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* [PATCH] arm64: Define only {pud/pmd}_{set/clear}_huge when usefull
@ 2021-05-14 11:08 Christophe Leroy
  2021-05-14 21:42 ` Andrew Morton
  0 siblings, 1 reply; 4+ messages in thread
From: Christophe Leroy @ 2021-05-14 11:08 UTC (permalink / raw)
  To: Andrew Morton, Nicholas Piggin, Mike Kravetz, Mike Rapoport,
	naresh.kamboju
  Cc: linux-arch, linuxppc-dev, linux-kernel, linux-arm-kernel,
	sparclinux, linux-mm

When PUD and/or PMD are folded, those functions are useless
and we now have a stub in linux/pgtable.h

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/arm64/mm/mmu.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 6dd9369e3ea0..98af085afe90 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1337,6 +1337,7 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 	return dt_virt;
 }
 
+#if CONFIG_PGTABLE_LEVELS > 3
 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
 {
 	pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
@@ -1351,6 +1352,16 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
 	return 1;
 }
 
+int pud_clear_huge(pud_t *pudp)
+{
+	if (!pud_sect(READ_ONCE(*pudp)))
+		return 0;
+	pud_clear(pudp);
+	return 1;
+}
+#endif
+
+#if CONFIG_PGTABLE_LEVELS > 2
 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
 {
 	pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));
@@ -1365,14 +1376,6 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
 	return 1;
 }
 
-int pud_clear_huge(pud_t *pudp)
-{
-	if (!pud_sect(READ_ONCE(*pudp)))
-		return 0;
-	pud_clear(pudp);
-	return 1;
-}
-
 int pmd_clear_huge(pmd_t *pmdp)
 {
 	if (!pmd_sect(READ_ONCE(*pmdp)))
@@ -1380,6 +1383,7 @@ int pmd_clear_huge(pmd_t *pmdp)
 	pmd_clear(pmdp);
 	return 1;
 }
+#endif
 
 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
 {
-- 
2.25.0



^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] arm64: Define only {pud/pmd}_{set/clear}_huge when usefull
  2021-05-14 11:08 [PATCH] arm64: Define only {pud/pmd}_{set/clear}_huge when usefull Christophe Leroy
@ 2021-05-14 21:42 ` Andrew Morton
  2021-05-15  3:58   ` Nathan Chancellor
  2021-05-15  6:28   ` Christophe Leroy
  0 siblings, 2 replies; 4+ messages in thread
From: Andrew Morton @ 2021-05-14 21:42 UTC (permalink / raw)
  To: Christophe Leroy
  Cc: Nicholas Piggin, Mike Kravetz, Mike Rapoport, naresh.kamboju,
	linux-arch, linuxppc-dev, linux-kernel, linux-arm-kernel,
	sparclinux, linux-mm

On Fri, 14 May 2021 11:08:53 +0000 (UTC) Christophe Leroy <christophe.leroy@csgroup.eu> wrote:

> When PUD and/or PMD are folded, those functions are useless
> and we now have a stub in linux/pgtable.h

OK, help me out here please.  What patch does this fix?


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] arm64: Define only {pud/pmd}_{set/clear}_huge when usefull
  2021-05-14 21:42 ` Andrew Morton
@ 2021-05-15  3:58   ` Nathan Chancellor
  2021-05-15  6:28   ` Christophe Leroy
  1 sibling, 0 replies; 4+ messages in thread
From: Nathan Chancellor @ 2021-05-15  3:58 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Christophe Leroy, Nicholas Piggin, Mike Kravetz, Mike Rapoport,
	naresh.kamboju, linux-arch, linuxppc-dev, linux-kernel,
	linux-arm-kernel, sparclinux, linux-mm

On Fri, May 14, 2021 at 02:42:00PM -0700, Andrew Morton wrote:
> On Fri, 14 May 2021 11:08:53 +0000 (UTC) Christophe Leroy <christophe.leroy@csgroup.eu> wrote:
> 
> > When PUD and/or PMD are folded, those functions are useless
> > and we now have a stub in linux/pgtable.h
> 
> OK, help me out here please.  What patch does this fix?
> 

Naresh's original report is here it seems:

https://lore.kernel.org/r/CA+G9fYv79t0+2W4Rt3wDkBShc4eY3M3utC5BHqUgGDwMYExYMw@mail.gmail.com/

I can reproduce the failure that he reported with
ARCH=arm64 allmodconfig and this patch resolves it for me.

Cheers,
Nathan


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] arm64: Define only {pud/pmd}_{set/clear}_huge when usefull
  2021-05-14 21:42 ` Andrew Morton
  2021-05-15  3:58   ` Nathan Chancellor
@ 2021-05-15  6:28   ` Christophe Leroy
  1 sibling, 0 replies; 4+ messages in thread
From: Christophe Leroy @ 2021-05-15  6:28 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Nicholas Piggin, Mike Kravetz, Mike Rapoport, naresh.kamboju,
	linux-arch, linuxppc-dev, linux-kernel, linux-arm-kernel,
	sparclinux, linux-mm



Le 14/05/2021 à 23:42, Andrew Morton a écrit :
> On Fri, 14 May 2021 11:08:53 +0000 (UTC) Christophe Leroy <christophe.leroy@csgroup.eu> wrote:
> 
>> When PUD and/or PMD are folded, those functions are useless
>> and we now have a stub in linux/pgtable.h
> 
> OK, help me out here please.  What patch does this fix?
> 

Both this one and the x86 one from the day before fix 1cff41494b15cd82c1ec418bb5c ("mm/pgtable: add 
stubs for {pmd/pub}_{set/clear}_huge")

I think both the x86 fix and the arm64 fix should be squashed into that patch at the end.

I checked, the only other architecture involving pud_set_huge() and friends is powerpc, and powerpc 
doesn't have this problem as it only defined those for book3s/64 platforms which have 4 level page 
tables by definition.

Thanks
Christophe


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-05-15  6:28 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-05-14 11:08 [PATCH] arm64: Define only {pud/pmd}_{set/clear}_huge when usefull Christophe Leroy
2021-05-14 21:42 ` Andrew Morton
2021-05-15  3:58   ` Nathan Chancellor
2021-05-15  6:28   ` Christophe Leroy

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