[PATCH 2/2] Revert "mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge"
Will Deacon
will at kernel.org
Tue Jul 20 05:35:12 PDT 2021
From: Jonathan Marek <jonathan at marek.ca>
This reverts commit c742199a014de23ee92055c2473d91fe5561ffdf.
c742199a014d ("mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge")
breaks arm64 in at least two ways for configurations where PUD or PMD
folding occur:
1. We no longer install huge-vmap mappings and silently fall back to
page-granular entries, despite being able to install block entries
at what is effectively the PGD level.
2. If the linear map is backed with block mappings, these will now
silently fail to be created in alloc_init_pud(), causing a panic
early during boot.
The pgtable selftests caught this, although a fix has not been
forthcoming and Christophe is AWOL at the moment, so just revert the
change for now to get a working -rc3 on which we can queue patches for
5.15.
Cc: Ard Biesheuvel <ardb at kernel.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Christophe Leroy <christophe.leroy at csgroup.eu>
Cc: Paul Mackerras <paulus at samba.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Nicholas Piggin <npiggin at gmail.com
Cc: Mike Rapoport <rppt at kernel.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Geert Uytterhoeven <geert at linux-m68k.org>
Cc: Marc Zyngier <maz at kernel.org>
Link: https://lore.kernel.org/linux-arm-kernel/CAMuHMdXShORDox-xxaeUfDW3wx2PeggFSqhVSHVZNKCGK-y_vQ@mail.gmail.com/
Link: https://lore.kernel.org/r/20210717160118.9855-1-jonathan@marek.ca
Fixes: c742199a014d ("mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge")
Signed-off-by: Jonathan Marek <jonathan at marek.ca>
Signed-off-by: Will Deacon <will at kernel.org>
---
arch/arm64/mm/mmu.c | 20 ++++++++------------
arch/x86/mm/pgtable.c | 34 +++++++++++++++-------------------
include/linux/pgtable.h | 26 +-------------------------
3 files changed, 24 insertions(+), 56 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index d74586508448..9ff0de1b2b93 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1339,7 +1339,6 @@ 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));
@@ -1354,16 +1353,6 @@ 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));
@@ -1378,6 +1367,14 @@ 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)))
@@ -1385,7 +1382,6 @@ int pmd_clear_huge(pmd_t *pmdp)
pmd_clear(pmdp);
return 1;
}
-#endif
int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
{
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 3364fe62b903..3481b35cb4ec 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -682,7 +682,6 @@ int p4d_clear_huge(p4d_t *p4d)
}
#endif
-#if CONFIG_PGTABLE_LEVELS > 3
/**
* pud_set_huge - setup kernel PUD mapping
*
@@ -721,23 +720,6 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
return 1;
}
-/**
- * pud_clear_huge - clear kernel PUD mapping when it is set
- *
- * Returns 1 on success and 0 on failure (no PUD map is found).
- */
-int pud_clear_huge(pud_t *pud)
-{
- if (pud_large(*pud)) {
- pud_clear(pud);
- return 1;
- }
-
- return 0;
-}
-#endif
-
-#if CONFIG_PGTABLE_LEVELS > 2
/**
* pmd_set_huge - setup kernel PMD mapping
*
@@ -768,6 +750,21 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
return 1;
}
+/**
+ * pud_clear_huge - clear kernel PUD mapping when it is set
+ *
+ * Returns 1 on success and 0 on failure (no PUD map is found).
+ */
+int pud_clear_huge(pud_t *pud)
+{
+ if (pud_large(*pud)) {
+ pud_clear(pud);
+ return 1;
+ }
+
+ return 0;
+}
+
/**
* pmd_clear_huge - clear kernel PMD mapping when it is set
*
@@ -782,7 +779,6 @@ int pmd_clear_huge(pmd_t *pmd)
return 0;
}
-#endif
#ifdef CONFIG_X86_64
/**
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index d147480cdefc..e24d2c992b11 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1397,34 +1397,10 @@ static inline int p4d_clear_huge(p4d_t *p4d)
}
#endif /* !__PAGETABLE_P4D_FOLDED */
-#ifndef __PAGETABLE_PUD_FOLDED
int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
-int pud_clear_huge(pud_t *pud);
-#else
-static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
-{
- return 0;
-}
-static inline int pud_clear_huge(pud_t *pud)
-{
- return 0;
-}
-#endif /* !__PAGETABLE_PUD_FOLDED */
-
-#ifndef __PAGETABLE_PMD_FOLDED
int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
+int pud_clear_huge(pud_t *pud);
int pmd_clear_huge(pmd_t *pmd);
-#else
-static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
-{
- return 0;
-}
-static inline int pmd_clear_huge(pmd_t *pmd)
-{
- return 0;
-}
-#endif /* !__PAGETABLE_PMD_FOLDED */
-
int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
int pud_free_pmd_page(pud_t *pud, unsigned long addr);
int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
--
2.32.0.402.g57bb445576-goog
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