From 780edd86a0b413c3620c5c42fd123a78b5b1587a Mon Sep 17 00:00:00 2001 From: Dimitris Papastamos Date: Tue, 2 Jan 2018 15:53:01 +0000 Subject: Use PFR0 to identify need for mitigation of CVE-2017-5915 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 A75. Change-Id: I4d5504cba516a67311fb5f0657b08f72909cbd38 Signed-off-by: Dimitris Papastamos --- lib/cpus/aarch64/cortex_a75.S | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'lib') diff --git a/lib/cpus/aarch64/cortex_a75.S b/lib/cpus/aarch64/cortex_a75.S index 1a9d9049..9b54b48f 100644 --- a/lib/cpus/aarch64/cortex_a75.S +++ b/lib/cpus/aarch64/cortex_a75.S @@ -13,8 +13,18 @@ func cortex_a75_reset_func #if IMAGE_BL31 && WORKAROUND_CVE_2017_5715 + mrs x0, id_aa64pfr0_el1 + ubfx x0, x0, #ID_AA64PFR0_CSV2_SHIFT, #ID_AA64PFR0_CSV2_LENGTH + /* + * If the field equals to 1 then branch targets trained in one + * context cannot affect speculative execution in a different context. + */ + cmp x0, #1 + beq 1f + adr x0, workaround_bpiall_vbar0_runtime_exceptions msr vbar_el3, x0 +1: #endif #if ENABLE_AMU -- cgit v1.2.3