1 files changed, 204 insertions, 107 deletions

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index d28dbcf596b6..0c429ec6fde8 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -22,6 +22,8 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/kexec.h>
 #include <linux/libfdt.h>
 #include <linux/mman.h>
 #include <linux/nodemask.h>
@@ -43,6 +45,9 @@
 #include <asm/mmu_context.h>
 #include <asm/ptdump.h>
 
+#define NO_BLOCK_MAPPINGS	BIT(0)
+#define NO_CONT_MAPPINGS	BIT(1)
+
 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
 
 u64 kimage_voffset __ro_after_init;
@@ -103,33 +108,27 @@ static bool pgattr_change_is_safe(u64 old, u64 new)
 	 */
 	static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE;
 
-	return old  == 0 || new  == 0 || ((old ^ new) & ~mask) == 0;
+	/* creating or taking down mappings is always safe */
+	if (old == 0 || new == 0)
+		return true;
+
+	/* live contiguous mappings may not be manipulated at all */
+	if ((old | new) & PTE_CONT)
+		return false;
+
+	return ((old ^ new) & ~mask) == 0;
 }
 
-static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
-				  unsigned long end, unsigned long pfn,
-				  pgprot_t prot,
-				  phys_addr_t (*pgtable_alloc)(void))
+static void init_pte(pmd_t *pmd, unsigned long addr, unsigned long end,
+		     phys_addr_t phys, pgprot_t prot)
 {
 	pte_t *pte;
 
-	BUG_ON(pmd_sect(*pmd));
-	if (pmd_none(*pmd)) {
-		phys_addr_t pte_phys;
-		BUG_ON(!pgtable_alloc);
-		pte_phys = pgtable_alloc();
-		pte = pte_set_fixmap(pte_phys);
-		__pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
-		pte_clear_fixmap();
-	}
-	BUG_ON(pmd_bad(*pmd));
-
 	pte = pte_set_fixmap_offset(pmd, addr);
 	do {
 		pte_t old_pte = *pte;
 
-		set_pte(pte, pfn_pte(pfn, prot));
-		pfn++;
+		set_pte(pte, pfn_pte(__phys_to_pfn(phys), prot));
 
 		/*
 		 * After the PTE entry has been populated once, we
@@ -137,32 +136,51 @@ static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 		 */
 		BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), pte_val(*pte)));
 
+		phys += PAGE_SIZE;
 	} while (pte++, addr += PAGE_SIZE, addr != end);
 
 	pte_clear_fixmap();
 }
 
-static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
-				  phys_addr_t phys, pgprot_t prot,
-				  phys_addr_t (*pgtable_alloc)(void),
-				  bool page_mappings_only)
+static void alloc_init_cont_pte(pmd_t *pmd, unsigned long addr,
+				unsigned long end, phys_addr_t phys,
+				pgprot_t prot,
+				phys_addr_t (*pgtable_alloc)(void),
+				int flags)
 {
-	pmd_t *pmd;
 	unsigned long next;
 
-	/*
-	 * Check for initial section mappings in the pgd/pud and remove them.
-	 */
-	BUG_ON(pud_sect(*pud));
-	if (pud_none(*pud)) {
-		phys_addr_t pmd_phys;
+	BUG_ON(pmd_sect(*pmd));
+	if (pmd_none(*pmd)) {
+		phys_addr_t pte_phys;
 		BUG_ON(!pgtable_alloc);
-		pmd_phys = pgtable_alloc();
-		pmd = pmd_set_fixmap(pmd_phys);
-		__pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
-		pmd_clear_fixmap();
+		pte_phys = pgtable_alloc();
+		__pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
 	}
-	BUG_ON(pud_bad(*pud));
+	BUG_ON(pmd_bad(*pmd));
+
+	do {
+		pgprot_t __prot = prot;
+
+		next = pte_cont_addr_end(addr, end);
+
+		/* use a contiguous mapping if the range is suitably aligned */
+		if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
+		    (flags & NO_CONT_MAPPINGS) == 0)
+			__prot = __pgprot(pgprot_val(prot) | PTE_CONT);
+
+		init_pte(pmd, addr, next, phys, __prot);
+
+		phys += next - addr;
+	} while (addr = next, addr != end);
+}
+
+static void init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
+		     phys_addr_t phys, pgprot_t prot,
+		     phys_addr_t (*pgtable_alloc)(void), int flags)
+{
+	unsigned long next;
+	pmd_t *pmd;
 
 	pmd = pmd_set_fixmap_offset(pud, addr);
 	do {
@@ -172,7 +190,7 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 
 		/* try section mapping first */
 		if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
-		      !page_mappings_only) {
+		    (flags & NO_BLOCK_MAPPINGS) == 0) {
 			pmd_set_huge(pmd, phys, prot);
 
 			/*
@@ -182,8 +200,8 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 			BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
 						      pmd_val(*pmd)));
 		} else {
-			alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
-				       prot, pgtable_alloc);
+			alloc_init_cont_pte(pmd, addr, next, phys, prot,
+					    pgtable_alloc, flags);
 
 			BUG_ON(pmd_val(old_pmd) != 0 &&
 			       pmd_val(old_pmd) != pmd_val(*pmd));
@@ -194,6 +212,41 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 	pmd_clear_fixmap();
 }
 
+static void alloc_init_cont_pmd(pud_t *pud, unsigned long addr,
+				unsigned long end, phys_addr_t phys,
+				pgprot_t prot,
+				phys_addr_t (*pgtable_alloc)(void), int flags)
+{
+	unsigned long next;
+
+	/*
+	 * Check for initial section mappings in the pgd/pud.
+	 */
+	BUG_ON(pud_sect(*pud));
+	if (pud_none(*pud)) {
+		phys_addr_t pmd_phys;
+		BUG_ON(!pgtable_alloc);
+		pmd_phys = pgtable_alloc();
+		__pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
+	}
+	BUG_ON(pud_bad(*pud));
+
+	do {
+		pgprot_t __prot = prot;
+
+		next = pmd_cont_addr_end(addr, end);
+
+		/* use a contiguous mapping if the range is suitably aligned */
+		if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
+		    (flags & NO_CONT_MAPPINGS) == 0)
+			__prot = __pgprot(pgprot_val(prot) | PTE_CONT);
+
+		init_pmd(pud, addr, next, phys, __prot, pgtable_alloc, flags);
+
+		phys += next - addr;
+	} while (addr = next, addr != end);
+}
+
 static inline bool use_1G_block(unsigned long addr, unsigned long next,
 			unsigned long phys)
 {
@@ -209,7 +262,7 @@ static inline bool use_1G_block(unsigned long addr, unsigned long next,
 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 				  phys_addr_t phys, pgprot_t prot,
 				  phys_addr_t (*pgtable_alloc)(void),
-				  bool page_mappings_only)
+				  int flags)
 {
 	pud_t *pud;
 	unsigned long next;
@@ -231,7 +284,8 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 		/*
 		 * For 4K granule only, attempt to put down a 1GB block
 		 */
-		if (use_1G_block(addr, next, phys) && !page_mappings_only) {
+		if (use_1G_block(addr, next, phys) &&
+		    (flags & NO_BLOCK_MAPPINGS) == 0) {
 			pud_set_huge(pud, phys, prot);
 
 			/*
@@ -241,8 +295,8 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 			BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
 						      pud_val(*pud)));
 		} else {
-			alloc_init_pmd(pud, addr, next, phys, prot,
-				       pgtable_alloc, page_mappings_only);
+			alloc_init_cont_pmd(pud, addr, next, phys, prot,
+					    pgtable_alloc, flags);
 
 			BUG_ON(pud_val(old_pud) != 0 &&
 			       pud_val(old_pud) != pud_val(*pud));
@@ -257,7 +311,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 				 unsigned long virt, phys_addr_t size,
 				 pgprot_t prot,
 				 phys_addr_t (*pgtable_alloc)(void),
-				 bool page_mappings_only)
+				 int flags)
 {
 	unsigned long addr, length, end, next;
 	pgd_t *pgd = pgd_offset_raw(pgdir, virt);
@@ -277,7 +331,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 	do {
 		next = pgd_addr_end(addr, end);
 		alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc,
-			       page_mappings_only);
+			       flags);
 		phys += next - addr;
 	} while (pgd++, addr = next, addr != end);
 }
@@ -306,82 +360,80 @@ static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 			&phys, virt);
 		return;
 	}
-	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, false);
+	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
+			     NO_CONT_MAPPINGS);
 }
 
 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 			       unsigned long virt, phys_addr_t size,
 			       pgprot_t prot, bool page_mappings_only)
 {
+	int flags = 0;
+
 	BUG_ON(mm == &init_mm);
 
+	if (page_mappings_only)
+		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
+
 	__create_pgd_mapping(mm->pgd, phys, virt, size, prot,
-			     pgd_pgtable_alloc, page_mappings_only);
+			     pgd_pgtable_alloc, flags);
 }
 
-static void create_mapping_late(phys_addr_t phys, unsigned long virt,
-				  phys_addr_t size, pgprot_t prot)
+static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
+				phys_addr_t size, pgprot_t prot)
 {
 	if (virt < VMALLOC_START) {
-		pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
+		pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
 			&phys, virt);
 		return;
 	}
 
-	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
-			     NULL, debug_pagealloc_enabled());
+	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
+			     NO_CONT_MAPPINGS);
+
+	/* flush the TLBs after updating live kernel mappings */
+	flush_tlb_kernel_range(virt, virt + size);
 }
 
-static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
+static void __init __map_memblock(pgd_t *pgd, phys_addr_t start,
+				  phys_addr_t end, pgprot_t prot, int flags)
 {
-	phys_addr_t kernel_start = __pa_symbol(_text);
-	phys_addr_t kernel_end = __pa_symbol(__init_begin);
-
-	/*
-	 * Take care not to create a writable alias for the
-	 * read-only text and rodata sections of the kernel image.
-	 */
-
-	/* No overlap with the kernel text/rodata */
-	if (end < kernel_start || start >= kernel_end) {
-		__create_pgd_mapping(pgd, start, __phys_to_virt(start),
-				     end - start, PAGE_KERNEL,
-				     early_pgtable_alloc,
-				     debug_pagealloc_enabled());
-		return;
-	}
-
-	/*
-	 * This block overlaps the kernel text/rodata mappings.
-	 * Map the portion(s) which don't overlap.
-	 */
-	if (start < kernel_start)
-		__create_pgd_mapping(pgd, start,
-				     __phys_to_virt(start),
-				     kernel_start - start, PAGE_KERNEL,
-				     early_pgtable_alloc,
-				     debug_pagealloc_enabled());
-	if (kernel_end < end)
-		__create_pgd_mapping(pgd, kernel_end,
-				     __phys_to_virt(kernel_end),
-				     end - kernel_end, PAGE_KERNEL,
-				     early_pgtable_alloc,
-				     debug_pagealloc_enabled());
+	__create_pgd_mapping(pgd, start, __phys_to_virt(start), end - start,
+			     prot, early_pgtable_alloc, flags);
+}
 
+void __init mark_linear_text_alias_ro(void)
+{
 	/*
-	 * Map the linear alias of the [_text, __init_begin) interval as
-	 * read-only/non-executable. This makes the contents of the
-	 * region accessible to subsystems such as hibernate, but
-	 * protects it from inadvertent modification or execution.
+	 * Remove the write permissions from the linear alias of .text/.rodata
 	 */
-	__create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
-			     kernel_end - kernel_start, PAGE_KERNEL_RO,
-			     early_pgtable_alloc, debug_pagealloc_enabled());
+	update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text),
+			    (unsigned long)__init_begin - (unsigned long)_text,
+			    PAGE_KERNEL_RO);
 }
 
 static void __init map_mem(pgd_t *pgd)
 {
+	phys_addr_t kernel_start = __pa_symbol(_text);
+	phys_addr_t kernel_end = __pa_symbol(__init_begin);
 	struct memblock_region *reg;
+	int flags = 0;
+
+	if (debug_pagealloc_enabled())
+		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
+
+	/*
+	 * Take care not to create a writable alias for the
+	 * read-only text and rodata sections of the kernel image.
+	 * So temporarily mark them as NOMAP to skip mappings in
+	 * the following for-loop
+	 */
+	memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
+#ifdef CONFIG_KEXEC_CORE
+	if (crashk_res.end)
+		memblock_mark_nomap(crashk_res.start,
+				    resource_size(&crashk_res));
+#endif
 
 	/* map all the memory banks */
 	for_each_memblock(memory, reg) {
@@ -393,33 +445,57 @@ static void __init map_mem(pgd_t *pgd)
 		if (memblock_is_nomap(reg))
 			continue;
 
-		__map_memblock(pgd, start, end);
+		__map_memblock(pgd, start, end, PAGE_KERNEL, flags);
+	}
+
+	/*
+	 * Map the linear alias of the [_text, __init_begin) interval
+	 * as non-executable now, and remove the write permission in
+	 * mark_linear_text_alias_ro() below (which will be called after
+	 * alternative patching has completed). This makes the contents
+	 * of the region accessible to subsystems such as hibernate,
+	 * but protects it from inadvertent modification or execution.
+	 * Note that contiguous mappings cannot be remapped in this way,
+	 * so we should avoid them here.
+	 */
+	__map_memblock(pgd, kernel_start, kernel_end,
+		       PAGE_KERNEL, NO_CONT_MAPPINGS);
+	memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
+
+#ifdef CONFIG_KEXEC_CORE
+	/*
+	 * Use page-level mappings here so that we can shrink the region
+	 * in page granularity and put back unused memory to buddy system
+	 * through /sys/kernel/kexec_crash_size interface.
+	 */
+	if (crashk_res.end) {
+		__map_memblock(pgd, crashk_res.start, crashk_res.end + 1,
+			       PAGE_KERNEL,
+			       NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
+		memblock_clear_nomap(crashk_res.start,
+				     resource_size(&crashk_res));
 	}
+#endif
 }
 
 void mark_rodata_ro(void)
 {
 	unsigned long section_size;
 
-	section_size = (unsigned long)_etext - (unsigned long)_text;
-	create_mapping_late(__pa_symbol(_text), (unsigned long)_text,
-			    section_size, PAGE_KERNEL_ROX);
 	/*
 	 * mark .rodata as read only. Use __init_begin rather than __end_rodata
 	 * to cover NOTES and EXCEPTION_TABLE.
 	 */
 	section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
-	create_mapping_late(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
+	update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
 			    section_size, PAGE_KERNEL_RO);
 
-	/* flush the TLBs after updating live kernel mappings */
-	flush_tlb_all();
-
 	debug_checkwx();
 }
 
 static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
-				      pgprot_t prot, struct vm_struct *vma)
+				      pgprot_t prot, struct vm_struct *vma,
+				      int flags)
 {
 	phys_addr_t pa_start = __pa_symbol(va_start);
 	unsigned long size = va_end - va_start;
@@ -428,7 +504,7 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
 	BUG_ON(!PAGE_ALIGNED(size));
 
 	__create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
-			     early_pgtable_alloc, debug_pagealloc_enabled());
+			     early_pgtable_alloc, flags);
 
 	vma->addr	= va_start;
 	vma->phys_addr	= pa_start;
@@ -439,18 +515,39 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
 	vm_area_add_early(vma);
 }
 
+static int __init parse_rodata(char *arg)
+{
+	return strtobool(arg, &rodata_enabled);
+}
+early_param("rodata", parse_rodata);
+
 /*
  * Create fine-grained mappings for the kernel.
  */
 static void __init map_kernel(pgd_t *pgd)
 {
-	static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
+	static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
+				vmlinux_initdata, vmlinux_data;
 
-	map_kernel_segment(pgd, _text, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
-	map_kernel_segment(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata);
-	map_kernel_segment(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
-			   &vmlinux_init);
-	map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
+	/*
+	 * External debuggers may need to write directly to the text
+	 * mapping to install SW breakpoints. Allow this (only) when
+	 * explicitly requested with rodata=off.
+	 */
+	pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
+
+	/*
+	 * Only rodata will be remapped with different permissions later on,
+	 * all other segments are allowed to use contiguous mappings.
+	 */
+	map_kernel_segment(pgd, _text, _etext, text_prot, &vmlinux_text, 0);
+	map_kernel_segment(pgd, __start_rodata, __inittext_begin, PAGE_KERNEL,
+			   &vmlinux_rodata, NO_CONT_MAPPINGS);
+	map_kernel_segment(pgd, __inittext_begin, __inittext_end, text_prot,
+			   &vmlinux_inittext, 0);
+	map_kernel_segment(pgd, __initdata_begin, __initdata_end, PAGE_KERNEL,
+			   &vmlinux_initdata, 0);
+	map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data, 0);
 
 	if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
 		/*