Re: [PATCH v3 09/20] perf arm-spe: Refactor address packet handling

From: André Przywara
Date: Fri Oct 23 2020 - 13:56:38 EST

On 22/10/2020 15:58, Leo Yan wrote:

Hi Leo,

> This patch is to refactor address packet handling, it defines macros for
> address packet's header and payload, these macros are used by decoder
> and the dump flow.
>
> Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
> ---
> .../util/arm-spe-decoder/arm-spe-decoder.c | 29 ++++++++--------
> .../arm-spe-decoder/arm-spe-pkt-decoder.c | 26 +++++++-------
> .../arm-spe-decoder/arm-spe-pkt-decoder.h | 34 ++++++++++++-------
> 3 files changed, 47 insertions(+), 42 deletions(-)
>
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c
> index cc18a1e8c212..776b3e6628bb 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c
> @@ -24,36 +24,35 @@
>
> static u64 arm_spe_calc_ip(int index, u64 payload)
> {
> - u8 *addr = (u8 *)&payload;
> - int ns, el;
> + u64 ns, el;
>
> /* Instruction virtual address or Branch target address */
> if (index == SPE_ADDR_PKT_HDR_INDEX_INS ||
> index == SPE_ADDR_PKT_HDR_INDEX_BRANCH) {
> - ns = addr[7] & SPE_ADDR_PKT_NS;
> - el = (addr[7] & SPE_ADDR_PKT_EL_MASK) >> SPE_ADDR_PKT_EL_OFFSET;
> + ns = SPE_ADDR_PKT_GET_NS(payload);
> + el = SPE_ADDR_PKT_GET_EL(payload);
> +
> + /* Clean highest byte */
> + payload = SPE_ADDR_PKT_ADDR_GET_BYTES_0_6(payload);
>
> /* Fill highest byte for EL1 or EL2 (VHE) mode */
> if (ns && (el == SPE_ADDR_PKT_EL1 || el == SPE_ADDR_PKT_EL2))
> - addr[7] = 0xff;
> - /* Clean highest byte for other cases */
> - else
> - addr[7] = 0x0;
> + payload |= 0xffULL << SPE_ADDR_PKT_ADDR_BYTE7_SHIFT;
>
> /* Data access virtual address */
> } else if (index == SPE_ADDR_PKT_HDR_INDEX_DATA_VIRT) {
>
> + /* Clean tags */
> + payload = SPE_ADDR_PKT_ADDR_GET_BYTES_0_6(payload);
> +
> /* Fill highest byte if bits [48..55] is 0xff */

Do you know where this comes from? If yes, can you replace the comment
with the reason, so that it says *why* and not *what* the code does?

> - if (addr[6] == 0xff)
> - addr[7] = 0xff;
> - /* Otherwise, cleanup tags */
> - else
> - addr[7] = 0x0;
> + if (SPE_ADDR_PKT_ADDR_GET_BYTE_6(payload) == 0xffULL)
> + payload |= 0xffULL << SPE_ADDR_PKT_ADDR_BYTE7_SHIFT;
>
> /* Data access physical address */
> } else if (index == SPE_ADDR_PKT_HDR_INDEX_DATA_PHYS) {
> - /* Cleanup byte 7 */
> - addr[7] = 0x0;
> + /* Clean highest byte */
> + payload = SPE_ADDR_PKT_ADDR_GET_BYTES_0_6(payload);
> } else {
> pr_err("unsupported address packet index: 0x%x\n", index);
> }
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> index 550cd7648c73..156f98d6b8b2 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> @@ -13,9 +13,6 @@
>
> #include "arm-spe-pkt-decoder.h"
>
> -#define NS_FLAG BIT(63)
> -#define EL_FLAG (BIT(62) | BIT(61))
> -
> #if __BYTE_ORDER == __BIG_ENDIAN
> #define le16_to_cpu bswap_16
> #define le32_to_cpu bswap_32
> @@ -167,10 +164,11 @@ static int arm_spe_get_addr(const unsigned char *buf, size_t len,
> const unsigned char ext_hdr, struct arm_spe_pkt *packet)
> {
> packet->type = ARM_SPE_ADDRESS;
> +
> if (ext_hdr)
> - packet->index = ((buf[0] & 0x3) << 3) | (buf[1] & 0x7);
> + packet->index = SPE_ADDR_PKT_HDR_EXTENDED_INDEX(buf[0], buf[1]);
> else
> - packet->index = buf[0] & 0x7;
> + packet->index = SPE_ADDR_PKT_HDR_SHORT_INDEX(buf[0]);
>
> return arm_spe_get_payload(buf, len, ext_hdr, packet);
> }
> @@ -274,20 +272,20 @@ static int arm_spe_pkt_desc_addr(const struct arm_spe_pkt *packet,
> u64 payload = packet->payload;
>
> switch (idx) {
> - case 0:
> - case 1:
> - ns = !!(packet->payload & NS_FLAG);
> - el = (packet->payload & EL_FLAG) >> 61;
> - payload &= ~(0xffULL << 56);
> + case SPE_ADDR_PKT_HDR_INDEX_INS:
> + case SPE_ADDR_PKT_HDR_INDEX_BRANCH:
> + ns = !!SPE_ADDR_PKT_GET_NS(payload);
> + el = SPE_ADDR_PKT_GET_EL(payload);
> + payload = SPE_ADDR_PKT_ADDR_GET_BYTES_0_6(payload);
> return arm_spe_pkt_snprintf(&buf, &buf_len,
> "%s 0x%llx el%d ns=%d",
> (idx == 1) ? "TGT" : "PC", payload, el, ns);
> - case 2:
> + case SPE_ADDR_PKT_HDR_INDEX_DATA_VIRT:
> return arm_spe_pkt_snprintf(&buf, &buf_len,
> "VA 0x%llx", payload);
> - case 3:
> - ns = !!(packet->payload & NS_FLAG);
> - payload &= ~(0xffULL << 56);
> + case SPE_ADDR_PKT_HDR_INDEX_DATA_PHYS:
> + ns = !!SPE_ADDR_PKT_GET_NS(payload);
> + payload = SPE_ADDR_PKT_ADDR_GET_BYTES_0_6(payload);
> return arm_spe_pkt_snprintf(&buf, &buf_len,
> "PA 0x%llx ns=%d", payload, ns);
> default:
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
> index 68552ff8a8f7..4111550d2bde 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
> @@ -59,19 +59,27 @@ struct arm_spe_pkt {
>
> #define SPE_HEADER_SZ(val) ((val & GENMASK_ULL(5, 4)) >> 4)
>
> -#define SPE_ADDR_PKT_HDR_INDEX_INS (0x0)
> -#define SPE_ADDR_PKT_HDR_INDEX_BRANCH (0x1)
> -#define SPE_ADDR_PKT_HDR_INDEX_DATA_VIRT (0x2)
> -#define SPE_ADDR_PKT_HDR_INDEX_DATA_PHYS (0x3)
> -
> -#define SPE_ADDR_PKT_NS BIT(7)
> -#define SPE_ADDR_PKT_CH BIT(6)
> -#define SPE_ADDR_PKT_EL_OFFSET (5)
> -#define SPE_ADDR_PKT_EL_MASK (0x3 << SPE_ADDR_PKT_EL_OFFSET)
> -#define SPE_ADDR_PKT_EL0 (0)
> -#define SPE_ADDR_PKT_EL1 (1)
> -#define SPE_ADDR_PKT_EL2 (2)
> -#define SPE_ADDR_PKT_EL3 (3)
> +/* Address packet header */
> +#define SPE_ADDR_PKT_HDR_SHORT_INDEX(h) ((h) & GENMASK_ULL(2, 0))
> +#define SPE_ADDR_PKT_HDR_EXTENDED_INDEX(h0, h1) (((h0) & GENMASK_ULL(1, 0)) << 3 | \
> + SPE_ADDR_PKT_HDR_SHORT_INDEX(h1))

Did you consider sharing those two with the identical definition for the
extended counter packet? This extended packet seems more like a generic
concept, regardless of the packet type.

> +#define SPE_ADDR_PKT_HDR_INDEX_INS 0x0
> +#define SPE_ADDR_PKT_HDR_INDEX_BRANCH 0x1
> +#define SPE_ADDR_PKT_HDR_INDEX_DATA_VIRT 0x2
> +#define SPE_ADDR_PKT_HDR_INDEX_DATA_PHYS 0x3
> +
> +/* Address packet payload */
> +#define SPE_ADDR_PKT_ADDR_BYTE7_SHIFT 56
> +#define SPE_ADDR_PKT_ADDR_GET_BYTES_0_6(v) ((v) & GENMASK_ULL(55, 0))
> +#define SPE_ADDR_PKT_ADDR_GET_BYTE_6(v) (((v) & GENMASK_ULL(55, 48)) >> 48)
> +
> +#define SPE_ADDR_PKT_GET_NS(v) (((v) & BIT(63)) >> 63)

You need BIT_ULL(63) here to make this work on 32-bit systems.

Cheers,
Andre

> +#define SPE_ADDR_PKT_GET_EL(v) (((v) & GENMASK_ULL(62, 61)) >> 61)
> +
> +#define SPE_ADDR_PKT_EL0 0
> +#define SPE_ADDR_PKT_EL1 1
> +#define SPE_ADDR_PKT_EL2 2
> +#define SPE_ADDR_PKT_EL3 3
>
> const char *arm_spe_pkt_name(enum arm_spe_pkt_type);
>
>