Cortex-A73: Implement workaround for errata 852427

In AArch32, execution of 2 instructions with opposite condition code
might lead to either a data corruption or a CPU deadlock. Set the bit
12 of the Diagnostic Register to prevent this.

Change-Id: I22b4f25fe933e2942fd785e411e7c0aa39d5c1f4
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 1f23b5bf6940cefa0dc291572f12301082151f48..116b4ba355e9a48c955a1c9445a89d14bc454773 100644 (file)
--- a/docs/cpu-specific-build-macros.rst
+++ b/docs/cpu-specific-build-macros.rst
@@ -134,6 +134,9 @@ For Cortex-A72, the following errata build flags are defined :
 
 For Cortex-A73, the following errata build flags are defined :
 
+-  ``ERRATA_A73_852427``: This applies errata 852427 workaround to Cortex-A73
+   CPU. This needs to be enabled only for revision r0p0 of the CPU.
+
 -  ``ERRATA_A73_855423``: This applies errata 855423 workaround to Cortex-A73
    CPU. This needs to be enabled only for revision <= r0p1 of the CPU.
 

diff --git a/include/lib/cpus/aarch64/cortex_a73.h b/include/lib/cpus/aarch64/cortex_a73.h
index 61b2b737bdc0150537940a2d51ed1f37d3d9f0ce..1238c0ef4df5343643db4f717a1410cbe4f05189 100644 (file)
--- a/include/lib/cpus/aarch64/cortex_a73.h
+++ b/include/lib/cpus/aarch64/cortex_a73.h
@@ -31,6 +31,8 @@
 
 #define CORTEX_A73_IMP_DEF_REG1_DISABLE_LOAD_PASS_STORE        (ULL(1) << 3)
 
+#define CORTEX_A73_DIAGNOSTIC_REGISTER S3_0_C15_C0_1
+
 #define CORTEX_A73_IMP_DEF_REG2                S3_0_C15_C0_2
 
 #endif /* CORTEX_A73_H */

diff --git a/lib/cpus/aarch64/cortex_a73.S b/lib/cpus/aarch64/cortex_a73.S
index 6cfa4b5231a0f416900f6d719a5a0a08547a5e79..5c8a8871d3f6d5f71d7dfe5f062a6b633d537795 100644 (file)
--- a/lib/cpus/aarch64/cortex_a73.S
+++ b/lib/cpus/aarch64/cortex_a73.S
@@ -35,6 +35,34 @@ func cortex_a73_disable_smp
        ret
 endfunc cortex_a73_disable_smp
 
+       /* ---------------------------------------------------
+        * Errata Workaround for Cortex A73 Errata #852427.
+        * This applies only to revision r0p0 of Cortex A73.
+        * Inputs:
+        * x0: variant[4:7] and revision[0:3] of current cpu.
+        * Shall clobber: x0-x17
+        * ---------------------------------------------------
+        */
+func errata_a73_852427_wa
+       /*
+        * Compare x0 against revision r0p0
+        */
+       mov     x17, x30
+       bl      check_errata_852427
+       cbz     x0, 1f
+       mrs     x1, CORTEX_A73_DIAGNOSTIC_REGISTER
+       orr     x1, x1, #(1 << 12)
+       msr     CORTEX_A73_DIAGNOSTIC_REGISTER, x1
+       isb
+1:
+       ret     x17
+endfunc errata_a73_852427_wa
+
+func check_errata_852427
+       mov     x1, #0x00
+       b       cpu_rev_var_ls
+endfunc check_errata_852427
+
        /* ---------------------------------------------------
         * Errata Workaround for Cortex A73 Errata #855423.
         * This applies only to revision <= r0p1 of Cortex A73.
@@ -71,8 +99,15 @@ endfunc check_errata_855423
 func cortex_a73_reset_func
        mov     x19, x30
        bl      cpu_get_rev_var
+       mov     x18, x0
+
+#if ERRATA_A73_852427
+       mov     x0, x18
+       bl      errata_a73_852427_wa
+#endif
 
 #if ERRATA_A73_855423
+       mov     x0, x18
        bl      errata_a73_855423_wa
 #endif
 
@@ -200,6 +235,7 @@ func cortex_a73_errata_report
         * Report all errata. The revision-variant information is passed to
         * checking functions of each errata.
         */
+       report_errata ERRATA_A73_852427, cortex_a73, 852427
        report_errata ERRATA_A73_855423, cortex_a73, 855423
        report_errata WORKAROUND_CVE_2017_5715, cortex_a73, cve_2017_5715
        report_errata WORKAROUND_CVE_2018_3639, cortex_a73, cve_2018_3639

diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 02208f0e8a4beaf24384bb3e91d19acba84e4653..23f6c23703a4fe1d1df788f3b6c9a2cb41d7f3f7 100644 (file)
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -119,6 +119,10 @@ ERRATA_A57_859972  ?=0
 # only to revision <= r0p3 of the Cortex A72 cpu.
 ERRATA_A72_859971      ?=0
 
+# Flag to apply erratum 852427 workaround during reset. This erratum applies
+# only to revision r0p0 of the Cortex A73 cpu.
+ERRATA_A73_852427      ?=0
+
 # Flag to apply erratum 855423 workaround during reset. This erratum applies
 # only to revision <= r0p1 of the Cortex A73 cpu.
 ERRATA_A73_855423      ?=0
@@ -212,6 +216,10 @@ $(eval $(call add_define,ERRATA_A57_859972))
 $(eval $(call assert_boolean,ERRATA_A72_859971))
 $(eval $(call add_define,ERRATA_A72_859971))
 
+# Process ERRATA_A73_852427 flag
+$(eval $(call assert_boolean,ERRATA_A73_852427))
+$(eval $(call add_define,ERRATA_A73_852427))
+
 # Process ERRATA_A73_855423 flag
 $(eval $(call assert_boolean,ERRATA_A73_855423))
 $(eval $(call add_define,ERRATA_A73_855423))