[xen staging] xen/arm: Check for PMU platform support

[patchbot@xxxxxxx]

commit f9294486926c865a3ef11cacd7cb6b26cce6f4a4
Author:     Michal Orzel <michal.orzel@xxxxxxx>
AuthorDate: Tue Oct 12 10:13:22 2021 +0200
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
CommitDate: Tue Oct 12 15:25:52 2021 -0700

    xen/arm: Check for PMU platform support
    
    ID_AA64DFR0_EL1/ID_DFR0_EL1 registers provide
    information about PMU support. Replace structure
    dbg64/dbg32 with a union and fill in all the
    register fields according to document:
    ARM Architecture Registers(DDI 0595, 2021-06).
    
    Add macros boot_dbg_feature64/boot_dbg_feature32
    to check for a debug feature. Add macro
    cpu_has_pmu to check for PMU support.
    Any value higher than 0 and less than 15 means
    that PMU is supported (we do not care about its
    version for now).
    
    Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
    [stefano: add in-code comment]
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 xen/include/asm-arm/cpufeature.h | 59 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 57 insertions(+), 2 deletions(-)

diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 5ca09b0bff..8a5afbaf0b 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -4,6 +4,7 @@
 #ifdef CONFIG_ARM_64
 #define cpu_feature64(c, feat)         ((c)->pfr64.feat)
 #define boot_cpu_feature64(feat)       (system_cpuinfo.pfr64.feat)
+#define boot_dbg_feature64(feat)       (system_cpuinfo.dbg64.feat)
 
 #define cpu_feature64_has_el0_32(c)    (cpu_feature64(c, el0) == 2)
 
@@ -22,6 +23,7 @@
 
 #define cpu_feature32(c, feat)         ((c)->pfr32.feat)
 #define boot_cpu_feature32(feat)       (system_cpuinfo.pfr32.feat)
+#define boot_dbg_feature32(feat)       (system_cpuinfo.dbg32.feat)
 
 #define cpu_has_arm       (boot_cpu_feature32(arm) == 1)
 #define cpu_has_thumb     (boot_cpu_feature32(thumb) >= 1)
@@ -32,8 +34,20 @@
 
 #ifdef CONFIG_ARM_32
 #define cpu_has_gentimer  (boot_cpu_feature32(gentimer) == 1)
+/*
+ * On Armv7, the value 0 is used to indicate that PMUv2 is not
+ * supported. IOW this doesn't tell us whether the PMU is not supported
+ * (a processor may implement PMUv1).
+ *
+ * For convenience, we treat 0 as not supported which matches the
+ * meaning on Armv8
+ */
+#define cpu_has_pmu       ((boot_dbg_feature32(perfmon) >= 1) && \
+                           (boot_dbg_feature32(perfmon) < 15))
 #else
 #define cpu_has_gentimer  (1)
+#define cpu_has_pmu       ((boot_dbg_feature64(pmu_ver) >= 1) && \
+                           (boot_dbg_feature64(pmu_ver) < 15))
 #endif
 #define cpu_has_security  (boot_cpu_feature32(security) > 0)
 
@@ -181,8 +195,28 @@ struct cpuinfo_arm {
         };
     } pfr64;
 
-    struct {
+    union {
         register_t bits[2];
+        struct {
+            /* DFR0 */
+            unsigned long debug_ver:4;
+            unsigned long trace_ver:4;
+            unsigned long pmu_ver:4;
+            unsigned long brps:4;
+            unsigned long __res0:4;
+            unsigned long wrps:4;
+            unsigned long __res1:4;
+            unsigned long ctx_cmps:4;
+            unsigned long pms_ver:4;
+            unsigned long double_lock:4;
+            unsigned long trace_filt:4;
+            unsigned long __res2:4;
+            unsigned long mtpmu:4;
+            unsigned long __res3:12;
+
+            /* DFR1 */
+            unsigned long __res4:64;
+        };
     } dbg64;
 
     struct {
@@ -321,8 +355,29 @@ struct cpuinfo_arm {
         };
     } pfr32;
 
-    struct {
+    union {
         register_t bits[2];
+        struct {
+            /* DFR0 */
+            unsigned long copdbg:4;
+            unsigned long copsdbg:4;
+            unsigned long mmapdbg:4;
+            unsigned long coptrc:4;
+            unsigned long mmaptrc:4;
+            unsigned long mprofdbg:4;
+            unsigned long perfmon:4;
+            unsigned long tracefilt:4;
+#ifdef CONFIG_ARM_64
+            unsigned long __res0:32;
+#endif
+
+            /* DFR1 */
+            unsigned long mtpmu:4;
+            unsigned long __res1:28;
+#ifdef CONFIG_ARM_64
+            unsigned long __res2:32;
+#endif
+        };
     } dbg32;
 
     struct {
--
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