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From:   Jim Cromie <jim.cromie@gmail.com>
To:     linux-kernel@vger.kernel.org, jbaron@akamai.com,
        gregkh@linuxfoundation.org, dri-devel@lists.freedesktop.org,
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        Jim Cromie <jim.cromie@gmail.com>
Subject: [PATCH v7b 16/25] dyndbg: refactor ddebug_classparam_clamp_input
Date:   Fri, 13 Oct 2023 16:48:08 -0600
Message-ID: <20231013224818.3456409-17-jim.cromie@gmail.com>
In-Reply-To: <20231013224818.3456409-1-jim.cromie@gmail.com>
References: <20231013224818.3456409-1-jim.cromie@gmail.com>
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Extract input validation code, from param_set_dyndbg_module_classes()
(the sys-node >handler) to new: ddebug_classparam_clamp_input(kp),
call it from former.  It takes kernel-param arg, so it can complain
about "foo: bad input".

Reuse ddparam_clamp_input(kp) in ddebug_sync_classbits(),
to validate inputs from parent's params, just like our own.
To support that reuse, alter ddebug_sync_classbits() and caller to
pass kp instead of kp->arg.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 70 ++++++++++++++++++++++++++++++---------------
 1 file changed, 47 insertions(+), 23 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index c11feca70d6f..17eefb35ac96 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -656,6 +656,30 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 
 #define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1)
 
+static void ddebug_class_param_clamp_input(unsigned long *inrep, const struct kernel_param *kp)
+{
+	const struct ddebug_class_param *dcp = kp->arg;
+	const struct ddebug_class_map *map = dcp->map;
+
+	switch (map->map_type) {
+	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",
+				KP_NAME(kp), *inrep, CLASSMAP_BITMASK(map->length));
+			*inrep &= CLASSMAP_BITMASK(map->length);
+		}
+		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",
+				KP_NAME(kp), *inrep, map->length);
+			*inrep = map->length;
+		}
+		break;
+	}
+}
 static int param_set_dyndbg_module_classes(const char *instr,
 					   const struct kernel_param *kp,
 					   const char *modnm)
@@ -674,26 +698,15 @@ static int param_set_dyndbg_module_classes(const char *instr,
 		pr_err("expecting numeric input, not: %s > %s\n", instr, KP_NAME(kp));
 		return -EINVAL;
 	}
+	ddebug_class_param_clamp_input(&inrep, kp);
 
 	switch (map->map_type) {
 	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",
-				KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length));
-			inrep &= CLASSMAP_BITMASK(map->length);
-		}
 		v2pr_info("bits:0x%lx > %s.%s\n", inrep, modnm ?: "*", KP_NAME(kp));
 		totct += ddebug_apply_class_bitmap(dcp, &inrep, *dcp->bits, modnm);
 		*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",
-				KP_NAME(kp), inrep, map->length);
-			inrep = map->length;
-		}
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
@@ -1160,16 +1173,27 @@ static const char * const ddebug_classmap_typenames[] = {
 		  ddebug_classmap_typenames[_cm->map_type]);		\
 	})
 
-static void ddebug_sync_classbits(const struct ddebug_class_param *dcp, const char *modname)
+static void ddebug_sync_classbits(const struct kernel_param *kp, const char *modname)
 {
-	/* clamp initial bitvec, mask off hi-bits */
-	if (*dcp->bits & ~CLASSMAP_BITMASK(dcp->map->length)) {
-		*dcp->bits &= CLASSMAP_BITMASK(dcp->map->length);
-		v2pr_info("preset classbits: %lx\n", *dcp->bits);
+	struct ddebug_class_param *dcp = kp->arg;
+	unsigned long new_bits;
+
+	ddebug_class_param_clamp_input(dcp->bits, kp);
+
+	switch (dcp->map->map_type) {
+	case DD_CLASS_TYPE_DISJOINT_BITS:
+		v2pr_info("  %s: classbits: 0x%lx\n", KP_NAME(kp), *dcp->bits);
+		ddebug_apply_class_bitmap(dcp, dcp->bits, 0UL, modname);
+		break;
+	case DD_CLASS_TYPE_LEVEL_NUM:
+		new_bits = CLASSMAP_BITMASK(*dcp->lvl);
+		v2pr_info("  %s: lvl:%ld bits:0x%lx\n", KP_NAME(kp), *dcp->lvl, new_bits);
+		ddebug_apply_class_bitmap(dcp, &new_bits, 0UL, modname);
+		break;
+	default:
+		pr_err("bad map type %d\n", dcp->map->map_type);
+		return;
 	}
-	/* force class'd prdbgs (in USEr module) to match (DEFINEr module) class-param */
-	ddebug_apply_class_bitmap(dcp, dcp->bits, ~0, modname);
-	ddebug_apply_class_bitmap(dcp, dcp->bits, 0, modname);
 }
 
 static void ddebug_match_apply_kparam(const struct kernel_param *kp,
@@ -1184,9 +1208,9 @@ static void ddebug_match_apply_kparam(const struct kernel_param *kp,
 	dcp = (struct ddebug_class_param *)kp->arg;
 
 	if (map == dcp->map) {
-		v2pr_info("found kp:%s =0x%lx", kp->name, *dcp->bits);
-		vpr_cm_info(map, "mapped to:");
-		ddebug_sync_classbits(dcp, modnm);
+		v2pr_info(" found kp:%s =0x%lx", kp->name, *dcp->bits);
+		vpr_cm_info(map, "  mapped to:");
+		ddebug_sync_classbits(kp, modnm);
 	}
 }
 
-- 
2.41.0