Merge tag 'parisc-for-6.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fix from Helge Deller:
 "On parisc we have suffered since years from random segfaults which
  seem to have been triggered due to cache inconsistencies. Those
  segfaults happened more often on machines with PA8800 and PA8900 CPUs,
  which have much bigger caches than the earlier machines.

  Dave Anglin has worked over the last few weeks to fix this bug. His
  patch has been successfully tested by various people on various
  machines and with various kernels (6.6, 6.8 and 6.9), and the debian
  buildd servers haven't shown a single random segfault with this patch.

  Since the cache handling has been reworked, the patch is slightly
  bigger than I would like in this stage, but the greatly improved
  stability IMHO justifies the inclusion now"

* tag 'parisc-for-6.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Try to fix random segmentation faults in package builds

3 files changed, 275 insertions, 180 deletions

diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h
index ba4c05bc24d6..8394718870e1 100644
--- a/arch/parisc/include/asm/cacheflush.h
+++ b/arch/parisc/include/asm/cacheflush.h
@@ -31,18 +31,17 @@ void flush_cache_all_local(void);
 void flush_cache_all(void);
 void flush_cache_mm(struct mm_struct *mm);
 
-void flush_kernel_dcache_page_addr(const void *addr);
-
 #define flush_kernel_dcache_range(start,size) \
 	flush_kernel_dcache_range_asm((start), (start)+(size));
 
+/* The only way to flush a vmap range is to flush whole cache */
 #define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 void flush_kernel_vmap_range(void *vaddr, int size);
 void invalidate_kernel_vmap_range(void *vaddr, int size);
 
-#define flush_cache_vmap(start, end)		flush_cache_all()
+void flush_cache_vmap(unsigned long start, unsigned long end);
 #define flush_cache_vmap_early(start, end)	do { } while (0)
-#define flush_cache_vunmap(start, end)		flush_cache_all()
+void flush_cache_vunmap(unsigned long start, unsigned long end);
 
 void flush_dcache_folio(struct folio *folio);
 #define flush_dcache_folio flush_dcache_folio
@@ -77,17 +76,11 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,
 void flush_cache_range(struct vm_area_struct *vma,
 		unsigned long start, unsigned long end);
 
-/* defined in pacache.S exported in cache.c used by flush_anon_page */
-void flush_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);
-
 #define ARCH_HAS_FLUSH_ANON_PAGE
 void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr);
 
 #define ARCH_HAS_FLUSH_ON_KUNMAP
-static inline void kunmap_flush_on_unmap(const void *addr)
-{
-	flush_kernel_dcache_page_addr(addr);
-}
+void kunmap_flush_on_unmap(const void *addr);
 
 #endif /* _PARISC_CACHEFLUSH_H */
 
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index 974accac05cd..babf65751e81 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -448,14 +448,17 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
 	return pte;
 }
 
+static inline pte_t ptep_get(pte_t *ptep)
+{
+	return READ_ONCE(*ptep);
+}
+#define ptep_get ptep_get
+
 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 {
 	pte_t pte;
 
-	if (!pte_young(*ptep))
-		return 0;
-
-	pte = *ptep;
+	pte = ptep_get(ptep);
 	if (!pte_young(pte)) {
 		return 0;
 	}
@@ -463,17 +466,10 @@ static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned
 	return 1;
 }
 
-struct mm_struct;
-static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
-{
-	pte_t old_pte;
-
-	old_pte = *ptep;
-	set_pte(ptep, __pte(0));
-
-	return old_pte;
-}
+int ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep);
+pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep);
 
+struct mm_struct;
 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	set_pte(ptep, pte_wrprotect(*ptep));
@@ -511,7 +507,8 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
-#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
+#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+#define __HAVE_ARCH_PTEP_CLEAR_FLUSH
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 #define __HAVE_ARCH_PTE_SAME
 
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 422f3e1e6d9c..483bfafd930c 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -20,6 +20,7 @@
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
 #include <linux/syscalls.h>
+#include <linux/vmalloc.h>
 #include <asm/pdc.h>
 #include <asm/cache.h>
 #include <asm/cacheflush.h>
@@ -31,20 +32,31 @@
 #include <asm/mmu_context.h>
 #include <asm/cachectl.h>
 
+#define PTR_PAGE_ALIGN_DOWN(addr) PTR_ALIGN_DOWN(addr, PAGE_SIZE)
+
+/*
+ * When nonzero, use _PAGE_ACCESSED bit to try to reduce the number
+ * of page flushes done flush_cache_page_if_present. There are some
+ * pros and cons in using this option. It may increase the risk of
+ * random segmentation faults.
+ */
+#define CONFIG_FLUSH_PAGE_ACCESSED	0
+
 int split_tlb __ro_after_init;
 int dcache_stride __ro_after_init;
 int icache_stride __ro_after_init;
 EXPORT_SYMBOL(dcache_stride);
 
+/* Internal implementation in arch/parisc/kernel/pacache.S */
 void flush_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);
 EXPORT_SYMBOL(flush_dcache_page_asm);
 void purge_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);
 void flush_icache_page_asm(unsigned long phys_addr, unsigned long vaddr);
-
-/* Internal implementation in arch/parisc/kernel/pacache.S */
 void flush_data_cache_local(void *);  /* flushes local data-cache only */
 void flush_instruction_cache_local(void); /* flushes local code-cache only */
 
+static void flush_kernel_dcache_page_addr(const void *addr);
+
 /* On some machines (i.e., ones with the Merced bus), there can be
  * only a single PxTLB broadcast at a time; this must be guaranteed
  * by software. We need a spinlock around all TLB flushes to ensure
@@ -321,6 +333,18 @@ __flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,
 {
 	if (!static_branch_likely(&parisc_has_cache))
 		return;
+
+	/*
+	 * The TLB is the engine of coherence on parisc.  The CPU is
+	 * entitled to speculate any page with a TLB mapping, so here
+	 * we kill the mapping then flush the page along a special flush
+	 * only alias mapping. This guarantees that the page is no-longer
+	 * in the cache for any process and nor may it be speculatively
+	 * read in (until the user or kernel specifically accesses it,
+	 * of course).
+	 */
+	flush_tlb_page(vma, vmaddr);
+
 	preempt_disable();
 	flush_dcache_page_asm(physaddr, vmaddr);
 	if (vma->vm_flags & VM_EXEC)
@@ -328,46 +352,44 @@ __flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,
 	preempt_enable();
 }
 
-static void flush_user_cache_page(struct vm_area_struct *vma, unsigned long vmaddr)
+static void flush_kernel_dcache_page_addr(const void *addr)
 {
-	unsigned long flags, space, pgd, prot;
-#ifdef CONFIG_TLB_PTLOCK
-	unsigned long pgd_lock;
-#endif
+	unsigned long vaddr = (unsigned long)addr;
+	unsigned long flags;
 
-	vmaddr &= PAGE_MASK;
+	/* Purge TLB entry to remove translation on all CPUs */
+	purge_tlb_start(flags);
+	pdtlb(SR_KERNEL, addr);
+	purge_tlb_end(flags);
 
+	/* Use tmpalias flush to prevent data cache move-in */
 	preempt_disable();
+	flush_dcache_page_asm(__pa(vaddr), vaddr);
+	preempt_enable();
+}
 
-	/* Set context for flush */
-	local_irq_save(flags);
-	prot = mfctl(8);
-	space = mfsp(SR_USER);
-	pgd = mfctl(25);
-#ifdef CONFIG_TLB_PTLOCK
-	pgd_lock = mfctl(28);
-#endif
-	switch_mm_irqs_off(NULL, vma->vm_mm, NULL);
-	local_irq_restore(flags);
-
-	flush_user_dcache_range_asm(vmaddr, vmaddr + PAGE_SIZE);
-	if (vma->vm_flags & VM_EXEC)
-		flush_user_icache_range_asm(vmaddr, vmaddr + PAGE_SIZE);
-	flush_tlb_page(vma, vmaddr);
+static void flush_kernel_icache_page_addr(const void *addr)
+{
+	unsigned long vaddr = (unsigned long)addr;
+	unsigned long flags;
 
-	/* Restore previous context */
-	local_irq_save(flags);
-#ifdef CONFIG_TLB_PTLOCK
-	mtctl(pgd_lock, 28);
-#endif
-	mtctl(pgd, 25);
-	mtsp(space, SR_USER);
-	mtctl(prot, 8);
-	local_irq_restore(flags);
+	/* Purge TLB entry to remove translation on all CPUs */
+	purge_tlb_start(flags);
+	pdtlb(SR_KERNEL, addr);
+	purge_tlb_end(flags);
 
+	/* Use tmpalias flush to prevent instruction cache move-in */
+	preempt_disable();
+	flush_icache_page_asm(__pa(vaddr), vaddr);
 	preempt_enable();
 }
 
+void kunmap_flush_on_unmap(const void *addr)
+{
+	flush_kernel_dcache_page_addr(addr);
+}
+EXPORT_SYMBOL(kunmap_flush_on_unmap);
+
 void flush_icache_pages(struct vm_area_struct *vma, struct page *page,
 		unsigned int nr)
 {
@@ -375,13 +397,16 @@ void flush_icache_pages(struct vm_area_struct *vma, struct page *page,
 
 	for (;;) {
 		flush_kernel_dcache_page_addr(kaddr);
-		flush_kernel_icache_page(kaddr);
+		flush_kernel_icache_page_addr(kaddr);
 		if (--nr == 0)
 			break;
 		kaddr += PAGE_SIZE;
 	}
 }
 
+/*
+ * Walk page directory for MM to find PTEP pointer for address ADDR.
+ */
 static inline pte_t *get_ptep(struct mm_struct *mm, unsigned long addr)
 {
 	pte_t *ptep = NULL;
@@ -410,6 +435,41 @@ static inline bool pte_needs_flush(pte_t pte)
 		== (_PAGE_PRESENT | _PAGE_ACCESSED);
 }
 
+/*
+ * Return user physical address. Returns 0 if page is not present.
+ */
+static inline unsigned long get_upa(struct mm_struct *mm, unsigned long addr)
+{
+	unsigned long flags, space, pgd, prot, pa;
+#ifdef CONFIG_TLB_PTLOCK
+	unsigned long pgd_lock;
+#endif
+
+	/* Save context */
+	local_irq_save(flags);
+	prot = mfctl(8);
+	space = mfsp(SR_USER);
+	pgd = mfctl(25);
+#ifdef CONFIG_TLB_PTLOCK
+	pgd_lock = mfctl(28);
+#endif
+
+	/* Set context for lpa_user */
+	switch_mm_irqs_off(NULL, mm, NULL);
+	pa = lpa_user(addr);
+
+	/* Restore previous context */
+#ifdef CONFIG_TLB_PTLOCK
+	mtctl(pgd_lock, 28);
+#endif
+	mtctl(pgd, 25);
+	mtsp(space, SR_USER);
+	mtctl(prot, 8);
+	local_irq_restore(flags);
+
+	return pa;
+}
+
 void flush_dcache_folio(struct folio *folio)
 {
 	struct address_space *mapping = folio_flush_mapping(folio);
@@ -458,50 +518,23 @@ void flush_dcache_folio(struct folio *folio)
 		if (addr + nr * PAGE_SIZE > vma->vm_end)
 			nr = (vma->vm_end - addr) / PAGE_SIZE;
 
-		if (parisc_requires_coherency()) {
-			for (i = 0; i < nr; i++) {
-				pte_t *ptep = get_ptep(vma->vm_mm,
-							addr + i * PAGE_SIZE);
-				if (!ptep)
-					continue;
-				if (pte_needs_flush(*ptep))
-					flush_user_cache_page(vma,
-							addr + i * PAGE_SIZE);
-				/* Optimise accesses to the same table? */
-				pte_unmap(ptep);
-			}
-		} else {
+		if (old_addr == 0 || (old_addr & (SHM_COLOUR - 1))
+					!= (addr & (SHM_COLOUR - 1))) {
+			for (i = 0; i < nr; i++)
+				__flush_cache_page(vma,
+					addr + i * PAGE_SIZE,
+					(pfn + i) * PAGE_SIZE);
 			/*
-			 * The TLB is the engine of coherence on parisc:
-			 * The CPU is entitled to speculate any page
-			 * with a TLB mapping, so here we kill the
-			 * mapping then flush the page along a special
-			 * flush only alias mapping. This guarantees that
-			 * the page is no-longer in the cache for any
-			 * process and nor may it be speculatively read
-			 * in (until the user or kernel specifically
-			 * accesses it, of course)
+			 * Software is allowed to have any number
+			 * of private mappings to a page.
 			 */
-			for (i = 0; i < nr; i++)
-				flush_tlb_page(vma, addr + i * PAGE_SIZE);
-			if (old_addr == 0 || (old_addr & (SHM_COLOUR - 1))
-					!= (addr & (SHM_COLOUR - 1))) {
-				for (i = 0; i < nr; i++)
-					__flush_cache_page(vma,
-						addr + i * PAGE_SIZE,
-						(pfn + i) * PAGE_SIZE);
-				/*
-				 * Software is allowed to have any number
-				 * of private mappings to a page.
-				 */
-				if (!(vma->vm_flags & VM_SHARED))
-					continue;
-				if (old_addr)
-					pr_err("INEQUIVALENT ALIASES 0x%lx and 0x%lx in file %pD\n",
-						old_addr, addr, vma->vm_file);
-				if (nr == folio_nr_pages(folio))
-					old_addr = addr;
-			}
+			if (!(vma->vm_flags & VM_SHARED))
+				continue;
+			if (old_addr)
+				pr_err("INEQUIVALENT ALIASES 0x%lx and 0x%lx in file %pD\n",
+					old_addr, addr, vma->vm_file);
+			if (nr == folio_nr_pages(folio))
+				old_addr = addr;
 		}
 		WARN_ON(++count == 4096);
 	}
@@ -591,35 +624,28 @@ extern void purge_kernel_dcache_page_asm(unsigned long);
 extern void clear_user_page_asm(void *, unsigned long);
 extern void copy_user_page_asm(void *, void *, unsigned long);
 
-void flush_kernel_dcache_page_addr(const void *addr)
-{
-	unsigned long flags;
-
-	flush_kernel_dcache_page_asm(addr);
-	purge_tlb_start(flags);
-	pdtlb(SR_KERNEL, addr);
-	purge_tlb_end(flags);
-}
-EXPORT_SYMBOL(flush_kernel_dcache_page_addr);
-
 static void flush_cache_page_if_present(struct vm_area_struct *vma,
-	unsigned long vmaddr, unsigned long pfn)
+	unsigned long vmaddr)
 {
+#if CONFIG_FLUSH_PAGE_ACCESSED
 	bool needs_flush = false;
-	pte_t *ptep;
+	pte_t *ptep, pte;
 
-	/*
-	 * The pte check is racy and sometimes the flush will trigger
-	 * a non-access TLB miss. Hopefully, the page has already been
-	 * flushed.
-	 */
 	ptep = get_ptep(vma->vm_mm, vmaddr);
 	if (ptep) {
-		needs_flush = pte_needs_flush(*ptep);
+		pte = ptep_get(ptep);
+		needs_flush = pte_needs_flush(pte);
 		pte_unmap(ptep);
 	}
 	if (needs_flush)
-		flush_cache_page(vma, vmaddr, pfn);
+		__flush_cache_page(vma, vmaddr, PFN_PHYS(pte_pfn(pte)));
+#else
+	struct mm_struct *mm = vma->vm_mm;
+	unsigned long physaddr = get_upa(mm, vmaddr);
+
+	if (physaddr)
+		__flush_cache_page(vma, vmaddr, PAGE_ALIGN_DOWN(physaddr));
+#endif
 }
 
 void copy_user_highpage(struct page *to, struct page *from,
@@ -629,7 +655,7 @@ void copy_user_highpage(struct page *to, struct page *from,
 
 	kfrom = kmap_local_page(from);
 	kto = kmap_local_page(to);
-	flush_cache_page_if_present(vma, vaddr, page_to_pfn(from));
+	__flush_cache_page(vma, vaddr, PFN_PHYS(page_to_pfn(from)));
 	copy_page_asm(kto, kfrom);
 	kunmap_local(kto);
 	kunmap_local(kfrom);
@@ -638,16 +664,17 @@ void copy_user_highpage(struct page *to, struct page *from,
 void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 		unsigned long user_vaddr, void *dst, void *src, int len)
 {
-	flush_cache_page_if_present(vma, user_vaddr, page_to_pfn(page));
+	__flush_cache_page(vma, user_vaddr, PFN_PHYS(page_to_pfn(page)));
 	memcpy(dst, src, len);
-	flush_kernel_dcache_range_asm((unsigned long)dst, (unsigned long)dst + len);
+	flush_kernel_dcache_page_addr(PTR_PAGE_ALIGN_DOWN(dst));
 }
 
 void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
 		unsigned long user_vaddr, void *dst, void *src, int len)
 {
-	flush_cache_page_if_present(vma, user_vaddr, page_to_pfn(page));
+	__flush_cache_page(vma, user_vaddr, PFN_PHYS(page_to_pfn(page)));
 	memcpy(dst, src, len);
+	flush_kernel_dcache_page_addr(PTR_PAGE_ALIGN_DOWN(src));
 }
 
 /* __flush_tlb_range()
@@ -681,32 +708,10 @@ int __flush_tlb_range(unsigned long sid, unsigned long start,
 
 static void flush_cache_pages(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 {
-	unsigned long addr, pfn;
-	pte_t *ptep;
-
-	for (addr = start; addr < end; addr += PAGE_SIZE) {
-		bool needs_flush = false;
-		/*
-		 * The vma can contain pages that aren't present. Although
-		 * the pte search is expensive, we need the pte to find the
-		 * page pfn and to check whether the page should be flushed.
-		 */
-		ptep = get_ptep(vma->vm_mm, addr);
-		if (ptep) {
-			needs_flush = pte_needs_flush(*ptep);
-			pfn = pte_pfn(*ptep);
-			pte_unmap(ptep);
-		}
-		if (needs_flush) {
-			if (parisc_requires_coherency()) {
-				flush_user_cache_page(vma, addr);
-			} else {
-				if (WARN_ON(!pfn_valid(pfn)))
-					return;
-				__flush_cache_page(vma, addr, PFN_PHYS(pfn));
-			}
-		}
-	}
+	unsigned long addr;
+
+	for (addr = start; addr < end; addr += PAGE_SIZE)
+		flush_cache_page_if_present(vma, addr);
 }
 
 static inline unsigned long mm_total_size(struct mm_struct *mm)
@@ -757,21 +762,19 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned
 		if (WARN_ON(IS_ENABLED(CONFIG_SMP) && arch_irqs_disabled()))
 			return;
 		flush_tlb_range(vma, start, end);
-		flush_cache_all();
+		if (vma->vm_flags & VM_EXEC)
+			flush_cache_all();
+		else
+			flush_data_cache();
 		return;
 	}
 
-	flush_cache_pages(vma, start, end);
+	flush_cache_pages(vma, start & PAGE_MASK, end);
 }
 
 void flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn)
 {
-	if (WARN_ON(!pfn_valid(pfn)))
-		return;
-	if (parisc_requires_coherency())
-		flush_user_cache_page(vma, vmaddr);
-	else
-		__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
+	__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
 }
 
 void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
@@ -779,34 +782,133 @@ void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned lon
 	if (!PageAnon(page))
 		return;
 
-	if (parisc_requires_coherency()) {
-		if (vma->vm_flags & VM_SHARED)
-			flush_data_cache();
-		else
-			flush_user_cache_page(vma, vmaddr);
+	__flush_cache_page(vma, vmaddr, PFN_PHYS(page_to_pfn(page)));
+}
+
+int ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr,
+			   pte_t *ptep)
+{
+	pte_t pte = ptep_get(ptep);
+
+	if (!pte_young(pte))
+		return 0;
+	set_pte(ptep, pte_mkold(pte));
+#if CONFIG_FLUSH_PAGE_ACCESSED
+	__flush_cache_page(vma, addr, PFN_PHYS(pte_pfn(pte)));
+#endif
+	return 1;
+}
+
+/*
+ * After a PTE is cleared, we have no way to flush the cache for
+ * the physical page. On PA8800 and PA8900 processors, these lines
+ * can cause random cache corruption. Thus, we must flush the cache
+ * as well as the TLB when clearing a PTE that's valid.
+ */
+pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr,
+		       pte_t *ptep)
+{
+	struct mm_struct *mm = (vma)->vm_mm;
+	pte_t pte = ptep_get_and_clear(mm, addr, ptep);
+	unsigned long pfn = pte_pfn(pte);
+
+	if (pfn_valid(pfn))
+		__flush_cache_page(vma, addr, PFN_PHYS(pfn));
+	else if (pte_accessible(mm, pte))
+		flush_tlb_page(vma, addr);
+
+	return pte;
+}
+
+/*
+ * The physical address for pages in the ioremap case can be obtained
+ * from the vm_struct struct. I wasn't able to successfully handle the
+ * vmalloc and vmap cases. We have an array of struct page pointers in
+ * the uninitialized vmalloc case but the flush failed using page_to_pfn.
+ */
+void flush_cache_vmap(unsigned long start, unsigned long end)
+{
+	unsigned long addr, physaddr;
+	struct vm_struct *vm;
+
+	/* Prevent cache move-in */
+	flush_tlb_kernel_range(start, end);
+
+	if (end - start >= parisc_cache_flush_threshold) {
+		flush_cache_all();
 		return;
 	}
 
-	flush_tlb_page(vma, vmaddr);
-	preempt_disable();
-	flush_dcache_page_asm(page_to_phys(page), vmaddr);
-	preempt_enable();
+	if (WARN_ON_ONCE(!is_vmalloc_addr((void *)start))) {
+		flush_cache_all();
+		return;
+	}
+
+	vm = find_vm_area((void *)start);
+	if (WARN_ON_ONCE(!vm)) {
+		flush_cache_all();
+		return;
+	}
+
+	/* The physical addresses of IOREMAP regions are contiguous */
+	if (vm->flags & VM_IOREMAP) {
+		physaddr = vm->phys_addr;
+		for (addr = start; addr < end; addr += PAGE_SIZE) {
+			preempt_disable();
+			flush_dcache_page_asm(physaddr, start);
+			flush_icache_page_asm(physaddr, start);
+			preempt_enable();
+			physaddr += PAGE_SIZE;
+		}
+		return;
+	}
+
+	flush_cache_all();
 }
+EXPORT_SYMBOL(flush_cache_vmap);
 
+/*
+ * The vm_struct has been retired and the page table is set up. The
+ * last page in the range is a guard page. Its physical address can't
+ * be determined using lpa, so there is no way to flush the range
+ * using flush_dcache_page_asm.
+ */
+void flush_cache_vunmap(unsigned long start, unsigned long end)
+{
+	/* Prevent cache move-in */
+	flush_tlb_kernel_range(start, end);
+	flush_data_cache();
+}
+EXPORT_SYMBOL(flush_cache_vunmap);
+
+/*
+ * On systems with PA8800/PA8900 processors, there is no way to flush
+ * a vmap range other than using the architected loop to flush the
+ * entire cache. The page directory is not set up, so we can't use
+ * fdc, etc. FDCE/FICE don't work to flush a portion of the cache.
+ * L2 is physically indexed but FDCE/FICE instructions in virtual
+ * mode output their virtual address on the core bus, not their
+ * real address. As a result, the L2 cache index formed from the
+ * virtual address will most likely not be the same as the L2 index
+ * formed from the real address.
+ */
 void flush_kernel_vmap_range(void *vaddr, int size)
 {
 	unsigned long start = (unsigned long)vaddr;
 	unsigned long end = start + size;
 
-	if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
-	    (unsigned long)size >= parisc_cache_flush_threshold) {
-		flush_tlb_kernel_range(start, end);
-		flush_data_cache();
+	flush_tlb_kernel_range(start, end);
+
+	if (!static_branch_likely(&parisc_has_dcache))
+		return;
+
+	/* If interrupts are disabled, we can only do local flush */
+	if (WARN_ON(IS_ENABLED(CONFIG_SMP) && arch_irqs_disabled())) {
+		flush_data_cache_local(NULL);
 		return;
 	}
 
-	flush_kernel_dcache_range_asm(start, end);
-	flush_tlb_kernel_range(start, end);
+	flush_data_cache();
 }
 EXPORT_SYMBOL(flush_kernel_vmap_range);
 
@@ -818,15 +920,18 @@ void invalidate_kernel_vmap_range(void *vaddr, int size)
 	/* Ensure DMA is complete */
 	asm_syncdma();
 
-	if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
-	    (unsigned long)size >= parisc_cache_flush_threshold) {
-		flush_tlb_kernel_range(start, end);
-		flush_data_cache();
+	flush_tlb_kernel_range(start, end);
+
+	if (!static_branch_likely(&parisc_has_dcache))
+		return;
+
+	/* If interrupts are disabled, we can only do local flush */
+	if (WARN_ON(IS_ENABLED(CONFIG_SMP) && arch_irqs_disabled())) {
+		flush_data_cache_local(NULL);
 		return;
 	}
 
-	purge_kernel_dcache_range_asm(start, end);
-	flush_tlb_kernel_range(start, end);
+	flush_data_cache();
 }
 EXPORT_SYMBOL(invalidate_kernel_vmap_range);