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[98.38.17.99]) by smtp.googlemail.com with ESMTPSA id 586e51a60fabf-491ee1ac486sm559401fac.16.2026.09.23.15.35.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Sep 2026 15:35:21 -0700 (PDT) From: Jim Cromie Date: Wed, 23 Sep 2026 16:34:43 -0600 Subject: [PATCH v11 19/38] dyndbg: reduce class param storage to u32 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260923-dd-cmap-part2-clean-v11-19-9b6c217fdf2f@gmail.com> References: <20260923-dd-cmap-part2-clean-v11-0-9b6c217fdf2f@gmail.com> In-Reply-To: <20260923-dd-cmap-part2-clean-v11-0-9b6c217fdf2f@gmail.com> To: Jason Baron , Shuah Khan , Andrew Morton , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Arnd Bergmann , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin , Jonathan Corbet , Greg Kroah-Hartman , Nathan Chancellor , Nicolas Schier , Shuah Khan , Randy Dunlap , "Rafael J. Wysocki" , Pavel Machek , Len Brown , Jonathan Corbet , Petr Mladek , Steven Rostedt , John Ogness , Sergey Senozhatsky Cc: linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-pm@vger.kernel.org, Jim Cromie X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1790202874; l=9168; i=jim.cromie@gmail.com; s=20260203; h=from:subject:message-id; bh=KrWDmxOWrStkRHpL+/KIB9FoXYHfOygI4SHDT7bhFXQ=; b=n61PSliLWiqYFTJFCREbivlOCHRW/O0VfaREZlJYcE/5TXOyFV10eGLOv06l5yqiOxM555tp2 0i8/oz+Ph01DQBsV+bUVMe7KNXZbCuiapW9HX1hjU/7sTnX+R6vEVTC X-Developer-Key: i=jim.cromie@gmail.com; a=ed25519; pk=C6E5ODlPQo7ZBynATXH9wg7K6HxP0pIXyf4s38Qw0XE= Currently, `struct ddebug_class_param` uses pointers to `unsigned long` values which store the state of `bits` and `lvl`, so it changes sizes depending upon the architecture. Make it always u32 for consistency. The bits field references __drm_debug, which was unsigned int, before commit f158936b60a7 ("drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.") changed it to unsigned long. This patch changes it back. That enlargement was a thinko; although modules can have up to 63 classes, and *could* have put all those classes in a single classmap, the reason for it is to support multiple classmaps (with non-overlapping class-id ranges). 32 bits is a practical limit for a class-param's usability since all classes are set together with a single write of a hex value; 16 would be a realistic limit, drm.debug has ~12 classes. #> echo 0x0fff > /sys/module/drm/parameters/debug Several followon patches add a number of compile-time validations, including a num-classes <=32 check. Signed-off-by: Jim Cromie --- v8: add a <32 limit to prevent undefined shifts on 32 bit number v5: u32 for all arches v4: undo change struct ddebug_class_param to _ddebug_class_param v3: fix undefd behavior when classmaps is all 64 bits. change module_param_named( type-arg from ulong to ullong) change struct ddebug_class_param to _ddebug_class_param in drivers/gpu/drm/drm_print.{c,h} api change later v2: patch was "make bits & lvl same size" but that size was unsigned long, only 32 bits on i386 etc use u64 for all bits, and %llu %llx u64-fix u64-drm-dbg --- drivers/gpu/drm/drm_print.c | 4 ++-- include/drm/drm_print.h | 2 +- include/linux/dynamic_debug.h | 4 ++-- lib/dynamic_debug.c | 37 ++++++++++++++++++++----------------- lib/test_dynamic_debug.c | 2 +- 5 files changed, 26 insertions(+), 23 deletions(-) diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index 86cef1a37678..794417c62097 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -40,7 +40,7 @@ * __drm_debug: Enable debug output. * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details. */ -unsigned long __drm_debug; +u32 __drm_debug; EXPORT_SYMBOL(__drm_debug); MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n" @@ -56,7 +56,7 @@ MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug cat "\t\tBit 9 (0x200) will enable DRMRES messages (managed resources code)"); #if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG) -module_param_named(debug, __drm_debug, ulong, 0600); +module_param_named(debug, __drm_debug, uint, 0600); #else /* classnames must match vals of enum drm_debug_category */ DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0, diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 2adc5ac688e1..50b3ba0ae76d 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -39,7 +39,7 @@ struct drm_device; struct seq_file; /* Do *not* use outside of drm_print.[ch]! */ -extern unsigned long __drm_debug; +extern u32 __drm_debug; /** * DOC: print diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 02a1abdc5b3f..27cae68552e5 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -102,8 +102,8 @@ struct _ddebug_info { struct ddebug_class_param { union { - unsigned long *bits; - unsigned int *lvl; + u32 *bits; + u32 *lvl; }; char flags[8]; const struct ddebug_class_map *map; diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 84a311fac657..72bfbec0ac02 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -586,6 +586,7 @@ static int ddebug_exec_query(char *query_string, const char *modname) pr_err("query parse failed\n"); return -EINVAL; } + /* actually go and implement the change */ nfound = ddebug_change(&query, &modifiers); v3pr_info_dq(&query, nfound ? "applied" : "no-match"); @@ -636,8 +637,7 @@ static int ddebug_exec_queries(char *query, const char *modname) /* apply a new class-param setting */ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp, - const unsigned long *new_bits, - const unsigned long old_bits, + const u32 *new_bits, const u32 old_bits, const char *query_modname) { #define QUERY_SIZE 128 @@ -647,24 +647,27 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp, int bi, ct; if (*new_bits != old_bits) - v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, + v2pr_info("apply bitmap: 0x%x to: 0x%x for %s\n", *new_bits, old_bits, query_modname ?: "'*'"); - for (bi = 0; bi < map->length; bi++) { - if (test_bit(bi, new_bits) == test_bit(bi, &old_bits)) + for (bi = 0; bi < map->length && bi < 32; bi++) { + bool new_b = !!(*new_bits & BIT(bi)); + bool old_b = !!(old_bits & BIT(bi)); + + if (new_b == old_b) continue; snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi], - test_bit(bi, new_bits) ? '+' : '-', dcp->flags); + new_b ? '+' : '-', dcp->flags); ct = ddebug_exec_queries(query, query_modname); matches += ct; - v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi, + v2pr_info("bit_%d: %d matches on class: %s -> 0x%x\n", bi, ct, map->class_names[bi], *new_bits); } if (*new_bits != old_bits) - v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, + v2pr_info("applied bitmap: 0x%x to: 0x%x for %s\n", *new_bits, old_bits, query_modname ?: "'*'"); return matches; @@ -673,7 +676,7 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp, /* stub to later conditionally add "$module." prefix where not already done */ #define KP_NAME(kp) kp->name -#define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1) +#define CLASSMAP_BITMASK(width) ((width) >= 32 ? ~0U : (1U << (width)) - 1) /* * param-setter helper to validate numeric input, clamp its value by @@ -685,10 +688,10 @@ static int param_set_dyndbg_module_classes(const char *instr, { const struct ddebug_class_param *dcp = kp->arg; const struct ddebug_class_map *map = dcp->map; - unsigned long inrep, new_bits, old_bits, old_val; + u32 inrep, new_bits, old_bits, old_val; int rc, totct = 0; - rc = kstrtoul(instr, 0, &inrep); + rc = kstrtou32(instr, 0, &inrep); if (rc) { int len = strcspn(instr, "\n"); @@ -701,26 +704,26 @@ static int param_set_dyndbg_module_classes(const char *instr, case DD_CLASS_TYPE_DISJOINT_BITS: /* expect bits. mask and warn if too many */ if (inrep & ~CLASSMAP_BITMASK(map->length)) { - pr_warn("%s: input: 0x%lx exceeds mask: 0x%lx, masking\n", + pr_warn("%s: input: 0x%x exceeds mask: 0x%x, masking\n", KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length)); inrep &= CLASSMAP_BITMASK(map->length); } old_val = READ_ONCE(*dcp->bits); - v2pr_info("bits:0x%lx > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp)); + v2pr_info("bits:0x%x > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp)); totct += ddebug_apply_class_bitmap(dcp, &inrep, old_val, mod_name); WRITE_ONCE(*dcp->bits, inrep); break; case DD_CLASS_TYPE_LEVEL_NUM: /* input is bitpos, of highest verbosity to be enabled */ if (inrep > map->length) { - pr_warn("%s: level:%ld exceeds max:%d, clamping\n", + pr_warn("%s: level:%u exceeds max:%d, clamping\n", KP_NAME(kp), inrep, map->length); inrep = map->length; } old_val = READ_ONCE(*dcp->lvl); old_bits = CLASSMAP_BITMASK(old_val); new_bits = CLASSMAP_BITMASK(inrep); - v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp)); + v2pr_info("lvl:%u bits:0x%x > %s\n", inrep, new_bits, KP_NAME(kp)); totct += ddebug_apply_class_bitmap(dcp, &new_bits, old_bits, mod_name); WRITE_ONCE(*dcp->lvl, inrep); break; @@ -766,9 +769,9 @@ int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp) switch (map->map_type) { case DD_CLASS_TYPE_DISJOINT_BITS: - return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", *dcp->bits); + return scnprintf(buffer, PAGE_SIZE, "0x%x\n", *dcp->bits); case DD_CLASS_TYPE_LEVEL_NUM: - return scnprintf(buffer, PAGE_SIZE, "%d\n", *dcp->lvl); + return scnprintf(buffer, PAGE_SIZE, "%u\n", *dcp->lvl); default: return -1; } diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c index 74d183ebf3e0..9e8e028461ad 100644 --- a/lib/test_dynamic_debug.c +++ b/lib/test_dynamic_debug.c @@ -40,7 +40,7 @@ module_param_cb(do_prints, ¶m_ops_do_prints, NULL, 0600); * - tie together sysname, mapname, bitsname, flagsname */ #define DD_SYS_WRAP(_model, _flags) \ - static unsigned long bits_##_model; \ + static u32 bits_##_model; \ static struct ddebug_class_param _flags##_model = { \ .bits = &bits_##_model, \ .flags = #_flags, \ -- 2.55.0