[tip: x86/misc] tools/x86/kcpuid: Parse subleaf ranges if provided

["tip-bot2 for Ahmed S. Darwish" <tip-bot2@linutronix.de>]

The following commit has been merged into the x86/misc branch of tip:

Commit-ID:     58921443e9b04bbb1866070ed14ea39578302cea
Gitweb:        https://git.kernel.org/tip/58921443e9b04bbb1866070ed14ea39578302cea
Author:        Ahmed S. Darwish <darwi@linutronix.de>
AuthorDate:    Thu, 18 Jul 2024 15:47:47 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 02 Aug 2024 09:17:19 +02:00

tools/x86/kcpuid: Parse subleaf ranges if provided

It's a common pattern in cpuid leaves to have the same bitfields format
repeated across a number of subleaves.  Typically, this is used for
enumerating hierarchial structures like cache and TLB levels, CPU
topology levels, etc.

Modify kcpuid.c to handle subleaf ranges in the CSV file subleaves
column.  For example, make it able to parse lines in the form:

 # LEAF, SUBLEAVES,  reg,    bits,    short_name             , ...
    0xb,       1:0,  eax,     4:0,    x2apic_id_shift        , ...
    0xb,       1:0,  ebx,    15:0,    domain_lcpus_count     , ...
    0xb,       1:0,  ecx,     7:0,    domain_nr              , ...

This way, full output can be printed to the user.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-8-darwi@linutronix.de

---
 tools/arch/x86/kcpuid/kcpuid.c | 50 +++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/tools/arch/x86/kcpuid/kcpuid.c b/tools/arch/x86/kcpuid/kcpuid.c
index 725a7a2..1b25c0a 100644
--- a/tools/arch/x86/kcpuid/kcpuid.c
+++ b/tools/arch/x86/kcpuid/kcpuid.c
@@ -305,6 +305,8 @@ static int parse_line(char *line)
 	struct bits_desc *bdesc;
 	int reg_index;
 	char *start, *end;
+	u32 subleaf_start, subleaf_end;
+	unsigned bit_start, bit_end;
 
 	/* Skip comments and NULL line */
 	if (line[0] == '#' || line[0] == '\n')
@@ -343,13 +345,25 @@ static int parse_line(char *line)
 		return 0;
 
 	/* subleaf */
-	sub = strtoul(tokens[1], NULL, 0);
-	if ((int)sub > func->nr)
-		return -1;
+	buf = tokens[1];
+	end = strtok(buf, ":");
+	start = strtok(NULL, ":");
+	subleaf_end = strtoul(end, NULL, 0);
+
+	/* A subleaf range is given? */
+	if (start) {
+		subleaf_start = strtoul(start, NULL, 0);
+		subleaf_end = min(subleaf_end, (u32)(func->nr - 1));
+		if (subleaf_start > subleaf_end)
+			return 0;
+	} else {
+		subleaf_start = subleaf_end;
+		if (subleaf_start > (u32)(func->nr - 1))
+			return 0;
+	}
 
-	leaf = &func->leafs[sub];
+	/* register */
 	buf = tokens[2];
-
 	if (strcasestr(buf, "EAX"))
 		reg_index = R_EAX;
 	else if (strcasestr(buf, "EBX"))
@@ -361,23 +375,23 @@ static int parse_line(char *line)
 	else
 		goto err_exit;
 
-	reg = &leaf->info[reg_index];
-	bdesc = &reg->descs[reg->nr++];
-
 	/* bit flag or bits field */
 	buf = tokens[3];
-
 	end = strtok(buf, ":");
-	bdesc->end = strtoul(end, NULL, 0);
-	bdesc->start = bdesc->end;
-
-	/* start != NULL means it is bit fields */
 	start = strtok(NULL, ":");
-	if (start)
-		bdesc->start = strtoul(start, NULL, 0);
-
-	strcpy(bdesc->simp, strtok(tokens[4], " \t"));
-	strcpy(bdesc->detail, tokens[5]);
+	bit_end = strtoul(end, NULL, 0);
+	bit_start = (start) ? strtoul(start, NULL, 0) : bit_end;
+
+	for (sub = subleaf_start; sub <= subleaf_end; sub++) {
+		leaf = &func->leafs[sub];
+		reg = &leaf->info[reg_index];
+		bdesc = &reg->descs[reg->nr++];
+
+		bdesc->end = bit_end;
+		bdesc->start = bit_start;
+		strcpy(bdesc->simp, strtok(tokens[4], " \t"));
+		strcpy(bdesc->detail, tokens[5]);
+	}
 	return 0;
 
 err_exit: