Merge tag 'virt-to-pfn-for-arch-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator into asm-generic

This is an attempt to harden the typing on virt_to_pfn()
and pfn_to_virt().

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

For symmetry, we do the same with pfn_to_virt().

The problem with this inconsistent typing was pointed out by
Russell King:
https://lore.kernel.org/linux-arm-kernel/YoJDKJXc0MJ2QZTb@shell.armlinux.org.uk/

And confirmed by Andrew Morton:
https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/

So the recognition of the problem is widespread.

These platforms have been chosen as initial conversion targets:

- ARM
- ARM64/Aarch64
- asm-generic (including for example x86)
- m68k

The idea is that if this goes in, it will block further misuse
of the function signatures due to the large compile coverage,
and then I can go in and fix the remaining architectures on a
one-by-one basis.

Some of the patches have been circulated before but were not
picked up by subsystem maintainers, so now the arch tree is
target for this series.

It has passed zeroday builds after a lot of iterations in my
personal tree, but there could be some randconfig outliers.
New added or deeply hidden problems appear all the time so
some minor fallout can be expected.

* tag 'virt-to-pfn-for-arch-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator:
  m68k/mm: Make pfn accessors static inlines
  arm64: memory: Make virt_to_pfn() a static inline
  ARM: mm: Make virt_to_pfn() a static inline
  asm-generic/page.h: Make pfn accessors static inlines
  xen/netback: Pass (void *) to virt_to_page()
  netfs: Pass a pointer to virt_to_page()
  cifs: Pass a pointer to virt_to_page() in cifsglob
  cifs: Pass a pointer to virt_to_page()
  riscv: mm: init: Pass a pointer to virt_to_page()
  ARC: init: Pass a pointer to virt_to_pfn() in init
  m68k: Pass a pointer to virt_to_pfn() virt_to_page()
  fs/proc/kcore.c: Pass a pointer to virt_addr_valid()

9 files changed, 28 insertions, 14 deletions

diff --git a/arch/m68k/include/asm/mcf_pgtable.h b/arch/m68k/include/asm/mcf_pgtable.h
index d97fbb812f63..43e8da8465f9 100644
--- a/arch/m68k/include/asm/mcf_pgtable.h
+++ b/arch/m68k/include/asm/mcf_pgtable.h
@@ -115,7 +115,7 @@ static inline void pgd_set(pgd_t *pgdp, pmd_t *pmdp)
 	pgd_val(*pgdp) = virt_to_phys(pmdp);
 }
 
-#define __pte_page(pte)	((unsigned long) (pte_val(pte) & PAGE_MASK))
+#define __pte_page(pte)	((void *) (pte_val(pte) & PAGE_MASK))
 #define pmd_page_vaddr(pmd)	((unsigned long) (pmd_val(pmd)))
 
 static inline int pte_none(pte_t pte)
@@ -134,7 +134,6 @@ static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
 	pte_val(*ptep) = 0;
 }
 
-#define pte_pagenr(pte)	((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
 #define pte_page(pte)	virt_to_page(__pte_page(pte))
 
 static inline int pmd_none2(pmd_t *pmd) { return !pmd_val(*pmd); }
diff --git a/arch/m68k/include/asm/page_mm.h b/arch/m68k/include/asm/page_mm.h
index 3903db2e8da7..363aa0f9ba8a 100644
--- a/arch/m68k/include/asm/page_mm.h
+++ b/arch/m68k/include/asm/page_mm.h
@@ -121,8 +121,15 @@ static inline void *__va(unsigned long x)
  * TODO: implement (fast) pfn<->pgdat_idx conversion functions, this makes lots
  * of the shifts unnecessary.
  */
-#define virt_to_pfn(kaddr)	(__pa(kaddr) >> PAGE_SHIFT)
-#define pfn_to_virt(pfn)	__va((pfn) << PAGE_SHIFT)
+static inline unsigned long virt_to_pfn(const void *kaddr)
+{
+	return __pa(kaddr) >> PAGE_SHIFT;
+}
+
+static inline void *pfn_to_virt(unsigned long pfn)
+{
+	return __va(pfn << PAGE_SHIFT);
+}
 
 extern int m68k_virt_to_node_shift;
 
diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h
index 060e4c0e7605..af3a10973233 100644
--- a/arch/m68k/include/asm/page_no.h
+++ b/arch/m68k/include/asm/page_no.h
@@ -19,8 +19,15 @@ extern unsigned long memory_end;
 #define __pa(vaddr)		((unsigned long)(vaddr))
 #define __va(paddr)		((void *)((unsigned long)(paddr)))
 
-#define virt_to_pfn(kaddr)	(__pa(kaddr) >> PAGE_SHIFT)
-#define pfn_to_virt(pfn)	__va((pfn) << PAGE_SHIFT)
+static inline unsigned long virt_to_pfn(const void *kaddr)
+{
+	return __pa(kaddr) >> PAGE_SHIFT;
+}
+
+static inline void *pfn_to_virt(unsigned long pfn)
+{
+	return __va(pfn << PAGE_SHIFT);
+}
 
 #define virt_to_page(addr)	(mem_map + (((unsigned long)(addr)-PAGE_OFFSET) >> PAGE_SHIFT))
 #define page_to_virt(page)	__va(((((page) - mem_map) << PAGE_SHIFT) + PAGE_OFFSET))
diff --git a/arch/m68k/include/asm/sun3_pgtable.h b/arch/m68k/include/asm/sun3_pgtable.h
index e582b0484a55..9e7bf8a5f8f8 100644
--- a/arch/m68k/include/asm/sun3_pgtable.h
+++ b/arch/m68k/include/asm/sun3_pgtable.h
@@ -91,7 +91,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 #define pmd_set(pmdp,ptep) do {} while (0)
 
 #define __pte_page(pte) \
-((unsigned long) __va ((pte_val (pte) & SUN3_PAGE_PGNUM_MASK) << PAGE_SHIFT))
+(__va ((pte_val (pte) & SUN3_PAGE_PGNUM_MASK) << PAGE_SHIFT))
 
 static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 {
@@ -111,7 +111,7 @@ static inline void pte_clear (struct mm_struct *mm, unsigned long addr, pte_t *p
 
 #define pte_page(pte)		virt_to_page(__pte_page(pte))
 #define pmd_pfn(pmd)		(pmd_val(pmd) >> PAGE_SHIFT)
-#define pmd_page(pmd)		virt_to_page(pmd_page_vaddr(pmd))
+#define pmd_page(pmd)		virt_to_page((void *)pmd_page_vaddr(pmd))
 
 
 static inline int pmd_none2 (pmd_t *pmd) { return !pmd_val (*pmd); }
diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
index 70aa0979e027..278e85fcecd4 100644
--- a/arch/m68k/mm/mcfmmu.c
+++ b/arch/m68k/mm/mcfmmu.c
@@ -69,7 +69,8 @@ void __init paging_init(void)
 
 		/* now change pg_table to kernel virtual addresses */
 		for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {
-			pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
+			pte_t pte = pfn_pte(virt_to_pfn((void *)address),
+					    PAGE_INIT);
 			if (address >= (unsigned long) high_memory)
 				pte_val(pte) = 0;
 
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index 911301224078..c75984e2d86b 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c
@@ -102,7 +102,7 @@ static struct list_head ptable_list[2] = {
 	LIST_HEAD_INIT(ptable_list[1]),
 };
 
-#define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page(page)->lru))
+#define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page((void *)(page))->lru))
 #define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
 #define PD_MARKBITS(dp) (*(unsigned int *)&PD_PAGE(dp)->index)
 
@@ -201,7 +201,7 @@ int free_pointer_table(void *table, int type)
 		list_del(dp);
 		mmu_page_dtor((void *)page);
 		if (type == TABLE_PTE)
-			pgtable_pte_page_dtor(virt_to_page(page));
+			pgtable_pte_page_dtor(virt_to_page((void *)page));
 		free_page (page);
 		return 1;
 	} else if (ptable_list[type].next != dp) {
diff --git a/arch/m68k/mm/sun3mmu.c b/arch/m68k/mm/sun3mmu.c
index b619d0d4319c..c5e6a23e0262 100644
--- a/arch/m68k/mm/sun3mmu.c
+++ b/arch/m68k/mm/sun3mmu.c
@@ -75,7 +75,7 @@ void __init paging_init(void)
 		/* now change pg_table to kernel virtual addresses */
 		pg_table = (pte_t *) __va ((unsigned long) pg_table);
 		for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
-			pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
+			pte_t pte = pfn_pte(virt_to_pfn((void *)address), PAGE_INIT);
 			if (address >= (unsigned long)high_memory)
 				pte_val (pte) = 0;
 			set_pte (pg_table, pte);
diff --git a/arch/m68k/sun3/dvma.c b/arch/m68k/sun3/dvma.c
index f15ff16b9997..83fcae6a0e79 100644
--- a/arch/m68k/sun3/dvma.c
+++ b/arch/m68k/sun3/dvma.c
@@ -29,7 +29,7 @@ static unsigned long dvma_page(unsigned long kaddr, unsigned long vaddr)
 	j = *(volatile unsigned long *)kaddr;
 	*(volatile unsigned long *)kaddr = j;
 
-	ptep = pfn_pte(virt_to_pfn(kaddr), PAGE_KERNEL);
+	ptep = pfn_pte(virt_to_pfn((void *)kaddr), PAGE_KERNEL);
 	pte = pte_val(ptep);
 //	pr_info("dvma_remap: addr %lx -> %lx pte %08lx\n", kaddr, vaddr, pte);
 	if(ptelist[(vaddr & 0xff000) >> PAGE_SHIFT] != pte) {
diff --git a/arch/m68k/sun3x/dvma.c b/arch/m68k/sun3x/dvma.c
index 08bb92113026..a6034ba05845 100644
--- a/arch/m68k/sun3x/dvma.c
+++ b/arch/m68k/sun3x/dvma.c
@@ -125,7 +125,7 @@ inline int dvma_map_cpu(unsigned long kaddr,
 			do {
 				pr_debug("mapping %08lx phys to %08lx\n",
 					 __pa(kaddr), vaddr);
-				set_pte(pte, pfn_pte(virt_to_pfn(kaddr),
+				set_pte(pte, pfn_pte(virt_to_pfn((void *)kaddr),
 						     PAGE_KERNEL));
 				pte++;
 				kaddr += PAGE_SIZE;