[PATCH 3/7] hwmon/coretemp: Handle large core id value

[Zhang Rui]

The coretemp driver supports up to a hard-coded limit of 128 cores.

Today, the driver can not support a core with an id above that limit.
Yet, the encoding of core_id's is arbitrary (BIOS APIC-id) and so they
may be sparse and they may be large.

Update the driver to map arbitrary core_id numbers into appropriate
array indexes so that 128 cores can be supported, no matter the encoding
of core_ids's.

Acked-by: Len Brown <len.brown@xxxxxxxxx>
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
---
 drivers/hwmon/coretemp.c | 55 +++++++++++++++++++++++++++++-----------
 1 file changed, 40 insertions(+), 15 deletions(-)

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index ccf0af5b988a..3f0f7d7612ae 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -46,9 +46,6 @@ MODULE_PARM_DESC(tjmax, "TjMax value in degrees Celsius");
 #define TOTAL_ATTRS		(MAX_CORE_ATTRS + 1)
 #define MAX_CORE_DATA		(NUM_REAL_CORES + BASE_SYSFS_ATTR_NO)
 
-#define TO_CORE_ID(cpu)		(cpu_data(cpu).cpu_core_id)
-#define TO_ATTR_NO(cpu)		(TO_CORE_ID(cpu) + BASE_SYSFS_ATTR_NO)
-
 #ifdef CONFIG_SMP
 #define for_each_sibling(i, cpu) \
 	for_each_cpu(i, topology_sibling_cpumask(cpu))
@@ -91,6 +88,8 @@ struct temp_data {
 struct platform_data {
 	struct device		*hwmon_dev;
 	u16			pkg_id;
+	u16			cpu_map[NUM_REAL_CORES];
+	struct ida		ida;
 	struct cpumask		cpumask;
 	struct temp_data	*core_data[MAX_CORE_DATA];
 	struct device_attribute name_attr;
@@ -441,7 +440,7 @@ static struct temp_data *init_temp_data(unsigned int cpu, int pkg_flag)
 							MSR_IA32_THERM_STATUS;
 	tdata->is_pkg_data = pkg_flag;
 	tdata->cpu = cpu;
-	tdata->cpu_core_id = TO_CORE_ID(cpu);
+	tdata->cpu_core_id = topology_core_id(cpu);
 	tdata->attr_size = MAX_CORE_ATTRS;
 	mutex_init(&tdata->update_lock);
 	return tdata;
@@ -454,7 +453,7 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
 	struct platform_data *pdata = platform_get_drvdata(pdev);
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
 	u32 eax, edx;
-	int err, attr_no;
+	int err, index, attr_no;
 
 	/*
 	 * Find attr number for sysfs:
@@ -462,14 +461,26 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
 	 * The attr number is always core id + 2
 	 * The Pkgtemp will always show up as temp1_*, if available
 	 */
-	attr_no = pkg_flag ? PKG_SYSFS_ATTR_NO : TO_ATTR_NO(cpu);
+	if (pkg_flag)
+		attr_no = PKG_SYSFS_ATTR_NO;
+	else {
+		index = ida_alloc(&pdata->ida, GFP_KERNEL);
+		if (index < 0)
+			return index;
+		pdata->cpu_map[index] = topology_core_id(cpu);
+		attr_no = index + BASE_SYSFS_ATTR_NO;
+	}
 
-	if (attr_no > MAX_CORE_DATA - 1)
-		return -ERANGE;
+	if (attr_no > MAX_CORE_DATA - 1) {
+		err = -ERANGE;
+		goto ida_free;
+	}
 
 	tdata = init_temp_data(cpu, pkg_flag);
-	if (!tdata)
-		return -ENOMEM;
+	if (!tdata) {
+		err = -ENOMEM;
+		goto ida_free;
+	}
 
 	/* Test if we can access the status register */
 	err = rdmsr_safe_on_cpu(cpu, tdata->status_reg, &eax, &edx);
@@ -505,6 +516,9 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
 exit_free:
 	pdata->core_data[attr_no] = NULL;
 	kfree(tdata);
+ida_free:
+	if (!pkg_flag)
+		ida_free(&pdata->ida, index);
 	return err;
 }
 
@@ -524,6 +538,8 @@ static void coretemp_remove_core(struct platform_data *pdata, int indx)
 
 	kfree(pdata->core_data[indx]);
 	pdata->core_data[indx] = NULL;
+
+	ida_free(&pdata->ida, indx - BASE_SYSFS_ATTR_NO);
 }
 
 static int coretemp_probe(struct platform_device *pdev)
@@ -537,6 +553,7 @@ static int coretemp_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	pdata->pkg_id = pdev->id;
+	ida_init(&pdata->ida);
 	platform_set_drvdata(pdev, pdata);
 
 	pdata->hwmon_dev = devm_hwmon_device_register_with_groups(dev, DRVNAME,
@@ -553,6 +570,7 @@ static int coretemp_remove(struct platform_device *pdev)
 		if (pdata->core_data[i])
 			coretemp_remove_core(pdata, i);
 
+	ida_destroy(&pdata->ida);
 	return 0;
 }
 
@@ -647,7 +665,7 @@ static int coretemp_cpu_offline(unsigned int cpu)
 	struct platform_device *pdev = coretemp_get_pdev(cpu);
 	struct platform_data *pd;
 	struct temp_data *tdata;
-	int indx, target;
+	int i, indx = -1, target;
 
 	/*
 	 * Don't execute this on suspend as the device remove locks
@@ -660,12 +678,19 @@ static int coretemp_cpu_offline(unsigned int cpu)
 	if (!pdev)
 		return 0;
 
-	/* The core id is too big, just return */
-	indx = TO_ATTR_NO(cpu);
-	if (indx > MAX_CORE_DATA - 1)
+	pd = platform_get_drvdata(pdev);
+
+	for (i = 0; i < NUM_REAL_CORES; i++) {
+		if (pd->cpu_map[i] == topology_core_id(cpu)) {
+			indx = i + BASE_SYSFS_ATTR_NO;
+			break;
+		}
+	}
+
+	/* Too many cores and this core is not pupolated, just return */
+	if (indx < 0)
 		return 0;
 
-	pd = platform_get_drvdata(pdev);
 	tdata = pd->core_data[indx];
 
 	cpumask_clear_cpu(cpu, &pd->cpumask);
-- 
2.34.1