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Commit b47fad3b authored by Robert Richter's avatar Robert Richter
Browse files

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: default avatarRobert Richter <robert.richter@amd.com>
parent 25da6950

arch/x86/include/asm/perf_event.h

+10 −9
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ union cpuid10_edx { 
#define IBS_OP_VAL		(1ULL<<18)

#define IBS_OP_ENABLE		(1ULL<<17)

#define IBS_OP_MAX_CNT		0x0000FFFFULL

#define IBS_OP_MAX_CNT_EXT	0x007FFFFFULL	/* not a register bit mask */



#ifdef CONFIG_PERF_EVENTS

extern void init_hw_perf_events(void);

arch/x86/oprofile/op_model_amd.c

+19 −3
Original line number Diff line number Diff line
@@ -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;