Thread (19 messages) 19 messages, 4 authors, 2016-09-20

Re: [PATCH v6 3/7] perf annotate: Add support for powerpc

From: Arnaldo Carvalho de Melo <acme@kernel.org>
Date: 2016-09-19 15:26:16
Also in: lkml

Em Fri, Aug 19, 2016 at 06:29:34PM +0530, Ravi Bangoria escreveu:
From: "Naveen N. Rao" <redacted>

+static struct ins *ins__find_powerpc(const char *name)
+{
+	int i;
+	struct ins *ins;
+	struct ins_ops *ops;
+	static struct instructions_powerpc head;
+	static bool list_initialized;
+
+	/*
+	 * - Interested only if instruction starts with 'b'.
+	 * - Few start with 'b', but aren't branch instructions.
+	 */
+	if (name[0] != 'b'             ||
+	    !strncmp(name, "bcd", 3)   ||
+	    !strncmp(name, "brinc", 5) ||
+	    !strncmp(name, "bper", 4))
+		return NULL;
+
+	if (!list_initialized) {
+		INIT_LIST_HEAD(&head.list);
+		list_initialized = true;
+	}
Why not ditch list_initialized and instead just declare the list as:

static struct instructions_powerpc head = {
	.list = LIST_HEAD_INIT(head.list),
}

Just like the kernel sources do? See for instance:

  net/core/net_namespace.c

struct net init_net = {
        .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
};
quoted hunk ↗ jump to hunk
+
+	/*
+	 * Return if we already have object of 'struct ins' for this instruction
+	 */
+	ins = list_search__ins_powerpc(&head, name);
+	if (ins)
+		return ins;
+
+	ops = &jump_ops;
+
+	i = strlen(name) - 1;
+	if (i < 0)
+		return NULL;
+
+	/* ignore optional hints at the end of the instructions */
+	if (name[i] == '+' || name[i] == '-')
+		i--;
+
+	if (name[i] == 'l' || (name[i] == 'a' && name[i-1] == 'l')) {
+		/*
+		 * if the instruction ends up with 'l' or 'la', then
+		 * those are considered 'calls' since they update LR.
+		 * ... except for 'bnl' which is branch if not less than
+		 * and the absolute form of the same.
+		 */
+		if (strcmp(name, "bnl") && strcmp(name, "bnl+") &&
+		    strcmp(name, "bnl-") && strcmp(name, "bnla") &&
+		    strcmp(name, "bnla+") && strcmp(name, "bnla-"))
+			ops = &call_ops;
+	}
+	if (name[i] == 'r' && name[i-1] == 'l')
+		/*
+		 * instructions ending with 'lr' are considered to be
+		 * return instructions
+		 */
+		ops = &ret_ops;
+
+	/*
+	 * Add instruction to list so next time no need to
+	 * allocate memory for it.
+	 */
+	return list_add__ins_powerpc(&head, name, ops);
+}
+
 static void ins__sort(struct ins *instructions, int nmemb)
 {
 	qsort(instructions, nmemb, sizeof(struct ins), ins__cmp);
@@ -585,6 +699,8 @@ static struct ins *ins__find(const char *name, const char *norm_arch)
 	} else if (!strcmp(norm_arch, NORM_ARM)) {
 		instructions = instructions_arm;
 		nmemb = ARRAY_SIZE(instructions_arm);
+	} else if (!strcmp(norm_arch, NORM_POWERPC)) {
+		return ins__find_powerpc(name);
 	} else {
 		pr_err("perf annotate not supported by %s arch\n", norm_arch);
 		return NULL;
-- 
2.5.5
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