From 59dc4ef48757e4de2dc2de13d13e43acd5d91aa0 Mon Sep 17 00:00:00 2001
From: Dimitris Papastamos <dimitris.papastamos@arm.com>
Date: Wed, 28 Mar 2018 12:06:40 +0100
Subject: [PATCH] Fixup SMCCC_FEATURES return value for SMCCC_ARCH_WORKAROUND_1
Only return -1 if the workaround for CVE-2017-5715 is not compiled in.
Change-Id: I1bd07c57d22b4a13cf51b35be141a1f1ffb065ff
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
---
docs/cpu-specific-build-macros.rst | 6 +++++-
services/arm_arch_svc/arm_arch_svc_setup.c | 11 ++++-------
2 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/docs/cpu-specific-build-macros.rst b/docs/cpu-specific-build-macros.rst
index 9e11cdff6..65f6adb8d 100644
--- a/docs/cpu-specific-build-macros.rst
+++ b/docs/cpu-specific-build-macros.rst
@@ -18,7 +18,11 @@ TF-A exports a series of build flags which control which security
vulnerability workarounds should be applied at runtime.
- ``WORKAROUND_CVE_2017_5715``: Enables the security workaround for
- `CVE-2017-5715`_. Defaults to 1.
+ `CVE-2017-5715`_. This flag can be set to 0 by the platform if none
+ of the PEs in the system need the workaround. Setting this flag to 0 provides
+ no performance benefit for non-affected platforms, it just helps to comply
+ with the recommendation in the spec regarding workaround discovery.
+ Defaults to 1.
CPU Errata Workarounds
----------------------
diff --git a/services/arm_arch_svc/arm_arch_svc_setup.c b/services/arm_arch_svc/arm_arch_svc_setup.c
index 83d3625f9..eb736c060 100644
--- a/services/arm_arch_svc/arm_arch_svc_setup.c
+++ b/services/arm_arch_svc/arm_arch_svc_setup.c
@@ -19,19 +19,16 @@ static int32_t smccc_version(void)
static int32_t smccc_arch_features(u_register_t arg)
{
- int ret;
-
switch (arg) {
case SMCCC_VERSION:
case SMCCC_ARCH_FEATURES:
return SMC_OK;
+#if WORKAROUND_CVE_2017_5715
case SMCCC_ARCH_WORKAROUND_1:
- ret = check_workaround_cve_2017_5715();
- if (ret == ERRATA_APPLIES)
- return 0;
- else if (ret == ERRATA_NOT_APPLIES)
+ if (check_workaround_cve_2017_5715() == ERRATA_NOT_APPLIES)
return 1;
- return -1; /* ERRATA_MISSING */
+ return 0; /* ERRATA_APPLIES || ERRATA_MISSING */
+#endif
default:
return SMC_UNK;
}
--
GitLab