[PATCH v2] lib: pmu: support the event ID encoded by a bitmap.
Anup Patel
anup at brainfault.org
Thu Nov 11 05:12:43 PST 2021
On Wed, Nov 10, 2021 at 10:32 AM Vincent Chen <vincent.chen at sifive.com> wrote:
>
> RISC-V privilege specification does not specify how to encode the event ID.
> Therefore, each platform is allowed to customize its own encoding rule.
> The common encoding methods are as follow, directly assigning a number to an
> event, or every bit in the mphmevent CSR controls one specified event or
> mixes the above two methods.
>
> To enable OpenSBI to support the above three encoding methods simultaneously,
> this patch modifies the content of "pmu,raw-event-to-mhpmcounters". The
> "pmu,raw-event-to-mhpmcounters" still describes the one or multiple raw
> events that could be counted by which mhpmcounters. But, the column number
> of "pmu,raw-event-to-mhpmcounters" is extended from 2 to 3. The 1st column
> (64bit) is the ID of the raw events. The 2nd column (64bit) is select_mask.
> It indicates which bits in the 1st column are encoded by a number. If a
> platform directly encodes each PMU event as a different number, in this
> case, the value of select_mask will be 0xffffffff_ffffffff. For the other
> extreme case, if a platform specified the 64 bits of mhpmevent to control
> 64 different monitor event, in this case, the value of select_mask will be
> zero. The 3rd column(32bit) is the counter map used to describe which
> mhpmcounters support the raw events. All the modifications in this patch
> are all based on the above change in "pmu,raw-event-to-mhpmcounters".
>
> Signed-off-by: Vincent Chen <vincent.chen at sifive.com>
The DT property prefix has changed from "pmu," to "riscv," so can you
rebase this patch on latest OpenSBI repo.
Regards,
Anup
> ---
> docs/pmu_support.md | 24 +++++++++++++++---------
> include/sbi/sbi_pmu.h | 2 +-
> lib/sbi/sbi_pmu.c | 35 +++++++++++++++++++++++++----------
> lib/utils/fdt/fdt_pmu.c | 16 +++++++++-------
> 4 files changed, 50 insertions(+), 27 deletions(-)
>
> diff --git a/docs/pmu_support.md b/docs/pmu_support.md
> index 6533c99..02428c1 100644
> --- a/docs/pmu_support.md
> +++ b/docs/pmu_support.md
> @@ -49,13 +49,19 @@ represent a bitmap of all the MHPMCOUNTERx. This property is mandatory if
> event-to-mhpmevent is present. Otherwise, it can be omitted. This property
> shouldn't encode any raw event.
>
> -* **pmu,raw-event-to-mhpmcounters**(Optional) - It represents an ONE-to-MANY
> -mapping between a raw event and all the MHPMCOUNTERx in a bitmap format that can
> -be used to monitor that raw event. The information is encoded in a table format
> -where each raw represent a specific raw event. The first column stores the
> -expected event selector value that should be encoded in the expected value to be
> -written in MHPMEVENTx. The second column stores a bitmap of all the MHPMCOUNTERx
> -that can be used for monitoring the specified event.
> +* **pmu,raw-event-to-mhpmcounters**(Optional) - It represents a ONE-to-MANY
> +or MANY-to-MANY mapping between the raw event(s) and all the MHPMCOUNTERx in
> +a bitmap format that can be used to monitor that raw event, which depends on
> +how the platform encodes the monitor events. Currently, only the following three
> +encoding methods are supported, encoding each event as a number, using a bitmap
> +to encode monitor events, and mixing the previous two methods. The information
> +is encoded in a table format where each raw represent the specific raw event(s).
> +The first and second column represents a selector value, which probably means a
> +monitor event ID (encoded by a number) or an event set (encoded by a bitmap).
> +To correctly decode this selector value, each platform needs to define a
> +select_mask in the third and fourth column to indicate which bits of the
> +selector value are encoded by a number. The fifth column stores a bitmap of all
> +the MHPMCOUNTERx that can be used for monitoring the specified event(s).
>
> *Note:* A platform may choose to provide the mapping between event & counters
> via platform hooks rather than the device tree.
> @@ -72,8 +78,8 @@ pmu {
> <0x00002 0x00002 0x00000004>,
> <0x00003 0x0000A 0x00000ff8>,
> <0x10000 0x10033 0x000ff000>,
> - pmu,raw-event-to-mhpmcounters = <0x0000 0x0002 0x00000f8>,
> - <0x0000 0x0003 0x00000ff0>,
> + pmu,raw-event-to-mhpmcounters = <0x0000 0x0002 0xffffffff 0xffffffff 0x00000f8>,
> + <0x0000 0x0003 0xffffffff 0xffffffff 0x00000ff0>,
> };
>
> ```
> diff --git a/include/sbi/sbi_pmu.h b/include/sbi/sbi_pmu.h
> index f018556..6a1c62c 100644
> --- a/include/sbi/sbi_pmu.h
> +++ b/include/sbi/sbi_pmu.h
> @@ -51,7 +51,7 @@ int sbi_pmu_add_hw_event_counter_map(u32 eidx_start, u32 eidx_end, u32 cmap);
> * @return 0 on success, error otherwise.
> */
>
> -int sbi_pmu_add_raw_event_counter_map(uint64_t select, u32 cmap);
> +int sbi_pmu_add_raw_event_counter_map(uint64_t select, uint64_t select_mask, u32 cmap);
>
> int sbi_pmu_ctr_read(uint32_t cidx, unsigned long *cval);
>
> diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
> index 6948a71..fb3be7b 100644
> --- a/lib/sbi/sbi_pmu.c
> +++ b/lib/sbi/sbi_pmu.c
> @@ -23,6 +23,13 @@ struct sbi_pmu_hw_event {
> uint32_t end_idx;
> /* Event selector value used only for raw events */
> uint64_t select;
> + /* A event selector value may be formed by a number and
> + * a bitmap. The select_mask is used to indicate which bits
> + * are encoded by a number. When the value of select_mask
> + * is zero, it means that the select value is all encoded by
> + * a bitmap.
> + */
> + uint64_t select_mask;
> };
>
> /** Representation of a firmware event */
> @@ -91,9 +98,9 @@ static bool pmu_event_range_overlap(struct sbi_pmu_hw_event *evtA,
> }
>
> static bool pmu_event_select_overlap(struct sbi_pmu_hw_event *evt,
> - uint64_t select_val)
> + uint64_t select_val, uint64_t select_mask)
> {
> - if (evt->select == select_val)
> + if ((evt->select == select_val) && (evt->select_mask == select_mask))
> return TRUE;
>
> return FALSE;
> @@ -168,7 +175,7 @@ int sbi_pmu_ctr_read(uint32_t cidx, unsigned long *cval)
> }
>
> static int pmu_add_hw_event_map(u32 eidx_start, u32 eidx_end, u32 cmap,
> - uint64_t select)
> + uint64_t select, uint64_t select_mask)
> {
> int i = 0;
> bool is_overlap;
> @@ -191,13 +198,15 @@ static int pmu_add_hw_event_map(u32 eidx_start, u32 eidx_end, u32 cmap,
> for (i = 0; i < num_hw_events; i++) {
> if (eidx_start == SBI_PMU_EVENT_RAW_IDX)
> /* All raw events have same event idx. Just do sanity check on select */
> - is_overlap = pmu_event_select_overlap(&hw_event_map[i], select);
> + is_overlap = pmu_event_select_overlap(&hw_event_map[i],
> + select, select_mask);
> else
> is_overlap = pmu_event_range_overlap(&hw_event_map[i], event);
> if (is_overlap)
> goto reset_event;
> }
>
> + event->select_mask = select_mask;
> event->counters = cmap;
> event->select = select;
> num_hw_events++;
> @@ -221,13 +230,13 @@ int sbi_pmu_add_hw_event_counter_map(u32 eidx_start, u32 eidx_end, u32 cmap)
> eidx_end == SBI_PMU_EVENT_RAW_IDX)
> return SBI_EINVAL;
>
> - return pmu_add_hw_event_map(eidx_start, eidx_end, cmap, 0);
> + return pmu_add_hw_event_map(eidx_start, eidx_end, cmap, 0, 0);
> }
>
> -int sbi_pmu_add_raw_event_counter_map(uint64_t select, u32 cmap)
> +int sbi_pmu_add_raw_event_counter_map(uint64_t select, uint64_t select_mask, u32 cmap)
> {
> return pmu_add_hw_event_map(SBI_PMU_EVENT_RAW_IDX,
> - SBI_PMU_EVENT_RAW_IDX, cmap, select);
> + SBI_PMU_EVENT_RAW_IDX, cmap, select, select_mask);
> }
>
> static int pmu_ctr_enable_irq_hw(int ctr_idx)
> @@ -510,9 +519,16 @@ static int pmu_ctr_find_hw(unsigned long cbase, unsigned long cmask, unsigned lo
> continue;
>
> /* For raw events, event data is used as the select value */
> - if ((event_idx == SBI_PMU_EVENT_RAW_IDX) && temp->select != data)
> - continue;
> + if (event_idx == SBI_PMU_EVENT_RAW_IDX) {
> + uint64_t select_mask = temp->select_mask;
>
> + /* Check the bit filed encoded by a real number */
> + if ((temp->select & select_mask) != (data & select_mask))
> + continue;
> + /* Check the bit filed encoded by a bitmap */
> + else if ((temp->select & ~select_mask & data) != (~select_mask & data))
> + continue;
> + }
> /* Fixed counters should not be part of the search */
> ctr_mask = temp->counters & (cmask << cbase) &
> (~SBI_PMU_FIXED_CTR_MASK);
> @@ -542,7 +558,6 @@ static int pmu_ctr_find_hw(unsigned long cbase, unsigned long cmask, unsigned lo
> else
> return SBI_EFAIL;
> }
> -
> ret = pmu_update_hw_mhpmevent(temp, ctr_idx, flags, event_idx, data);
>
> if (!ret)
> diff --git a/lib/utils/fdt/fdt_pmu.c b/lib/utils/fdt/fdt_pmu.c
> index 4d86e77..44a9e17 100644
> --- a/lib/utils/fdt/fdt_pmu.c
> +++ b/lib/utils/fdt/fdt_pmu.c
> @@ -65,7 +65,7 @@ int fdt_pmu_setup(void *fdt)
> const u32 *event_val;
> const u32 *event_ctr_map;
> struct fdt_pmu_hw_event_select *event;
> - uint64_t raw_selector;
> + uint64_t raw_selector, select_mask;
> u32 event_idx_start, event_idx_end, ctr_map;
>
> if (!fdt)
> @@ -99,14 +99,16 @@ int fdt_pmu_setup(void *fdt)
> }
>
> event_val = fdt_getprop(fdt, pmu_offset, "pmu,raw-event-to-mhpmcounters", &len);
> - if (!event_val || len < 8)
> + if (!event_val || len < 20)
> return SBI_EFAIL;
> - len = len / (sizeof(u32) * 3);
> + len = len / (sizeof(u32) * 5);
> for (i = 0; i < len; i++) {
> - raw_selector = fdt32_to_cpu(event_val[3 * i]);
> - raw_selector = (raw_selector << 32) | fdt32_to_cpu(event_val[3 * i + 1]);
> - ctr_map = fdt32_to_cpu(event_val[3 * i + 2]);
> - result = sbi_pmu_add_raw_event_counter_map(raw_selector, ctr_map);
> + raw_selector = fdt32_to_cpu(event_val[5 * i]);
> + raw_selector = (raw_selector << 32) | fdt32_to_cpu(event_val[5 * i + 1]);
> + select_mask = fdt32_to_cpu(event_val[5 * i + 2]);
> + select_mask = (select_mask << 32) | fdt32_to_cpu(event_val[5 * i + 3]);
> + ctr_map = fdt32_to_cpu(event_val[5 * i + 4]);
> + result = sbi_pmu_add_raw_event_counter_map(raw_selector, select_mask, ctr_map);
> if (!result)
> hw_event_count++;
> }
> --
> 2.17.1
>
>
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