Add workaround for errata 790748 for Cortex-A75

Internal timing conditions might cause the CPU to stop processing
interrupts. Set bit 13 of CPUACTLR_EL1 to prevent this.

Change-Id: Ifdd19dbcdb71bb0d9609cab1315c478aaedb03ba
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>

diff --git a/docs/cpu-specific-build-macros.rst b/docs/cpu-specific-build-macros.rst
index dbb18569b54017fd1fa8d3c034cdd76a6fe6c2ba..73ed38230c3e6da91a6c867ca406afbb6c434f69 100644 (file)
--- a/docs/cpu-specific-build-macros.rst
+++ b/docs/cpu-specific-build-macros.rst
@@ -142,6 +142,9 @@ For Cortex-A75, the following errata build flags are defined :
 -  ``ERRATA_A75_764081``: This applies errata 764081 workaround to Cortex-A75
    CPU. This needs to be enabled only for revision r0p0 of the CPU.
 
+-  ``ERRATA_A75_790748``: This applies errata 790748 workaround to Cortex-A75
+    CPU. This needs to be enabled only for revision r0p0 of the CPU.
+
 DSU Errata Workarounds
 ----------------------
 

diff --git a/lib/cpus/aarch64/cortex_a75.S b/lib/cpus/aarch64/cortex_a75.S
index 8d04294dc5a40151ec22fe220c201026df104b56..20401889074b1a502428129bfd4c437c7a6788e8 100644 (file)
--- a/lib/cpus/aarch64/cortex_a75.S
+++ b/lib/cpus/aarch64/cortex_a75.S
@@ -38,6 +38,34 @@ func check_errata_764081
        b       cpu_rev_var_ls
 endfunc check_errata_764081
 
+       /* --------------------------------------------------
+        * Errata Workaround for Cortex A75 Errata #790748.
+        * This applies only to revision r0p0 of Cortex A75.
+        * Inputs:
+        * x0: variant[4:7] and revision[0:3] of current cpu.
+        * Shall clobber: x0-x17
+        * --------------------------------------------------
+        */
+func errata_a75_790748_wa
+       /*
+        * Compare x0 against revision r0p0
+        */
+       mov     x17, x30
+       bl      check_errata_790748
+       cbz     x0, 1f
+       mrs     x1, CORTEX_A75_CPUACTLR_EL1
+       orr     x1, x1 ,#(1 << 13)
+       msr     CORTEX_A75_CPUACTLR_EL1, x1
+       isb
+1:
+       ret     x17
+endfunc errata_a75_790748_wa
+
+func check_errata_790748
+       mov     x1, #0x00
+       b       cpu_rev_var_ls
+endfunc check_errata_790748
+
        /* -------------------------------------------------
         * The CPU Ops reset function for Cortex-A75.
         * -------------------------------------------------
@@ -45,11 +73,18 @@ endfunc check_errata_764081
 func cortex_a75_reset_func
        mov     x19, x30
        bl      cpu_get_rev_var
+       mov     x18, x0
 
 #if ERRATA_A75_764081
+       mov     x0, x18
        bl      errata_a75_764081_wa
 #endif
 
+#if ERRATA_A75_790748
+       mov     x0, x18
+       bl      errata_a75_790748_wa
+#endif
+
 #if IMAGE_BL31 && WORKAROUND_CVE_2017_5715
        cpu_check_csv2  x0, 1f
        adr     x0, wa_cve_2017_5715_bpiall_vbar
@@ -148,6 +183,7 @@ func cortex_a75_errata_report
         * checking functions of each errata.
         */
        report_errata ERRATA_A75_764081, cortex_a75, 764081
+       report_errata ERRATA_A75_790748, cortex_a75, 790748
        report_errata WORKAROUND_CVE_2017_5715, cortex_a75, cve_2017_5715
        report_errata WORKAROUND_CVE_2018_3639, cortex_a75, cve_2018_3639
        report_errata ERRATA_DSU_936184, cortex_a75, dsu_936184

diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index be7d3bde8538eab4556a7c2dc0edbeab79c8f406..a7acd2f8b01c4b527212918c6bbf5dc66d81c61a 100644 (file)
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -127,6 +127,10 @@ ERRATA_A73_855423  ?=0
 # only to revision <= r0p0 of the Cortex A75 cpu.
 ERRATA_A75_764081      ?=0
 
+# Flag to apply erratum 790748 workaround during reset. This erratum applies
+# only to revision <= r0p0 of the Cortex A75 cpu.
+ERRATA_A75_790748      ?=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      ?=1
@@ -204,6 +208,10 @@ $(eval $(call add_define,ERRATA_A73_855423))
 $(eval $(call assert_boolean,ERRATA_A75_764081))
 $(eval $(call add_define,ERRATA_A75_764081))
 
+# Process ERRATA_A75_790748 flag
+$(eval $(call assert_boolean,ERRATA_A75_790748))
+$(eval $(call add_define,ERRATA_A75_790748))
+
 # Process ERRATA_N1_1043202 flag
 $(eval $(call assert_boolean,ERRATA_N1_1043202))
 $(eval $(call add_define,ERRATA_N1_1043202))