Re: [PATCH v2] acpi/processor: sanitize _PDC buffer bits when running as Xen dom0

[kernel test robot <lkp@intel.com>]

Hi Jason,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/x86/core]
[also build test ERROR on v6.5]
[cannot apply to rafael-pm/linux-next linus/master next-20230906]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jason-Andryuk/acpi-processor-sanitize-_PDC-buffer-bits-when-running-as-Xen-dom0/20230907-022235
base:   tip/x86/core
patch link:    https://lore.kernel.org/r/20230906182125.48642-1-jandryuk%40gmail.com
patch subject: [PATCH v2] acpi/processor: sanitize _PDC buffer bits when running as Xen dom0
config: x86_64-randconfig-r011-20230907 (https://download.01.org/0day-ci/archive/20230907/202309070625.dJUDcGZg-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230907/202309070625.dJUDcGZg-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309070625.dJUDcGZg-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/acpi/processor_pdc.c: In function 'acpi_processor_eval_pdc':
>> drivers/acpi/processor_pdc.c:147:17: error: implicit declaration of function 'xen_sanitize_pdc' [-Werror=implicit-function-declaration]
     147 |                 xen_sanitize_pdc(buffer);
         |                 ^~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/xen_sanitize_pdc +147 drivers/acpi/processor_pdc.c

   116	
   117	/*
   118	 * _PDC is required for a BIOS-OS handshake for most of the newer
   119	 * ACPI processor features.
   120	 */
   121	static acpi_status
   122	acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
   123	{
   124		acpi_status status = AE_OK;
   125		union acpi_object *obj;
   126		u32 *buffer = NULL;
   127	
   128		obj = pdc_in->pointer;
   129		buffer = (u32 *)(obj->buffer.pointer);
   130	
   131		if (boot_option_idle_override == IDLE_NOMWAIT) {
   132			/*
   133			 * If mwait is disabled for CPU C-states, the C2C3_FFH access
   134			 * mode will be disabled in the parameter of _PDC object.
   135			 * Of course C1_FFH access mode will also be disabled.
   136			 */
   137			buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
   138		}
   139	
   140		if (xen_initial_domain()) {
   141			/*
   142			 * When Linux is running as Xen dom0, the hypervisor is the
   143			 * entity in charge of the processor power management, and so
   144			 * Xen needs to check the OS capabilities reported in the _PDC
   145			 * buffer matches what the hypervisor driver supports.
   146			 */
 > 147			xen_sanitize_pdc(buffer);
   148		}
   149	
   150		status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
   151	
   152		if (ACPI_FAILURE(status))
   153			acpi_handle_debug(handle,
   154			    "Could not evaluate _PDC, using legacy perf control\n");
   155	
   156		return status;
   157	}
   158	

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