aboutsummaryrefslogtreecommitdiff
path: root/arch/arm
diff options
context:
space:
mode:
authorRussell King <rmk+kernel@armlinux.org.uk>2018-05-10 13:09:54 +0100
committerDavid A. Long <dave.long@linaro.org>2018-10-30 23:23:38 -0400
commitfc7059f0527376ff7853c111d1fefe66d7761f21 (patch)
treeda5c538ad204145675792762fe2d8c9ed01161a1 /arch/arm
parent4c2280b10e50c7964bd72c893994b9ad92fe01d7 (diff)
downloadlinux-linaro-stable-fc7059f0527376ff7853c111d1fefe66d7761f21.tar.gz
ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit
Commit e388b80288aade31135aca23d32eee93dd106795 upstream. When the branch predictor hardening is enabled, firmware must have set the IBE bit in the auxiliary control register. If this bit has not been set, the Spectre workarounds will not be functional. Add validation that this bit is set, and print a warning at alert level if this is not the case. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Boot-tested-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Tony Lindgren <tony@atomide.com> Signed-off-by: David A. Long <dave.long@linaro.org>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mm/Makefile2
-rw-r--r--arch/arm/mm/proc-v7-bugs.c36
-rw-r--r--arch/arm/mm/proc-v7.S4
3 files changed, 39 insertions, 3 deletions
diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index 7f76d96ce546..35307176e46c 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -92,7 +92,7 @@ obj-$(CONFIG_CPU_MOHAWK) += proc-mohawk.o
obj-$(CONFIG_CPU_FEROCEON) += proc-feroceon.o
obj-$(CONFIG_CPU_V6) += proc-v6.o
obj-$(CONFIG_CPU_V6K) += proc-v6.o
-obj-$(CONFIG_CPU_V7) += proc-v7.o
+obj-$(CONFIG_CPU_V7) += proc-v7.o proc-v7-bugs.o
obj-$(CONFIG_CPU_V7M) += proc-v7m.o
AFLAGS_proc-v6.o :=-Wa,-march=armv6
diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
new file mode 100644
index 000000000000..e46557db6446
--- /dev/null
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/smp.h>
+
+static __maybe_unused void cpu_v7_check_auxcr_set(bool *warned,
+ u32 mask, const char *msg)
+{
+ u32 aux_cr;
+
+ asm("mrc p15, 0, %0, c1, c0, 1" : "=r" (aux_cr));
+
+ if ((aux_cr & mask) != mask) {
+ if (!*warned)
+ pr_err("CPU%u: %s", smp_processor_id(), msg);
+ *warned = true;
+ }
+}
+
+static DEFINE_PER_CPU(bool, spectre_warned);
+
+static void check_spectre_auxcr(bool *warned, u32 bit)
+{
+ if (IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR) &&
+ cpu_v7_check_auxcr_set(warned, bit,
+ "Spectre v2: firmware did not set auxiliary control register IBE bit, system vulnerable\n");
+}
+
+void cpu_v7_ca8_ibe(void)
+{
+ check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(6));
+}
+
+void cpu_v7_ca15_ibe(void)
+{
+ check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0));
+}
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index c2950317c7c2..1436ad424f2a 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -511,7 +511,7 @@ __v7_setup_stack:
globl_equ cpu_ca8_do_suspend, cpu_v7_do_suspend
globl_equ cpu_ca8_do_resume, cpu_v7_do_resume
#endif
- define_processor_functions ca8, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+ define_processor_functions ca8, dabort=v7_early_abort, pabort=v7_pabort, suspend=1, bugs=cpu_v7_ca8_ibe
@ Cortex-A9 - needs more registers preserved across suspend/resume
@ and bpiall switch_mm for hardening
@@ -544,7 +544,7 @@ __v7_setup_stack:
globl_equ cpu_ca15_suspend_size, cpu_v7_suspend_size
globl_equ cpu_ca15_do_suspend, cpu_v7_do_suspend
globl_equ cpu_ca15_do_resume, cpu_v7_do_resume
- define_processor_functions ca15, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+ define_processor_functions ca15, dabort=v7_early_abort, pabort=v7_pabort, suspend=1, bugs=cpu_v7_ca15_ibe
#ifdef CONFIG_CPU_PJ4B
define_processor_functions pj4b, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
#endif