From e19f97ed67d8f9b60e4ce14a7551d3dd45825570 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Wed, 4 Dec 2019 16:54:28 -0800 Subject: [PATCH] um: add support for folded p4d page tables The UML port uses 4 and 5 level fixups to support higher level page table directories in the generic VM code. Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate and drop usage of __ARCH_USE_5LEVEL_HACK. Link: http://lkml.kernel.org/r/1572938135-31886-13-git-send-email-rppt@kernel.org Signed-off-by: Mike Rapoport Cc: Anatoly Pugachev Cc: Anton Ivanov Cc: Arnd Bergmann Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Helge Deller Cc: "James E.J. Bottomley" Cc: Jeff Dike Cc: "Kirill A. Shutemov" Cc: Mark Salter Cc: Matt Turner Cc: Michal Simek Cc: Peter Rosin Cc: Richard Weinberger Cc: Rolf Eike Beer Cc: Russell King Cc: Russell King Cc: Sam Creasey Cc: Vincent Chen Cc: Vineet Gupta Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/include/asm/pgtable-2level.h | 1 - arch/um/include/asm/pgtable-3level.h | 1 - arch/um/include/asm/pgtable.h | 3 ++ arch/um/kernel/mem.c | 8 +++- arch/um/kernel/skas/mmu.c | 12 +++++- arch/um/kernel/skas/uaccess.c | 7 +++- arch/um/kernel/tlb.c | 56 +++++++++++++++++++++++++--- arch/um/kernel/trap.c | 4 +- 8 files changed, 78 insertions(+), 14 deletions(-) diff --git a/arch/um/include/asm/pgtable-2level.h b/arch/um/include/asm/pgtable-2level.h index 32b3d26a7109..32106d31e4ab 100644 --- a/arch/um/include/asm/pgtable-2level.h +++ b/arch/um/include/asm/pgtable-2level.h @@ -8,7 +8,6 @@ #ifndef __UM_PGTABLE_2LEVEL_H #define __UM_PGTABLE_2LEVEL_H -#define __ARCH_USE_5LEVEL_HACK #include /* PGDIR_SHIFT determines what a third-level page table entry can map */ diff --git a/arch/um/include/asm/pgtable-3level.h b/arch/um/include/asm/pgtable-3level.h index 9812269fefc9..8a3b689e0f86 100644 --- a/arch/um/include/asm/pgtable-3level.h +++ b/arch/um/include/asm/pgtable-3level.h @@ -7,7 +7,6 @@ #ifndef __UM_PGTABLE_3LEVEL_H #define __UM_PGTABLE_3LEVEL_H -#define __ARCH_USE_5LEVEL_HACK #include /* PGDIR_SHIFT determines what a third-level page table entry can map */ diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h index 36a44d58f373..2daa58df2190 100644 --- a/arch/um/include/asm/pgtable.h +++ b/arch/um/include/asm/pgtable.h @@ -106,6 +106,9 @@ extern unsigned long end_iomem; #define pud_newpage(x) (pud_val(x) & _PAGE_NEWPAGE) #define pud_mkuptodate(x) (pud_val(x) &= ~_PAGE_NEWPAGE) +#define p4d_newpage(x) (p4d_val(x) & _PAGE_NEWPAGE) +#define p4d_mkuptodate(x) (p4d_val(x) &= ~_PAGE_NEWPAGE) + #define pmd_page(pmd) phys_to_page(pmd_val(pmd) & PAGE_MASK) #define pte_page(x) pfn_to_page(pte_pfn(x)) diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c index 417ff647fb37..30885d0b94ac 100644 --- a/arch/um/kernel/mem.c +++ b/arch/um/kernel/mem.c @@ -96,6 +96,7 @@ static void __init fixrange_init(unsigned long start, unsigned long end, pgd_t *pgd_base) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; int i, j; @@ -107,7 +108,8 @@ static void __init fixrange_init(unsigned long start, unsigned long end, pgd = pgd_base + i; for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { - pud = pud_offset(pgd, vaddr); + p4d = p4d_offset(pgd, vaddr); + pud = pud_offset(p4d, vaddr); if (pud_none(*pud)) one_md_table_init(pud); pmd = pmd_offset(pud, vaddr); @@ -124,6 +126,7 @@ static void __init fixaddr_user_init( void) #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA long size = FIXADDR_USER_END - FIXADDR_USER_START; pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -144,7 +147,8 @@ static void __init fixaddr_user_init( void) for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, p += PAGE_SIZE) { pgd = swapper_pg_dir + pgd_index(vaddr); - pud = pud_offset(pgd, vaddr); + p4d = p4d_offset(pgd, vaddr); + pud = pud_offset(p4d, vaddr); pmd = pmd_offset(pud, vaddr); pte = pte_offset_kernel(pmd, vaddr); pte_set_val(*pte, p, PAGE_READONLY); diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c index b5e3d91fc9c2..3f0d9a573fd6 100644 --- a/arch/um/kernel/skas/mmu.c +++ b/arch/um/kernel/skas/mmu.c @@ -19,15 +19,21 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc, unsigned long kernel) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; pgd = pgd_offset(mm, proc); - pud = pud_alloc(mm, pgd, proc); - if (!pud) + + p4d = p4d_alloc(mm, pgd, proc); + if (!p4d) goto out; + pud = pud_alloc(mm, p4d, proc); + if (!pud) + goto out_pud; + pmd = pmd_alloc(mm, pud, proc); if (!pmd) goto out_pmd; @@ -44,6 +50,8 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc, pmd_free(mm, pmd); out_pmd: pud_free(mm, pud); + out_pud: + p4d_free(mm, p4d); out: return -ENOMEM; } diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c index 3236052f20e6..d617f8dc9c19 100644 --- a/arch/um/kernel/skas/uaccess.c +++ b/arch/um/kernel/skas/uaccess.c @@ -17,6 +17,7 @@ pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; @@ -27,7 +28,11 @@ pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr) if (!pgd_present(*pgd)) return NULL; - pud = pud_offset(pgd, addr); + p4d = p4d_offset(pgd, addr); + if (!p4d_present(*p4d)) + return NULL; + + pud = pud_offset(p4d, addr); if (!pud_present(*pud)) return NULL; diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c index 8425a22142b7..80a358c6d652 100644 --- a/arch/um/kernel/tlb.c +++ b/arch/um/kernel/tlb.c @@ -277,7 +277,7 @@ static inline int update_pmd_range(pud_t *pud, unsigned long addr, return ret; } -static inline int update_pud_range(pgd_t *pgd, unsigned long addr, +static inline int update_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, struct host_vm_change *hvc) { @@ -285,7 +285,7 @@ static inline int update_pud_range(pgd_t *pgd, unsigned long addr, unsigned long next; int ret = 0; - pud = pud_offset(pgd, addr); + pud = pud_offset(p4d, addr); do { next = pud_addr_end(addr, end); if (!pud_present(*pud)) { @@ -299,6 +299,28 @@ static inline int update_pud_range(pgd_t *pgd, unsigned long addr, return ret; } +static inline int update_p4d_range(pgd_t *pgd, unsigned long addr, + unsigned long end, + struct host_vm_change *hvc) +{ + p4d_t *p4d; + unsigned long next; + int ret = 0; + + p4d = p4d_offset(pgd, addr); + do { + next = p4d_addr_end(addr, end); + if (!p4d_present(*p4d)) { + if (hvc->force || p4d_newpage(*p4d)) { + ret = add_munmap(addr, next - addr, hvc); + p4d_mkuptodate(*p4d); + } + } else + ret = update_pud_range(p4d, addr, next, hvc); + } while (p4d++, addr = next, ((addr < end) && !ret)); + return ret; +} + void fix_range_common(struct mm_struct *mm, unsigned long start_addr, unsigned long end_addr, int force) { @@ -316,8 +338,8 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr, ret = add_munmap(addr, next - addr, &hvc); pgd_mkuptodate(*pgd); } - } - else ret = update_pud_range(pgd, addr, next, &hvc); + } else + ret = update_p4d_range(pgd, addr, next, &hvc); } while (pgd++, addr = next, ((addr < end_addr) && !ret)); if (!ret) @@ -338,6 +360,7 @@ static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end) { struct mm_struct *mm; pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -364,7 +387,23 @@ static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end) continue; } - pud = pud_offset(pgd, addr); + p4d = p4d_offset(pgd, addr); + if (!p4d_present(*p4d)) { + last = ADD_ROUND(addr, P4D_SIZE); + if (last > end) + last = end; + if (p4d_newpage(*p4d)) { + updated = 1; + err = add_munmap(addr, last - addr, &hvc); + if (err < 0) + panic("munmap failed, errno = %d\n", + -err); + } + addr = last; + continue; + } + + pud = pud_offset(p4d, addr); if (!pud_present(*pud)) { last = ADD_ROUND(addr, PUD_SIZE); if (last > end) @@ -424,6 +463,7 @@ static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end) void flush_tlb_page(struct vm_area_struct *vma, unsigned long address) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -437,7 +477,11 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long address) if (!pgd_present(*pgd)) goto kill; - pud = pud_offset(pgd, address); + p4d = p4d_offset(pgd, address); + if (!p4d_present(*p4d)) + goto kill; + + pud = pud_offset(p4d, address); if (!pud_present(*pud)) goto kill; diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index e62296c66c95..818553064f04 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -28,6 +28,7 @@ int handle_page_fault(unsigned long address, unsigned long ip, struct mm_struct *mm = current->mm; struct vm_area_struct *vma; pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -104,7 +105,8 @@ good_area: } pgd = pgd_offset(mm, address); - pud = pud_offset(pgd, address); + p4d = p4d_offset(pgd, address); + pud = pud_offset(p4d, address); pmd = pmd_offset(pud, address); pte = pte_offset_kernel(pmd, address); } while (!pte_present(*pte));