oprofile, x86: Add support for IBS periodic op counter extension

The count value for IBS op sampling has been extended by 7 bits. The
feature is reflected in bit 6 (OpCntExt) of the IBS capability
register (CPUID Fn8000_001B_EAX).

Signed-off-by: Robert Richter <robert.richter@amd.com>

1 files changed, 19 insertions, 3 deletions

diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index 9de33fa9531a..65f0a1eb6b86 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -83,6 +83,7 @@ static struct ibs_state ibs_state;
 #define IBS_CAPS_RDWROPCNT              (1U<<3)
 #define IBS_CAPS_OPCNT                  (1U<<4)
 #define IBS_CAPS_BRNTRGT                (1U<<5)
+#define IBS_CAPS_OPCNTEXT               (1U<<6)
 
 #define IBS_CAPS_DEFAULT                (IBS_CAPS_AVAIL         \
                                          | IBS_CAPS_FETCHSAM    \
@@ -246,8 +247,16 @@ static inline void op_amd_start_ibs(void)
 
         memset(&ibs_state, 0, sizeof(ibs_state));
 
+        /*
+         * Note: Since the max count settings may out of range we
+         * write back the actual used values so that userland can read
+         * it.
+         */
+
         if (ibs_config.fetch_enabled) {
-                val = (ibs_config.max_cnt_fetch >> 4) & IBS_FETCH_MAX_CNT;
+                val = ibs_config.max_cnt_fetch >> 4;
+                val = min(val, IBS_FETCH_MAX_CNT);
+                ibs_config.max_cnt_fetch = val << 4;
                 val |= ibs_config.rand_en ? IBS_FETCH_RAND_EN : 0;
                 val |= IBS_FETCH_ENABLE;
                 wrmsrl(MSR_AMD64_IBSFETCHCTL, val);
@@ -261,6 +270,7 @@ static inline void op_amd_start_ibs(void)
                          * op_amd_randomize_ibs_op() for details.
                          */
                         val = clamp(val, 0x0081ULL, 0xFF80ULL);
+                        ibs_config.max_cnt_op = val << 4;
                 } else {
                         /*
                          * The start value is randomized with a
@@ -268,9 +278,15 @@ static inline void op_amd_start_ibs(void)
                          * with the half of the randomized range. Also
                          * avoid underflows.
                          */
-                        val = min(val + IBS_RANDOM_MAXCNT_OFFSET,
-                                  IBS_OP_MAX_CNT);
+                        val += IBS_RANDOM_MAXCNT_OFFSET;
+                        if (ibs_caps & IBS_CAPS_OPCNTEXT)
+                                val = min(val, IBS_OP_MAX_CNT_EXT);
+                        else
+                                val = min(val, IBS_OP_MAX_CNT);
+                        ibs_config.max_cnt_op =
+                                (val - IBS_RANDOM_MAXCNT_OFFSET) << 4;
                 }
+                val = ((val & ~IBS_OP_MAX_CNT) << 4) | (val & IBS_OP_MAX_CNT);
                 val |= ibs_config.dispatched_ops ? IBS_OP_CNT_CTL : 0;
                 val |= IBS_OP_ENABLE;
                 ibs_state.ibs_op_ctl = val;