[PATCH] drm/xe/rtp: Drop sentinels from arg to xe_rtp_process_to_sr()
Lucas De Marchi
lucas.demarchi at intel.com
Fri Mar 7 15:57:08 UTC 2025
On Fri, Mar 07, 2025 at 12:00:14PM +0000, Tvrtko Ursulin wrote:
>
>On 07/03/2025 04:00, Lucas De Marchi wrote:
>>There's a mismatch on API: while xe_rtp_process_to_sr() processes
>>entries until an entry without name, the active tracking with
>>xe_rtp_process_ctx_enable_active_tracking() needs to use the number of
>>elements. The number of elements is taken everywhere using ARRAY_SIZE(),
>>but that will have one entry too many. This leads to the following
>>warning, as reported by lkp:
>>
>> drivers/gpu/drm/xe/xe_tuning.c: In function 'xe_tuning_dump':
>>>>include/drm/drm_print.h:228:31: warning: '%s' directive argument is null [-Wformat-overflow=]
>> 228 | drm_printf((printer), "%.*s" fmt, (indent), "\t\t\t\t\tX", ##__VA_ARGS__)
>> | ^~~~~~
>> drivers/gpu/drm/xe/xe_tuning.c:226:17: note: in expansion of macro 'drm_printf_indent'
>> 226 | drm_printf_indent(p, 1, "%s\n", engine_tunings[idx].name);
>> | ^~~~~~~~~~~~~~~~~
>>
>>That's because it will still process the last entry when tracking the
>>active tunings. The same issue exists in the WAs. Change
>>xe_rtp_process_to_sr() to also take the number of elements so the empty
>>entry can be removed and the warning should go away. Fixing on the
>>active-tracking side would more fragile as the it would need a `- 1`
>>everywhere and continue to use a different approach for number of
>>elements.
>
>Patch looks fine, and dropping the terminators is good. But I can't
>say I understand the warning. How it will process the last entry if
>entry->name is NULL? Hence bitmap will not have the bit set, hence the
>dump cannot iterate over it. I must be missing something, I wanted to
>say obvious, but I hope it really isn't. :))
yeah... I could reproduce it only with the compiler provided by 0day,
for microblaze arch. Even the same gcc version for x86 didn't reproduce
it.
>
>Regards,
>
>Tvrtko
>
>>Aside from the warning, it's a non-issue as there would always be enough
>>bits allocated and the last entry would never be active since
>>xe_rtp_process_to_sr() stops on the sentinel.
^ this paragraph tries to explain why it's harmless, which made me not
even add a Fixes trailer. Indeed xe_rtp_process_to_sr() will never
process it, hence the bit will never be set. The I can see is that later
when we are dumping, we are using for_each_bit_set(), passing as max the
bit related to the empty entry. So maybe there's a diff in bitops for
that arch that makes the compiler **think** the last element could be
accessed. The alternative fix I started was to pass `ARRAY_SIZE(...) - 1`
in the for_each_bit_set(). But that looked ugly.
Note that it's a build time warning - if that really happens in runtime
there's probably something terribly broken with that arch.
Lucas De Marchi
>>
>>Reported-by: kernel test robot <lkp at intel.com>
>>Closes: https://lore.kernel.org/oe-kbuild-all/202503021906.P2MwAvyK-lkp@intel.com/
>>Cc: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>>Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
>>---
>> drivers/gpu/drm/xe/tests/xe_rtp_test.c | 2 +-
>> drivers/gpu/drm/xe/xe_hw_engine.c | 6 ++----
>> drivers/gpu/drm/xe/xe_reg_whitelist.c | 4 ++--
>> drivers/gpu/drm/xe/xe_rtp.c | 6 +++++-
>> drivers/gpu/drm/xe/xe_rtp.h | 2 +-
>> drivers/gpu/drm/xe/xe_tuning.c | 12 ++++--------
>> drivers/gpu/drm/xe/xe_wa.c | 12 +++---------
>> 7 files changed, 18 insertions(+), 26 deletions(-)
>>
>>diff --git a/drivers/gpu/drm/xe/tests/xe_rtp_test.c b/drivers/gpu/drm/xe/tests/xe_rtp_test.c
>>index 36a3b5420fef6a1977a04d169d4946f75ee523c4..b0254b014fe45013aa0c5b3fbbe7a58fe8584a31 100644
>>--- a/drivers/gpu/drm/xe/tests/xe_rtp_test.c
>>+++ b/drivers/gpu/drm/xe/tests/xe_rtp_test.c
>>@@ -320,7 +320,7 @@ static void xe_rtp_process_to_sr_tests(struct kunit *test)
>> count_rtp_entries++;
>> xe_rtp_process_ctx_enable_active_tracking(&ctx, &active, count_rtp_entries);
>>- xe_rtp_process_to_sr(&ctx, param->entries, reg_sr);
>>+ xe_rtp_process_to_sr(&ctx, param->entries, count_rtp_entries, reg_sr);
>> xa_for_each(®_sr->xa, idx, sre) {
>> if (idx == param->expected_reg.addr)
>>diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
>>index fc447751fe786c0035d888047a856780a572e526..223b95de388cb8919a7d1ab52e1305be990672ad 100644
>>--- a/drivers/gpu/drm/xe/xe_hw_engine.c
>>+++ b/drivers/gpu/drm/xe/xe_hw_engine.c
>>@@ -400,10 +400,9 @@ xe_hw_engine_setup_default_lrc_state(struct xe_hw_engine *hwe)
>> PREEMPT_GPGPU_THREAD_GROUP_LEVEL)),
>> XE_RTP_ENTRY_FLAG(FOREACH_ENGINE)
>> },
>>- {}
>> };
>>- xe_rtp_process_to_sr(&ctx, lrc_setup, &hwe->reg_lrc);
>>+ xe_rtp_process_to_sr(&ctx, lrc_setup, ARRAY_SIZE(lrc_setup), &hwe->reg_lrc);
>> }
>> static void
>>@@ -459,10 +458,9 @@ hw_engine_setup_default_state(struct xe_hw_engine *hwe)
>> XE_RTP_ACTIONS(SET(CSFE_CHICKEN1(0), CS_PRIORITY_MEM_READ,
>> XE_RTP_ACTION_FLAG(ENGINE_BASE)))
>> },
>>- {}
>> };
>>- xe_rtp_process_to_sr(&ctx, engine_entries, &hwe->reg_sr);
>>+ xe_rtp_process_to_sr(&ctx, engine_entries, ARRAY_SIZE(engine_entries), &hwe->reg_sr);
>> }
>> static const struct engine_info *find_engine_info(enum xe_engine_class class, int instance)
>>diff --git a/drivers/gpu/drm/xe/xe_reg_whitelist.c b/drivers/gpu/drm/xe/xe_reg_whitelist.c
>>index edab5d4e3ba5e7708565f8bc51df50c0b4a46f39..23f6c81d99946f97413e411289116aaa10365f3f 100644
>>--- a/drivers/gpu/drm/xe/xe_reg_whitelist.c
>>+++ b/drivers/gpu/drm/xe/xe_reg_whitelist.c
>>@@ -88,7 +88,6 @@ static const struct xe_rtp_entry_sr register_whitelist[] = {
>> RING_FORCE_TO_NONPRIV_ACCESS_RD |
>> RING_FORCE_TO_NONPRIV_RANGE_4))
>> },
>>- {}
>> };
>> static void whitelist_apply_to_hwe(struct xe_hw_engine *hwe)
>>@@ -137,7 +136,8 @@ void xe_reg_whitelist_process_engine(struct xe_hw_engine *hwe)
>> {
>> struct xe_rtp_process_ctx ctx = XE_RTP_PROCESS_CTX_INITIALIZER(hwe);
>>- xe_rtp_process_to_sr(&ctx, register_whitelist, &hwe->reg_whitelist);
>>+ xe_rtp_process_to_sr(&ctx, register_whitelist, ARRAY_SIZE(register_whitelist),
>>+ &hwe->reg_whitelist);
>> whitelist_apply_to_hwe(hwe);
>> }
>>diff --git a/drivers/gpu/drm/xe/xe_rtp.c b/drivers/gpu/drm/xe/xe_rtp.c
>>index 7a1c78fdfc92ee9a7e8862c2a65ce99b1f2a5ff1..13bb62d3e615e89d1e996692732b1859561ac55e 100644
>>--- a/drivers/gpu/drm/xe/xe_rtp.c
>>+++ b/drivers/gpu/drm/xe/xe_rtp.c
>>@@ -237,6 +237,7 @@ static void rtp_mark_active(struct xe_device *xe,
>> * the save-restore argument.
>> * @ctx: The context for processing the table, with one of device, gt or hwe
>> * @entries: Table with RTP definitions
>>+ * @n_entries: Number of entries to process, usually ARRAY_SIZE(entries)
>> * @sr: Save-restore struct where matching rules execute the action. This can be
>> * viewed as the "coalesced view" of multiple the tables. The bits for each
>> * register set are expected not to collide with previously added entries
>>@@ -247,6 +248,7 @@ static void rtp_mark_active(struct xe_device *xe,
>> */
>> void xe_rtp_process_to_sr(struct xe_rtp_process_ctx *ctx,
>> const struct xe_rtp_entry_sr *entries,
>>+ size_t n_entries,
>> struct xe_reg_sr *sr)
>> {
>> const struct xe_rtp_entry_sr *entry;
>>@@ -259,7 +261,9 @@ void xe_rtp_process_to_sr(struct xe_rtp_process_ctx *ctx,
>> if (IS_SRIOV_VF(xe))
>> return;
>>- for (entry = entries; entry && entry->name; entry++) {
>>+ xe_assert(xe, entries);
>>+
>>+ for (entry = entries; entry - entries < n_entries; entry++) {
>> bool match = false;
>> if (entry->flags & XE_RTP_ENTRY_FLAG_FOREACH_ENGINE) {
>>diff --git a/drivers/gpu/drm/xe/xe_rtp.h b/drivers/gpu/drm/xe/xe_rtp.h
>>index 38b9f13bba5e54f9c6e863bb578c00fce7a8c452..4fe736a11c42b954c2256fa21a49b0c2e39901e2 100644
>>--- a/drivers/gpu/drm/xe/xe_rtp.h
>>+++ b/drivers/gpu/drm/xe/xe_rtp.h
>>@@ -430,7 +430,7 @@ void xe_rtp_process_ctx_enable_active_tracking(struct xe_rtp_process_ctx *ctx,
>> void xe_rtp_process_to_sr(struct xe_rtp_process_ctx *ctx,
>> const struct xe_rtp_entry_sr *entries,
>>- struct xe_reg_sr *sr);
>>+ size_t n_entries, struct xe_reg_sr *sr);
>> void xe_rtp_process(struct xe_rtp_process_ctx *ctx,
>> const struct xe_rtp_entry *entries);
>>diff --git a/drivers/gpu/drm/xe/xe_tuning.c b/drivers/gpu/drm/xe/xe_tuning.c
>>index 77bc958f5a42cd017d3c363825dfd05cd73f872e..49ddbda7cdef66da49469b687b2296cc2d00b283 100644
>>--- a/drivers/gpu/drm/xe/xe_tuning.c
>>+++ b/drivers/gpu/drm/xe/xe_tuning.c
>>@@ -85,8 +85,6 @@ static const struct xe_rtp_entry_sr gt_tunings[] = {
>> XE_RTP_RULES(MEDIA_VERSION(2000)),
>> XE_RTP_ACTIONS(SET(XE2LPM_SCRATCH3_LBCF, RWFLUSHALLEN))
>> },
>>-
>>- {}
>> };
>> static const struct xe_rtp_entry_sr engine_tunings[] = {
>>@@ -100,7 +98,6 @@ static const struct xe_rtp_entry_sr engine_tunings[] = {
>> ENGINE_CLASS(RENDER)),
>> XE_RTP_ACTIONS(SET(SAMPLER_MODE, INDIRECT_STATE_BASE_ADDR_OVERRIDE))
>> },
>>- {}
>> };
>> static const struct xe_rtp_entry_sr lrc_tunings[] = {
>>@@ -138,8 +135,6 @@ static const struct xe_rtp_entry_sr lrc_tunings[] = {
>> XE_RTP_ACTIONS(FIELD_SET(FF_MODE, VS_HIT_MAX_VALUE_MASK,
>> REG_FIELD_PREP(VS_HIT_MAX_VALUE_MASK, 0x3f)))
>> },
>>-
>>- {}
>> };
>> /**
>>@@ -180,7 +175,7 @@ void xe_tuning_process_gt(struct xe_gt *gt)
>> xe_rtp_process_ctx_enable_active_tracking(&ctx,
>> gt->tuning_active.gt,
>> ARRAY_SIZE(gt_tunings));
>>- xe_rtp_process_to_sr(&ctx, gt_tunings, >->reg_sr);
>>+ xe_rtp_process_to_sr(&ctx, gt_tunings, ARRAY_SIZE(gt_tunings), >->reg_sr);
>> }
>> EXPORT_SYMBOL_IF_KUNIT(xe_tuning_process_gt);
>>@@ -191,7 +186,8 @@ void xe_tuning_process_engine(struct xe_hw_engine *hwe)
>> xe_rtp_process_ctx_enable_active_tracking(&ctx,
>> hwe->gt->tuning_active.engine,
>> ARRAY_SIZE(engine_tunings));
>>- xe_rtp_process_to_sr(&ctx, engine_tunings, &hwe->reg_sr);
>>+ xe_rtp_process_to_sr(&ctx, engine_tunings, ARRAY_SIZE(engine_tunings),
>>+ &hwe->reg_sr);
>> }
>> EXPORT_SYMBOL_IF_KUNIT(xe_tuning_process_engine);
>>@@ -210,7 +206,7 @@ void xe_tuning_process_lrc(struct xe_hw_engine *hwe)
>> xe_rtp_process_ctx_enable_active_tracking(&ctx,
>> hwe->gt->tuning_active.lrc,
>> ARRAY_SIZE(lrc_tunings));
>>- xe_rtp_process_to_sr(&ctx, lrc_tunings, &hwe->reg_lrc);
>>+ xe_rtp_process_to_sr(&ctx, lrc_tunings, ARRAY_SIZE(lrc_tunings), &hwe->reg_lrc);
>> }
>> void xe_tuning_dump(struct xe_gt *gt, struct drm_printer *p)
>>diff --git a/drivers/gpu/drm/xe/xe_wa.c b/drivers/gpu/drm/xe/xe_wa.c
>>index 55eb453f4b1fb39d4127609a28e4a5ebe9b5a051..a25afb757f7088c7f831867717b42982e9ea754c 100644
>>--- a/drivers/gpu/drm/xe/xe_wa.c
>>+++ b/drivers/gpu/drm/xe/xe_wa.c
>>@@ -279,8 +279,6 @@ static const struct xe_rtp_entry_sr gt_was[] = {
>> XE_RTP_ACTIONS(SET(VDBOX_CGCTL3F10(0), RAMDFTUNIT_CLKGATE_DIS)),
>> XE_RTP_ENTRY_FLAG(FOREACH_ENGINE),
>> },
>>-
>>- {}
>> };
>> static const struct xe_rtp_entry_sr engine_was[] = {
>>@@ -624,8 +622,6 @@ static const struct xe_rtp_entry_sr engine_was[] = {
>> FUNC(xe_rtp_match_first_render_or_compute)),
>> XE_RTP_ACTIONS(SET(TDL_TSL_CHICKEN, RES_CHK_SPR_DIS))
>> },
>>-
>>- {}
>> };
>> static const struct xe_rtp_entry_sr lrc_was[] = {
>>@@ -825,8 +821,6 @@ static const struct xe_rtp_entry_sr lrc_was[] = {
>> DIS_PARTIAL_AUTOSTRIP |
>> DIS_AUTOSTRIP))
>> },
>>-
>>- {}
>> };
>> static __maybe_unused const struct xe_rtp_entry oob_was[] = {
>>@@ -868,7 +862,7 @@ void xe_wa_process_gt(struct xe_gt *gt)
>> xe_rtp_process_ctx_enable_active_tracking(&ctx, gt->wa_active.gt,
>> ARRAY_SIZE(gt_was));
>>- xe_rtp_process_to_sr(&ctx, gt_was, >->reg_sr);
>>+ xe_rtp_process_to_sr(&ctx, gt_was, ARRAY_SIZE(gt_was), >->reg_sr);
>> }
>> EXPORT_SYMBOL_IF_KUNIT(xe_wa_process_gt);
>>@@ -886,7 +880,7 @@ void xe_wa_process_engine(struct xe_hw_engine *hwe)
>> xe_rtp_process_ctx_enable_active_tracking(&ctx, hwe->gt->wa_active.engine,
>> ARRAY_SIZE(engine_was));
>>- xe_rtp_process_to_sr(&ctx, engine_was, &hwe->reg_sr);
>>+ xe_rtp_process_to_sr(&ctx, engine_was, ARRAY_SIZE(engine_was), &hwe->reg_sr);
>> }
>> /**
>>@@ -903,7 +897,7 @@ void xe_wa_process_lrc(struct xe_hw_engine *hwe)
>> xe_rtp_process_ctx_enable_active_tracking(&ctx, hwe->gt->wa_active.lrc,
>> ARRAY_SIZE(lrc_was));
>>- xe_rtp_process_to_sr(&ctx, lrc_was, &hwe->reg_lrc);
>>+ xe_rtp_process_to_sr(&ctx, lrc_was, ARRAY_SIZE(lrc_was), &hwe->reg_lrc);
>> }
>> /**
>>
>>---
>>base-commit: 6f2e5afc45e3ca8bf46427ae21a9c1029ea6cdb3
>>change-id: 20250306-fix-print-warning-43d20fc31309
>>
>>Best regards,
>
More information about the Intel-xe
mailing list