tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y
head:   e864f43593ccf9180c61738abdf1c1dde091367d
commit: 938de2324afb53acd20893cd8eec8ee6f80de646 [5835/9999] x86/MCE/AMD: Carve out the MC4_MISC thresholding quirk
config: i386-randconfig-r005-20210118 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=938de2324afb53acd20893cd8eec8ee6f80de646
        git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
        git fetch --no-tags linux-stable-rc linux-4.19.y
        git checkout 938de2324afb53acd20893cd8eec8ee6f80de646
        # save the attached .config to linux build tree
        make W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> arch/x86/kernel/cpu/mcheck/mce_amd.c:552:6: warning: no previous prototype for 'disable_err_thresholding' [-Wmissing-prototypes]
     552 | void disable_err_thresholding(struct cpuinfo_x86 *c)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~
   arch/x86/kernel/cpu/mcheck/mce_amd.c:864:39: warning: no previous prototype for 'smp_deferred_error_interrupt' [-Wmissing-prototypes]
     864 | asmlinkage __visible void __irq_entry smp_deferred_error_interrupt(struct pt_regs *regs)
         |                                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/disable_err_thresholding +552 arch/x86/kernel/cpu/mcheck/mce_amd.c

   547	
   548	/*
   549	 * Turn off MC4_MISC thresholding banks on all family 0x15 models since
   550	 * they're not supported there.
   551	 */
 > 552	void disable_err_thresholding(struct cpuinfo_x86 *c)
   553	{
   554		int i;
   555		u64 hwcr;
   556		bool need_toggle;
   557		u32 msrs[] = {
   558			0x00000413, /* MC4_MISC0 */
   559			0xc0000408, /* MC4_MISC1 */
   560		};
   561	
   562		if (c->x86 != 0x15)
   563			return;
   564	
   565		rdmsrl(MSR_K7_HWCR, hwcr);
   566	
   567		/* McStatusWrEn has to be set */
   568		need_toggle = !(hwcr & BIT(18));
   569	
   570		if (need_toggle)
   571			wrmsrl(MSR_K7_HWCR, hwcr | BIT(18));
   572	
   573		/* Clear CntP bit safely */
   574		for (i = 0; i < ARRAY_SIZE(msrs); i++)
   575			msr_clear_bit(msrs[i], 62);
   576	
   577		/* restore old settings */
   578		if (need_toggle)
   579			wrmsrl(MSR_K7_HWCR, hwcr);
   580	}
   581	

---
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