hwmon: (coretemp) Replace x86_model checks with VFM ones

Intel CPUs have been using Family 6 for a while. The Family-model checks
in the coretemp driver implicitly assume Family 6. With the upcoming
Family 18 and 19 models, some of these checks fall apart.

While reading the temperature target MSR, cpu_has_tjmax() performs model
checks only to determine if a device warning should be printed. Instead
of expanding the checks, get rid of the function and print the warning
once unconditionally if the MSR read fails. The checks aren't worth
preventing a single line warning to dmesg.

Update the rest of the x86_model checks with VFM ones to make them more
robust. This automatically covers the upcoming Family 18 and 19 as well
as any future extended families.

Add a code comment to reflect that none of the CPUs in Family 5 or
Family 15 set X86_FEATURE_DTHERM. The VFM checks do not impact these
CPUs since the driver does not load on them.

Signed-off-by: Dave Hansen <[e-mail]>
Signed-off-by: Sohil Mehta <[e-mail]>
Reviewed-by: Dave Hansen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/hwmon/coretemp.c

···
 };
 
 struct tjmax_model {
-	u8 model;
-	u8 mask;
+	u32 vfm;
+	u8 stepping_mask;
 	int tjmax;
 };
 
 #define ANY 0xff
 
 static const struct tjmax_model tjmax_model_table[] = {
-	{ 0x1c, 10, 100000 },	/* D4xx, K4xx, N4xx, D5xx, K5xx, N5xx */
-	{ 0x1c, ANY, 90000 },	/* Z5xx, N2xx, possibly others
-				 * Note: Also matches 230 and 330,
-				 * which are covered by tjmax_table
-				 */
-	{ 0x26, ANY, 90000 },	/* Atom Tunnel Creek (Exx), Lincroft (Z6xx)
-				 * Note: TjMax for E6xxT is 110C, but CPU type
-				 * is undetectable by software
-				 */
-	{ 0x27, ANY, 90000 },	/* Atom Medfield (Z2460) */
-	{ 0x35, ANY, 90000 },	/* Atom Clover Trail/Cloverview (Z27x0) */
-	{ 0x36, ANY, 100000 },	/* Atom Cedar Trail/Cedarview (N2xxx, D2xxx)
-				 * Also matches S12x0 (stepping 9), covered by
-				 * PCI table
-				 */
+	{ INTEL_ATOM_BONNELL,	      10,  100000 },	/* D4xx, K4xx, N4xx, D5xx, K5xx, N5xx */
+	{ INTEL_ATOM_BONNELL,	      ANY, 90000 },	/* Z5xx, N2xx, possibly others
+							 * Note: Also matches 230 and 330,
+							 * which are covered by tjmax_table
+							 */
+	{ INTEL_ATOM_BONNELL_MID,     ANY, 90000 },	/* Atom Tunnel Creek (Exx), Lincroft (Z6xx)
+							 * Note: TjMax for E6xxT is 110C, but CPU type
+							 * is undetectable by software
+							 */
+	{ INTEL_ATOM_SALTWELL_MID,    ANY, 90000 },	/* Atom Medfield (Z2460) */
+	{ INTEL_ATOM_SALTWELL_TABLET, ANY, 90000 },	/* Atom Clover Trail/Cloverview (Z27x0) */
+	{ INTEL_ATOM_SALTWELL,	      ANY, 100000 },	/* Atom Cedar Trail/Cedarview (N2xxx, D2xxx)
+							 * Also matches S12x0 (stepping 9), covered by
+							 * PCI table
+							 */
 };
 
 static bool is_pkg_temp_data(struct temp_data *tdata)
···
 	}
 	pci_dev_put(host_bridge);
 
+	/*
+	 * This is literally looking for "CPU  XXX" in the model string.
+	 * Not checking it against the model as well. Just purely a
+	 * string search.
+	 */
 	for (i = 0; i < ARRAY_SIZE(tjmax_table); i++) {
 		if (strstr(c->x86_model_id, tjmax_table[i].id))
 			return tjmax_table[i].tjmax;
···
 
 	for (i = 0; i < ARRAY_SIZE(tjmax_model_table); i++) {
 		const struct tjmax_model *tm = &tjmax_model_table[i];
-		if (c->x86_model == tm->model &&
-		    (tm->mask == ANY || c->x86_stepping == tm->mask))
+		if (c->x86_vfm == tm->vfm &&
+		    (tm->stepping_mask == ANY ||
+		     tm->stepping_mask == c->x86_stepping))
 			return tm->tjmax;
 	}
 
 	/* Early chips have no MSR for TjMax */
 
-	if (c->x86_model == 0xf && c->x86_stepping < 4)
+	if (c->x86_vfm == INTEL_CORE2_MEROM && c->x86_stepping < 4)
 		usemsr_ee = 0;
 
-	if (c->x86_model > 0xe && usemsr_ee) {
+	if (c->x86_vfm > INTEL_CORE_YONAH && usemsr_ee) {
 		u8 platform_id;
 
 		/*
···
 				 "Unable to access MSR 0x17, assuming desktop"
 				 " CPU\n");
 			usemsr_ee = 0;
-		} else if (c->x86_model < 0x17 && !(eax & 0x10000000)) {
+		} else if (c->x86_vfm < INTEL_CORE2_PENRYN &&
+			   !(eax & 0x10000000)) {
 			/*
 			 * Trust bit 28 up to Penryn, I could not find any
 			 * documentation on that; if you happen to know
···
 			 * Mobile Penryn CPU seems to be platform ID 7 or 5
 			 * (guesswork)
 			 */
-			if (c->x86_model == 0x17 &&
+			if (c->x86_vfm == INTEL_CORE2_PENRYN &&
 			    (platform_id == 5 || platform_id == 7)) {
 				/*
 				 * If MSR EE bit is set, set it to 90 degrees C,
···
 	return tjmax;
 }
 
-static bool cpu_has_tjmax(struct cpuinfo_x86 *c)
-{
-	u8 model = c->x86_model;
-
-	return model > 0xe &&
-	       model != 0x1c &&
-	       model != 0x26 &&
-	       model != 0x27 &&
-	       model != 0x35 &&
-	       model != 0x36;
-}
-
 static int get_tjmax(struct temp_data *tdata, struct device *dev)
 {
 	struct cpuinfo_x86 *c = &cpu_data(tdata->cpu);
···
 	 */
 	err = rdmsr_safe_on_cpu(tdata->cpu, MSR_IA32_TEMPERATURE_TARGET, &eax, &edx);
 	if (err) {
-		if (cpu_has_tjmax(c))
-			dev_warn(dev, "Unable to read TjMax from CPU %u\n", tdata->cpu);
+		dev_warn_once(dev, "Unable to read TjMax from CPU %u\n", tdata->cpu);
 	} else {
 		val = (eax >> 16) & 0xff;
 		if (val)
···
 	 * Readings might stop update when processor visited too deep sleep,
 	 * fixed for stepping D0 (6EC).
 	 */
-	if (c->x86_model == 0xe && c->x86_stepping < 0xc && c->microcode < 0x39) {
+	if (c->x86_vfm == INTEL_CORE_YONAH && c->x86_stepping < 0xc && c->microcode < 0x39) {
 		pr_err("Errata AE18 not fixed, update BIOS or microcode of the CPU!\n");
 		return -ENODEV;
 	}
···
 	 * MSR_IA32_TEMPERATURE_TARGET register. Atoms don't have the register
 	 * at all.
 	 */
-	if (c->x86_model > 0xe && c->x86_model != 0x1c)
+	if (c->x86_vfm > INTEL_CORE_YONAH && c->x86_vfm != INTEL_ATOM_BONNELL)
 		if (get_ttarget(tdata, &pdev->dev) >= 0)
 			tdata->attr_size++;
 
···
 	/*
 	 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
 	 * sensors. We check this bit only, all the early CPUs
-	 * without thermal sensors will be filtered out.
+	 * without thermal sensors will be filtered out. This
+	 * includes all the Family 5 and Family 15 (Pentium 4)
+	 * models, since they never set the CPUID bit.
 	 */
 	if (!x86_match_cpu(coretemp_ids))
 		return -ENODEV;