coresight: etm4x: Move ETM to prohibited region for disable

If the CPU implements Arm v8.4 Trace filter controls (FEAT_TRF),
move the ETM to trace prohibited region using TRFCR, while disabling.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210405164307.1720226-9-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 15016f7..0029790 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -31,6 +31,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/property.h>
 
+#include <asm/barrier.h>
 #include <asm/sections.h>
 #include <asm/sysreg.h>
 #include <asm/local.h>
@@ -654,6 +655,7 @@ static int etm4_enable(struct coresight_device *csdev,
 static void etm4_disable_hw(void *info)
 {
        u32 control;
+       u64 trfcr;
        struct etmv4_drvdata *drvdata = info;
        struct etmv4_config *config = &drvdata->config;
        struct coresight_device *csdev = drvdata->csdev;
@@ -676,6 +678,16 @@ static void etm4_disable_hw(void *info)
        /* EN, bit[0] Trace unit enable bit */
        control &= ~0x1;
 
+       /*
+        * If the CPU supports v8.4 Trace filter Control,
+        * set the ETM to trace prohibited region.
+        */
+       if (drvdata->trfc) {
+               trfcr = read_sysreg_s(SYS_TRFCR_EL1);
+               write_sysreg_s(trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE),
+                              SYS_TRFCR_EL1);
+               isb();
+       }
        /*
         * Make sure everything completes before disabling, as recommended
         * by section 7.3.77 ("TRCVICTLR, ViewInst Main Control Register,
@@ -683,12 +695,16 @@ static void etm4_disable_hw(void *info)
         */
        dsb(sy);
        isb();
+       /* Trace synchronization barrier, is a nop if not supported */
+       tsb_csync();
        etm4x_relaxed_write32(csa, control, TRCPRGCTLR);
 
        /* wait for TRCSTATR.PMSTABLE to go to '1' */
        if (coresight_timeout(csa, TRCSTATR, TRCSTATR_PMSTABLE_BIT, 1))
                dev_err(etm_dev,
                        "timeout while waiting for PM stable Trace Status\n");
+       if (drvdata->trfc)
+               write_sysreg_s(trfcr, SYS_TRFCR_EL1);
 
        /* read the status of the single shot comparators */
        for (i = 0; i < drvdata->nr_ss_cmp; i++) {
@@ -873,7 +889,7 @@ static bool etm4_init_csdev_access(struct etmv4_drvdata *drvdata,
        return false;
 }
 
-static void cpu_enable_tracing(void)
+static void cpu_enable_tracing(struct etmv4_drvdata *drvdata)
 {
        u64 dfr0 = read_sysreg(id_aa64dfr0_el1);
        u64 trfcr;
@@ -881,6 +897,7 @@ static void cpu_enable_tracing(void)
        if (!cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_TRACE_FILT_SHIFT))
                return;
 
+       drvdata->trfc = true;
        /*
         * If the CPU supports v8.4 SelfHosted Tracing, enable
         * tracing at the kernel EL and EL0, forcing to use the
@@ -1082,7 +1099,7 @@ static void etm4_init_arch_data(void *info)
        /* NUMCNTR, bits[30:28] number of counters available for tracing */
        drvdata->nr_cntr = BMVAL(etmidr5, 28, 30);
        etm4_cs_lock(drvdata, csa);
-       cpu_enable_tracing();
+       cpu_enable_tracing(drvdata);
 }
 
 static inline u32 etm4_get_victlr_access_type(struct etmv4_config *config)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 0af6057..f6478ef 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -862,6 +862,7 @@ struct etmv4_save_state {
  * @nooverflow:        Indicate if overflow prevention is supported.
  * @atbtrig:   If the implementation can support ATB triggers
  * @lpoverride:        If the implementation can support low-power state over.
+ * @trfc:      If the implementation supports Arm v8.4 trace filter controls.
  * @config:    structure holding configuration parameters.
  * @save_state:        State to be preserved across power loss
  * @state_needs_restore: True when there is context to restore after PM exit
@@ -912,6 +913,7 @@ struct etmv4_drvdata {
        bool                            nooverflow;
        bool                            atbtrig;
        bool                            lpoverride;
+       bool                            trfc;
        struct etmv4_config             config;
        struct etmv4_save_state         *save_state;
        bool                            state_needs_restore;