This patch adds support for the handling of the MMU faults (exception entry code introduced by a previous patch) and page table management.
The user translation table is pointed to by TTBR0 and the kernel one (swapper_pg_dir) by TTBR1. There is no translation information shared or address space overlapping between user and kernel page tables. Signed-off-by: Will Deacon <will.dea...@arm.com> Signed-off-by: Catalin Marinas <catalin.mari...@arm.com> Acked-by: Tony Lindgren <t...@atomide.com> --- arch/arm64/include/asm/page.h | 67 +++++ arch/arm64/include/asm/pgalloc.h | 113 ++++++++ arch/arm64/mm/copypage.c | 34 +++ arch/arm64/mm/extable.c | 17 ++ arch/arm64/mm/fault.c | 534 ++++++++++++++++++++++++++++++++++++++ arch/arm64/mm/mm.h | 2 + arch/arm64/mm/mmap.c | 144 ++++++++++ arch/arm64/mm/pgd.c | 54 ++++ 8 files changed, 965 insertions(+), 0 deletions(-) create mode 100644 arch/arm64/include/asm/page.h create mode 100644 arch/arm64/include/asm/pgalloc.h create mode 100644 arch/arm64/mm/copypage.c create mode 100644 arch/arm64/mm/extable.c create mode 100644 arch/arm64/mm/fault.c create mode 100644 arch/arm64/mm/mm.h create mode 100644 arch/arm64/mm/mmap.c create mode 100644 arch/arm64/mm/pgd.c diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h new file mode 100644 index 0000000..46bf666 --- /dev/null +++ b/arch/arm64/include/asm/page.h @@ -0,0 +1,67 @@ +/* + * Based on arch/arm/include/asm/page.h + * + * Copyright (C) 1995-2003 Russell King + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef __ASM_PAGE_H +#define __ASM_PAGE_H + +/* PAGE_SHIFT determines the page size */ +#ifdef CONFIG_ARM64_64K_PAGES +#define PAGE_SHIFT 16 +#else +#define PAGE_SHIFT 12 +#endif +#define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT) +#define PAGE_MASK (~(PAGE_SIZE-1)) + +/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */ +#define __HAVE_ARCH_GATE_AREA 1 + +#ifndef __ASSEMBLY__ + +#ifdef CONFIG_ARM64_64K_PAGES +#include <asm/pgtable-2level-types.h> +#else +#include <asm/pgtable-3level-types.h> +#endif + +extern void __cpu_clear_user_page(void *p, unsigned long user); +extern void __cpu_copy_user_page(void *to, const void *from, + unsigned long user); +extern void copy_page(void *to, const void *from); +extern void clear_page(void *to); + +#define clear_user_page(addr,vaddr,pg) __cpu_clear_user_page(addr, vaddr) +#define copy_user_page(to,from,vaddr,pg) __cpu_copy_user_page(to, from, vaddr) + +typedef struct page *pgtable_t; + +#ifdef CONFIG_HAVE_ARCH_PFN_VALID +extern int pfn_valid(unsigned long); +#endif + +#include <asm/memory.h> + +#endif /* !__ASSEMBLY__ */ + +#define VM_DATA_DEFAULT_FLAGS \ + (((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0) | \ + VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC) + +#include <asm-generic/getorder.h> + +#endif diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h new file mode 100644 index 0000000..f214069 --- /dev/null +++ b/arch/arm64/include/asm/pgalloc.h @@ -0,0 +1,113 @@ +/* + * Based on arch/arm/include/asm/pgalloc.h + * + * Copyright (C) 2000-2001 Russell King + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef __ASM_PGALLOC_H +#define __ASM_PGALLOC_H + +#include <asm/pgtable-hwdef.h> +#include <asm/processor.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> + +#define check_pgt_cache() do { } while (0) + +#ifndef CONFIG_ARM64_64K_PAGES + +static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr) +{ + return (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_REPEAT); +} + +static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd) +{ + BUG_ON((unsigned long)pmd & (PAGE_SIZE-1)); + free_page((unsigned long)pmd); +} + +static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) +{ + set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE)); +} + +#endif /* CONFIG_ARM64_64K_PAGES */ + +extern pgd_t *pgd_alloc(struct mm_struct *mm); +extern void pgd_free(struct mm_struct *mm, pgd_t *pgd); + +#define PGALLOC_GFP (GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO) + +static inline pte_t * +pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr) +{ + return (pte_t *)__get_free_page(PGALLOC_GFP); +} + +static inline pgtable_t +pte_alloc_one(struct mm_struct *mm, unsigned long addr) +{ + struct page *pte; + + pte = alloc_pages(PGALLOC_GFP, 0); + if (pte) + pgtable_page_ctor(pte); + + return pte; +} + +/* + * Free a PTE table. + */ +static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) +{ + if (pte) + free_page((unsigned long)pte); +} + +static inline void pte_free(struct mm_struct *mm, pgtable_t pte) +{ + pgtable_page_dtor(pte); + __free_page(pte); +} + +static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte, + pmdval_t prot) +{ + set_pmd(pmdp, __pmd(pte | prot)); +} + +/* + * Populate the pmdp entry with a pointer to the pte. This pmd is part + * of the mm address space. + */ +static inline void +pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep) +{ + /* + * The pmd must be loaded with the physical address of the PTE table + */ + __pmd_populate(pmdp, __pa(ptep), PMD_TYPE_TABLE); +} + +static inline void +pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep) +{ + __pmd_populate(pmdp, page_to_phys(ptep), PMD_TYPE_TABLE); +} +#define pmd_pgtable(pmd) pmd_page(pmd) + +#endif diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c new file mode 100644 index 0000000..9aecbac --- /dev/null +++ b/arch/arm64/mm/copypage.c @@ -0,0 +1,34 @@ +/* + * Based on arch/arm/mm/copypage.c + * + * Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved. + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/mm.h> + +#include <asm/page.h> +#include <asm/cacheflush.h> + +void __cpu_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr) +{ + copy_page(kto, kfrom); + __flush_dcache_area(kto, PAGE_SIZE); +} + +void __cpu_clear_user_page(void *kaddr, unsigned long vaddr) +{ + clear_page(kaddr); +} diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c new file mode 100644 index 0000000..7944427 --- /dev/null +++ b/arch/arm64/mm/extable.c @@ -0,0 +1,17 @@ +/* + * Based on arch/arm/mm/extable.c + */ + +#include <linux/module.h> +#include <linux/uaccess.h> + +int fixup_exception(struct pt_regs *regs) +{ + const struct exception_table_entry *fixup; + + fixup = search_exception_tables(instruction_pointer(regs)); + if (fixup) + regs->pc = fixup->fixup; + + return fixup != NULL; +} diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c new file mode 100644 index 0000000..1909a69 --- /dev/null +++ b/arch/arm64/mm/fault.c @@ -0,0 +1,534 @@ +/* + * Based on arch/arm/mm/fault.c + * + * Copyright (C) 1995 Linus Torvalds + * Copyright (C) 1995-2004 Russell King + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/module.h> +#include <linux/signal.h> +#include <linux/mm.h> +#include <linux/hardirq.h> +#include <linux/init.h> +#include <linux/kprobes.h> +#include <linux/uaccess.h> +#include <linux/page-flags.h> +#include <linux/sched.h> +#include <linux/highmem.h> +#include <linux/perf_event.h> + +#include <asm/exception.h> +#include <asm/debug-monitors.h> +#include <asm/system_misc.h> +#include <asm/pgtable.h> +#include <asm/tlbflush.h> + +/* + * Dump out the page tables associated with 'addr' in mm 'mm'. + */ +void show_pte(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pgd; + + if (!mm) + mm = &init_mm; + + pr_alert("pgd = %p\n", mm->pgd); + pgd = pgd_offset(mm, addr); + pr_alert("[%08lx] *pgd=%016llx", addr, pgd_val(*pgd)); + + do { + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + if (pgd_none_or_clear_bad(pgd)) + break; + + pud = pud_offset(pgd, addr); + if (pud_none_or_clear_bad(pud)) + break; + + pmd = pmd_offset(pud, addr); + printk(", *pmd=%016llx", pmd_val(*pmd)); + if (pmd_none_or_clear_bad(pmd)) + break; + + pte = pte_offset_map(pmd, addr); + printk(", *pte=%016llx", pte_val(*pte)); + pte_unmap(pte); + } while(0); + + printk("\n"); +} + +/* + * The kernel tried to access some page that wasn't present. + */ +static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr, + unsigned int esr, struct pt_regs *regs) +{ + /* + * Are we prepared to handle this kernel fault? + */ + if (fixup_exception(regs)) + return; + + /* + * No handler, we'll have to terminate things with extreme prejudice. + */ + bust_spinlocks(1); + pr_alert("Unable to handle kernel %s at virtual address %08lx\n", + (addr < PAGE_SIZE) ? "NULL pointer dereference" : + "paging request", addr); + + show_pte(mm, addr); + die("Oops", regs, esr); + bust_spinlocks(0); + do_exit(SIGKILL); +} + +/* + * Something tried to access memory that isn't in our memory map. User mode + * accesses just cause a SIGSEGV + */ +static void __do_user_fault(struct task_struct *tsk, unsigned long addr, + unsigned int esr, unsigned int sig, int code, + struct pt_regs *regs) +{ + struct siginfo si; + + if (show_unhandled_signals) { + pr_info("%s[%d]: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n", + tsk->comm, task_pid_nr(tsk), sig, addr, esr); + show_pte(tsk->mm, addr); + show_regs(regs); + } + + tsk->thread.fault_address = addr; + si.si_signo = sig; + si.si_errno = 0; + si.si_code = code; + si.si_addr = (void __user *)addr; + force_sig_info(sig, &si, tsk); +} + +void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) +{ + struct task_struct *tsk = current; + struct mm_struct *mm = tsk->active_mm; + + /* + * If we are in kernel mode at this point, we have no context to + * handle this fault with. + */ + if (user_mode(regs)) + __do_user_fault(tsk, addr, esr, SIGSEGV, SEGV_MAPERR, regs); + else + __do_kernel_fault(mm, addr, esr, regs); +} + +#define VM_FAULT_BADMAP 0x010000 +#define VM_FAULT_BADACCESS 0x020000 + +#define ESR_WRITE (1 << 6) +#define ESR_LNX_EXEC (1 << 24) + +/* + * Check that the permissions on the VMA allow for the fault which occurred. + * If we encountered a write fault, we must have write permission, otherwise + * we allow any permission. + */ +static inline bool access_error(unsigned int esr, struct vm_area_struct *vma) +{ + unsigned int mask = VM_READ | VM_WRITE | VM_EXEC; + + if (esr & ESR_WRITE) + mask = VM_WRITE; + if (esr & ESR_LNX_EXEC) + mask = VM_EXEC; + + return vma->vm_flags & mask ? false : true; +} + +static int __do_page_fault(struct mm_struct *mm, unsigned long addr, + unsigned int esr, unsigned int flags, + struct task_struct *tsk) +{ + struct vm_area_struct *vma; + int fault; + + vma = find_vma(mm, addr); + fault = VM_FAULT_BADMAP; + if (unlikely(!vma)) + goto out; + if (unlikely(vma->vm_start > addr)) + goto check_stack; + + /* + * Ok, we have a good vm_area for this memory access, so we can handle + * it. + */ +good_area: + if (access_error(esr, vma)) { + fault = VM_FAULT_BADACCESS; + goto out; + } + + return handle_mm_fault(mm, vma, addr & PAGE_MASK, flags); + +check_stack: + if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) + goto good_area; +out: + return fault; +} + +static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, + struct pt_regs *regs) +{ + struct task_struct *tsk; + struct mm_struct *mm; + int fault, sig, code; + int write = esr & ESR_WRITE; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE | + (write ? FAULT_FLAG_WRITE : 0); + + tsk = current; + mm = tsk->mm; + + /* Enable interrupts if they were enabled in the parent context. */ + if (interrupts_enabled(regs)) + local_irq_enable(); + + /* + * If we're in an interrupt or have no user context, we must not take + * the fault. + */ + if (in_atomic() || !mm) + goto no_context; + + /* + * As per x86, we may deadlock here. However, since the kernel only + * validly references user space from well defined areas of the code, + * we can bug out early if this is from code which shouldn't. + */ + if (!down_read_trylock(&mm->mmap_sem)) { + if (!user_mode(regs) && !search_exception_tables(regs->pc)) + goto no_context; +retry: + down_read(&mm->mmap_sem); + } else { + /* + * The above down_read_trylock() might have succeeded in which + * case, we'll have missed the might_sleep() from down_read(). + */ + might_sleep(); +#ifdef CONFIG_DEBUG_VM + if (!user_mode(regs) && !search_exception_tables(regs->pc)) + goto no_context; +#endif + } + + fault = __do_page_fault(mm, addr, esr, flags, tsk); + + /* + * If we need to retry but a fatal signal is pending, handle the + * signal first. We do not need to release the mmap_sem because it + * would already be released in __lock_page_or_retry in mm/filemap.c. + */ + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + return 0; + + /* + * Major/minor page fault accounting is only done on the initial + * attempt. If we go through a retry, it is extremely likely that the + * page will be found in page cache at that point. + */ + + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) { + tsk->maj_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, + addr); + } else { + tsk->min_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, + addr); + } + if (fault & VM_FAULT_RETRY) { + /* + * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of + * starvation. + */ + flags &= ~FAULT_FLAG_ALLOW_RETRY; + goto retry; + } + } + + up_read(&mm->mmap_sem); + + /* + * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR + */ + if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | + VM_FAULT_BADACCESS)))) + return 0; + + if (fault & VM_FAULT_OOM) { + /* + * We ran out of memory, call the OOM killer, and return to + * userspace (which will retry the fault, or kill us if we got + * oom-killed). + */ + pagefault_out_of_memory(); + return 0; + } + + /* + * If we are in kernel mode at this point, we have no context to + * handle this fault with. + */ + if (!user_mode(regs)) + goto no_context; + + if (fault & VM_FAULT_SIGBUS) { + /* + * We had some memory, but were unable to successfully fix up + * this page fault. + */ + sig = SIGBUS; + code = BUS_ADRERR; + } else { + /* + * Something tried to access memory that isn't in our memory + * map. + */ + sig = SIGSEGV; + code = fault == VM_FAULT_BADACCESS ? + SEGV_ACCERR : SEGV_MAPERR; + } + + __do_user_fault(tsk, addr, esr, sig, code, regs); + return 0; + +no_context: + __do_kernel_fault(mm, addr, esr, regs); + return 0; +} + +/* + * First Level Translation Fault Handler + * + * We enter here because the first level page table doesn't contain a valid + * entry for the address. + * + * If the address is in kernel space (>= TASK_SIZE), then we are probably + * faulting in the vmalloc() area. + * + * If the init_task's first level page tables contains the relevant entry, we + * copy the it to this task. If not, we send the process a signal, fixup the + * exception, or oops the kernel. + * + * NOTE! We MUST NOT take any locks for this case. We may be in an interrupt + * or a critical region, and should only copy the information from the master + * page table, nothing more. + */ +static int __kprobes do_translation_fault(unsigned long addr, + unsigned int esr, + struct pt_regs *regs) +{ + if (addr < TASK_SIZE) + return do_page_fault(addr, esr, regs); + + do_bad_area(addr, esr, regs); + return 0; +} + +/* + * Some section permission faults need to be handled gracefully. They can + * happen due to a __{get,put}_user during an oops. + */ +static int do_sect_fault(unsigned long addr, unsigned int esr, + struct pt_regs *regs) +{ + do_bad_area(addr, esr, regs); + return 0; +} + +/* + * This abort handler always returns "fault". + */ +static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) +{ + return 1; +} + +static struct fault_info { + int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs); + int sig; + int code; + const char *name; +} fault_info[] = { + { do_bad, SIGBUS, 0, "ttbr address size fault" }, + { do_bad, SIGBUS, 0, "level 1 address size fault" }, + { do_bad, SIGBUS, 0, "level 2 address size fault" }, + { do_bad, SIGBUS, 0, "level 3 address size fault" }, + { do_translation_fault, SIGSEGV, SEGV_MAPERR, "input address range fault" }, + { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" }, + { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, + { do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, + { do_bad, SIGBUS, 0, "reserved access flag fault" }, + { do_bad, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, + { do_bad, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, + { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" }, + { do_bad, SIGBUS, 0, "reserved permission fault" }, + { do_bad, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, + { do_sect_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, + { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, + { do_bad, SIGBUS, 0, "synchronous external abort" }, + { do_bad, SIGBUS, 0, "asynchronous external abort" }, + { do_bad, SIGBUS, 0, "unknown 18" }, + { do_bad, SIGBUS, 0, "unknown 19" }, + { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous parity error" }, + { do_bad, SIGBUS, 0, "asynchronous parity error" }, + { do_bad, SIGBUS, 0, "unknown 26" }, + { do_bad, SIGBUS, 0, "unknown 27" }, + { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" }, + { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" }, + { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" }, + { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" }, + { do_bad, SIGBUS, 0, "unknown 32" }, + { do_bad, SIGBUS, BUS_ADRALN, "alignment fault" }, + { do_bad, SIGBUS, 0, "debug event" }, + { do_bad, SIGBUS, 0, "unknown 35" }, + { do_bad, SIGBUS, 0, "unknown 36" }, + { do_bad, SIGBUS, 0, "unknown 37" }, + { do_bad, SIGBUS, 0, "unknown 38" }, + { do_bad, SIGBUS, 0, "unknown 39" }, + { do_bad, SIGBUS, 0, "unknown 40" }, + { do_bad, SIGBUS, 0, "unknown 41" }, + { do_bad, SIGBUS, 0, "unknown 42" }, + { do_bad, SIGBUS, 0, "unknown 43" }, + { do_bad, SIGBUS, 0, "unknown 44" }, + { do_bad, SIGBUS, 0, "unknown 45" }, + { do_bad, SIGBUS, 0, "unknown 46" }, + { do_bad, SIGBUS, 0, "unknown 47" }, + { do_bad, SIGBUS, 0, "unknown 48" }, + { do_bad, SIGBUS, 0, "unknown 49" }, + { do_bad, SIGBUS, 0, "unknown 50" }, + { do_bad, SIGBUS, 0, "unknown 51" }, + { do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" }, + { do_bad, SIGBUS, 0, "unknown 53" }, + { do_bad, SIGBUS, 0, "unknown 54" }, + { do_bad, SIGBUS, 0, "unknown 55" }, + { do_bad, SIGBUS, 0, "unknown 56" }, + { do_bad, SIGBUS, 0, "unknown 57" }, + { do_bad, SIGBUS, 0, "implementation fault (coprocessor abort)" }, + { do_bad, SIGBUS, 0, "unknown 59" }, + { do_bad, SIGBUS, 0, "unknown 60" }, + { do_bad, SIGBUS, 0, "unknown 61" }, + { do_bad, SIGBUS, 0, "unknown 62" }, + { do_bad, SIGBUS, 0, "unknown 63" }, +}; + +/* + * Dispatch a data abort to the relevant handler. + */ +asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, + struct pt_regs *regs) +{ + const struct fault_info *inf = fault_info + (esr & 63); + struct siginfo info; + + if (!inf->fn(addr, esr, regs)) + return; + + pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n", + inf->name, esr, addr); + + info.si_signo = inf->sig; + info.si_errno = 0; + info.si_code = inf->code; + info.si_addr = (void __user *)addr; + arm64_notify_die("", regs, &info, esr); +} + +/* + * Handle stack alignment exceptions. + */ +asmlinkage void __exception do_sp_pc_abort(unsigned long addr, + unsigned int esr, + struct pt_regs *regs) +{ + struct siginfo info; + + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRALN; + info.si_addr = (void __user *)addr; + arm64_notify_die("", regs, &info, esr); +} + +static struct fault_info debug_fault_info[] = { + { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" }, + { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" }, + { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" }, + { do_bad, SIGBUS, 0, "unknown 3" }, + { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" }, + { do_bad, SIGTRAP, 0, "aarch32 vector catch" }, + { do_bad, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" }, + { do_bad, SIGBUS, 0, "unknown 7" }, +}; + +void __init hook_debug_fault_code(int nr, + int (*fn)(unsigned long, unsigned int, struct pt_regs *), + int sig, int code, const char *name) +{ + BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info)); + + debug_fault_info[nr].fn = fn; + debug_fault_info[nr].sig = sig; + debug_fault_info[nr].code = code; + debug_fault_info[nr].name = name; +} + +asmlinkage int __exception do_debug_exception(unsigned long addr, + unsigned int esr, + struct pt_regs *regs) +{ + const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr); + struct siginfo info; + + if (!inf->fn(addr, esr, regs)) + return 1; + + pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n", + inf->name, esr, addr); + + info.si_signo = inf->sig; + info.si_errno = 0; + info.si_code = inf->code; + info.si_addr = (void __user *)addr; + arm64_notify_die("", regs, &info, esr); + + return 0; +} diff --git a/arch/arm64/mm/mm.h b/arch/arm64/mm/mm.h new file mode 100644 index 0000000..c84f68b --- /dev/null +++ b/arch/arm64/mm/mm.h @@ -0,0 +1,2 @@ +extern void __flush_dcache_page(struct address_space *mapping, struct page *page); +extern void __init bootmem_init(void); diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c new file mode 100644 index 0000000..7c7be78 --- /dev/null +++ b/arch/arm64/mm/mmap.c @@ -0,0 +1,144 @@ +/* + * Based on arch/arm/mm/mmap.c + * + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/elf.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/export.h> +#include <linux/shm.h> +#include <linux/sched.h> +#include <linux/io.h> +#include <linux/personality.h> +#include <linux/random.h> + +#include <asm/cputype.h> + +/* + * Leave enough space between the mmap area and the stack to honour ulimit in + * the face of randomisation. + */ +#define MIN_GAP (SZ_128M + ((STACK_RND_MASK << PAGE_SHIFT) + 1)) +#define MAX_GAP (STACK_TOP/6*5) + +static int mmap_is_legacy(void) +{ + if (current->personality & ADDR_COMPAT_LAYOUT) + return 1; + + if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) + return 1; + + return sysctl_legacy_va_layout; +} + +/* + * Since get_random_int() returns the same value within a 1 jiffy window, we + * will almost always get the same randomisation for the stack and mmap + * region. This will mean the relative distance between stack and mmap will be + * the same. + * + * To avoid this we can shift the randomness by 1 bit. + */ +static unsigned long mmap_rnd(void) +{ + unsigned long rnd = 0; + + if (current->flags & PF_RANDOMIZE) + rnd = (long)get_random_int() & (STACK_RND_MASK >> 1); + + return rnd << (PAGE_SHIFT + 1); +} + +static unsigned long mmap_base(void) +{ + unsigned long gap = rlimit(RLIMIT_STACK); + + if (gap < MIN_GAP) + gap = MIN_GAP; + else if (gap > MAX_GAP) + gap = MAX_GAP; + + return PAGE_ALIGN(STACK_TOP - gap - mmap_rnd()); +} + +/* + * This function, called very early during the creation of a new process VM + * image, sets up which VM layout function to use: + */ +void arch_pick_mmap_layout(struct mm_struct *mm) +{ + /* + * Fall back to the standard layout if the personality bit is set, or + * if the expected stack growth is unlimited: + */ + if (mmap_is_legacy()) { + mm->mmap_base = TASK_UNMAPPED_BASE; + mm->get_unmapped_area = arch_get_unmapped_area; + mm->unmap_area = arch_unmap_area; + } else { + mm->mmap_base = mmap_base(); + mm->get_unmapped_area = arch_get_unmapped_area_topdown; + mm->unmap_area = arch_unmap_area_topdown; + } +} +EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); + + +/* + * You really shouldn't be using read() or write() on /dev/mem. This might go + * away in the future. + */ +int valid_phys_addr_range(unsigned long addr, size_t size) +{ + if (addr < PHYS_OFFSET) + return 0; + if (addr + size > __pa(high_memory - 1) + 1) + return 0; + + return 1; +} + +/* + * Do not allow /dev/mem mappings beyond the supported physical range. + */ +int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) +{ + return !(((pfn << PAGE_SHIFT) + size) & ~PHYS_MASK); +} + +#ifdef CONFIG_STRICT_DEVMEM + +#include <linux/ioport.h> + +/* + * devmem_is_allowed() checks to see if /dev/mem access to a certain address + * is valid. The argument is a physical page number. We mimic x86 here by + * disallowing access to system RAM as well as device-exclusive MMIO regions. + * This effectively disable read()/write() on /dev/mem. + */ +int devmem_is_allowed(unsigned long pfn) +{ + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) + return 0; + if (!page_is_ram(pfn)) + return 1; + return 0; +} + +#endif diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c new file mode 100644 index 0000000..7083cda --- /dev/null +++ b/arch/arm64/mm/pgd.c @@ -0,0 +1,54 @@ +/* + * PGD allocation/freeing + * + * Copyright (C) 2012 ARM Ltd. + * Author: Catalin Marinas <catalin.mari...@arm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/mm.h> +#include <linux/gfp.h> +#include <linux/highmem.h> +#include <linux/slab.h> + +#include <asm/pgalloc.h> +#include <asm/page.h> +#include <asm/tlbflush.h> + +#include "mm.h" + +#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t)) + +pgd_t *pgd_alloc(struct mm_struct *mm) +{ + pgd_t *new_pgd; + + if (PGD_SIZE == PAGE_SIZE) + new_pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL); + else + new_pgd = kzalloc(PGD_SIZE, GFP_KERNEL); + + if (!new_pgd) + return NULL; + + return new_pgd; +} + +void pgd_free(struct mm_struct *mm, pgd_t *pgd) +{ + if (PGD_SIZE == PAGE_SIZE) + free_page((unsigned long)pgd); + else + kfree(pgd); +} -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
