cpus: denver: report CVE_2017_5715 mitigation to higher layers

This patch uses the 'declare_cpu_ops_wa' macro, to set the check function,
to report that Denver cores are mitigated.

Denver cores are vulnerable to this anomaly and require the mitigation to
be enabled always.

Change-Id: I1bb6eefdec8c01fb8b645e112f8d04d4bb8811ef
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

diff --git a/lib/cpus/aarch64/denver.S b/lib/cpus/aarch64/denver.S
index f04dbd6c49211b57d48e52559d9c5703575bf22b..a981d02c7a589140891efdf6250d5eb5cac335b8 100644 (file)
--- a/lib/cpus/aarch64/denver.S
+++ b/lib/cpus/aarch64/denver.S
@@ -189,6 +189,25 @@ func denver_disable_dco
        ret
 endfunc denver_disable_dco
 
+func check_errata_cve_2017_5715
+       mov     x0, #ERRATA_MISSING
+#if WORKAROUND_CVE_2017_5715
+       /*
+        * Check if the CPU supports the special instruction
+        * required to flush the indirect branch predictor and
+        * RSB. Support for this operation can be determined by
+        * comparing bits 19:16 of ID_AFR0_EL1 with 0b0001.
+        */
+       mrs     x1, id_afr0_el1
+       mov     x2, #0x10000
+       and     x1, x1, x2
+       cbz     x1, 1f
+       mov     x0, #ERRATA_APPLIES
+1:
+#endif
+       ret
+endfunc check_errata_cve_2017_5715
+
        /* -------------------------------------------------
         * The CPU Ops reset function for Denver.
         * -------------------------------------------------
@@ -248,6 +267,27 @@ func denver_cluster_pwr_dwn
        ret
 endfunc denver_cluster_pwr_dwn
 
+#if REPORT_ERRATA
+       /*
+        * Errata printing function for Denver. Must follow AAPCS.
+        */
+func denver_errata_report
+       stp     x8, x30, [sp, #-16]!
+
+       bl      cpu_get_rev_var
+       mov     x8, x0
+
+       /*
+        * Report all errata. The revision-variant information is passed to
+        * checking functions of each errata.
+        */
+       report_errata WORKAROUND_CVE_2017_5715, denver, cve_2017_5715
+
+       ldp     x8, x30, [sp], #16
+       ret
+endfunc denver_errata_report
+#endif
+
        /* ---------------------------------------------
         * This function provides Denver specific
         * register information for crash reporting.
@@ -267,27 +307,37 @@ func denver_cpu_reg_dump
        ret
 endfunc denver_cpu_reg_dump
 
-declare_cpu_ops denver, DENVER_MIDR_PN0, \
+declare_cpu_ops_wa denver, DENVER_MIDR_PN0, \
        denver_reset_func, \
+       check_errata_cve_2017_5715, \
+       CPU_NO_EXTRA2_FUNC, \
        denver_core_pwr_dwn, \
        denver_cluster_pwr_dwn
 
-declare_cpu_ops denver, DENVER_MIDR_PN1, \
+declare_cpu_ops_wa denver, DENVER_MIDR_PN1, \
        denver_reset_func, \
+       check_errata_cve_2017_5715, \
+       CPU_NO_EXTRA2_FUNC, \
        denver_core_pwr_dwn, \
        denver_cluster_pwr_dwn
 
-declare_cpu_ops denver, DENVER_MIDR_PN2, \
+declare_cpu_ops_wa denver, DENVER_MIDR_PN2, \
        denver_reset_func, \
+       check_errata_cve_2017_5715, \
+       CPU_NO_EXTRA2_FUNC, \
        denver_core_pwr_dwn, \
        denver_cluster_pwr_dwn
 
-declare_cpu_ops denver, DENVER_MIDR_PN3, \
+declare_cpu_ops_wa denver, DENVER_MIDR_PN3, \
        denver_reset_func, \
+       check_errata_cve_2017_5715, \
+       CPU_NO_EXTRA2_FUNC, \
        denver_core_pwr_dwn, \
        denver_cluster_pwr_dwn
 
-declare_cpu_ops denver, DENVER_MIDR_PN4, \
+declare_cpu_ops_wa denver, DENVER_MIDR_PN4, \
        denver_reset_func, \
+       check_errata_cve_2017_5715, \
+       CPU_NO_EXTRA2_FUNC, \
        denver_core_pwr_dwn, \
        denver_cluster_pwr_dwn