diff options
Diffstat (limited to 'arch/s390/mm/vmem.c')
| -rw-r--r-- | arch/s390/mm/vmem.c | 697 |
1 files changed, 697 insertions, 0 deletions
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c new file mode 100644 index 000000000..3cbb46182 --- /dev/null +++ b/arch/s390/mm/vmem.c @@ -0,0 +1,697 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright IBM Corp. 2006 + */ + +#include <linux/memory_hotplug.h> +#include <linux/memblock.h> +#include <linux/pfn.h> +#include <linux/mm.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/hugetlb.h> +#include <linux/slab.h> +#include <asm/page-states.h> +#include <asm/cacheflush.h> +#include <asm/nospec-branch.h> +#include <asm/pgalloc.h> +#include <asm/setup.h> +#include <asm/tlbflush.h> +#include <asm/sections.h> +#include <asm/set_memory.h> + +static DEFINE_MUTEX(vmem_mutex); + +static void __ref *vmem_alloc_pages(unsigned int order) +{ + unsigned long size = PAGE_SIZE << order; + + if (slab_is_available()) + return (void *)__get_free_pages(GFP_KERNEL, order); + return memblock_alloc(size, size); +} + +static void vmem_free_pages(unsigned long addr, int order) +{ + /* We don't expect boot memory to be removed ever. */ + if (!slab_is_available() || + WARN_ON_ONCE(PageReserved(virt_to_page(addr)))) + return; + free_pages(addr, order); +} + +void *vmem_crst_alloc(unsigned long val) +{ + unsigned long *table; + + table = vmem_alloc_pages(CRST_ALLOC_ORDER); + if (!table) + return NULL; + crst_table_init(table, val); + if (slab_is_available()) + arch_set_page_dat(virt_to_page(table), CRST_ALLOC_ORDER); + return table; +} + +pte_t __ref *vmem_pte_alloc(void) +{ + unsigned long size = PTRS_PER_PTE * sizeof(pte_t); + pte_t *pte; + + if (slab_is_available()) + pte = (pte_t *) page_table_alloc(&init_mm); + else + pte = (pte_t *) memblock_alloc(size, size); + if (!pte) + return NULL; + memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE); + return pte; +} + +static void vmem_pte_free(unsigned long *table) +{ + /* We don't expect boot memory to be removed ever. */ + if (!slab_is_available() || + WARN_ON_ONCE(PageReserved(virt_to_page(table)))) + return; + page_table_free(&init_mm, table); +} + +#define PAGE_UNUSED 0xFD + +/* + * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges + * from unused_sub_pmd_start to next PMD_SIZE boundary. + */ +static unsigned long unused_sub_pmd_start; + +static void vmemmap_flush_unused_sub_pmd(void) +{ + if (!unused_sub_pmd_start) + return; + memset((void *)unused_sub_pmd_start, PAGE_UNUSED, + ALIGN(unused_sub_pmd_start, PMD_SIZE) - unused_sub_pmd_start); + unused_sub_pmd_start = 0; +} + +static void vmemmap_mark_sub_pmd_used(unsigned long start, unsigned long end) +{ + /* + * As we expect to add in the same granularity as we remove, it's + * sufficient to mark only some piece used to block the memmap page from + * getting removed (just in case the memmap never gets initialized, + * e.g., because the memory block never gets onlined). + */ + memset((void *)start, 0, sizeof(struct page)); +} + +static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end) +{ + /* + * We only optimize if the new used range directly follows the + * previously unused range (esp., when populating consecutive sections). + */ + if (unused_sub_pmd_start == start) { + unused_sub_pmd_start = end; + if (likely(IS_ALIGNED(unused_sub_pmd_start, PMD_SIZE))) + unused_sub_pmd_start = 0; + return; + } + vmemmap_flush_unused_sub_pmd(); + vmemmap_mark_sub_pmd_used(start, end); +} + +static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end) +{ + unsigned long page = ALIGN_DOWN(start, PMD_SIZE); + + vmemmap_flush_unused_sub_pmd(); + + /* Could be our memmap page is filled with PAGE_UNUSED already ... */ + vmemmap_mark_sub_pmd_used(start, end); + + /* Mark the unused parts of the new memmap page PAGE_UNUSED. */ + if (!IS_ALIGNED(start, PMD_SIZE)) + memset((void *)page, PAGE_UNUSED, start - page); + /* + * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of + * consecutive sections. Remember for the last added PMD the last + * unused range in the populated PMD. + */ + if (!IS_ALIGNED(end, PMD_SIZE)) + unused_sub_pmd_start = end; +} + +/* Returns true if the PMD is completely unused and can be freed. */ +static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end) +{ + unsigned long page = ALIGN_DOWN(start, PMD_SIZE); + + vmemmap_flush_unused_sub_pmd(); + memset((void *)start, PAGE_UNUSED, end - start); + return !memchr_inv((void *)page, PAGE_UNUSED, PMD_SIZE); +} + +/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */ +static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr, + unsigned long end, bool add, bool direct) +{ + unsigned long prot, pages = 0; + int ret = -ENOMEM; + pte_t *pte; + + prot = pgprot_val(PAGE_KERNEL); + if (!MACHINE_HAS_NX) + prot &= ~_PAGE_NOEXEC; + + pte = pte_offset_kernel(pmd, addr); + for (; addr < end; addr += PAGE_SIZE, pte++) { + if (!add) { + if (pte_none(*pte)) + continue; + if (!direct) + vmem_free_pages((unsigned long) pfn_to_virt(pte_pfn(*pte)), 0); + pte_clear(&init_mm, addr, pte); + } else if (pte_none(*pte)) { + if (!direct) { + void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); + + if (!new_page) + goto out; + set_pte(pte, __pte(__pa(new_page) | prot)); + } else { + set_pte(pte, __pte(__pa(addr) | prot)); + } + } else { + continue; + } + pages++; + } + ret = 0; +out: + if (direct) + update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages); + return ret; +} + +static void try_free_pte_table(pmd_t *pmd, unsigned long start) +{ + pte_t *pte; + int i; + + /* We can safely assume this is fully in 1:1 mapping & vmemmap area */ + pte = pte_offset_kernel(pmd, start); + for (i = 0; i < PTRS_PER_PTE; i++, pte++) { + if (!pte_none(*pte)) + return; + } + vmem_pte_free((unsigned long *) pmd_deref(*pmd)); + pmd_clear(pmd); +} + +/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */ +static int __ref modify_pmd_table(pud_t *pud, unsigned long addr, + unsigned long end, bool add, bool direct) +{ + unsigned long next, prot, pages = 0; + int ret = -ENOMEM; + pmd_t *pmd; + pte_t *pte; + + prot = pgprot_val(SEGMENT_KERNEL); + if (!MACHINE_HAS_NX) + prot &= ~_SEGMENT_ENTRY_NOEXEC; + + pmd = pmd_offset(pud, addr); + for (; addr < end; addr = next, pmd++) { + next = pmd_addr_end(addr, end); + if (!add) { + if (pmd_none(*pmd)) + continue; + if (pmd_large(*pmd)) { + if (IS_ALIGNED(addr, PMD_SIZE) && + IS_ALIGNED(next, PMD_SIZE)) { + if (!direct) + vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE)); + pmd_clear(pmd); + pages++; + } else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) { + vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE)); + pmd_clear(pmd); + } + continue; + } + } else if (pmd_none(*pmd)) { + if (IS_ALIGNED(addr, PMD_SIZE) && + IS_ALIGNED(next, PMD_SIZE) && + MACHINE_HAS_EDAT1 && direct && + !debug_pagealloc_enabled()) { + set_pmd(pmd, __pmd(__pa(addr) | prot)); + pages++; + continue; + } else if (!direct && MACHINE_HAS_EDAT1) { + void *new_page; + + /* + * Use 1MB frames for vmemmap if available. We + * always use large frames even if they are only + * partially used. Otherwise we would have also + * page tables since vmemmap_populate gets + * called for each section separately. + */ + new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE); + if (new_page) { + set_pmd(pmd, __pmd(__pa(new_page) | prot)); + if (!IS_ALIGNED(addr, PMD_SIZE) || + !IS_ALIGNED(next, PMD_SIZE)) { + vmemmap_use_new_sub_pmd(addr, next); + } + continue; + } + } + pte = vmem_pte_alloc(); + if (!pte) + goto out; + pmd_populate(&init_mm, pmd, pte); + } else if (pmd_large(*pmd)) { + if (!direct) + vmemmap_use_sub_pmd(addr, next); + continue; + } + ret = modify_pte_table(pmd, addr, next, add, direct); + if (ret) + goto out; + if (!add) + try_free_pte_table(pmd, addr & PMD_MASK); + } + ret = 0; +out: + if (direct) + update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages); + return ret; +} + +static void try_free_pmd_table(pud_t *pud, unsigned long start) +{ + const unsigned long end = start + PUD_SIZE; + pmd_t *pmd; + int i; + + /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */ + if (end > VMALLOC_START) + return; +#ifdef CONFIG_KASAN + if (start < KASAN_SHADOW_END && end > KASAN_SHADOW_START) + return; +#endif + pmd = pmd_offset(pud, start); + for (i = 0; i < PTRS_PER_PMD; i++, pmd++) + if (!pmd_none(*pmd)) + return; + vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER); + pud_clear(pud); +} + +static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end, + bool add, bool direct) +{ + unsigned long next, prot, pages = 0; + int ret = -ENOMEM; + pud_t *pud; + pmd_t *pmd; + + prot = pgprot_val(REGION3_KERNEL); + if (!MACHINE_HAS_NX) + prot &= ~_REGION_ENTRY_NOEXEC; + pud = pud_offset(p4d, addr); + for (; addr < end; addr = next, pud++) { + next = pud_addr_end(addr, end); + if (!add) { + if (pud_none(*pud)) + continue; + if (pud_large(*pud)) { + if (IS_ALIGNED(addr, PUD_SIZE) && + IS_ALIGNED(next, PUD_SIZE)) { + pud_clear(pud); + pages++; + } + continue; + } + } else if (pud_none(*pud)) { + if (IS_ALIGNED(addr, PUD_SIZE) && + IS_ALIGNED(next, PUD_SIZE) && + MACHINE_HAS_EDAT2 && direct && + !debug_pagealloc_enabled()) { + set_pud(pud, __pud(__pa(addr) | prot)); + pages++; + continue; + } + pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); + if (!pmd) + goto out; + pud_populate(&init_mm, pud, pmd); + } else if (pud_large(*pud)) { + continue; + } + ret = modify_pmd_table(pud, addr, next, add, direct); + if (ret) + goto out; + if (!add) + try_free_pmd_table(pud, addr & PUD_MASK); + } + ret = 0; +out: + if (direct) + update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages); + return ret; +} + +static void try_free_pud_table(p4d_t *p4d, unsigned long start) +{ + const unsigned long end = start + P4D_SIZE; + pud_t *pud; + int i; + + /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */ + if (end > VMALLOC_START) + return; +#ifdef CONFIG_KASAN + if (start < KASAN_SHADOW_END && end > KASAN_SHADOW_START) + return; +#endif + + pud = pud_offset(p4d, start); + for (i = 0; i < PTRS_PER_PUD; i++, pud++) { + if (!pud_none(*pud)) + return; + } + vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER); + p4d_clear(p4d); +} + +static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end, + bool add, bool direct) +{ + unsigned long next; + int ret = -ENOMEM; + p4d_t *p4d; + pud_t *pud; + + p4d = p4d_offset(pgd, addr); + for (; addr < end; addr = next, p4d++) { + next = p4d_addr_end(addr, end); + if (!add) { + if (p4d_none(*p4d)) + continue; + } else if (p4d_none(*p4d)) { + pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); + if (!pud) + goto out; + p4d_populate(&init_mm, p4d, pud); + } + ret = modify_pud_table(p4d, addr, next, add, direct); + if (ret) + goto out; + if (!add) + try_free_pud_table(p4d, addr & P4D_MASK); + } + ret = 0; +out: + return ret; +} + +static void try_free_p4d_table(pgd_t *pgd, unsigned long start) +{ + const unsigned long end = start + PGDIR_SIZE; + p4d_t *p4d; + int i; + + /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */ + if (end > VMALLOC_START) + return; +#ifdef CONFIG_KASAN + if (start < KASAN_SHADOW_END && end > KASAN_SHADOW_START) + return; +#endif + + p4d = p4d_offset(pgd, start); + for (i = 0; i < PTRS_PER_P4D; i++, p4d++) { + if (!p4d_none(*p4d)) + return; + } + vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER); + pgd_clear(pgd); +} + +static int modify_pagetable(unsigned long start, unsigned long end, bool add, + bool direct) +{ + unsigned long addr, next; + int ret = -ENOMEM; + pgd_t *pgd; + p4d_t *p4d; + + if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end))) + return -EINVAL; + for (addr = start; addr < end; addr = next) { + next = pgd_addr_end(addr, end); + pgd = pgd_offset_k(addr); + + if (!add) { + if (pgd_none(*pgd)) + continue; + } else if (pgd_none(*pgd)) { + p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); + if (!p4d) + goto out; + pgd_populate(&init_mm, pgd, p4d); + } + ret = modify_p4d_table(pgd, addr, next, add, direct); + if (ret) + goto out; + if (!add) + try_free_p4d_table(pgd, addr & PGDIR_MASK); + } + ret = 0; +out: + if (!add) + flush_tlb_kernel_range(start, end); + return ret; +} + +static int add_pagetable(unsigned long start, unsigned long end, bool direct) +{ + return modify_pagetable(start, end, true, direct); +} + +static int remove_pagetable(unsigned long start, unsigned long end, bool direct) +{ + return modify_pagetable(start, end, false, direct); +} + +/* + * Add a physical memory range to the 1:1 mapping. + */ +static int vmem_add_range(unsigned long start, unsigned long size) +{ + return add_pagetable(start, start + size, true); +} + +/* + * Remove a physical memory range from the 1:1 mapping. + */ +static void vmem_remove_range(unsigned long start, unsigned long size) +{ + remove_pagetable(start, start + size, true); +} + +/* + * Add a backed mem_map array to the virtual mem_map array. + */ +int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, + struct vmem_altmap *altmap) +{ + int ret; + + mutex_lock(&vmem_mutex); + /* We don't care about the node, just use NUMA_NO_NODE on allocations */ + ret = add_pagetable(start, end, false); + if (ret) + remove_pagetable(start, end, false); + mutex_unlock(&vmem_mutex); + return ret; +} + +void vmemmap_free(unsigned long start, unsigned long end, + struct vmem_altmap *altmap) +{ + mutex_lock(&vmem_mutex); + remove_pagetable(start, end, false); + mutex_unlock(&vmem_mutex); +} + +void vmem_remove_mapping(unsigned long start, unsigned long size) +{ + mutex_lock(&vmem_mutex); + vmem_remove_range(start, size); + mutex_unlock(&vmem_mutex); +} + +struct range arch_get_mappable_range(void) +{ + struct range mhp_range; + + mhp_range.start = 0; + mhp_range.end = VMEM_MAX_PHYS - 1; + return mhp_range; +} + +int vmem_add_mapping(unsigned long start, unsigned long size) +{ + struct range range = arch_get_mappable_range(); + int ret; + + if (start < range.start || + start + size > range.end + 1 || + start + size < start) + return -ERANGE; + + mutex_lock(&vmem_mutex); + ret = vmem_add_range(start, size); + if (ret) + vmem_remove_range(start, size); + mutex_unlock(&vmem_mutex); + return ret; +} + +/* + * Allocate new or return existing page-table entry, but do not map it + * to any physical address. If missing, allocate segment- and region- + * table entries along. Meeting a large segment- or region-table entry + * while traversing is an error, since the function is expected to be + * called against virtual regions reserverd for 4KB mappings only. + */ +pte_t *vmem_get_alloc_pte(unsigned long addr, bool alloc) +{ + pte_t *ptep = NULL; + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = pgd_offset_k(addr); + if (pgd_none(*pgd)) { + if (!alloc) + goto out; + p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); + if (!p4d) + goto out; + pgd_populate(&init_mm, pgd, p4d); + } + p4d = p4d_offset(pgd, addr); + if (p4d_none(*p4d)) { + if (!alloc) + goto out; + pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); + if (!pud) + goto out; + p4d_populate(&init_mm, p4d, pud); + } + pud = pud_offset(p4d, addr); + if (pud_none(*pud)) { + if (!alloc) + goto out; + pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); + if (!pmd) + goto out; + pud_populate(&init_mm, pud, pmd); + } else if (WARN_ON_ONCE(pud_large(*pud))) { + goto out; + } + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) { + if (!alloc) + goto out; + pte = vmem_pte_alloc(); + if (!pte) + goto out; + pmd_populate(&init_mm, pmd, pte); + } else if (WARN_ON_ONCE(pmd_large(*pmd))) { + goto out; + } + ptep = pte_offset_kernel(pmd, addr); +out: + return ptep; +} + +int __vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot, bool alloc) +{ + pte_t *ptep, pte; + + if (!IS_ALIGNED(addr, PAGE_SIZE)) + return -EINVAL; + ptep = vmem_get_alloc_pte(addr, alloc); + if (!ptep) + return -ENOMEM; + __ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL); + pte = mk_pte_phys(phys, prot); + set_pte(ptep, pte); + return 0; +} + +int vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot) +{ + int rc; + + mutex_lock(&vmem_mutex); + rc = __vmem_map_4k_page(addr, phys, prot, true); + mutex_unlock(&vmem_mutex); + return rc; +} + +void vmem_unmap_4k_page(unsigned long addr) +{ + pte_t *ptep; + + mutex_lock(&vmem_mutex); + ptep = virt_to_kpte(addr); + __ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL); + pte_clear(&init_mm, addr, ptep); + mutex_unlock(&vmem_mutex); +} + +/* + * map whole physical memory to virtual memory (identity mapping) + * we reserve enough space in the vmalloc area for vmemmap to hotplug + * additional memory segments. + */ +void __init vmem_map_init(void) +{ + phys_addr_t base, end; + u64 i; + + for_each_mem_range(i, &base, &end) + vmem_add_range(base, end - base); + __set_memory((unsigned long)_stext, + (unsigned long)(_etext - _stext) >> PAGE_SHIFT, + SET_MEMORY_RO | SET_MEMORY_X); + __set_memory((unsigned long)_etext, + (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT, + SET_MEMORY_RO); + __set_memory((unsigned long)_sinittext, + (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT, + SET_MEMORY_RO | SET_MEMORY_X); + __set_memory(__stext_amode31, (__etext_amode31 - __stext_amode31) >> PAGE_SHIFT, + SET_MEMORY_RO | SET_MEMORY_X); + + /* lowcore requires 4k mapping for real addresses / prefixing */ + set_memory_4k(0, LC_PAGES); + + /* lowcore must be executable for LPSWE */ + if (!static_key_enabled(&cpu_has_bear)) + set_memory_x(0, 1); + + pr_info("Write protected kernel read-only data: %luk\n", + (unsigned long)(__end_rodata - _stext) >> 10); +} |