asm-generic: add correct MAX_POSSIBLE_PHYSMEM_BITS setting

This is a single bugfix for a bug that Stefan Agner found on 32-bit
 Arm, but that exists on several other architectures.
 
 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'asm-generic-fixes-5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic fix from Arnd Bergmann:
 "Add correct MAX_POSSIBLE_PHYSMEM_BITS setting to asm-generic.

  This is a single bugfix for a bug that Stefan Agner found on 32-bit
  Arm, but that exists on several other architectures"

* tag 'asm-generic-fixes-5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed

arch/arc/include/asm/pgtable.h

@@ -134,8 +134,10 @@
 
 #ifdef CONFIG_ARC_HAS_PAE40
 #define PTE_BITS_NON_RWX_IN_PD1	(0xff00000000 | PAGE_MASK | _PAGE_CACHEABLE)
+#define MAX_POSSIBLE_PHYSMEM_BITS 40
 #else
 #define PTE_BITS_NON_RWX_IN_PD1	(PAGE_MASK | _PAGE_CACHEABLE)
+#define MAX_POSSIBLE_PHYSMEM_BITS 32
 #endif
 
 /**************************************************************************

arch/arm/include/asm/pgtable-2level.h

@@ -75,6 +75,8 @@
 #define PTE_HWTABLE_OFF		(PTE_HWTABLE_PTRS * sizeof(pte_t))
 #define PTE_HWTABLE_SIZE	(PTRS_PER_PTE * sizeof(u32))
 
+#define MAX_POSSIBLE_PHYSMEM_BITS	32
+
 /*
  * PMD_SHIFT determines the size of the area a second-level page table can map
  * PGDIR_SHIFT determines what a third-level page table entry can map

arch/arm/include/asm/pgtable-3level.h

@@ -25,6 +25,8 @@
 #define PTE_HWTABLE_OFF		(0)
 #define PTE_HWTABLE_SIZE	(PTRS_PER_PTE * sizeof(u64))
 
+#define MAX_POSSIBLE_PHYSMEM_BITS 40
+
 /*
  * PGDIR_SHIFT determines the size a top-level page table entry can map.
  */

arch/mips/include/asm/pgtable-32.h

@@ -154,6 +154,7 @@ static inline void pmd_clear(pmd_t *pmdp)
 
 #if defined(CONFIG_XPA)
 
+#define MAX_POSSIBLE_PHYSMEM_BITS 40
 #define pte_pfn(x)		(((unsigned long)((x).pte_high >> _PFN_SHIFT)) | (unsigned long)((x).pte_low << _PAGE_PRESENT_SHIFT))
 static inline pte_t
 pfn_pte(unsigned long pfn, pgprot_t prot)
@@ -169,6 +170,7 @@ pfn_pte(unsigned long pfn, pgprot_t prot)
 
 #elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
 
+#define MAX_POSSIBLE_PHYSMEM_BITS 36
 #define pte_pfn(x)		((unsigned long)((x).pte_high >> 6))
 
 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
@@ -183,6 +185,7 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
 
 #else
 
+#define MAX_POSSIBLE_PHYSMEM_BITS 32
 #ifdef CONFIG_CPU_VR41XX
 #define pte_pfn(x)		((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
 #define pfn_pte(pfn, prot)	__pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))

arch/powerpc/include/asm/book3s/32/pgtable.h

@@ -36,8 +36,10 @@ static inline bool pte_user(pte_t pte)
  */
 #ifdef CONFIG_PTE_64BIT
 #define PTE_RPN_MASK	(~((1ULL << PTE_RPN_SHIFT) - 1))
+#define MAX_POSSIBLE_PHYSMEM_BITS 36
 #else
 #define PTE_RPN_MASK	(~((1UL << PTE_RPN_SHIFT) - 1))
+#define MAX_POSSIBLE_PHYSMEM_BITS 32
 #endif
 
 /*

arch/powerpc/include/asm/nohash/32/pgtable.h

@@ -153,8 +153,10 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
  */
 #if defined(CONFIG_PPC32) && defined(CONFIG_PTE_64BIT)
 #define PTE_RPN_MASK	(~((1ULL << PTE_RPN_SHIFT) - 1))
+#define MAX_POSSIBLE_PHYSMEM_BITS 36
 #else
 #define PTE_RPN_MASK	(~((1UL << PTE_RPN_SHIFT) - 1))
+#define MAX_POSSIBLE_PHYSMEM_BITS 32
 #endif
 
 /*

arch/riscv/include/asm/pgtable-32.h

@@ -14,4 +14,6 @@
 #define PGDIR_SIZE      (_AC(1, UL) << PGDIR_SHIFT)
 #define PGDIR_MASK      (~(PGDIR_SIZE - 1))
 
+#define MAX_POSSIBLE_PHYSMEM_BITS 34
+
 #endif /* _ASM_RISCV_PGTABLE_32_H */

include/linux/pgtable.h

@@ -1427,6 +1427,19 @@ typedef unsigned int pgtbl_mod_mask;
 
 #endif /* !__ASSEMBLY__ */
 
+#if !defined(MAX_POSSIBLE_PHYSMEM_BITS) && !defined(CONFIG_64BIT)
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+/*
+ * ZSMALLOC needs to know the highest PFN on 32-bit architectures
+ * with physical address space extension, but falls back to
+ * BITS_PER_LONG otherwise.
+ */
+#error Missing MAX_POSSIBLE_PHYSMEM_BITS definition
+#else
+#define MAX_POSSIBLE_PHYSMEM_BITS 32
+#endif
+#endif
+
 #ifndef has_transparent_hugepage
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 #define has_transparent_hugepage() 1