From c9b5ad546e7d486465a3dd8c89245ac3707a4384 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 14 Jun 2016 12:56:01 +0200 Subject: s390/mm: tag normal pages vs pages used in page tables The ESSA instruction has a new option that allows to tag pages that are not used as a page table. Without the tag the hypervisor has to assume that any guest page could be used in a page table inside the guest. This forces the hypervisor to flush all guest TLB entries whenever a host page table entry is invalidated. With the tag the host can skip the TLB flush if the page is tagged as normal page. Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/page-states.h | 1 + arch/s390/include/asm/page.h | 3 + arch/s390/include/asm/setup.h | 3 +- arch/s390/kernel/suspend.c | 24 ++++- arch/s390/kernel/vdso.c | 2 + arch/s390/mm/init.c | 2 + arch/s390/mm/page-states.c | 192 +++++++++++++++++++++++++++++++++--- arch/s390/mm/pgalloc.c | 2 + 8 files changed, 208 insertions(+), 21 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/page-states.h b/arch/s390/include/asm/page-states.h index 42267a2..ca21b28 100644 --- a/arch/s390/include/asm/page-states.h +++ b/arch/s390/include/asm/page-states.h @@ -13,6 +13,7 @@ #define ESSA_SET_POT_VOLATILE 4 #define ESSA_SET_STABLE_RESIDENT 5 #define ESSA_SET_STABLE_IF_RESIDENT 6 +#define ESSA_SET_STABLE_NODAT 7 #define ESSA_MAX ESSA_SET_STABLE_IF_RESIDENT diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h index 624deaa..b463df8 100644 --- a/arch/s390/include/asm/page.h +++ b/arch/s390/include/asm/page.h @@ -133,6 +133,9 @@ static inline int page_reset_referenced(unsigned long addr) struct page; void arch_free_page(struct page *page, int order); void arch_alloc_page(struct page *page, int order); +void arch_set_page_dat(struct page *page, int order); +void arch_set_page_nodat(struct page *page, int order); +int arch_test_page_nodat(struct page *page); void arch_set_page_states(int make_stable); static inline int devmem_is_allowed(unsigned long pfn) diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h index cd78155..11e59ba 100644 --- a/arch/s390/include/asm/setup.h +++ b/arch/s390/include/asm/setup.h @@ -106,7 +106,8 @@ extern void pfault_fini(void); void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault); -extern void cmma_init(void); +void cmma_init(void); +void cmma_init_nodat(void); extern void (*_machine_restart)(char *command); extern void (*_machine_halt)(void); diff --git a/arch/s390/kernel/suspend.c b/arch/s390/kernel/suspend.c index 39e2f41..c8ea715 100644 --- a/arch/s390/kernel/suspend.c +++ b/arch/s390/kernel/suspend.c @@ -98,10 +98,16 @@ int page_key_alloc(unsigned long pages) */ void page_key_read(unsigned long *pfn) { + struct page *page; unsigned long addr; - - addr = (unsigned long) page_address(pfn_to_page(*pfn)); - *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr); + unsigned char key; + + page = pfn_to_page(*pfn); + addr = (unsigned long) page_address(page); + key = (unsigned char) page_get_storage_key(addr) & 0x7f; + if (arch_test_page_nodat(page)) + key |= 0x80; + *(unsigned char *) pfn = key; } /* @@ -126,8 +132,16 @@ void page_key_memorize(unsigned long *pfn) */ void page_key_write(void *address) { - page_set_storage_key((unsigned long) address, - page_key_rp->data[page_key_rx], 0); + struct page *page; + unsigned char key; + + key = page_key_rp->data[page_key_rx]; + page_set_storage_key((unsigned long) address, key & 0x7f, 0); + page = virt_to_page(address); + if (key & 0x80) + arch_set_page_nodat(page, 0); + else + arch_set_page_dat(page, 0); if (++page_key_rx >= PAGE_KEY_DATA_SIZE) return; page_key_rp = page_key_rp->next; diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c index b89d19f6..eacda05 100644 --- a/arch/s390/kernel/vdso.c +++ b/arch/s390/kernel/vdso.c @@ -157,6 +157,8 @@ int vdso_alloc_per_cpu(struct lowcore *lowcore) page_frame = get_zeroed_page(GFP_KERNEL); if (!segment_table || !page_table || !page_frame) goto out; + arch_set_page_dat(virt_to_page(segment_table), SEGMENT_ORDER); + arch_set_page_dat(virt_to_page(page_table), 0); /* Initialize per-cpu vdso data page */ vd = (struct vdso_per_cpu_data *) page_frame; diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 8111694..3aee54b 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -137,6 +137,8 @@ void __init mem_init(void) free_all_bootmem(); setup_zero_pages(); /* Setup zeroed pages. */ + cmma_init_nodat(); + mem_init_print_info(NULL); } diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c index 69a7b01..07fa7b8 100644 --- a/arch/s390/mm/page-states.c +++ b/arch/s390/mm/page-states.c @@ -10,9 +10,10 @@ #include #include #include +#include #include #include - +#include #include static int cmma_flag = 1; @@ -36,14 +37,16 @@ __setup("cmma=", cmma); static inline int cmma_test_essa(void) { register unsigned long tmp asm("0") = 0; - register int rc asm("1") = -EOPNOTSUPP; + register int rc asm("1"); + /* test ESSA_GET_STATE */ asm volatile( - " .insn rrf,0xb9ab0000,%1,%1,0,0\n" + " .insn rrf,0xb9ab0000,%1,%1,%2,0\n" "0: la %0,0\n" "1:\n" EX_TABLE(0b,1b) - : "+&d" (rc), "+&d" (tmp)); + : "=&d" (rc), "+&d" (tmp) + : "i" (ESSA_GET_STATE), "0" (-EOPNOTSUPP)); return rc; } @@ -51,11 +54,26 @@ void __init cmma_init(void) { if (!cmma_flag) return; - if (cmma_test_essa()) + if (cmma_test_essa()) { cmma_flag = 0; + return; + } + if (test_facility(147)) + cmma_flag = 2; } -static inline void set_page_unstable(struct page *page, int order) +static inline unsigned char get_page_state(struct page *page) +{ + unsigned char state; + + asm volatile(" .insn rrf,0xb9ab0000,%0,%1,%2,0" + : "=&d" (state) + : "a" (page_to_phys(page)), + "i" (ESSA_GET_STATE)); + return state & 0x3f; +} + +static inline void set_page_unused(struct page *page, int order) { int i, rc; @@ -66,14 +84,18 @@ static inline void set_page_unstable(struct page *page, int order) "i" (ESSA_SET_UNUSED)); } -void arch_free_page(struct page *page, int order) +static inline void set_page_stable_dat(struct page *page, int order) { - if (!cmma_flag) - return; - set_page_unstable(page, order); + int i, rc; + + for (i = 0; i < (1 << order); i++) + asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" + : "=&d" (rc) + : "a" (page_to_phys(page + i)), + "i" (ESSA_SET_STABLE)); } -static inline void set_page_stable(struct page *page, int order) +static inline void set_page_stable_nodat(struct page *page, int order) { int i, rc; @@ -81,14 +103,154 @@ static inline void set_page_stable(struct page *page, int order) asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" : "=&d" (rc) : "a" (page_to_phys(page + i)), - "i" (ESSA_SET_STABLE)); + "i" (ESSA_SET_STABLE_NODAT)); +} + +static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end) +{ + unsigned long next; + struct page *page; + pmd_t *pmd; + + pmd = pmd_offset(pud, addr); + do { + next = pmd_addr_end(addr, end); + if (pmd_none(*pmd) || pmd_large(*pmd)) + continue; + page = virt_to_page(pmd_val(*pmd)); + set_bit(PG_arch_1, &page->flags); + } while (pmd++, addr = next, addr != end); +} + +static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end) +{ + unsigned long next; + struct page *page; + pud_t *pud; + int i; + + pud = pud_offset(p4d, addr); + do { + next = pud_addr_end(addr, end); + if (pud_none(*pud) || pud_large(*pud)) + continue; + if (!pud_folded(*pud)) { + page = virt_to_page(pud_val(*pud)); + for (i = 0; i < 3; i++) + set_bit(PG_arch_1, &page[i].flags); + } + mark_kernel_pmd(pud, addr, next); + } while (pud++, addr = next, addr != end); +} + +static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end) +{ + unsigned long next; + struct page *page; + p4d_t *p4d; + int i; + + p4d = p4d_offset(pgd, addr); + do { + next = p4d_addr_end(addr, end); + if (p4d_none(*p4d)) + continue; + if (!p4d_folded(*p4d)) { + page = virt_to_page(p4d_val(*p4d)); + for (i = 0; i < 3; i++) + set_bit(PG_arch_1, &page[i].flags); + } + mark_kernel_pud(p4d, addr, next); + } while (p4d++, addr = next, addr != end); +} + +static void mark_kernel_pgd(void) +{ + unsigned long addr, next; + struct page *page; + pgd_t *pgd; + int i; + + addr = 0; + pgd = pgd_offset_k(addr); + do { + next = pgd_addr_end(addr, MODULES_END); + if (pgd_none(*pgd)) + continue; + if (!pgd_folded(*pgd)) { + page = virt_to_page(pgd_val(*pgd)); + for (i = 0; i < 3; i++) + set_bit(PG_arch_1, &page[i].flags); + } + mark_kernel_p4d(pgd, addr, next); + } while (pgd++, addr = next, addr != MODULES_END); +} + +void __init cmma_init_nodat(void) +{ + struct memblock_region *reg; + struct page *page; + unsigned long start, end, ix; + + if (cmma_flag < 2) + return; + /* Mark pages used in kernel page tables */ + mark_kernel_pgd(); + + /* Set all kernel pages not used for page tables to stable/no-dat */ + for_each_memblock(memory, reg) { + start = memblock_region_memory_base_pfn(reg); + end = memblock_region_memory_end_pfn(reg); + page = pfn_to_page(start); + for (ix = start; ix < end; ix++, page++) { + if (__test_and_clear_bit(PG_arch_1, &page->flags)) + continue; /* skip page table pages */ + if (!list_empty(&page->lru)) + continue; /* skip free pages */ + set_page_stable_nodat(page, 0); + } + } +} + +void arch_free_page(struct page *page, int order) +{ + if (!cmma_flag) + return; + set_page_unused(page, order); } void arch_alloc_page(struct page *page, int order) { if (!cmma_flag) return; - set_page_stable(page, order); + if (cmma_flag < 2) + set_page_stable_dat(page, order); + else + set_page_stable_nodat(page, order); +} + +void arch_set_page_dat(struct page *page, int order) +{ + if (!cmma_flag) + return; + set_page_stable_dat(page, order); +} + +void arch_set_page_nodat(struct page *page, int order) +{ + if (cmma_flag < 2) + return; + set_page_stable_nodat(page, order); +} + +int arch_test_page_nodat(struct page *page) +{ + unsigned char state; + + if (cmma_flag < 2) + return 0; + state = get_page_state(page); + return !!(state & 0x20); } void arch_set_page_states(int make_stable) @@ -108,9 +270,9 @@ void arch_set_page_states(int make_stable) list_for_each(l, &zone->free_area[order].free_list[t]) { page = list_entry(l, struct page, lru); if (make_stable) - set_page_stable(page, order); + set_page_stable_dat(page, 0); else - set_page_unstable(page, order); + set_page_unused(page, order); } } spin_unlock_irqrestore(&zone->lock, flags); diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c index 18918e3..a4de34c 100644 --- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -57,6 +57,7 @@ unsigned long *crst_table_alloc(struct mm_struct *mm) if (!page) return NULL; + arch_set_page_dat(page, 2); return (unsigned long *) page_to_phys(page); } @@ -214,6 +215,7 @@ unsigned long *page_table_alloc(struct mm_struct *mm) __free_page(page); return NULL; } + arch_set_page_dat(page, 0); /* Initialize page table */ table = (unsigned long *) page_to_phys(page); if (mm_alloc_pgste(mm)) { -- cgit v1.1