Re: [PATCH 4/4] perf cs-etm: Add exception level consistency check

From: James Clark
Date: Tue May 30 2023 - 05:12:53 EST

Next message: David Hildenbrand: "Re: [PATCH v10 5/5] selftest: add a testcase of ksm zero pages"
Previous message: Bert Karwatzki: "Re: [PATCH net] net: ipa: Use the correct value for IPA_STATUS_SIZE"
In reply to: Mike Leach: "Re: [PATCH 4/4] perf cs-etm: Add exception level consistency check"
Next in thread: Mike Leach: "Re: [PATCH 4/4] perf cs-etm: Add exception level consistency check"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On 25/05/2023 12:39, Mike Leach wrote:
> Hi James,
>
> My concern here is that for etmv3 trace, OpenCSD will only provide
> memory spaces as either secure or non-secure, The ETMv3 does not
> trace, and hence OpenCSD cannot provide the different ELs.
> The memory callback will be either OCSD_MEM_SPACE_S or OCSD_MEM_SPACE_N.
>

As long as none of the bits are set for EL1-EL3 then no validation will
be done so it should be fine. But I will try to test ETMv3.

> Can this patch - and the set handle this. (assuming perf supports our
> ETMv3 coresight kernel driver)

For the whole set, the tracked EL will stay as ocsd_EL_unknown and
cs_etm__get_machine() will return host so the behavior will be unchanged
from before. This is assuming OpenCSD will set the EL to unknown in
elem->context.exception_level in this case.

>
> Regards
>
> Mike
>
> On Wed, 24 May 2023 at 14:20, James Clark <james.clark@xxxxxxx> wrote:
>>
>> Assert that our own tracking of the exception level matches what
>> OpenCSD provides. OpenCSD doesn't distinguish between EL0 and EL1 in the
>> memory access callback so the extra tracking was required. But a rough
>> assert can still be done.
>>
>> Signed-off-by: James Clark <james.clark@xxxxxxx>
>> ---
>> .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 6 +--
>> .../perf/util/cs-etm-decoder/cs-etm-decoder.h | 4 +-
>> tools/perf/util/cs-etm.c | 37 +++++++++++++------
>> 3 files changed, 32 insertions(+), 15 deletions(-)
>>
>> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> index ac227cd03eb0..50b3c248d1e5 100644
>> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> @@ -52,15 +52,15 @@ struct cs_etm_decoder {
>> static u32
>> cs_etm_decoder__mem_access(const void *context,
>> const ocsd_vaddr_t address,
>> - const ocsd_mem_space_acc_t mem_space __maybe_unused,
>> + const ocsd_mem_space_acc_t mem_space,
>> const u8 trace_chan_id,
>> const u32 req_size,
>> u8 *buffer)
>> {
>> struct cs_etm_decoder *decoder = (struct cs_etm_decoder *) context;
>>
>> - return decoder->mem_access(decoder->data, trace_chan_id,
>> - address, req_size, buffer);
>> + return decoder->mem_access(decoder->data, trace_chan_id, address,
>> + req_size, buffer, mem_space);
>> }
>>
>> int cs_etm_decoder__add_mem_access_cb(struct cs_etm_decoder *decoder,
>> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
>> index 21d403f55d96..272c2efe78ee 100644
>> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
>> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
>> @@ -11,6 +11,7 @@
>> #define INCLUDE__CS_ETM_DECODER_H__
>>
>> #include <linux/types.h>
>> +#include <opencsd/ocsd_if_types.h>
>> #include <stdio.h>
>>
>> struct cs_etm_decoder;
>> @@ -19,7 +20,8 @@ struct cs_etm_packet_queue;
>>
>> struct cs_etm_queue;
>>
>> -typedef u32 (*cs_etm_mem_cb_type)(struct cs_etm_queue *, u8, u64, size_t, u8 *);
>> +typedef u32 (*cs_etm_mem_cb_type)(struct cs_etm_queue *, u8, u64, size_t, u8 *,
>> + const ocsd_mem_space_acc_t);
>>
>> struct cs_etmv3_trace_params {
>> u32 reg_ctrl;
>> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
>> index b9ba19327f26..ccf34ed8ddf2 100644
>> --- a/tools/perf/util/cs-etm.c
>> +++ b/tools/perf/util/cs-etm.c
>> @@ -931,7 +931,8 @@ static u8 cs_etm__cpu_mode(struct cs_etm_queue *etmq, u64 address,
>> }
>>
>> static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u8 trace_chan_id,
>> - u64 address, size_t size, u8 *buffer)
>> + u64 address, size_t size, u8 *buffer,
>> + const ocsd_mem_space_acc_t mem_space)
>> {
>> u8 cpumode;
>> u64 offset;
>> @@ -947,6 +948,20 @@ static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u8 trace_chan_id,
>> if (!tidq)
>> return 0;
>>
>> + /*
>> + * We've already tracked EL along side the PID in cs_etm__set_thread()
>> + * so double check that it matches what OpenCSD thinks as well. It
>> + * doesn't distinguish between EL0 and EL1 for this mem access callback
>> + * so we had to do the extra tracking.
>> + */
>> + if (mem_space & OCSD_MEM_SPACE_EL1N) {
>> + /* Includes both non secure EL1 and EL0 */
>> + assert(tidq->el == ocsd_EL1 || tidq->el == ocsd_EL0);
>> + } else if (mem_space & OCSD_MEM_SPACE_EL2)
>> + assert(tidq->el == ocsd_EL2);
>> + else if (mem_space & OCSD_MEM_SPACE_EL3)
>> + assert(tidq->el == ocsd_EL3);
>> +
>> cpumode = cs_etm__cpu_mode(etmq, address, tidq->el);
>>
>> if (!thread__find_map(tidq->thread, cpumode, address, &al))
>> @@ -1195,8 +1210,8 @@ static inline int cs_etm__t32_instr_size(struct cs_etm_queue *etmq,
>> {
>> u8 instrBytes[2];
>>
>> - cs_etm__mem_access(etmq, trace_chan_id, addr,
>> - ARRAY_SIZE(instrBytes), instrBytes);
>> + cs_etm__mem_access(etmq, trace_chan_id, addr, ARRAY_SIZE(instrBytes),
>> + instrBytes, 0);
>> /*
>> * T32 instruction size is indicated by bits[15:11] of the first
>> * 16-bit word of the instruction: 0b11101, 0b11110 and 0b11111
>> @@ -1387,8 +1402,8 @@ static void cs_etm__copy_insn(struct cs_etm_queue *etmq,
>> else
>> sample->insn_len = 4;
>>
>> - cs_etm__mem_access(etmq, trace_chan_id, sample->ip,
>> - sample->insn_len, (void *)sample->insn);
>> + cs_etm__mem_access(etmq, trace_chan_id, sample->ip, sample->insn_len,
>> + (void *)sample->insn, 0);
>> }
>>
>> u64 cs_etm__convert_sample_time(struct cs_etm_queue *etmq, u64 cs_timestamp)
>> @@ -1940,8 +1955,8 @@ static bool cs_etm__is_svc_instr(struct cs_etm_queue *etmq, u8 trace_chan_id,
>> * so below only read 2 bytes as instruction size for T32.
>> */
>> addr = end_addr - 2;
>> - cs_etm__mem_access(etmq, trace_chan_id, addr,
>> - sizeof(instr16), (u8 *)&instr16);
>> + cs_etm__mem_access(etmq, trace_chan_id, addr, sizeof(instr16),
>> + (u8 *)&instr16, 0);
>> if ((instr16 & 0xFF00) == 0xDF00)
>> return true;
>>
>> @@ -1956,8 +1971,8 @@ static bool cs_etm__is_svc_instr(struct cs_etm_queue *etmq, u8 trace_chan_id,
>> * +---------+---------+-------------------------+
>> */
>> addr = end_addr - 4;
>> - cs_etm__mem_access(etmq, trace_chan_id, addr,
>> - sizeof(instr32), (u8 *)&instr32);
>> + cs_etm__mem_access(etmq, trace_chan_id, addr, sizeof(instr32),
>> + (u8 *)&instr32, 0);
>> if ((instr32 & 0x0F000000) == 0x0F000000 &&
>> (instr32 & 0xF0000000) != 0xF0000000)
>> return true;
>> @@ -1973,8 +1988,8 @@ static bool cs_etm__is_svc_instr(struct cs_etm_queue *etmq, u8 trace_chan_id,
>> * +-----------------------+---------+-----------+
>> */
>> addr = end_addr - 4;
>> - cs_etm__mem_access(etmq, trace_chan_id, addr,
>> - sizeof(instr32), (u8 *)&instr32);
>> + cs_etm__mem_access(etmq, trace_chan_id, addr, sizeof(instr32),
>> + (u8 *)&instr32, 0);
>> if ((instr32 & 0xFFE0001F) == 0xd4000001)
>> return true;
>>
>> --
>> 2.34.1
>>
>
>

Next message: David Hildenbrand: "Re: [PATCH v10 5/5] selftest: add a testcase of ksm zero pages"
Previous message: Bert Karwatzki: "Re: [PATCH net] net: ipa: Use the correct value for IPA_STATUS_SIZE"
In reply to: Mike Leach: "Re: [PATCH 4/4] perf cs-etm: Add exception level consistency check"
Next in thread: Mike Leach: "Re: [PATCH 4/4] perf cs-etm: Add exception level consistency check"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]