Re: [PATCHv10 2/3] powerpc/kernel: Extend arrays' size to make room for a hole in cpu_possible_mask

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

Hi Pingfan,

kernel test robot noticed the following build errors:

[auto build test ERROR on powerpc/next]
[also build test ERROR on powerpc/fixes linus/master v6.7-rc7 next-20231222]
[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/Pingfan-Liu/powerpc-kernel-Remove-check-on-paca_ptrs_size/20231227-104412
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/20231227024126.12424-1-kernelfans%40gmail.com
patch subject: [PATCHv10 2/3] powerpc/kernel: Extend arrays' size to make room for a hole in cpu_possible_mask
config: powerpc-iss476-smp_defconfig (https://download.01.org/0day-ci/archive/20231228/202312280350.GpyKSrB6-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231228/202312280350.GpyKSrB6-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/202312280350.GpyKSrB6-lkp@intel.com/

All errors (new ones prefixed by >>):

   powerpc-linux-ld: arch/powerpc/kernel/setup-common.o: in function `smp_setup_cpu_maps':
>> arch/powerpc/kernel/setup-common.c:440:(.init.text+0x6a): undefined reference to `paca_last_cpu_num'
>> powerpc-linux-ld: arch/powerpc/kernel/setup-common.c:440:(.init.text+0x72): undefined reference to `paca_last_cpu_num'

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for HOTPLUG_CPU
   Depends on [n]: SMP [=y] && (PPC_PSERIES [=n] || PPC_PMAC [=n] || PPC_POWERNV [=n] || FSL_SOC_BOOKE [=n])
   Selected by [y]:
   - PM_SLEEP_SMP [=y] && SMP [=y] && (ARCH_SUSPEND_POSSIBLE [=y] || ARCH_HIBERNATION_POSSIBLE [=y]) && PM_SLEEP [=y]


vim +440 arch/powerpc/kernel/setup-common.c

   413	
   414	/**
   415	 * setup_cpu_maps - initialize the following cpu maps:
   416	 *                  cpu_possible_mask
   417	 *                  cpu_present_mask
   418	 *
   419	 * Having the possible map set up early allows us to restrict allocations
   420	 * of things like irqstacks to nr_cpu_ids rather than NR_CPUS.
   421	 *
   422	 * We do not initialize the online map here; cpus set their own bits in
   423	 * cpu_online_mask as they come up.
   424	 *
   425	 * This function is valid only for Open Firmware systems.  finish_device_tree
   426	 * must be called before using this.
   427	 *
   428	 * While we're here, we may as well set the "physical" cpu ids in the paca.
   429	 *
   430	 * NOTE: This must match the parsing done in early_init_dt_scan_cpus.
   431	 */
   432	void __init smp_setup_cpu_maps(void)
   433	{
   434		struct device_node *dn;
   435		int cpu = 0;
   436		int nthreads = 1;
   437	
   438		DBG("smp_setup_cpu_maps()\n");
   439	
 > 440		cpu_to_phys_id = memblock_alloc(paca_last_cpu_num * sizeof(u32),
   441						__alignof__(u32));
   442		if (!cpu_to_phys_id)
   443			panic("%s: Failed to allocate %zu bytes align=0x%zx\n",
   444			      __func__, nr_cpu_ids * sizeof(u32), __alignof__(u32));
   445	
   446		for_each_node_by_type(dn, "cpu") {
   447			const __be32 *intserv;
   448			__be32 cpu_be;
   449			int j, len;
   450	
   451			DBG("  * %pOF...\n", dn);
   452	
   453			intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s",
   454					&len);
   455			if (intserv) {
   456				DBG("    ibm,ppc-interrupt-server#s -> %lu threads\n",
   457				    (len / sizeof(int)));
   458			} else {
   459				DBG("    no ibm,ppc-interrupt-server#s -> 1 thread\n");
   460				intserv = of_get_property(dn, "reg", &len);
   461				if (!intserv) {
   462					cpu_be = cpu_to_be32(cpu);
   463					/* XXX: what is this? uninitialized?? */
   464					intserv = &cpu_be;	/* assume logical == phys */
   465					len = 4;
   466				}
   467			}
   468	
   469			nthreads = len / sizeof(int);
   470	
   471			for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
   472				bool avail;
   473	
   474				DBG("    thread %d -> cpu %d (hard id %d)\n",
   475				    j, cpu, be32_to_cpu(intserv[j]));
   476	
   477				avail = of_device_is_available(dn);
   478				if (!avail)
   479					avail = !of_property_match_string(dn,
   480							"enable-method", "spin-table");
   481	
   482				set_cpu_present(cpu, avail);
   483				set_cpu_possible(cpu, true);
   484				cpu_to_phys_id[cpu] = be32_to_cpu(intserv[j]);
   485				cpu++;
   486			}
   487	
   488			if (cpu >= nr_cpu_ids) {
   489				of_node_put(dn);
   490				break;
   491			}
   492		}
   493	
   494		/* If no SMT supported, nthreads is forced to 1 */
   495		if (!cpu_has_feature(CPU_FTR_SMT)) {
   496			DBG("  SMT disabled ! nthreads forced to 1\n");
   497			nthreads = 1;
   498		}
   499	

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