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Commit 32478006 authored by Jan Beulich's avatar Jan Beulich Committed by Guenter Roeck
Browse files

hwmon: (coretemp) fix reading of microcode revision (v2) 



According to the documentation, simply reading the respective MSR
isn't sufficient: It should be written with zeros, cpuid(1) be
executed, and then read (see arch/x86/kernel/cpu/intel.c for an
example).

v2: Fail probe when microcode revision cannot be determined, but is
needed to check for proper operation.

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jean Delvare <khali@linux-fr.org>
Acked-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarGuenter Roeck <guenter.roeck@ericsson.com>
parent 17c10d61

drivers/hwmon/coretemp.c

+18 −2
Original line number Diff line number Diff line
@@ -289,6 +289,15 @@ static int __devinit get_tjmax(struct cpuinfo_x86 *c, u32 id, 
	}

}



static void __devinit get_ucode_rev_on_cpu(void *edx)

{

	u32 eax;



	wrmsr(MSR_IA32_UCODE_REV, 0, 0);

	sync_core();

	rdmsr(MSR_IA32_UCODE_REV, eax, *(u32 *)edx);

}



static int __devinit coretemp_probe(struct platform_device *pdev)

{

	struct coretemp_data *data;
@@ -324,8 +333,15 @@ static int __devinit coretemp_probe(struct platform_device *pdev) 


	if ((c->x86_model == 0xe) && (c->x86_mask < 0xc)) {

		/* check for microcode update */

		rdmsr_on_cpu(data->id, MSR_IA32_UCODE_REV, &eax, &edx);

		if (edx < 0x39) {

		err = smp_call_function_single(data->id, get_ucode_rev_on_cpu,

					       &edx, 1);

		if (err) {

			dev_err(&pdev->dev,

				"Cannot determine microcode revision of "

				"CPU#%u (%d)!\n", data->id, err);

			err = -ENODEV;

			goto exit_free;

		} else if (edx < 0x39) {

			err = -ENODEV;

			dev_err(&pdev->dev,

				"Errata AE18 not fixed, update BIOS or "