[PATCH] use SMBIOS tables on ARM for lscpu

* [PATCH] use SMBIOS tables on ARM for lscpu
@ 2020-09-24 21:56 Jeffrey Bastian
  2020-09-29 11:35 ` Karel Zak
  0 siblings, 1 reply; 3+ messages in thread
From: Jeffrey Bastian @ 2020-09-24 21:56 UTC (permalink / raw)
  To: util-linux

ARM SBBR (Sever Base Boot Requirements) require SMBIOS tables, and
SMBIOS Type 4 describes the CPU manufacturer and model name (among other
details).  If SMBIOS Type 4 is present, use it to extract these strings.

Example output (before and after the patch) on an HP m400, Lenovo HR330A,
and HPE Apollo 70:

[root@hp-m400 ~]# /usr/bin/lscpu | grep -i -e vendor -e model -e stepping
Vendor ID:           APM
Model:               1
Model name:          X-Gene
Stepping:            0x0
[root@hp-m400 ~]# ./lscpu | grep -i -e vendor -e model -e stepping
Vendor ID:                       AppliedMicro
Model:                           1
Model name:                      X-Gene
Stepping:                        0x0

[root@lenovo-hr330a ~]# /usr/bin/lscpu | grep -i -e vendor -e model -e stepping
Vendor ID:           APM
Model:               2
Model name:          X-Gene
Stepping:            0x3
[root@lenovo-hr330a ~]# ./lscpu | grep -i -e vendor -e model -e stepping
Vendor ID:                       Ampere(TM)
Model:                           2
Model name:                      eMAG
Stepping:                        0x3

[root@hpe-apollo-70 ~]# /usr/bin/lscpu | grep -i -e vendor -e model -e stepping
Vendor ID:           Cavium
Model:               1
Model name:          ThunderX2 99xx
Stepping:            0x1
[root@hpe-apollo-70 ~]# ./lscpu | grep -i -e vendor -e model -e stepping
Vendor ID:                       Cavium Inc.
Model:                           1
Model name:                      Cavium ThunderX2(R) CPU CN9980 v2.1 @ 2.20GHz
Stepping:                        0x1

Signed-off-by: Jeffrey Bastian <jbastian@redhat.com>
---
  sys-utils/lscpu-arm.c | 88 ++++++++++++++++++++++++++++++++++++++++++-
  1 file changed, 87 insertions(+), 1 deletion(-)

diff --git a/sys-utils/lscpu-arm.c b/sys-utils/lscpu-arm.c
index 270866191875..82cc23ca830c 100644
--- a/sys-utils/lscpu-arm.c
+++ b/sys-utils/lscpu-arm.c
@@ -22,7 +22,15 @@
   *  - Linux kernel: arch/armX/include/asm/cputype.h
   *  - GCC sources: config/arch/arch-cores.def
   *  - Ancient wisdom
+ *  - SMBIOS tables (if applicable)
   */
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
  #include "lscpu.h"
  
  struct id_part {
@@ -202,7 +210,7 @@ static const struct hw_impl hw_implementer[] = {
      { -1,   unknown_part, "unknown" },
  };
  
-void arm_cpu_decode(struct lscpu_desc *desc)
+static void _arm_cpu_decode(struct lscpu_desc *desc)
  {
  	int j, impl, part;
  	const struct id_part *parts = NULL;
@@ -260,3 +268,81 @@ void arm_cpu_decode(struct lscpu_desc *desc)
  		desc->stepping = xstrdup(buf);
  	}
  }
+
+/* TODO: struct dmi_header, to_dmi_header() and dmi_string() are copied
+ * from lscpu-dmi.c.  Move them to a library?
+ */
+struct dmi_header
+{
+	uint8_t type;
+	uint8_t length;
+	uint16_t handle;
+	uint8_t *data;
+};
+
+static void to_dmi_header(struct dmi_header *h, uint8_t *data)
+{
+	h->type = data[0];
+	h->length = data[1];
+	memcpy(&h->handle, data + 2, sizeof(h->handle));
+	h->data = data;
+}
+
+static char *dmi_string(const struct dmi_header *dm, uint8_t s)
+{
+	char *bp = (char *)dm->data;
+
+	if (s == 0)
+		return NULL;
+
+	bp += dm->length;
+	while (s > 1 && *bp)
+	{
+		bp += strlen(bp);
+		bp++;
+		s--;
+	}
+
+	if (!*bp)
+		return NULL;
+
+	return bp;
+}
+
+#define _PATH_SYS_DMI_TYPE4	"/sys/firmware/dmi/entries/4-0/raw"
+#define PROC_MFR_OFFSET		0x07
+#define PROC_VERSION_OFFSET	0x10
+
+static void _arm_cpu_smbios(struct lscpu_desc *desc)
+{
+	uint8_t data[8192];
+	char buf[128];
+	struct dmi_header h;
+	int raw_fd = -1;
+
+	raw_fd = open(_PATH_SYS_DMI_TYPE4, O_RDONLY);
+	if (raw_fd == -1) {
+		return;
+	}
+	read(raw_fd, data, 8192);
+	close(raw_fd);
+
+	to_dmi_header(&h, data);
+
+	strncpy(buf, dmi_string(&h, data[PROC_MFR_OFFSET]), 127);
+	desc->vendor = xstrdup(buf);
+
+	strncpy(buf, dmi_string(&h, data[PROC_VERSION_OFFSET]), 127);
+	desc->modelname = xstrdup(buf);
+}
+
+void arm_cpu_decode(struct lscpu_desc *desc)
+{
+	/* use SMBIOS Type 4 data if available,
+	 * else fall back to manual decoding using the tables above */
+	if (access(_PATH_SYS_DMI_TYPE4, R_OK) != -1) {
+		_arm_cpu_smbios(desc);
+	} else {
+		_arm_cpu_decode(desc);
+	}
+}
-- 
2.26.2


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