mm/sparse: fix check_usemap_section_nr warnings

I see a "virt_to_phys used for non-linear address" warning from
check_usemap_section_nr() on arm64 platforms.

In current implementation of NODE_DATA, if CONFIG_NEED_MULTIPLE_NODES=y,
pglist_data is dynamically allocated and assigned to node_data[].

For example, in arch/arm64/include/asm/mmzone.h:

  extern struct pglist_data *node_data[];
  #define NODE_DATA(nid)          (node_data[(nid)])

If CONFIG_NEED_MULTIPLE_NODES=n, pglist_data is defined as a global
variable named "contig_page_data".

For example, in include/linux/mmzone.h:

  extern struct pglist_data contig_page_data;
  #define NODE_DATA(nid)          (&contig_page_data)

If CONFIG_DEBUG_VIRTUAL is not enabled, __pa() can handle both
dynamically allocated linear addresses and symbol addresses.  However,
if (CONFIG_DEBUG_VIRTUAL=y && CONFIG_NEED_MULTIPLE_NODES=n) we can see
the "virt_to_phys used for non-linear address" warning because that
&contig_page_data is not a linear address on arm64.

Warning message:

  virt_to_phys used for non-linear address: (contig_page_data+0x0/0x1c00)
  WARNING: CPU: 0 PID: 0 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0x58/0x68
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Tainted: G        W         5.13.0-rc1-00074-g1140ab592e2e #3
  Hardware name: linux,dummy-virt (DT)
  pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--)
  Call trace:
     __virt_to_phys+0x58/0x68
     check_usemap_section_nr+0x50/0xfc
     sparse_init_nid+0x1ac/0x28c
     sparse_init+0x1c4/0x1e0
     bootmem_init+0x60/0x90
     setup_arch+0x184/0x1f0
     start_kernel+0x78/0x488

To fix it, create a small function to handle both translation.

Link: https://lkml.kernel.org/r/1623058729-27264-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Kazu <k-hagio-ab@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/sparse.c b/mm/sparse.c
index b2ada9dc00cb400c707fee147b8591f156a62025..55c18aff3e423b105fb61e884fc44b9659a3dda2 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -344,6 +344,15 @@ size_t mem_section_usage_size(void)
        return sizeof(struct mem_section_usage) + usemap_size();
 }
 
+static inline phys_addr_t pgdat_to_phys(struct pglist_data *pgdat)
+{
+#ifndef CONFIG_NEED_MULTIPLE_NODES
+       return __pa_symbol(pgdat);
+#else
+       return __pa(pgdat);
+#endif
+}
+
 #ifdef CONFIG_MEMORY_HOTREMOVE
 static struct mem_section_usage * __init
 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
@@ -362,7 +371,7 @@ sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
         * from the same section as the pgdat where possible to avoid
         * this problem.
         */
-       goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
+       goal = pgdat_to_phys(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
        limit = goal + (1UL << PA_SECTION_SHIFT);
        nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
 again:
@@ -390,7 +399,7 @@ static void __init check_usemap_section_nr(int nid,
        }
 
        usemap_snr = pfn_to_section_nr(__pa(usage) >> PAGE_SHIFT);
-       pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
+       pgdat_snr = pfn_to_section_nr(pgdat_to_phys(pgdat) >> PAGE_SHIFT);
        if (usemap_snr == pgdat_snr)
                return;