diff options
Diffstat (limited to 'arch/alpha/mm')
| -rw-r--r-- | arch/alpha/mm/Makefile | 8 | ||||
| -rw-r--r-- | arch/alpha/mm/fault.c | 245 | ||||
| -rw-r--r-- | arch/alpha/mm/init.c | 304 |
3 files changed, 557 insertions, 0 deletions
diff --git a/arch/alpha/mm/Makefile b/arch/alpha/mm/Makefile new file mode 100644 index 000000000..bd770302e --- /dev/null +++ b/arch/alpha/mm/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Makefile for the linux alpha-specific parts of the memory manager. +# + +ccflags-y := -Werror + +obj-y := init.o fault.o diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c new file mode 100644 index 000000000..2b49aa94e --- /dev/null +++ b/arch/alpha/mm/fault.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/alpha/mm/fault.c + * + * Copyright (C) 1995 Linus Torvalds + */ + +#include <linux/sched/signal.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <asm/io.h> + +#define __EXTERN_INLINE inline +#include <asm/mmu_context.h> +#include <asm/tlbflush.h> +#undef __EXTERN_INLINE + +#include <linux/signal.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/ptrace.h> +#include <linux/mman.h> +#include <linux/smp.h> +#include <linux/interrupt.h> +#include <linux/extable.h> +#include <linux/uaccess.h> +#include <linux/perf_event.h> + +extern void die_if_kernel(char *,struct pt_regs *,long, unsigned long *); + + +/* + * Force a new ASN for a task. + */ + +#ifndef CONFIG_SMP +unsigned long last_asn = ASN_FIRST_VERSION; +#endif + +void +__load_new_mm_context(struct mm_struct *next_mm) +{ + unsigned long mmc; + struct pcb_struct *pcb; + + mmc = __get_new_mm_context(next_mm, smp_processor_id()); + next_mm->context[smp_processor_id()] = mmc; + + pcb = ¤t_thread_info()->pcb; + pcb->asn = mmc & HARDWARE_ASN_MASK; + pcb->ptbr = ((unsigned long) next_mm->pgd - IDENT_ADDR) >> PAGE_SHIFT; + + __reload_thread(pcb); +} + + +/* + * This routine handles page faults. It determines the address, + * and the problem, and then passes it off to handle_mm_fault(). + * + * mmcsr: + * 0 = translation not valid + * 1 = access violation + * 2 = fault-on-read + * 3 = fault-on-execute + * 4 = fault-on-write + * + * cause: + * -1 = instruction fetch + * 0 = load + * 1 = store + * + * Registers $9 through $15 are saved in a block just prior to `regs' and + * are saved and restored around the call to allow exception code to + * modify them. + */ + +/* Macro for exception fixup code to access integer registers. */ +#define dpf_reg(r) \ + (((unsigned long *)regs)[(r) <= 8 ? (r) : (r) <= 15 ? (r)-16 : \ + (r) <= 18 ? (r)+10 : (r)-10]) + +asmlinkage void +do_page_fault(unsigned long address, unsigned long mmcsr, + long cause, struct pt_regs *regs) +{ + struct vm_area_struct * vma; + struct mm_struct *mm = current->mm; + const struct exception_table_entry *fixup; + int si_code = SEGV_MAPERR; + vm_fault_t fault; + unsigned int flags = FAULT_FLAG_DEFAULT; + + /* As of EV6, a load into $31/$f31 is a prefetch, and never faults + (or is suppressed by the PALcode). Support that for older CPUs + by ignoring such an instruction. */ + if (cause == 0) { + unsigned int insn; + __get_user(insn, (unsigned int __user *)regs->pc); + if ((insn >> 21 & 0x1f) == 0x1f && + /* ldq ldl ldt lds ldg ldf ldwu ldbu */ + (1ul << (insn >> 26) & 0x30f00001400ul)) { + regs->pc += 4; + return; + } + } + + /* If we're in an interrupt context, or have no user context, + we must not take the fault. */ + if (!mm || faulthandler_disabled()) + goto no_context; + +#ifdef CONFIG_ALPHA_LARGE_VMALLOC + if (address >= TASK_SIZE) + goto vmalloc_fault; +#endif + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); +retry: + vma = lock_mm_and_find_vma(mm, address, regs); + if (!vma) + goto bad_area_nosemaphore; + + /* Ok, we have a good vm_area for this memory access, so + we can handle it. */ + si_code = SEGV_ACCERR; + if (cause < 0) { + if (!(vma->vm_flags & VM_EXEC)) + goto bad_area; + } else if (!cause) { + /* Allow reads even for write-only mappings */ + if (!(vma->vm_flags & (VM_READ | VM_WRITE))) + goto bad_area; + } else { + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + flags |= FAULT_FLAG_WRITE; + } + + /* If for any reason at all we couldn't handle the fault, + make sure we exit gracefully rather than endlessly redo + the fault. */ + fault = handle_mm_fault(vma, address, flags, regs); + + if (fault_signal_pending(fault, regs)) + return; + + /* The fault is fully completed (including releasing mmap lock) */ + if (fault & VM_FAULT_COMPLETED) + return; + + if (unlikely(fault & VM_FAULT_ERROR)) { + if (fault & VM_FAULT_OOM) + goto out_of_memory; + else if (fault & VM_FAULT_SIGSEGV) + goto bad_area; + else if (fault & VM_FAULT_SIGBUS) + goto do_sigbus; + BUG(); + } + + if (fault & VM_FAULT_RETRY) { + flags |= FAULT_FLAG_TRIED; + + /* No need to mmap_read_unlock(mm) as we would + * have already released it in __lock_page_or_retry + * in mm/filemap.c. + */ + + goto retry; + } + + mmap_read_unlock(mm); + + return; + + /* Something tried to access memory that isn't in our memory map. + Fix it, but check if it's kernel or user first. */ + bad_area: + mmap_read_unlock(mm); + + bad_area_nosemaphore: + if (user_mode(regs)) + goto do_sigsegv; + + no_context: + /* Are we prepared to handle this fault as an exception? */ + if ((fixup = search_exception_tables(regs->pc)) != 0) { + unsigned long newpc; + newpc = fixup_exception(dpf_reg, fixup, regs->pc); + regs->pc = newpc; + return; + } + + /* Oops. The kernel tried to access some bad page. We'll have to + terminate things with extreme prejudice. */ + printk(KERN_ALERT "Unable to handle kernel paging request at " + "virtual address %016lx\n", address); + die_if_kernel("Oops", regs, cause, (unsigned long*)regs - 16); + make_task_dead(SIGKILL); + + /* We ran out of memory, or some other thing happened to us that + made us unable to handle the page fault gracefully. */ + out_of_memory: + mmap_read_unlock(mm); + if (!user_mode(regs)) + goto no_context; + pagefault_out_of_memory(); + return; + + do_sigbus: + mmap_read_unlock(mm); + /* Send a sigbus, regardless of whether we were in kernel + or user mode. */ + force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *) address); + if (!user_mode(regs)) + goto no_context; + return; + + do_sigsegv: + force_sig_fault(SIGSEGV, si_code, (void __user *) address); + return; + +#ifdef CONFIG_ALPHA_LARGE_VMALLOC + vmalloc_fault: + if (user_mode(regs)) + goto do_sigsegv; + else { + /* Synchronize this task's top level page-table + with the "reference" page table from init. */ + long index = pgd_index(address); + pgd_t *pgd, *pgd_k; + + pgd = current->active_mm->pgd + index; + pgd_k = swapper_pg_dir + index; + if (!pgd_present(*pgd) && pgd_present(*pgd_k)) { + pgd_val(*pgd) = pgd_val(*pgd_k); + return; + } + goto no_context; + } +#endif +} diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c new file mode 100644 index 000000000..a155180d7 --- /dev/null +++ b/arch/alpha/mm/init.c @@ -0,0 +1,304 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/alpha/mm/init.c + * + * Copyright (C) 1995 Linus Torvalds + */ + +/* 2.3.x zone allocator, 1999 Andrea Arcangeli <andrea@suse.de> */ + +#include <linux/pagemap.h> +#include <linux/signal.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/ptrace.h> +#include <linux/mman.h> +#include <linux/mm.h> +#include <linux/swap.h> +#include <linux/init.h> +#include <linux/memblock.h> /* max_low_pfn */ +#include <linux/vmalloc.h> +#include <linux/gfp.h> + +#include <linux/uaccess.h> +#include <asm/pgalloc.h> +#include <asm/hwrpb.h> +#include <asm/dma.h> +#include <asm/mmu_context.h> +#include <asm/console.h> +#include <asm/tlb.h> +#include <asm/setup.h> +#include <asm/sections.h> + +extern void die_if_kernel(char *,struct pt_regs *,long); + +static struct pcb_struct original_pcb; + +pgd_t * +pgd_alloc(struct mm_struct *mm) +{ + pgd_t *ret, *init; + + ret = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); + init = pgd_offset(&init_mm, 0UL); + if (ret) { +#ifdef CONFIG_ALPHA_LARGE_VMALLOC + memcpy (ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD, + (PTRS_PER_PGD - USER_PTRS_PER_PGD - 1)*sizeof(pgd_t)); +#else + pgd_val(ret[PTRS_PER_PGD-2]) = pgd_val(init[PTRS_PER_PGD-2]); +#endif + + /* The last PGD entry is the VPTB self-map. */ + pgd_val(ret[PTRS_PER_PGD-1]) + = pte_val(mk_pte(virt_to_page(ret), PAGE_KERNEL)); + } + return ret; +} + + +/* + * BAD_PAGE is the page that is used for page faults when linux + * is out-of-memory. Older versions of linux just did a + * do_exit(), but using this instead means there is less risk + * for a process dying in kernel mode, possibly leaving an inode + * unused etc.. + * + * BAD_PAGETABLE is the accompanying page-table: it is initialized + * to point to BAD_PAGE entries. + * + * ZERO_PAGE is a special page that is used for zero-initialized + * data and COW. + */ +pmd_t * +__bad_pagetable(void) +{ + memset(absolute_pointer(EMPTY_PGT), 0, PAGE_SIZE); + return (pmd_t *) EMPTY_PGT; +} + +pte_t +__bad_page(void) +{ + memset(absolute_pointer(EMPTY_PGE), 0, PAGE_SIZE); + return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED)); +} + +static inline unsigned long +load_PCB(struct pcb_struct *pcb) +{ + register unsigned long sp __asm__("$30"); + pcb->ksp = sp; + return __reload_thread(pcb); +} + +/* Set up initial PCB, VPTB, and other such nicities. */ + +static inline void +switch_to_system_map(void) +{ + unsigned long newptbr; + unsigned long original_pcb_ptr; + + /* Initialize the kernel's page tables. Linux puts the vptb in + the last slot of the L1 page table. */ + memset(swapper_pg_dir, 0, PAGE_SIZE); + newptbr = ((unsigned long) swapper_pg_dir - PAGE_OFFSET) >> PAGE_SHIFT; + pgd_val(swapper_pg_dir[1023]) = + (newptbr << 32) | pgprot_val(PAGE_KERNEL); + + /* Set the vptb. This is often done by the bootloader, but + shouldn't be required. */ + if (hwrpb->vptb != 0xfffffffe00000000UL) { + wrvptptr(0xfffffffe00000000UL); + hwrpb->vptb = 0xfffffffe00000000UL; + hwrpb_update_checksum(hwrpb); + } + + /* Also set up the real kernel PCB while we're at it. */ + init_thread_info.pcb.ptbr = newptbr; + init_thread_info.pcb.flags = 1; /* set FEN, clear everything else */ + original_pcb_ptr = load_PCB(&init_thread_info.pcb); + tbia(); + + /* Save off the contents of the original PCB so that we can + restore the original console's page tables for a clean reboot. + + Note that the PCB is supposed to be a physical address, but + since KSEG values also happen to work, folks get confused. + Check this here. */ + + if (original_pcb_ptr < PAGE_OFFSET) { + original_pcb_ptr = (unsigned long) + phys_to_virt(original_pcb_ptr); + } + original_pcb = *(struct pcb_struct *) original_pcb_ptr; +} + +int callback_init_done; + +void * __init +callback_init(void * kernel_end) +{ + struct crb_struct * crb; + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + void *two_pages; + + /* Starting at the HWRPB, locate the CRB. */ + crb = (struct crb_struct *)((char *)hwrpb + hwrpb->crb_offset); + + if (alpha_using_srm) { + /* Tell the console whither it is to be remapped. */ + if (srm_fixup(VMALLOC_START, (unsigned long)hwrpb)) + __halt(); /* "We're boned." --Bender */ + + /* Edit the procedure descriptors for DISPATCH and FIXUP. */ + crb->dispatch_va = (struct procdesc_struct *) + (VMALLOC_START + (unsigned long)crb->dispatch_va + - crb->map[0].va); + crb->fixup_va = (struct procdesc_struct *) + (VMALLOC_START + (unsigned long)crb->fixup_va + - crb->map[0].va); + } + + switch_to_system_map(); + + /* Allocate one PGD and one PMD. In the case of SRM, we'll need + these to actually remap the console. There is an assumption + here that only one of each is needed, and this allows for 8MB. + On systems with larger consoles, additional pages will be + allocated as needed during the mapping process. + + In the case of not SRM, but not CONFIG_ALPHA_LARGE_VMALLOC, + we need to allocate the PGD we use for vmalloc before we start + forking other tasks. */ + + two_pages = (void *) + (((unsigned long)kernel_end + ~PAGE_MASK) & PAGE_MASK); + kernel_end = two_pages + 2*PAGE_SIZE; + memset(two_pages, 0, 2*PAGE_SIZE); + + pgd = pgd_offset_k(VMALLOC_START); + p4d = p4d_offset(pgd, VMALLOC_START); + pud = pud_offset(p4d, VMALLOC_START); + pud_set(pud, (pmd_t *)two_pages); + pmd = pmd_offset(pud, VMALLOC_START); + pmd_set(pmd, (pte_t *)(two_pages + PAGE_SIZE)); + + if (alpha_using_srm) { + static struct vm_struct console_remap_vm; + unsigned long nr_pages = 0; + unsigned long vaddr; + unsigned long i, j; + + /* calculate needed size */ + for (i = 0; i < crb->map_entries; ++i) + nr_pages += crb->map[i].count; + + /* register the vm area */ + console_remap_vm.flags = VM_ALLOC; + console_remap_vm.size = nr_pages << PAGE_SHIFT; + vm_area_register_early(&console_remap_vm, PAGE_SIZE); + + vaddr = (unsigned long)console_remap_vm.addr; + + /* Set up the third level PTEs and update the virtual + addresses of the CRB entries. */ + for (i = 0; i < crb->map_entries; ++i) { + unsigned long pfn = crb->map[i].pa >> PAGE_SHIFT; + crb->map[i].va = vaddr; + for (j = 0; j < crb->map[i].count; ++j) { + /* Newer consoles (especially on larger + systems) may require more pages of + PTEs. Grab additional pages as needed. */ + if (pmd != pmd_offset(pud, vaddr)) { + memset(kernel_end, 0, PAGE_SIZE); + pmd = pmd_offset(pud, vaddr); + pmd_set(pmd, (pte_t *)kernel_end); + kernel_end += PAGE_SIZE; + } + set_pte(pte_offset_kernel(pmd, vaddr), + pfn_pte(pfn, PAGE_KERNEL)); + pfn++; + vaddr += PAGE_SIZE; + } + } + } + + callback_init_done = 1; + return kernel_end; +} + +/* + * paging_init() sets up the memory map. + */ +void __init paging_init(void) +{ + unsigned long max_zone_pfn[MAX_NR_ZONES] = {0, }; + unsigned long dma_pfn; + + dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT; + max_pfn = max_low_pfn; + + max_zone_pfn[ZONE_DMA] = dma_pfn; + max_zone_pfn[ZONE_NORMAL] = max_pfn; + + /* Initialize mem_map[]. */ + free_area_init(max_zone_pfn); + + /* Initialize the kernel's ZERO_PGE. */ + memset(absolute_pointer(ZERO_PGE), 0, PAGE_SIZE); +} + +#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM) +void +srm_paging_stop (void) +{ + /* Move the vptb back to where the SRM console expects it. */ + swapper_pg_dir[1] = swapper_pg_dir[1023]; + tbia(); + wrvptptr(0x200000000UL); + hwrpb->vptb = 0x200000000UL; + hwrpb_update_checksum(hwrpb); + + /* Reload the page tables that the console had in use. */ + load_PCB(&original_pcb); + tbia(); +} +#endif + +void __init +mem_init(void) +{ + set_max_mapnr(max_low_pfn); + high_memory = (void *) __va(max_low_pfn * PAGE_SIZE); + memblock_free_all(); +} + +static const pgprot_t protection_map[16] = { + [VM_NONE] = _PAGE_P(_PAGE_FOE | _PAGE_FOW | + _PAGE_FOR), + [VM_READ] = _PAGE_P(_PAGE_FOE | _PAGE_FOW), + [VM_WRITE] = _PAGE_P(_PAGE_FOE), + [VM_WRITE | VM_READ] = _PAGE_P(_PAGE_FOE), + [VM_EXEC] = _PAGE_P(_PAGE_FOW | _PAGE_FOR), + [VM_EXEC | VM_READ] = _PAGE_P(_PAGE_FOW), + [VM_EXEC | VM_WRITE] = _PAGE_P(0), + [VM_EXEC | VM_WRITE | VM_READ] = _PAGE_P(0), + [VM_SHARED] = _PAGE_S(_PAGE_FOE | _PAGE_FOW | + _PAGE_FOR), + [VM_SHARED | VM_READ] = _PAGE_S(_PAGE_FOE | _PAGE_FOW), + [VM_SHARED | VM_WRITE] = _PAGE_S(_PAGE_FOE), + [VM_SHARED | VM_WRITE | VM_READ] = _PAGE_S(_PAGE_FOE), + [VM_SHARED | VM_EXEC] = _PAGE_S(_PAGE_FOW | _PAGE_FOR), + [VM_SHARED | VM_EXEC | VM_READ] = _PAGE_S(_PAGE_FOW), + [VM_SHARED | VM_EXEC | VM_WRITE] = _PAGE_S(0), + [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = _PAGE_S(0) +}; +DECLARE_VM_GET_PAGE_PROT |