[RFC] kallsyms C_SYMBOL_PREFIX support

[Yoshinori Sato]

kallsyms does not consider SYMBOL_PREFIX of C.
Consequently do not work in architecture using prefix character (h8300, v850) really.

Because I can want to use this, I made a patch.
Please comment.

-- 
Yoshinori Sato
<ysato@xxxxxxxxxxxxxxxxxxxx>

===== scripts/kallsyms.c 1.16 vs edited =====
--- 1.16/scripts/kallsyms.c	2005-01-01 19:22:13 +09:00
+++ edited/scripts/kallsyms.c	2005-04-12 15:50:47 +09:00
@@ -69,6 +69,7 @@
 static int size, cnt;
 static unsigned long long _stext, _etext, _sinittext, _einittext;
 static int all_symbols = 0;
+static char symbol_prefix_char = '\0';
 
 struct token {
 	unsigned char data[MAX_TOK_SIZE];
@@ -93,7 +94,7 @@
 static void
 usage(void)
 {
-	fprintf(stderr, "Usage: kallsyms [--all-symbols] < in.map > out.S\n");
+	fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
 	exit(1);
 }
 
@@ -112,6 +113,7 @@
 read_symbol(FILE *in, struct sym_entry *s)
 {
 	char str[500];
+	char *sym;
 	int rc;
 
 	rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str);
@@ -123,27 +125,32 @@
 		return -1;
 	}
 
+	sym = str;
+	/* skip prefix char */
+	if (symbol_prefix_char && str[0] == symbol_prefix_char)
+		sym++;
+
 	/* Ignore most absolute/undefined (?) symbols. */
-	if (strcmp(str, "_stext") == 0)
+	if (strcmp(sym, "_stext") == 0)
 		_stext = s->addr;
-	else if (strcmp(str, "_etext") == 0)
+	else if (strcmp(sym, "_etext") == 0)
 		_etext = s->addr;
-	else if (strcmp(str, "_sinittext") == 0)
+	else if (strcmp(sym, "_sinittext") == 0)
 		_sinittext = s->addr;
-	else if (strcmp(str, "_einittext") == 0)
+	else if (strcmp(sym, "_einittext") == 0)
 		_einittext = s->addr;
 	else if (toupper(s->type) == 'A')
 	{
 		/* Keep these useful absolute symbols */
-		if (strcmp(str, "__kernel_syscall_via_break") &&
-		    strcmp(str, "__kernel_syscall_via_epc") &&
-		    strcmp(str, "__kernel_sigtramp") &&
-		    strcmp(str, "__gp"))
+		if (strcmp(sym, "__kernel_syscall_via_break") &&
+		    strcmp(sym, "__kernel_syscall_via_epc") &&
+		    strcmp(sym, "__kernel_sigtramp") &&
+		    strcmp(sym, "__gp"))
 			return -1;
 
 	}
 	else if (toupper(s->type) == 'U' ||
-		 is_arm_mapping_symbol(str))
+		 is_arm_mapping_symbol(sym))
 		return -1;
 
 	/* include the type field in the symbol name, so that it gets
@@ -177,6 +184,11 @@
 		"_SDA2_BASE_",		/* ppc */
 		NULL };
 	int i;
+	int offset = 1;
+
+	/* skip prefix char */
+	if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char)
+		offset++;
 
 	/* if --all-symbols is not specified, then symbols outside the text
 	 * and inittext sections are discarded */
@@ -190,17 +202,17 @@
 		 * they may get dropped in pass 2, which breaks the kallsyms
 		 * rules.
 		 */
-		if ((s->addr == _etext && strcmp(s->sym + 1, "_etext")) ||
-		    (s->addr == _einittext && strcmp(s->sym + 1, "_einittext")))
+		if ((s->addr == _etext && strcmp(s->sym + offset, "_etext")) ||
+		    (s->addr == _einittext && strcmp(s->sym + offset, "_einittext")))
 			return 0;
 	}
 
 	/* Exclude symbols which vary between passes. */
-	if (strstr(s->sym + 1, "_compiled."))
+	if (strstr(s->sym + offset, "_compiled."))
 		return 0;
 
 	for (i = 0; special_symbols[i]; i++)
-		if( strcmp(s->sym + 1, special_symbols[i]) == 0 )
+		if( strcmp(s->sym + offset, special_symbols[i]) == 0 )
 			return 0;
 
 	return 1;
@@ -225,9 +237,15 @@
 
 static void output_label(char *label)
 {
-	printf(".globl %s\n",label);
+	if (symbol_prefix_char)
+		printf(".globl %c%s\n", symbol_prefix_char, label);
+	else
+		printf(".globl %s\n", label);
 	printf("\tALGN\n");
-	printf("%s:\n",label);
+	if (symbol_prefix_char)
+		printf("%c%s:\n", symbol_prefix_char, label);
+	else
+		printf("%s:\n", label);
 }
 
 /* uncompress a compressed symbol. When this function is called, the best table
@@ -665,6 +683,13 @@
 
 	insert_real_symbols_in_table();
 
+	/* When valid symbol is not registered, exit to error */
+	if (good_head.left == good_head.right &&
+	    bad_head.left == bad_head.right) {
+		fprintf(stderr, "No valid symbol.\n");
+		exit(1);
+	}
+
 	optimize_result();
 }
 
@@ -672,9 +697,21 @@
 int
 main(int argc, char **argv)
 {
-	if (argc == 2 && strcmp(argv[1], "--all-symbols") == 0)
-		all_symbols = 1;
-	else if (argc != 1)
+	if (argc >= 2) {
+		int i;
+		for (i = 1; i < argc; i++) { 
+			if(strcmp(argv[i], "--all-symbols") == 0)
+				all_symbols = 1;
+			else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
+				char *p = &argv[i][16];
+				/* skip quote */
+				if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\''))
+					p++;
+				symbol_prefix_char = *p;
+			} else
+				usage();
+		}
+	} else if (argc != 1)
 		usage();
 
 	read_map(stdin);
@@ -683,4 +720,3 @@
 
 	return 0;
 }
-
-
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