Merge tag 'omap-for-v4.18/fixes-rc4-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes

Two omap fixes for v4.18-rc cycle

Turns out the recent patches for ARM branch predictor hardening are
not working on omap5 and dra7 as planned because the secondary CPU
is parked to the bootrom code. We can't configure it in the bootloader.
So we must enable invalidates of BTB for omap5 and dra7 secondary
core in the kernel.

And there's a fix for reserved register access for am3517. The
usb otg module on am3517 is not the same as for other omap3.

* tag 'omap-for-v4.18/fixes-rc4-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  ARM: dts: am3517.dtsi:  Disable reference to OMAP3 OTG controller
  ARM: DRA7/OMAP5: Enable ACTLR[0] (Enable invalidates of BTB) for secondary cores

Signed-off-by: Olof Johansson <olof@lixom.net>

1 files changed, 41 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index 69df3620eca5..1c73694c871a 100644
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -109,6 +109,45 @@ void omap5_erratum_workaround_801819(void)
 static inline void omap5_erratum_workaround_801819(void) { }
 #endif
 
+#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
+/*
+ * Configure ACR and enable ACTLR[0] (Enable invalidates of BTB with
+ * ICIALLU) to activate the workaround for secondary Core.
+ * NOTE: it is assumed that the primary core's configuration is done
+ * by the boot loader (kernel will detect a misconfiguration and complain
+ * if this is not done).
+ *
+ * In General Purpose(GP) devices, ACR bit settings can only be done
+ * by ROM code in "secure world" using the smc call and there is no
+ * option to update the "firmware" on such devices. This also works for
+ * High security(HS) devices, as a backup option in case the
+ * "update" is not done in the "security firmware".
+ */
+static void omap5_secondary_harden_predictor(void)
+{
+	u32 acr, acr_mask;
+
+	asm volatile ("mrc p15, 0, %0, c1, c0, 1" : "=r" (acr));
+
+	/*
+	 * ACTLR[0] (Enable invalidates of BTB with ICIALLU)
+	 */
+	acr_mask = BIT(0);
+
+	/* Do we already have it done.. if yes, skip expensive smc */
+	if ((acr & acr_mask) == acr_mask)
+		return;
+
+	acr |= acr_mask;
+	omap_smc1(OMAP5_DRA7_MON_SET_ACR_INDEX, acr);
+
+	pr_debug("%s: ARM ACR setup for CVE_2017_5715 applied on CPU%d\n",
+		 __func__, smp_processor_id());
+}
+#else
+static inline void omap5_secondary_harden_predictor(void) { }
+#endif
+
 static void omap4_secondary_init(unsigned int cpu)
 {
 	/*
@@ -131,6 +170,8 @@ static void omap4_secondary_init(unsigned int cpu)
 		set_cntfreq();
 		/* Configure ACR to disable streaming WA for 801819 */
 		omap5_erratum_workaround_801819();
+		/* Enable ACR to allow for ICUALLU workaround */
+		omap5_secondary_harden_predictor();
 	}
 
 	/*