[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v9 1/8] xen/arm: Split page table related code to mmu/pt.c
The extraction of MMU related code is the basis of MPU support. This commit starts this work by firstly splitting the page table related code to mmu/pt.c, so that we will not end up with again massive mm.c files. Introduce a mmu specific directory and setup the Makefiles for it. Move the page table related functions and macros from arch/arm/mm.c to arch/arm/mmu/pt.c. Take the opportunity to fix the in-code comment coding styles when possible, and drop the unnecessary #include headers in the original arch/arm/mm.c. Signed-off-by: Henry Wang <Henry.Wang@xxxxxxx> Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx> Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx> --- v9: - No change. v8: - Add Julien's Reviewed-by tag. v7: - Do not move pte_of_xenaddr() to mmu/pt.c. - Do not expose global variable phys_offset. v6: - Rework the original patch "[v5,07/13] xen/arm: Extract MMU-specific code", only split the page table related code out in this patch. --- xen/arch/arm/Makefile | 1 + xen/arch/arm/mm.c | 717 ------------------------------------- xen/arch/arm/mmu/Makefile | 1 + xen/arch/arm/mmu/pt.c | 736 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 738 insertions(+), 717 deletions(-) create mode 100644 xen/arch/arm/mmu/Makefile create mode 100644 xen/arch/arm/mmu/pt.c diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile index 7bf07e9920..c45b08b31e 100644 --- a/xen/arch/arm/Makefile +++ b/xen/arch/arm/Makefile @@ -1,5 +1,6 @@ obj-$(CONFIG_ARM_32) += arm32/ obj-$(CONFIG_ARM_64) += arm64/ +obj-$(CONFIG_MMU) += mmu/ obj-$(CONFIG_ACPI) += acpi/ obj-$(CONFIG_HAS_PCI) += pci/ ifneq ($(CONFIG_NO_PLAT),y) diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index c34cc94c90..fd02493564 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -9,22 +9,14 @@ */ #include <xen/domain_page.h> -#include <xen/errno.h> #include <xen/grant_table.h> #include <xen/guest_access.h> -#include <xen/init.h> #include <xen/libfdt/libfdt.h> #include <xen/mm.h> -#include <xen/pfn.h> -#include <xen/pmap.h> -#include <xen/sched.h> #include <xen/sizes.h> -#include <xen/types.h> -#include <xen/vmap.h> #include <xsm/xsm.h> -#include <asm/fixmap.h> #include <asm/setup.h> #include <public/memory.h> @@ -35,19 +27,6 @@ #undef mfn_to_virt #define mfn_to_virt(mfn) __mfn_to_virt(mfn_x(mfn)) -#ifdef NDEBUG -static inline void -__attribute__ ((__format__ (__printf__, 1, 2))) -mm_printk(const char *fmt, ...) {} -#else -#define mm_printk(fmt, args...) \ - do \ - { \ - dprintk(XENLOG_ERR, fmt, ## args); \ - WARN(); \ - } while (0) -#endif - /* Static start-of-day pagetables that we use before the allocators * are up. These are used by all CPUs during bringup before switching * to the CPUs own pagetables. @@ -92,12 +71,10 @@ DEFINE_BOOT_PAGE_TABLES(boot_third, XEN_NR_ENTRIES(2)); */ #ifdef CONFIG_ARM_64 -#define HYP_PT_ROOT_LEVEL 0 DEFINE_PAGE_TABLE(xen_pgtable); static DEFINE_PAGE_TABLE(xen_first); #define THIS_CPU_PGTABLE xen_pgtable #else -#define HYP_PT_ROOT_LEVEL 1 /* Per-CPU pagetable pages */ /* xen_pgtable == root of the trie (zeroeth level on 64-bit, first on 32-bit) */ DEFINE_PER_CPU(lpae_t *, xen_pgtable); @@ -200,179 +177,6 @@ static void __init __maybe_unused build_assertions(void) #undef CHECK_DIFFERENT_SLOT } -static lpae_t *xen_map_table(mfn_t mfn) -{ - /* - * During early boot, map_domain_page() may be unusable. Use the - * PMAP to map temporarily a page-table. - */ - if ( system_state == SYS_STATE_early_boot ) - return pmap_map(mfn); - - return map_domain_page(mfn); -} - -static void xen_unmap_table(const lpae_t *table) -{ - /* - * During early boot, xen_map_table() will not use map_domain_page() - * but the PMAP. - */ - if ( system_state == SYS_STATE_early_boot ) - pmap_unmap(table); - else - unmap_domain_page(table); -} - -void dump_pt_walk(paddr_t ttbr, paddr_t addr, - unsigned int root_level, - unsigned int nr_root_tables) -{ - static const char *level_strs[4] = { "0TH", "1ST", "2ND", "3RD" }; - const mfn_t root_mfn = maddr_to_mfn(ttbr); - DECLARE_OFFSETS(offsets, addr); - lpae_t pte, *mapping; - unsigned int level, root_table; - -#ifdef CONFIG_ARM_32 - BUG_ON(root_level < 1); -#endif - BUG_ON(root_level > 3); - - if ( nr_root_tables > 1 ) - { - /* - * Concatenated root-level tables. The table number will be - * the offset at the previous level. It is not possible to - * concatenate a level-0 root. - */ - BUG_ON(root_level == 0); - root_table = offsets[root_level - 1]; - printk("Using concatenated root table %u\n", root_table); - if ( root_table >= nr_root_tables ) - { - printk("Invalid root table offset\n"); - return; - } - } - else - root_table = 0; - - mapping = xen_map_table(mfn_add(root_mfn, root_table)); - - for ( level = root_level; ; level++ ) - { - if ( offsets[level] > XEN_PT_LPAE_ENTRIES ) - break; - - pte = mapping[offsets[level]]; - - printk("%s[0x%03x] = 0x%"PRIx64"\n", - level_strs[level], offsets[level], pte.bits); - - if ( level == 3 || !pte.walk.valid || !pte.walk.table ) - break; - - /* For next iteration */ - xen_unmap_table(mapping); - mapping = xen_map_table(lpae_get_mfn(pte)); - } - - xen_unmap_table(mapping); -} - -void dump_hyp_walk(vaddr_t addr) -{ - uint64_t ttbr = READ_SYSREG64(TTBR0_EL2); - - printk("Walking Hypervisor VA 0x%"PRIvaddr" " - "on CPU%d via TTBR 0x%016"PRIx64"\n", - addr, smp_processor_id(), ttbr); - - dump_pt_walk(ttbr, addr, HYP_PT_ROOT_LEVEL, 1); -} - -lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned int attr) -{ - lpae_t e = (lpae_t) { - .pt = { - .valid = 1, /* Mappings are present */ - .table = 0, /* Set to 1 for links and 4k maps */ - .ai = attr, - .ns = 1, /* Hyp mode is in the non-secure world */ - .up = 1, /* See below */ - .ro = 0, /* Assume read-write */ - .af = 1, /* No need for access tracking */ - .ng = 1, /* Makes TLB flushes easier */ - .contig = 0, /* Assume non-contiguous */ - .xn = 1, /* No need to execute outside .text */ - .avail = 0, /* Reference count for domheap mapping */ - }}; - /* - * For EL2 stage-1 page table, up (aka AP[1]) is RES1 as the translation - * regime applies to only one exception level (see D4.4.4 and G4.6.1 - * in ARM DDI 0487B.a). If this changes, remember to update the - * hard-coded values in head.S too. - */ - - switch ( attr ) - { - case MT_NORMAL_NC: - /* - * ARM ARM: Overlaying the shareability attribute (DDI - * 0406C.b B3-1376 to 1377) - * - * A memory region with a resultant memory type attribute of Normal, - * and a resultant cacheability attribute of Inner Non-cacheable, - * Outer Non-cacheable, must have a resultant shareability attribute - * of Outer Shareable, otherwise shareability is UNPREDICTABLE. - * - * On ARMv8 sharability is ignored and explicitly treated as Outer - * Shareable for Normal Inner Non_cacheable, Outer Non-cacheable. - */ - e.pt.sh = LPAE_SH_OUTER; - break; - case MT_DEVICE_nGnRnE: - case MT_DEVICE_nGnRE: - /* - * Shareability is ignored for non-Normal memory, Outer is as - * good as anything. - * - * On ARMv8 sharability is ignored and explicitly treated as Outer - * Shareable for any device memory type. - */ - e.pt.sh = LPAE_SH_OUTER; - break; - default: - e.pt.sh = LPAE_SH_INNER; /* Xen mappings are SMP coherent */ - break; - } - - ASSERT(!(mfn_to_maddr(mfn) & ~PADDR_MASK)); - - lpae_set_mfn(e, mfn); - - return e; -} - -/* Map a 4k page in a fixmap entry */ -void set_fixmap(unsigned int map, mfn_t mfn, unsigned int flags) -{ - int res; - - res = map_pages_to_xen(FIXMAP_ADDR(map), mfn, 1, flags); - BUG_ON(res != 0); -} - -/* Remove a mapping from a fixmap entry */ -void clear_fixmap(unsigned int map) -{ - int res; - - res = destroy_xen_mappings(FIXMAP_ADDR(map), FIXMAP_ADDR(map) + PAGE_SIZE); - BUG_ON(res != 0); -} - void flush_page_to_ram(unsigned long mfn, bool sync_icache) { void *v = map_domain_page(_mfn(mfn)); @@ -733,527 +537,6 @@ void *__init arch_vmap_virt_end(void) return (void *)(VMAP_VIRT_START + VMAP_VIRT_SIZE); } -/* - * This function should only be used to remap device address ranges - * TODO: add a check to verify this assumption - */ -void *ioremap_attr(paddr_t start, size_t len, unsigned int attributes) -{ - mfn_t mfn = _mfn(PFN_DOWN(start)); - unsigned int offs = start & (PAGE_SIZE - 1); - unsigned int nr = PFN_UP(offs + len); - void *ptr = __vmap(&mfn, nr, 1, 1, attributes, VMAP_DEFAULT); - - if ( ptr == NULL ) - return NULL; - - return ptr + offs; -} - -void *ioremap(paddr_t pa, size_t len) -{ - return ioremap_attr(pa, len, PAGE_HYPERVISOR_NOCACHE); -} - -static int create_xen_table(lpae_t *entry) -{ - mfn_t mfn; - void *p; - lpae_t pte; - - if ( system_state != SYS_STATE_early_boot ) - { - struct page_info *pg = alloc_domheap_page(NULL, 0); - - if ( pg == NULL ) - return -ENOMEM; - - mfn = page_to_mfn(pg); - } - else - mfn = alloc_boot_pages(1, 1); - - p = xen_map_table(mfn); - clear_page(p); - xen_unmap_table(p); - - pte = mfn_to_xen_entry(mfn, MT_NORMAL); - pte.pt.table = 1; - write_pte(entry, pte); - /* - * No ISB here. It is deferred to xen_pt_update() as the new table - * will not be used for hardware translation table access as part of - * the mapping update. - */ - - return 0; -} - -#define XEN_TABLE_MAP_FAILED 0 -#define XEN_TABLE_SUPER_PAGE 1 -#define XEN_TABLE_NORMAL_PAGE 2 - -/* - * Take the currently mapped table, find the corresponding entry, - * and map the next table, if available. - * - * The read_only parameters indicates whether intermediate tables should - * be allocated when not present. - * - * Return values: - * XEN_TABLE_MAP_FAILED: Either read_only was set and the entry - * was empty, or allocating a new page failed. - * XEN_TABLE_NORMAL_PAGE: next level mapped normally - * XEN_TABLE_SUPER_PAGE: The next entry points to a superpage. - */ -static int xen_pt_next_level(bool read_only, unsigned int level, - lpae_t **table, unsigned int offset) -{ - lpae_t *entry; - int ret; - mfn_t mfn; - - entry = *table + offset; - - if ( !lpae_is_valid(*entry) ) - { - if ( read_only ) - return XEN_TABLE_MAP_FAILED; - - ret = create_xen_table(entry); - if ( ret ) - return XEN_TABLE_MAP_FAILED; - } - - /* The function xen_pt_next_level is never called at the 3rd level */ - if ( lpae_is_mapping(*entry, level) ) - return XEN_TABLE_SUPER_PAGE; - - mfn = lpae_get_mfn(*entry); - - xen_unmap_table(*table); - *table = xen_map_table(mfn); - - return XEN_TABLE_NORMAL_PAGE; -} - -/* Sanity check of the entry */ -static bool xen_pt_check_entry(lpae_t entry, mfn_t mfn, unsigned int level, - unsigned int flags) -{ - /* Sanity check when modifying an entry. */ - if ( (flags & _PAGE_PRESENT) && mfn_eq(mfn, INVALID_MFN) ) - { - /* We don't allow modifying an invalid entry. */ - if ( !lpae_is_valid(entry) ) - { - mm_printk("Modifying invalid entry is not allowed.\n"); - return false; - } - - /* We don't allow modifying a table entry */ - if ( !lpae_is_mapping(entry, level) ) - { - mm_printk("Modifying a table entry is not allowed.\n"); - return false; - } - - /* We don't allow changing memory attributes. */ - if ( entry.pt.ai != PAGE_AI_MASK(flags) ) - { - mm_printk("Modifying memory attributes is not allowed (0x%x -> 0x%x).\n", - entry.pt.ai, PAGE_AI_MASK(flags)); - return false; - } - - /* We don't allow modifying entry with contiguous bit set. */ - if ( entry.pt.contig ) - { - mm_printk("Modifying entry with contiguous bit set is not allowed.\n"); - return false; - } - } - /* Sanity check when inserting a mapping */ - else if ( flags & _PAGE_PRESENT ) - { - /* We should be here with a valid MFN. */ - ASSERT(!mfn_eq(mfn, INVALID_MFN)); - - /* - * We don't allow replacing any valid entry. - * - * Note that the function xen_pt_update() relies on this - * assumption and will skip the TLB flush. The function will need - * to be updated if the check is relaxed. - */ - if ( lpae_is_valid(entry) ) - { - if ( lpae_is_mapping(entry, level) ) - mm_printk("Changing MFN for a valid entry is not allowed (%#"PRI_mfn" -> %#"PRI_mfn").\n", - mfn_x(lpae_get_mfn(entry)), mfn_x(mfn)); - else - mm_printk("Trying to replace a table with a mapping.\n"); - return false; - } - } - /* Sanity check when removing a mapping. */ - else if ( (flags & (_PAGE_PRESENT|_PAGE_POPULATE)) == 0 ) - { - /* We should be here with an invalid MFN. */ - ASSERT(mfn_eq(mfn, INVALID_MFN)); - - /* We don't allow removing a table */ - if ( lpae_is_table(entry, level) ) - { - mm_printk("Removing a table is not allowed.\n"); - return false; - } - - /* We don't allow removing a mapping with contiguous bit set. */ - if ( entry.pt.contig ) - { - mm_printk("Removing entry with contiguous bit set is not allowed.\n"); - return false; - } - } - /* Sanity check when populating the page-table. No check so far. */ - else - { - ASSERT(flags & _PAGE_POPULATE); - /* We should be here with an invalid MFN */ - ASSERT(mfn_eq(mfn, INVALID_MFN)); - } - - return true; -} - -/* Update an entry at the level @target. */ -static int xen_pt_update_entry(mfn_t root, unsigned long virt, - mfn_t mfn, unsigned int target, - unsigned int flags) -{ - int rc; - unsigned int level; - lpae_t *table; - /* - * The intermediate page tables are read-only when the MFN is not valid - * and we are not populating page table. - * This means we either modify permissions or remove an entry. - */ - bool read_only = mfn_eq(mfn, INVALID_MFN) && !(flags & _PAGE_POPULATE); - lpae_t pte, *entry; - - /* convenience aliases */ - DECLARE_OFFSETS(offsets, (paddr_t)virt); - - /* _PAGE_POPULATE and _PAGE_PRESENT should never be set together. */ - ASSERT((flags & (_PAGE_POPULATE|_PAGE_PRESENT)) != (_PAGE_POPULATE|_PAGE_PRESENT)); - - table = xen_map_table(root); - for ( level = HYP_PT_ROOT_LEVEL; level < target; level++ ) - { - rc = xen_pt_next_level(read_only, level, &table, offsets[level]); - if ( rc == XEN_TABLE_MAP_FAILED ) - { - /* - * We are here because xen_pt_next_level has failed to map - * the intermediate page table (e.g the table does not exist - * and the pt is read-only). It is a valid case when - * removing a mapping as it may not exist in the page table. - * In this case, just ignore it. - */ - if ( flags & (_PAGE_PRESENT|_PAGE_POPULATE) ) - { - mm_printk("%s: Unable to map level %u\n", __func__, level); - rc = -ENOENT; - goto out; - } - else - { - rc = 0; - goto out; - } - } - else if ( rc != XEN_TABLE_NORMAL_PAGE ) - break; - } - - if ( level != target ) - { - mm_printk("%s: Shattering superpage is not supported\n", __func__); - rc = -EOPNOTSUPP; - goto out; - } - - entry = table + offsets[level]; - - rc = -EINVAL; - if ( !xen_pt_check_entry(*entry, mfn, level, flags) ) - goto out; - - /* If we are only populating page-table, then we are done. */ - rc = 0; - if ( flags & _PAGE_POPULATE ) - goto out; - - /* We are removing the page */ - if ( !(flags & _PAGE_PRESENT) ) - memset(&pte, 0x00, sizeof(pte)); - else - { - /* We are inserting a mapping => Create new pte. */ - if ( !mfn_eq(mfn, INVALID_MFN) ) - { - pte = mfn_to_xen_entry(mfn, PAGE_AI_MASK(flags)); - - /* - * First and second level pages set pte.pt.table = 0, but - * third level entries set pte.pt.table = 1. - */ - pte.pt.table = (level == 3); - } - else /* We are updating the permission => Copy the current pte. */ - pte = *entry; - - /* Set permission */ - pte.pt.ro = PAGE_RO_MASK(flags); - pte.pt.xn = PAGE_XN_MASK(flags); - /* Set contiguous bit */ - pte.pt.contig = !!(flags & _PAGE_CONTIG); - } - - write_pte(entry, pte); - /* - * No ISB or TLB flush here. They are deferred to xen_pt_update() - * as the entry will not be used as part of the mapping update. - */ - - rc = 0; - -out: - xen_unmap_table(table); - - return rc; -} - -/* Return the level where mapping should be done */ -static int xen_pt_mapping_level(unsigned long vfn, mfn_t mfn, unsigned long nr, - unsigned int flags) -{ - unsigned int level; - unsigned long mask; - - /* - * Don't take into account the MFN when removing mapping (i.e - * MFN_INVALID) to calculate the correct target order. - * - * Per the Arm Arm, `vfn` and `mfn` must be both superpage aligned. - * They are or-ed together and then checked against the size of - * each level. - * - * `left` is not included and checked separately to allow - * superpage mapping even if it is not properly aligned (the - * user may have asked to map 2MB + 4k). - */ - mask = !mfn_eq(mfn, INVALID_MFN) ? mfn_x(mfn) : 0; - mask |= vfn; - - /* - * Always use level 3 mapping unless the caller request block - * mapping. - */ - if ( likely(!(flags & _PAGE_BLOCK)) ) - level = 3; - else if ( !(mask & (BIT(FIRST_ORDER, UL) - 1)) && - (nr >= BIT(FIRST_ORDER, UL)) ) - level = 1; - else if ( !(mask & (BIT(SECOND_ORDER, UL) - 1)) && - (nr >= BIT(SECOND_ORDER, UL)) ) - level = 2; - else - level = 3; - - return level; -} - -#define XEN_PT_4K_NR_CONTIG 16 - -/* - * Check whether the contiguous bit can be set. Return the number of - * contiguous entry allowed. If not allowed, return 1. - */ -static unsigned int xen_pt_check_contig(unsigned long vfn, mfn_t mfn, - unsigned int level, unsigned long left, - unsigned int flags) -{ - unsigned long nr_contig; - - /* - * Allow the contiguous bit to set when the caller requests block - * mapping. - */ - if ( !(flags & _PAGE_BLOCK) ) - return 1; - - /* - * We don't allow to remove mapping with the contiguous bit set. - * So shortcut the logic and directly return 1. - */ - if ( mfn_eq(mfn, INVALID_MFN) ) - return 1; - - /* - * The number of contiguous entries varies depending on the page - * granularity used. The logic below assumes 4KB. - */ - BUILD_BUG_ON(PAGE_SIZE != SZ_4K); - - /* - * In order to enable the contiguous bit, we should have enough entries - * to map left and both the virtual and physical address should be - * aligned to the size of 16 translation tables entries. - */ - nr_contig = BIT(XEN_PT_LEVEL_ORDER(level), UL) * XEN_PT_4K_NR_CONTIG; - - if ( (left < nr_contig) || ((mfn_x(mfn) | vfn) & (nr_contig - 1)) ) - return 1; - - return XEN_PT_4K_NR_CONTIG; -} - -static DEFINE_SPINLOCK(xen_pt_lock); - -static int xen_pt_update(unsigned long virt, - mfn_t mfn, - /* const on purpose as it is used for TLB flush */ - const unsigned long nr_mfns, - unsigned int flags) -{ - int rc = 0; - unsigned long vfn = virt >> PAGE_SHIFT; - unsigned long left = nr_mfns; - - /* - * For arm32, page-tables are different on each CPUs. Yet, they share - * some common mappings. It is assumed that only common mappings - * will be modified with this function. - * - * XXX: Add a check. - */ - const mfn_t root = maddr_to_mfn(READ_SYSREG64(TTBR0_EL2)); - - /* - * The hardware was configured to forbid mapping both writeable and - * executable. - * When modifying/creating mapping (i.e _PAGE_PRESENT is set), - * prevent any update if this happen. - */ - if ( (flags & _PAGE_PRESENT) && !PAGE_RO_MASK(flags) && - !PAGE_XN_MASK(flags) ) - { - mm_printk("Mappings should not be both Writeable and Executable.\n"); - return -EINVAL; - } - - if ( flags & _PAGE_CONTIG ) - { - mm_printk("_PAGE_CONTIG is an internal only flag.\n"); - return -EINVAL; - } - - if ( !IS_ALIGNED(virt, PAGE_SIZE) ) - { - mm_printk("The virtual address is not aligned to the page-size.\n"); - return -EINVAL; - } - - spin_lock(&xen_pt_lock); - - while ( left ) - { - unsigned int order, level, nr_contig, new_flags; - - level = xen_pt_mapping_level(vfn, mfn, left, flags); - order = XEN_PT_LEVEL_ORDER(level); - - ASSERT(left >= BIT(order, UL)); - - /* - * Check if we can set the contiguous mapping and update the - * flags accordingly. - */ - nr_contig = xen_pt_check_contig(vfn, mfn, level, left, flags); - new_flags = flags | ((nr_contig > 1) ? _PAGE_CONTIG : 0); - - for ( ; nr_contig > 0; nr_contig-- ) - { - rc = xen_pt_update_entry(root, vfn << PAGE_SHIFT, mfn, level, - new_flags); - if ( rc ) - break; - - vfn += 1U << order; - if ( !mfn_eq(mfn, INVALID_MFN) ) - mfn = mfn_add(mfn, 1U << order); - - left -= (1U << order); - } - - if ( rc ) - break; - } - - /* - * The TLBs flush can be safely skipped when a mapping is inserted - * as we don't allow mapping replacement (see xen_pt_check_entry()). - * Although we still need an ISB to ensure any DSB in - * write_pte() will complete because the mapping may be used soon - * after. - * - * For all the other cases, the TLBs will be flushed unconditionally - * even if the mapping has failed. This is because we may have - * partially modified the PT. This will prevent any unexpected - * behavior afterwards. - */ - if ( !((flags & _PAGE_PRESENT) && !mfn_eq(mfn, INVALID_MFN)) ) - flush_xen_tlb_range_va(virt, PAGE_SIZE * nr_mfns); - else - isb(); - - spin_unlock(&xen_pt_lock); - - return rc; -} - -int map_pages_to_xen(unsigned long virt, - mfn_t mfn, - unsigned long nr_mfns, - unsigned int flags) -{ - return xen_pt_update(virt, mfn, nr_mfns, flags); -} - -int __init populate_pt_range(unsigned long virt, unsigned long nr_mfns) -{ - return xen_pt_update(virt, INVALID_MFN, nr_mfns, _PAGE_POPULATE); -} - -int destroy_xen_mappings(unsigned long s, unsigned long e) -{ - ASSERT(IS_ALIGNED(s, PAGE_SIZE)); - ASSERT(IS_ALIGNED(e, PAGE_SIZE)); - ASSERT(s <= e); - return xen_pt_update(s, INVALID_MFN, (e - s) >> PAGE_SHIFT, 0); -} - -int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int flags) -{ - ASSERT(IS_ALIGNED(s, PAGE_SIZE)); - ASSERT(IS_ALIGNED(e, PAGE_SIZE)); - ASSERT(s <= e); - return xen_pt_update(s, INVALID_MFN, (e - s) >> PAGE_SHIFT, flags); -} - /* Release all __init and __initdata ranges to be reused */ void free_init_memory(void) { diff --git a/xen/arch/arm/mmu/Makefile b/xen/arch/arm/mmu/Makefile new file mode 100644 index 0000000000..bdfc2e077d --- /dev/null +++ b/xen/arch/arm/mmu/Makefile @@ -0,0 +1 @@ +obj-y += pt.o diff --git a/xen/arch/arm/mmu/pt.c b/xen/arch/arm/mmu/pt.c new file mode 100644 index 0000000000..e6fc5ed45a --- /dev/null +++ b/xen/arch/arm/mmu/pt.c @@ -0,0 +1,736 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * xen/arch/arm/mmu/pt.c + * + * MMU system page table related functions. + */ + +#include <xen/domain_page.h> +#include <xen/init.h> +#include <xen/pfn.h> +#include <xen/sizes.h> +#include <xen/vmap.h> + +#include <asm/fixmap.h> + +#ifdef NDEBUG +static inline void +__attribute__ ((__format__ (__printf__, 1, 2))) +mm_printk(const char *fmt, ...) {} +#else +#define mm_printk(fmt, args...) \ + do \ + { \ + dprintk(XENLOG_ERR, fmt, ## args); \ + WARN(); \ + } while (0) +#endif + +#ifdef CONFIG_ARM_64 +#define HYP_PT_ROOT_LEVEL 0 +#else +#define HYP_PT_ROOT_LEVEL 1 +#endif + +static lpae_t *xen_map_table(mfn_t mfn) +{ + /* + * During early boot, map_domain_page() may be unusable. Use the + * PMAP to map temporarily a page-table. + */ + if ( system_state == SYS_STATE_early_boot ) + return pmap_map(mfn); + + return map_domain_page(mfn); +} + +static void xen_unmap_table(const lpae_t *table) +{ + /* + * During early boot, xen_map_table() will not use map_domain_page() + * but the PMAP. + */ + if ( system_state == SYS_STATE_early_boot ) + pmap_unmap(table); + else + unmap_domain_page(table); +} + +void dump_pt_walk(paddr_t ttbr, paddr_t addr, + unsigned int root_level, + unsigned int nr_root_tables) +{ + static const char *level_strs[4] = { "0TH", "1ST", "2ND", "3RD" }; + const mfn_t root_mfn = maddr_to_mfn(ttbr); + DECLARE_OFFSETS(offsets, addr); + lpae_t pte, *mapping; + unsigned int level, root_table; + +#ifdef CONFIG_ARM_32 + BUG_ON(root_level < 1); +#endif + BUG_ON(root_level > 3); + + if ( nr_root_tables > 1 ) + { + /* + * Concatenated root-level tables. The table number will be + * the offset at the previous level. It is not possible to + * concatenate a level-0 root. + */ + BUG_ON(root_level == 0); + root_table = offsets[root_level - 1]; + printk("Using concatenated root table %u\n", root_table); + if ( root_table >= nr_root_tables ) + { + printk("Invalid root table offset\n"); + return; + } + } + else + root_table = 0; + + mapping = xen_map_table(mfn_add(root_mfn, root_table)); + + for ( level = root_level; ; level++ ) + { + if ( offsets[level] > XEN_PT_LPAE_ENTRIES ) + break; + + pte = mapping[offsets[level]]; + + printk("%s[0x%03x] = 0x%"PRIx64"\n", + level_strs[level], offsets[level], pte.bits); + + if ( level == 3 || !pte.walk.valid || !pte.walk.table ) + break; + + /* For next iteration */ + xen_unmap_table(mapping); + mapping = xen_map_table(lpae_get_mfn(pte)); + } + + xen_unmap_table(mapping); +} + +void dump_hyp_walk(vaddr_t addr) +{ + uint64_t ttbr = READ_SYSREG64(TTBR0_EL2); + + printk("Walking Hypervisor VA 0x%"PRIvaddr" " + "on CPU%d via TTBR 0x%016"PRIx64"\n", + addr, smp_processor_id(), ttbr); + + dump_pt_walk(ttbr, addr, HYP_PT_ROOT_LEVEL, 1); +} + +lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned int attr) +{ + lpae_t e = (lpae_t) { + .pt = { + .valid = 1, /* Mappings are present */ + .table = 0, /* Set to 1 for links and 4k maps */ + .ai = attr, + .ns = 1, /* Hyp mode is in the non-secure world */ + .up = 1, /* See below */ + .ro = 0, /* Assume read-write */ + .af = 1, /* No need for access tracking */ + .ng = 1, /* Makes TLB flushes easier */ + .contig = 0, /* Assume non-contiguous */ + .xn = 1, /* No need to execute outside .text */ + .avail = 0, /* Reference count for domheap mapping */ + }}; + /* + * For EL2 stage-1 page table, up (aka AP[1]) is RES1 as the translation + * regime applies to only one exception level (see D4.4.4 and G4.6.1 + * in ARM DDI 0487B.a). If this changes, remember to update the + * hard-coded values in head.S too. + */ + + switch ( attr ) + { + case MT_NORMAL_NC: + /* + * ARM ARM: Overlaying the shareability attribute (DDI + * 0406C.b B3-1376 to 1377) + * + * A memory region with a resultant memory type attribute of Normal, + * and a resultant cacheability attribute of Inner Non-cacheable, + * Outer Non-cacheable, must have a resultant shareability attribute + * of Outer Shareable, otherwise shareability is UNPREDICTABLE. + * + * On ARMv8 sharability is ignored and explicitly treated as Outer + * Shareable for Normal Inner Non_cacheable, Outer Non-cacheable. + */ + e.pt.sh = LPAE_SH_OUTER; + break; + case MT_DEVICE_nGnRnE: + case MT_DEVICE_nGnRE: + /* + * Shareability is ignored for non-Normal memory, Outer is as + * good as anything. + * + * On ARMv8 sharability is ignored and explicitly treated as Outer + * Shareable for any device memory type. + */ + e.pt.sh = LPAE_SH_OUTER; + break; + default: + e.pt.sh = LPAE_SH_INNER; /* Xen mappings are SMP coherent */ + break; + } + + ASSERT(!(mfn_to_maddr(mfn) & ~PADDR_MASK)); + + lpae_set_mfn(e, mfn); + + return e; +} + +/* Map a 4k page in a fixmap entry */ +void set_fixmap(unsigned int map, mfn_t mfn, unsigned int flags) +{ + int res; + + res = map_pages_to_xen(FIXMAP_ADDR(map), mfn, 1, flags); + BUG_ON(res != 0); +} + +/* Remove a mapping from a fixmap entry */ +void clear_fixmap(unsigned int map) +{ + int res; + + res = destroy_xen_mappings(FIXMAP_ADDR(map), FIXMAP_ADDR(map) + PAGE_SIZE); + BUG_ON(res != 0); +} + +/* + * This function should only be used to remap device address ranges + * TODO: add a check to verify this assumption + */ +void *ioremap_attr(paddr_t start, size_t len, unsigned int attributes) +{ + mfn_t mfn = _mfn(PFN_DOWN(start)); + unsigned int offs = start & (PAGE_SIZE - 1); + unsigned int nr = PFN_UP(offs + len); + void *ptr = __vmap(&mfn, nr, 1, 1, attributes, VMAP_DEFAULT); + + if ( ptr == NULL ) + return NULL; + + return ptr + offs; +} + +void *ioremap(paddr_t pa, size_t len) +{ + return ioremap_attr(pa, len, PAGE_HYPERVISOR_NOCACHE); +} + +static int create_xen_table(lpae_t *entry) +{ + mfn_t mfn; + void *p; + lpae_t pte; + + if ( system_state != SYS_STATE_early_boot ) + { + struct page_info *pg = alloc_domheap_page(NULL, 0); + + if ( pg == NULL ) + return -ENOMEM; + + mfn = page_to_mfn(pg); + } + else + mfn = alloc_boot_pages(1, 1); + + p = xen_map_table(mfn); + clear_page(p); + xen_unmap_table(p); + + pte = mfn_to_xen_entry(mfn, MT_NORMAL); + pte.pt.table = 1; + write_pte(entry, pte); + /* + * No ISB here. It is deferred to xen_pt_update() as the new table + * will not be used for hardware translation table access as part of + * the mapping update. + */ + + return 0; +} + +#define XEN_TABLE_MAP_FAILED 0 +#define XEN_TABLE_SUPER_PAGE 1 +#define XEN_TABLE_NORMAL_PAGE 2 + +/* + * Take the currently mapped table, find the corresponding entry, + * and map the next table, if available. + * + * The read_only parameters indicates whether intermediate tables should + * be allocated when not present. + * + * Return values: + * XEN_TABLE_MAP_FAILED: Either read_only was set and the entry + * was empty, or allocating a new page failed. + * XEN_TABLE_NORMAL_PAGE: next level mapped normally + * XEN_TABLE_SUPER_PAGE: The next entry points to a superpage. + */ +static int xen_pt_next_level(bool read_only, unsigned int level, + lpae_t **table, unsigned int offset) +{ + lpae_t *entry; + int ret; + mfn_t mfn; + + entry = *table + offset; + + if ( !lpae_is_valid(*entry) ) + { + if ( read_only ) + return XEN_TABLE_MAP_FAILED; + + ret = create_xen_table(entry); + if ( ret ) + return XEN_TABLE_MAP_FAILED; + } + + /* The function xen_pt_next_level is never called at the 3rd level */ + if ( lpae_is_mapping(*entry, level) ) + return XEN_TABLE_SUPER_PAGE; + + mfn = lpae_get_mfn(*entry); + + xen_unmap_table(*table); + *table = xen_map_table(mfn); + + return XEN_TABLE_NORMAL_PAGE; +} + +/* Sanity check of the entry */ +static bool xen_pt_check_entry(lpae_t entry, mfn_t mfn, unsigned int level, + unsigned int flags) +{ + /* Sanity check when modifying an entry. */ + if ( (flags & _PAGE_PRESENT) && mfn_eq(mfn, INVALID_MFN) ) + { + /* We don't allow modifying an invalid entry. */ + if ( !lpae_is_valid(entry) ) + { + mm_printk("Modifying invalid entry is not allowed.\n"); + return false; + } + + /* We don't allow modifying a table entry */ + if ( !lpae_is_mapping(entry, level) ) + { + mm_printk("Modifying a table entry is not allowed.\n"); + return false; + } + + /* We don't allow changing memory attributes. */ + if ( entry.pt.ai != PAGE_AI_MASK(flags) ) + { + mm_printk("Modifying memory attributes is not allowed (0x%x -> 0x%x).\n", + entry.pt.ai, PAGE_AI_MASK(flags)); + return false; + } + + /* We don't allow modifying entry with contiguous bit set. */ + if ( entry.pt.contig ) + { + mm_printk("Modifying entry with contiguous bit set is not allowed.\n"); + return false; + } + } + /* Sanity check when inserting a mapping */ + else if ( flags & _PAGE_PRESENT ) + { + /* We should be here with a valid MFN. */ + ASSERT(!mfn_eq(mfn, INVALID_MFN)); + + /* + * We don't allow replacing any valid entry. + * + * Note that the function xen_pt_update() relies on this + * assumption and will skip the TLB flush. The function will need + * to be updated if the check is relaxed. + */ + if ( lpae_is_valid(entry) ) + { + if ( lpae_is_mapping(entry, level) ) + mm_printk("Changing MFN for a valid entry is not allowed (%#"PRI_mfn" -> %#"PRI_mfn").\n", + mfn_x(lpae_get_mfn(entry)), mfn_x(mfn)); + else + mm_printk("Trying to replace a table with a mapping.\n"); + return false; + } + } + /* Sanity check when removing a mapping. */ + else if ( (flags & (_PAGE_PRESENT|_PAGE_POPULATE)) == 0 ) + { + /* We should be here with an invalid MFN. */ + ASSERT(mfn_eq(mfn, INVALID_MFN)); + + /* We don't allow removing a table */ + if ( lpae_is_table(entry, level) ) + { + mm_printk("Removing a table is not allowed.\n"); + return false; + } + + /* We don't allow removing a mapping with contiguous bit set. */ + if ( entry.pt.contig ) + { + mm_printk("Removing entry with contiguous bit set is not allowed.\n"); + return false; + } + } + /* Sanity check when populating the page-table. No check so far. */ + else + { + ASSERT(flags & _PAGE_POPULATE); + /* We should be here with an invalid MFN */ + ASSERT(mfn_eq(mfn, INVALID_MFN)); + } + + return true; +} + +/* Update an entry at the level @target. */ +static int xen_pt_update_entry(mfn_t root, unsigned long virt, + mfn_t mfn, unsigned int target, + unsigned int flags) +{ + int rc; + unsigned int level; + lpae_t *table; + /* + * The intermediate page tables are read-only when the MFN is not valid + * and we are not populating page table. + * This means we either modify permissions or remove an entry. + */ + bool read_only = mfn_eq(mfn, INVALID_MFN) && !(flags & _PAGE_POPULATE); + lpae_t pte, *entry; + + /* convenience aliases */ + DECLARE_OFFSETS(offsets, (paddr_t)virt); + + /* _PAGE_POPULATE and _PAGE_PRESENT should never be set together. */ + ASSERT((flags & (_PAGE_POPULATE|_PAGE_PRESENT)) != (_PAGE_POPULATE|_PAGE_PRESENT)); + + table = xen_map_table(root); + for ( level = HYP_PT_ROOT_LEVEL; level < target; level++ ) + { + rc = xen_pt_next_level(read_only, level, &table, offsets[level]); + if ( rc == XEN_TABLE_MAP_FAILED ) + { + /* + * We are here because xen_pt_next_level has failed to map + * the intermediate page table (e.g the table does not exist + * and the pt is read-only). It is a valid case when + * removing a mapping as it may not exist in the page table. + * In this case, just ignore it. + */ + if ( flags & (_PAGE_PRESENT|_PAGE_POPULATE) ) + { + mm_printk("%s: Unable to map level %u\n", __func__, level); + rc = -ENOENT; + goto out; + } + else + { + rc = 0; + goto out; + } + } + else if ( rc != XEN_TABLE_NORMAL_PAGE ) + break; + } + + if ( level != target ) + { + mm_printk("%s: Shattering superpage is not supported\n", __func__); + rc = -EOPNOTSUPP; + goto out; + } + + entry = table + offsets[level]; + + rc = -EINVAL; + if ( !xen_pt_check_entry(*entry, mfn, level, flags) ) + goto out; + + /* If we are only populating page-table, then we are done. */ + rc = 0; + if ( flags & _PAGE_POPULATE ) + goto out; + + /* We are removing the page */ + if ( !(flags & _PAGE_PRESENT) ) + memset(&pte, 0x00, sizeof(pte)); + else + { + /* We are inserting a mapping => Create new pte. */ + if ( !mfn_eq(mfn, INVALID_MFN) ) + { + pte = mfn_to_xen_entry(mfn, PAGE_AI_MASK(flags)); + + /* + * First and second level pages set pte.pt.table = 0, but + * third level entries set pte.pt.table = 1. + */ + pte.pt.table = (level == 3); + } + else /* We are updating the permission => Copy the current pte. */ + pte = *entry; + + /* Set permission */ + pte.pt.ro = PAGE_RO_MASK(flags); + pte.pt.xn = PAGE_XN_MASK(flags); + /* Set contiguous bit */ + pte.pt.contig = !!(flags & _PAGE_CONTIG); + } + + write_pte(entry, pte); + /* + * No ISB or TLB flush here. They are deferred to xen_pt_update() + * as the entry will not be used as part of the mapping update. + */ + + rc = 0; + +out: + xen_unmap_table(table); + + return rc; +} + +/* Return the level where mapping should be done */ +static int xen_pt_mapping_level(unsigned long vfn, mfn_t mfn, unsigned long nr, + unsigned int flags) +{ + unsigned int level; + unsigned long mask; + + /* + * Don't take into account the MFN when removing mapping (i.e + * MFN_INVALID) to calculate the correct target order. + * + * Per the Arm Arm, `vfn` and `mfn` must be both superpage aligned. + * They are or-ed together and then checked against the size of + * each level. + * + * `left` is not included and checked separately to allow + * superpage mapping even if it is not properly aligned (the + * user may have asked to map 2MB + 4k). + */ + mask = !mfn_eq(mfn, INVALID_MFN) ? mfn_x(mfn) : 0; + mask |= vfn; + + /* + * Always use level 3 mapping unless the caller request block + * mapping. + */ + if ( likely(!(flags & _PAGE_BLOCK)) ) + level = 3; + else if ( !(mask & (BIT(FIRST_ORDER, UL) - 1)) && + (nr >= BIT(FIRST_ORDER, UL)) ) + level = 1; + else if ( !(mask & (BIT(SECOND_ORDER, UL) - 1)) && + (nr >= BIT(SECOND_ORDER, UL)) ) + level = 2; + else + level = 3; + + return level; +} + +#define XEN_PT_4K_NR_CONTIG 16 + +/* + * Check whether the contiguous bit can be set. Return the number of + * contiguous entry allowed. If not allowed, return 1. + */ +static unsigned int xen_pt_check_contig(unsigned long vfn, mfn_t mfn, + unsigned int level, unsigned long left, + unsigned int flags) +{ + unsigned long nr_contig; + + /* + * Allow the contiguous bit to set when the caller requests block + * mapping. + */ + if ( !(flags & _PAGE_BLOCK) ) + return 1; + + /* + * We don't allow to remove mapping with the contiguous bit set. + * So shortcut the logic and directly return 1. + */ + if ( mfn_eq(mfn, INVALID_MFN) ) + return 1; + + /* + * The number of contiguous entries varies depending on the page + * granularity used. The logic below assumes 4KB. + */ + BUILD_BUG_ON(PAGE_SIZE != SZ_4K); + + /* + * In order to enable the contiguous bit, we should have enough entries + * to map left and both the virtual and physical address should be + * aligned to the size of 16 translation tables entries. + */ + nr_contig = BIT(XEN_PT_LEVEL_ORDER(level), UL) * XEN_PT_4K_NR_CONTIG; + + if ( (left < nr_contig) || ((mfn_x(mfn) | vfn) & (nr_contig - 1)) ) + return 1; + + return XEN_PT_4K_NR_CONTIG; +} + +static DEFINE_SPINLOCK(xen_pt_lock); + +static int xen_pt_update(unsigned long virt, + mfn_t mfn, + /* const on purpose as it is used for TLB flush */ + const unsigned long nr_mfns, + unsigned int flags) +{ + int rc = 0; + unsigned long vfn = virt >> PAGE_SHIFT; + unsigned long left = nr_mfns; + + /* + * For arm32, page-tables are different on each CPUs. Yet, they share + * some common mappings. It is assumed that only common mappings + * will be modified with this function. + * + * XXX: Add a check. + */ + const mfn_t root = maddr_to_mfn(READ_SYSREG64(TTBR0_EL2)); + + /* + * The hardware was configured to forbid mapping both writeable and + * executable. + * When modifying/creating mapping (i.e _PAGE_PRESENT is set), + * prevent any update if this happen. + */ + if ( (flags & _PAGE_PRESENT) && !PAGE_RO_MASK(flags) && + !PAGE_XN_MASK(flags) ) + { + mm_printk("Mappings should not be both Writeable and Executable.\n"); + return -EINVAL; + } + + if ( flags & _PAGE_CONTIG ) + { + mm_printk("_PAGE_CONTIG is an internal only flag.\n"); + return -EINVAL; + } + + if ( !IS_ALIGNED(virt, PAGE_SIZE) ) + { + mm_printk("The virtual address is not aligned to the page-size.\n"); + return -EINVAL; + } + + spin_lock(&xen_pt_lock); + + while ( left ) + { + unsigned int order, level, nr_contig, new_flags; + + level = xen_pt_mapping_level(vfn, mfn, left, flags); + order = XEN_PT_LEVEL_ORDER(level); + + ASSERT(left >= BIT(order, UL)); + + /* + * Check if we can set the contiguous mapping and update the + * flags accordingly. + */ + nr_contig = xen_pt_check_contig(vfn, mfn, level, left, flags); + new_flags = flags | ((nr_contig > 1) ? _PAGE_CONTIG : 0); + + for ( ; nr_contig > 0; nr_contig-- ) + { + rc = xen_pt_update_entry(root, vfn << PAGE_SHIFT, mfn, level, + new_flags); + if ( rc ) + break; + + vfn += 1U << order; + if ( !mfn_eq(mfn, INVALID_MFN) ) + mfn = mfn_add(mfn, 1U << order); + + left -= (1U << order); + } + + if ( rc ) + break; + } + + /* + * The TLBs flush can be safely skipped when a mapping is inserted + * as we don't allow mapping replacement (see xen_pt_check_entry()). + * Although we still need an ISB to ensure any DSB in + * write_pte() will complete because the mapping may be used soon + * after. + * + * For all the other cases, the TLBs will be flushed unconditionally + * even if the mapping has failed. This is because we may have + * partially modified the PT. This will prevent any unexpected + * behavior afterwards. + */ + if ( !((flags & _PAGE_PRESENT) && !mfn_eq(mfn, INVALID_MFN)) ) + flush_xen_tlb_range_va(virt, PAGE_SIZE * nr_mfns); + else + isb(); + + spin_unlock(&xen_pt_lock); + + return rc; +} + +int map_pages_to_xen(unsigned long virt, + mfn_t mfn, + unsigned long nr_mfns, + unsigned int flags) +{ + return xen_pt_update(virt, mfn, nr_mfns, flags); +} + +int __init populate_pt_range(unsigned long virt, unsigned long nr_mfns) +{ + return xen_pt_update(virt, INVALID_MFN, nr_mfns, _PAGE_POPULATE); +} + +int destroy_xen_mappings(unsigned long s, unsigned long e) +{ + ASSERT(IS_ALIGNED(s, PAGE_SIZE)); + ASSERT(IS_ALIGNED(e, PAGE_SIZE)); + ASSERT(s <= e); + return xen_pt_update(s, INVALID_MFN, (e - s) >> PAGE_SHIFT, 0); +} + +int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int flags) +{ + ASSERT(IS_ALIGNED(s, PAGE_SIZE)); + ASSERT(IS_ALIGNED(e, PAGE_SIZE)); + ASSERT(s <= e); + return xen_pt_update(s, INVALID_MFN, (e - s) >> PAGE_SHIFT, flags); +} + +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */ -- 2.25.1
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