1 files changed, 75 insertions, 66 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 85cf12219dea..3bded76e8d5c 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -93,6 +93,18 @@ void arch_report_meminfo(struct seq_file *m)
 static inline void split_page_count(int level) { }
 #endif
 
+static inline int
+within(unsigned long addr, unsigned long start, unsigned long end)
+{
+	return addr >= start && addr < end;
+}
+
+static inline int
+within_inclusive(unsigned long addr, unsigned long start, unsigned long end)
+{
+	return addr >= start && addr <= end;
+}
+
 #ifdef CONFIG_X86_64
 
 static inline unsigned long highmap_start_pfn(void)
@@ -106,20 +118,25 @@ static inline unsigned long highmap_end_pfn(void)
 	return __pa_symbol(roundup(_brk_end, PMD_SIZE) - 1) >> PAGE_SHIFT;
 }
 
-#endif
-
-static inline int
-within(unsigned long addr, unsigned long start, unsigned long end)
+static bool __cpa_pfn_in_highmap(unsigned long pfn)
 {
-	return addr >= start && addr < end;
+	/*
+	 * Kernel text has an alias mapping at a high address, known
+	 * here as "highmap".
+	 */
+	return within_inclusive(pfn, highmap_start_pfn(), highmap_end_pfn());
 }
 
-static inline int
-within_inclusive(unsigned long addr, unsigned long start, unsigned long end)
+#else
+
+static bool __cpa_pfn_in_highmap(unsigned long pfn)
 {
-	return addr >= start && addr <= end;
+	/* There is no highmap on 32-bit */
+	return false;
 }
 
+#endif
+
 /*
  * Flushing functions
  */
@@ -172,7 +189,7 @@ static void __cpa_flush_all(void *arg)
 
 static void cpa_flush_all(unsigned long cache)
 {
-	BUG_ON(irqs_disabled());
+	BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
 
 	on_each_cpu(__cpa_flush_all, (void *) cache, 1);
 }
@@ -236,7 +253,7 @@ static void cpa_flush_array(unsigned long *start, int numpages, int cache,
 	unsigned long do_wbinvd = cache && numpages >= 1024; /* 4M threshold */
 #endif
 
-	BUG_ON(irqs_disabled());
+	BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
 
 	on_each_cpu(__cpa_flush_all, (void *) do_wbinvd, 1);
 
@@ -298,9 +315,11 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 
 	/*
 	 * The .rodata section needs to be read-only. Using the pfn
-	 * catches all aliases.
+	 * catches all aliases.  This also includes __ro_after_init,
+	 * so do not enforce until kernel_set_to_readonly is true.
 	 */
-	if (within(pfn, __pa_symbol(__start_rodata) >> PAGE_SHIFT,
+	if (kernel_set_to_readonly &&
+	    within(pfn, __pa_symbol(__start_rodata) >> PAGE_SHIFT,
 		   __pa_symbol(__end_rodata) >> PAGE_SHIFT))
 		pgprot_val(forbidden) |= _PAGE_RW;
 
@@ -512,6 +531,23 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
 #endif
 }
 
+static pgprot_t pgprot_clear_protnone_bits(pgprot_t prot)
+{
+	/*
+	 * _PAGE_GLOBAL means "global page" for present PTEs.
+	 * But, it is also used to indicate _PAGE_PROTNONE
+	 * for non-present PTEs.
+	 *
+	 * This ensures that a _PAGE_GLOBAL PTE going from
+	 * present to non-present is not confused as
+	 * _PAGE_PROTNONE.
+	 */
+	if (!(pgprot_val(prot) & _PAGE_PRESENT))
+		pgprot_val(prot) &= ~_PAGE_GLOBAL;
+
+	return prot;
+}
+
 static int
 try_preserve_large_page(pte_t *kpte, unsigned long address,
 			struct cpa_data *cpa)
@@ -566,6 +602,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
 	 * up accordingly.
 	 */
 	old_pte = *kpte;
+	/* Clear PSE (aka _PAGE_PAT) and move PAT bit to correct position */
 	req_prot = pgprot_large_2_4k(old_prot);
 
 	pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr);
@@ -577,19 +614,9 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
 	 * different bit positions in the two formats.
 	 */
 	req_prot = pgprot_4k_2_large(req_prot);
-
-	/*
-	 * Set the PSE and GLOBAL flags only if the PRESENT flag is
-	 * set otherwise pmd_present/pmd_huge will return true even on
-	 * a non present pmd. The canon_pgprot will clear _PAGE_GLOBAL
-	 * for the ancient hardware that doesn't support it.
-	 */
+	req_prot = pgprot_clear_protnone_bits(req_prot);
 	if (pgprot_val(req_prot) & _PAGE_PRESENT)
-		pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL;
-	else
-		pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL);
-
-	req_prot = canon_pgprot(req_prot);
+		pgprot_val(req_prot) |= _PAGE_PSE;
 
 	/*
 	 * old_pfn points to the large page base pfn. So we need
@@ -674,8 +701,12 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
 	switch (level) {
 	case PG_LEVEL_2M:
 		ref_prot = pmd_pgprot(*(pmd_t *)kpte);
-		/* clear PSE and promote PAT bit to correct position */
+		/*
+		 * Clear PSE (aka _PAGE_PAT) and move
+		 * PAT bit to correct position.
+		 */
 		ref_prot = pgprot_large_2_4k(ref_prot);
+
 		ref_pfn = pmd_pfn(*(pmd_t *)kpte);
 		break;
 
@@ -698,23 +729,14 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
 		return 1;
 	}
 
-	/*
-	 * Set the GLOBAL flags only if the PRESENT flag is set
-	 * otherwise pmd/pte_present will return true even on a non
-	 * present pmd/pte. The canon_pgprot will clear _PAGE_GLOBAL
-	 * for the ancient hardware that doesn't support it.
-	 */
-	if (pgprot_val(ref_prot) & _PAGE_PRESENT)
-		pgprot_val(ref_prot) |= _PAGE_GLOBAL;
-	else
-		pgprot_val(ref_prot) &= ~_PAGE_GLOBAL;
+	ref_prot = pgprot_clear_protnone_bits(ref_prot);
 
 	/*
 	 * Get the target pfn from the original entry:
 	 */
 	pfn = ref_pfn;
 	for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc)
-		set_pte(&pbase[i], pfn_pte(pfn, canon_pgprot(ref_prot)));
+		set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
 
 	if (virt_addr_valid(address)) {
 		unsigned long pfn = PFN_DOWN(__pa(address));
@@ -930,19 +952,7 @@ static void populate_pte(struct cpa_data *cpa,
 
 	pte = pte_offset_kernel(pmd, start);
 
-	/*
-	 * Set the GLOBAL flags only if the PRESENT flag is
-	 * set otherwise pte_present will return true even on
-	 * a non present pte. The canon_pgprot will clear
-	 * _PAGE_GLOBAL for the ancient hardware that doesn't
-	 * support it.
-	 */
-	if (pgprot_val(pgprot) & _PAGE_PRESENT)
-		pgprot_val(pgprot) |= _PAGE_GLOBAL;
-	else
-		pgprot_val(pgprot) &= ~_PAGE_GLOBAL;
-
-	pgprot = canon_pgprot(pgprot);
+	pgprot = pgprot_clear_protnone_bits(pgprot);
 
 	while (num_pages-- && start < end) {
 		set_pte(pte, pfn_pte(cpa->pfn, pgprot));
@@ -1190,6 +1200,10 @@ static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr,
 		cpa->numpages = 1;
 		cpa->pfn = __pa(vaddr) >> PAGE_SHIFT;
 		return 0;
+
+	} else if (__cpa_pfn_in_highmap(cpa->pfn)) {
+		/* Faults in the highmap are OK, so do not warn: */
+		return -EFAULT;
 	} else {
 		WARN(1, KERN_WARNING "CPA: called for zero pte. "
 			"vaddr = %lx cpa->vaddr = %lx\n", vaddr,
@@ -1234,24 +1248,14 @@ repeat:
 
 		new_prot = static_protections(new_prot, address, pfn);
 
-		/*
-		 * Set the GLOBAL flags only if the PRESENT flag is
-		 * set otherwise pte_present will return true even on
-		 * a non present pte. The canon_pgprot will clear
-		 * _PAGE_GLOBAL for the ancient hardware that doesn't
-		 * support it.
-		 */
-		if (pgprot_val(new_prot) & _PAGE_PRESENT)
-			pgprot_val(new_prot) |= _PAGE_GLOBAL;
-		else
-			pgprot_val(new_prot) &= ~_PAGE_GLOBAL;
+		new_prot = pgprot_clear_protnone_bits(new_prot);
 
 		/*
 		 * We need to keep the pfn from the existing PTE,
 		 * after all we're only going to change it's attributes
 		 * not the memory it points to
 		 */
-		new_pte = pfn_pte(pfn, canon_pgprot(new_prot));
+		new_pte = pfn_pte(pfn, new_prot);
 		cpa->pfn = pfn;
 		/*
 		 * Do we really change anything ?
@@ -1352,8 +1356,7 @@ static int cpa_process_alias(struct cpa_data *cpa)
 	 * to touch the high mapped kernel as well:
 	 */
 	if (!within(vaddr, (unsigned long)_text, _brk_end) &&
-	    within_inclusive(cpa->pfn, highmap_start_pfn(),
-			     highmap_end_pfn())) {
+	    __cpa_pfn_in_highmap(cpa->pfn)) {
 		unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) +
 					       __START_KERNEL_map - phys_base;
 		alias_cpa = *cpa;
@@ -1428,11 +1431,11 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
 	memset(&cpa, 0, sizeof(cpa));
 
 	/*
-	 * Check, if we are requested to change a not supported
-	 * feature:
+	 * Check, if we are requested to set a not supported
+	 * feature.  Clearing non-supported features is OK.
 	 */
 	mask_set = canon_pgprot(mask_set);
-	mask_clr = canon_pgprot(mask_clr);
+
 	if (!pgprot_val(mask_set) && !pgprot_val(mask_clr) && !force_split)
 		return 0;
 
@@ -1775,6 +1778,12 @@ int set_memory_4k(unsigned long addr, int numpages)
 					__pgprot(0), 1, 0, NULL);
 }
 
+int set_memory_nonglobal(unsigned long addr, int numpages)
+{
+	return change_page_attr_clear(&addr, numpages,
+				      __pgprot(_PAGE_GLOBAL), 0);
+}
+
 static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
 {
 	struct cpa_data cpa;