Use PFR0 to identify need for mitigation of CVE-2017-5715
If the CSV2 field reads as 1 then branch targets trained in one
context cannot affect speculative execution in a different context.
In that case skip the workaround on Cortex A72 and A73.
Change-Id: Ide24fb6efc77c548e4296295adc38dca87d042ee
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
diff --git a/lib/cpus/aarch64/cortex_a72.S b/lib/cpus/aarch64/cortex_a72.S
index 9633aa8..199820c 100644
--- a/lib/cpus/aarch64/cortex_a72.S
+++ b/lib/cpus/aarch64/cortex_a72.S
@@ -98,12 +98,16 @@
endfunc check_errata_859971
func check_errata_cve_2017_5715
+ cpu_check_csv2 x0, 1f
#if WORKAROUND_CVE_2017_5715
mov x0, #ERRATA_APPLIES
#else
mov x0, #ERRATA_MISSING
#endif
ret
+1:
+ mov x0, #ERRATA_NOT_APPLIES
+ ret
endfunc check_errata_cve_2017_5715
/* -------------------------------------------------
@@ -121,8 +125,10 @@
#endif
#if IMAGE_BL31 && WORKAROUND_CVE_2017_5715
+ cpu_check_csv2 x0, 1f
adr x0, workaround_mmu_runtime_exceptions
msr vbar_el3, x0
+1:
#endif
/* ---------------------------------------------