lib: sbi: Implement SBI PMU extension

RISC-V SBI specfication 0.3 defines a PMU extension that allows supervisor
mode to start/stop/configure pmu related events. This patch implements
all of the functionality defined in the specification.

Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
This commit is contained in:
Atish Patra
2021-07-10 09:18:13 -07:00
committed by Anup Patel
parent ae72ec0915
commit 37f9b0f2f2
5 changed files with 99 additions and 1 deletions

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@@ -39,6 +39,7 @@ extern struct sbi_ecall_extension ecall_ipi;
extern struct sbi_ecall_extension ecall_vendor;
extern struct sbi_ecall_extension ecall_hsm;
extern struct sbi_ecall_extension ecall_srst;
extern struct sbi_ecall_extension ecall_pmu;
u16 sbi_ecall_version_major(void);

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@@ -20,6 +20,7 @@ libsbi-objs-y += sbi_ecall.o
libsbi-objs-y += sbi_ecall_base.o
libsbi-objs-y += sbi_ecall_hsm.o
libsbi-objs-y += sbi_ecall_legacy.o
libsbi-objs-y += sbi_ecall_pmu.o
libsbi-objs-y += sbi_ecall_replace.o
libsbi-objs-y += sbi_ecall_vendor.o
libsbi-objs-y += sbi_emulate_csr.o

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@@ -162,6 +162,9 @@ int sbi_ecall_init(void)
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_srst);
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_pmu);
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_legacy);

93
lib/sbi/sbi_ecall_pmu.c Normal file
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@@ -0,0 +1,93 @@
/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2021 Western Digital Corporation or its affiliates.
*
* Authors:
* Atish Patra <atish.patra@wdc.com>
*/
#include <sbi/sbi_ecall.h>
#include <sbi/sbi_ecall_interface.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_hart.h>
#include <sbi/sbi_trap.h>
#include <sbi/sbi_version.h>
#include <sbi/sbi_pmu.h>
#include <sbi/sbi_scratch.h>
#include <sbi/riscv_asm.h>
static int sbi_ecall_pmu_handler(unsigned long extid, unsigned long funcid,
const struct sbi_trap_regs *regs,
unsigned long *out_val,
struct sbi_trap_info *out_trap)
{
int ret = 0;
uint64_t temp;
switch (funcid) {
case SBI_EXT_PMU_NUM_COUNTERS:
ret = sbi_pmu_num_ctr();
if (ret >= 0) {
*out_val = ret;
ret = 0;
}
break;
case SBI_EXT_PMU_COUNTER_GET_INFO:
ret = sbi_pmu_ctr_get_info(regs->a0, out_val);
break;
case SBI_EXT_PMU_COUNTER_CFG_MATCH:
#if __riscv_xlen == 32
temp = ((uint64_t)regs->a5 << 32) | regs->a4;
#else
temp = regs->a4;
#endif
ret = sbi_pmu_ctr_cfg_match(regs->a0, regs->a1, regs->a2,
regs->a3, temp);
if (ret >= 0) {
*out_val = ret;
ret = 0;
}
break;
case SBI_EXT_PMU_COUNTER_FW_READ:
ret = sbi_pmu_ctr_read(regs->a0, out_val);
break;
case SBI_EXT_PMU_COUNTER_START:
#if __riscv_xlen == 32
temp = ((uint64_t)regs->a4 << 32) | regs->a3;
#else
temp = regs->a3;
#endif
ret = sbi_pmu_ctr_start(regs->a0, regs->a1, regs->a2, temp);
break;
case SBI_EXT_PMU_COUNTER_STOP:
ret = sbi_pmu_ctr_stop(regs->a0, regs->a1, regs->a2);
break;
default:
ret = SBI_ENOTSUPP;
};
return ret;
}
static int sbi_ecall_pmu_probe(unsigned long extid, unsigned long *out_val)
{
struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
/* SBI PMU extension is useless without mcount inhibit features */
if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
*out_val = 1;
else
*out_val = 0;
return 0;
}
struct sbi_ecall_extension ecall_pmu = {
.extid_start = SBI_EXT_PMU,
.extid_end = SBI_EXT_PMU,
.handle = sbi_ecall_pmu_handler,
.probe = sbi_ecall_pmu_probe,
};

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@@ -375,7 +375,7 @@ static int pmu_update_hw_mhpmevent(struct sbi_pmu_hw_event *hw_evt, int ctr_idx,
if (!mhpmevent_val || ctr_idx < 3 || ctr_idx >= SBI_PMU_HW_CTR_MAX)
return SBI_EFAIL;
/* TODO: The upper 8 bits of mhpmevent is reserved by sscofpmf extension.
/* TODO: The upper 16 bits of mhpmevent is reserved by sscofpmf extension.
* Update those bits based on the flags received from supervisor.
* The OVF bit also should be cleared here in case it was not cleared
* during event stop.