2743100

Cortex-A77 erratum 2743100 is a Cat B erratum that applies to revisions
r0p0, r1p0, r1p1, and is still open. The workaround is to insert a dsb
before the isb in the power down sequence.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1152370/latest

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I8e49a2dac8611f31ace249a17ae7a90cd60e742a

diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 03b3ee5bacf1f182331f62e04f645063d916ad04..55e265c9ab32ef49e957bccb532fb29514c7390c 100644 (file)
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -280,6 +280,9 @@ For Cortex-A77, the following errata build flags are defined :
  -  ``ERRATA_A77_1800714``: This applies errata 1800714 workaround to Cortex-A77
     CPU. This needs to be enabled for revisions <= r1p1 of the CPU.
 
+ -  ``ERRATA_A77_2743100``: This applies errata 2743100 workaround to Cortex-A77
+    CPU. This needs to be enabled for r0p0, r1p0, and r1p1, it is still open.
+
 For Cortex-A78, the following errata build flags are defined :
 
 -  ``ERRATA_A78_1688305``: This applies errata 1688305 workaround to Cortex-A78

diff --git a/lib/cpus/aarch64/cortex_a77.S b/lib/cpus/aarch64/cortex_a77.S
index 8cafe4a06912ae22cfcb15962e7b5e52bb081ab8..2882df7bdddc0a63e5f7fcf473ea3a05bb17fcfa 100644 (file)
--- a/lib/cpus/aarch64/cortex_a77.S
+++ b/lib/cpus/aarch64/cortex_a77.S
@@ -227,6 +227,30 @@ func check_errata_2356587
        b       cpu_rev_var_ls
 endfunc check_errata_2356587
 
+       /* -----------------------------------------------------------------
+        * Errata Workaround for Cortex A77 Errata #2743100
+        * This applies to revisions r0p0, r1p0, and r1p1 and is still open.
+        * x0: variant[4:7] and revision[0:3] of current cpu.
+        * Shall clobber: x0-x17
+        * -----------------------------------------------------------------
+        */
+func errata_a77_2743100_wa
+       mov     x17, x30
+       bl      check_errata_2743100
+       cbz     x0, 1f
+
+       /* dsb before isb of power down sequence */
+       dsb     sy
+1:
+       ret     x17
+endfunc errata_a77_2743100_wa
+
+func check_errata_2743100
+       /* Applies to r0p0, r1p0, and r1p1 right now */
+       mov     x1, #0x11
+       b       cpu_rev_var_ls
+endfunc check_errata_2743100
+
 func check_errata_cve_2022_23960
 #if WORKAROUND_CVE_2022_23960
        mov     x0, #ERRATA_APPLIES
@@ -330,6 +354,12 @@ func cortex_a77_core_pwr_dwn
        mrs     x0, CORTEX_A77_CPUPWRCTLR_EL1
        orr     x0, x0, #CORTEX_A77_CPUPWRCTLR_EL1_CORE_PWRDN_BIT
        msr     CORTEX_A77_CPUPWRCTLR_EL1, x0
+#if ERRATA_A77_2743100
+       mov     x15, x30
+       bl      cpu_get_rev_var
+       bl      errata_a77_2743100_wa
+       mov     x30, x15
+#endif /* ERRATA_A77_2743100 */
        isb
        ret
 endfunc cortex_a77_core_pwr_dwn
@@ -354,6 +384,7 @@ func cortex_a77_errata_report
        report_errata ERRATA_A77_1925769, cortex_a77, 1925769
        report_errata ERRATA_A77_1946167, cortex_a77, 1946167
        report_errata ERRATA_A77_2356587, cortex_a77, 2356587
+       report_errata ERRATA_A77_2743100, cortex_a77, 2743100
        report_errata WORKAROUND_CVE_2022_23960, cortex_a77, cve_2022_23960
 
        ldp     x8, x30, [sp], #16

diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index eb6d20f38816cd23cda0c8aca178f16b2cb06375..f19c16e49fd61be2a63355b07011610e910e2ca1 100644 (file)
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -315,6 +315,10 @@ ERRATA_A77_2356587 ?=0
 # to revisions <= r1p1 of the Cortex A77 cpu.
 ERRATA_A77_1800714     ?=0
 
+# Flag to apply erratum 2743100 workaround during power down. This erratum
+# applies to revisions r0p0, r1p0, and r1p1, it is still open.
+ERRATA_A77_2743100     ?=0
+
 # Flag to apply erratum 1688305 workaround during reset. This erratum applies
 # to revisions r0p0 - r1p0 of the A78 cpu.
 ERRATA_A78_1688305     ?=0
@@ -948,6 +952,10 @@ $(eval $(call add_define,ERRATA_A77_2356587))
 $(eval $(call assert_boolean,ERRATA_A77_1800714))
 $(eval $(call add_define,ERRATA_A77_1800714))
 
+# Process ERRATA_A77_2743100 flag
+$(eval $(call assert_boolean,ERRATA_A77_2743100))
+$(eval $(call add_define,ERRATA_A77_2743100))
+
 # Process ERRATA_A78_1688305 flag
 $(eval $(call assert_boolean,ERRATA_A78_1688305))
 $(eval $(call add_define,ERRATA_A78_1688305))