Re: + mm-rename-pud_page_vaddr-to-pud_pgtable-and-make-it-return-pmd_t.patch added to -mm tree
From: Aneesh Kumar K.V
Date: Wed Jun 16 2021 - 10:12:31 EST
kernel test robot <lkp@xxxxxxxxx> writes:
> Hi,
>
> I love your patch! Perhaps something to improve:
>
> [auto build test WARNING on powerpc/next]
> [also build test WARNING on tip/x86/mm asm-generic/master linus/master sparc/master v5.13-rc6 next-20210615]
> [cannot apply to sparc-next/master]
> [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]
>
> url: https://github.com/0day-ci/linux/commits/akpm-linux-foundation-org/mm-rename-pud_page_vaddr-to-pud_pgtable-and-make-it-return-pmd_t-patch-added-to-mm-tree/20210616-161816
> base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
> config: m68k-allmodconfig (attached as .config)
> compiler: m68k-linux-gcc (GCC) 9.3.0
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://github.com/0day-ci/linux/commit/2ccec57c1def84dab91722c14fd5907ed7423426
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review akpm-linux-foundation-org/mm-rename-pud_page_vaddr-to-pud_pgtable-and-make-it-return-pmd_t-patch-added-to-mm-tree/20210616-161816
> git checkout 2ccec57c1def84dab91722c14fd5907ed7423426
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
> All warnings (new ones prefixed by >>):
>
> arch/m68k/mm/motorola.c: In function 'kernel_ptr_table':
>>> arch/m68k/mm/motorola.c:265:8: warning: assignment to 'long unsigned int' from 'pmd_t *' {aka 'struct <anonymous> *'} makes integer from pointer without a cast [-Wint-conversion]
> 265 | pmd = pgd_page_vaddr(kernel_pg_dir[i]);
> | ^
> arch/m68k/mm/motorola.c: At top level:
> arch/m68k/mm/motorola.c:390:13: warning: no previous prototype for 'paging_init' [-Wmissing-prototypes]
> 390 | void __init paging_init(void)
> | ^~~~~~~~~~~
>
>
> vim +265 arch/m68k/mm/motorola.c
>
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 248
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 249 static pmd_t * __init kernel_ptr_table(void)
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 250 {
> ef9285f69f0efb Peter Zijlstra 2020-01-31 251 if (!last_pmd_table) {
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 252 unsigned long pmd, last;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 253 int i;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 254
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 255 /* Find the last ptr table that was used in head.S and
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 256 * reuse the remaining space in that page for further
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 257 * ptr tables.
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 258 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 259 last = (unsigned long)kernel_pg_dir;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 260 for (i = 0; i < PTRS_PER_PGD; i++) {
> 60e50f34b13e9e Mike Rapoport 2019-12-04 261 pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
> 60e50f34b13e9e Mike Rapoport 2019-12-04 262
> 60e50f34b13e9e Mike Rapoport 2019-12-04 263 if (!pud_present(*pud))
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 264 continue;
> 60e50f34b13e9e Mike Rapoport 2019-12-04 @265 pmd = pgd_page_vaddr(kernel_pg_dir[i]);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 266 if (pmd > last)
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 267 last = pmd;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 268 }
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 269
> ef9285f69f0efb Peter Zijlstra 2020-01-31 270 last_pmd_table = (pmd_t *)last;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 271 #ifdef DEBUG
> ef9285f69f0efb Peter Zijlstra 2020-01-31 272 printk("kernel_ptr_init: %p\n", last_pmd_table);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 273 #endif
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 274 }
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 275
> ef9285f69f0efb Peter Zijlstra 2020-01-31 276 last_pmd_table += PTRS_PER_PMD;
> 41f1bf37a63ecd Geert Uytterhoeven 2020-08-26 277 if (PAGE_ALIGNED(last_pmd_table)) {
> 7e158826564fbb Geert Uytterhoeven 2020-08-26 278 last_pmd_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
> ef9285f69f0efb Peter Zijlstra 2020-01-31 279 if (!last_pmd_table)
> 8a7f97b902f4fb Mike Rapoport 2019-03-11 280 panic("%s: Failed to allocate %lu bytes align=%lx\n",
> 8a7f97b902f4fb Mike Rapoport 2019-03-11 281 __func__, PAGE_SIZE, PAGE_SIZE);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 282
> ef9285f69f0efb Peter Zijlstra 2020-01-31 283 clear_page(last_pmd_table);
> ef9285f69f0efb Peter Zijlstra 2020-01-31 284 mmu_page_ctor(last_pmd_table);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 285 }
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 286
> ef9285f69f0efb Peter Zijlstra 2020-01-31 287 return last_pmd_table;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 288 }
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 289
>
We may want to fixup pgd_page_vaddr correctly later. pgd_page_vaddr() gets
cast to different pointer types based on architecture. But for now this
should work? This ensure we keep the pgd_page_vaddr() same as before.
diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
index 982de5102fc1..2f1d0aad645c 100644
--- a/include/asm-generic/pgtable-nop4d.h
+++ b/include/asm-generic/pgtable-nop4d.h
@@ -42,7 +42,7 @@ static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
#define __p4d(x) ((p4d_t) { __pgd(x) })
#define pgd_page(pgd) (p4d_page((p4d_t){ pgd }))
-#define pgd_page_vaddr(pgd) (p4d_pgtable((p4d_t){ pgd }))
+#define pgd_page_vaddr(pgd) ((unsigned long)(p4d_pgtable((p4d_t){ pgd })))
/*
* allocating and freeing a p4d is trivial: the 1-entry p4d is