mirror of
https://github.com/edk2-porting/linux-next.git
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csky: Sync riscv mm/fault.c for easy maintenance
Sync arch/riscv/mm/fault.c into arch/csky for easy maintenance. Here are the patches related to the modification:cac4d1d"riscv/mm/fault: Move no context handling to no_context()"ac416a7"riscv/mm/fault: Move vmalloc fault handling to vmalloc_fault()"6c11ffb"riscv/mm/fault: Move fault error handling to mm_fault_error()"afb8c6f"riscv/mm/fault: Move access error check to function"bda281d"riscv/mm/fault: Simplify fault error handling"a51271d"riscv/mm/fault: Move bad area handling to bad_area()" Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Guo Ren
parent
0f7e8efab2
commit
bd0bf90e30
@ -21,6 +21,8 @@ do { \
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struct pt_regs;
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void die(struct pt_regs *regs, const char *str);
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void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr);
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void show_regs(struct pt_regs *regs);
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void show_code(struct pt_regs *regs);
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@ -1,29 +1,10 @@
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// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#include <linux/signal.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/version.h>
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#include <linux/vt_kern.h>
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#include <linux/extable.h>
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#include <linux/uaccess.h>
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#include <linux/perf_event.h>
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#include <linux/kprobes.h>
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#include <asm/hardirq.h>
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#include <asm/mmu_context.h>
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#include <asm/traps.h>
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#include <asm/page.h>
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#include <linux/mmu_context.h>
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#include <linux/perf_event.h>
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int fixup_exception(struct pt_regs *regs)
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{
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@ -70,76 +51,169 @@ static inline void csky_cmpxchg_fixup(struct pt_regs *regs)
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}
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#endif
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static inline void no_context(struct pt_regs *regs, unsigned long addr)
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{
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current->thread.trap_no = trap_no(regs);
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/* Are we prepared to handle this kernel fault? */
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if (fixup_exception(regs))
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return;
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/*
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* Oops. The kernel tried to access some bad page. We'll have to
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* terminate things with extreme prejudice.
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*/
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bust_spinlocks(1);
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pr_alert("Unable to handle kernel paging request at virtual "
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"addr 0x%08lx, pc: 0x%08lx\n", addr, regs->pc);
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die(regs, "Oops");
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do_exit(SIGKILL);
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}
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static inline void mm_fault_error(struct pt_regs *regs, unsigned long addr, vm_fault_t fault)
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{
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current->thread.trap_no = trap_no(regs);
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if (fault & VM_FAULT_OOM) {
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/*
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* We ran out of memory, call the OOM killer, and return the userspace
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* (which will retry the fault, or kill us if we got oom-killed).
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*/
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if (!user_mode(regs)) {
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no_context(regs, addr);
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return;
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}
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pagefault_out_of_memory();
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return;
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} else if (fault & VM_FAULT_SIGBUS) {
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/* Kernel mode? Handle exceptions or die */
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if (!user_mode(regs)) {
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no_context(regs, addr);
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return;
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}
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do_trap(regs, SIGBUS, BUS_ADRERR, addr);
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return;
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}
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BUG();
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}
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static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code, unsigned long addr)
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{
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/*
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* Something tried to access memory that isn't in our memory map.
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* Fix it, but check if it's kernel or user first.
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*/
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mmap_read_unlock(mm);
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/* User mode accesses just cause a SIGSEGV */
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if (user_mode(regs)) {
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do_trap(regs, SIGSEGV, code, addr);
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return;
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}
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no_context(regs, addr);
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}
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static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
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{
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pgd_t *pgd, *pgd_k;
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pud_t *pud, *pud_k;
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pmd_t *pmd, *pmd_k;
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pte_t *pte_k;
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int offset;
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/* User mode accesses just cause a SIGSEGV */
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if (user_mode(regs)) {
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do_trap(regs, SIGSEGV, code, addr);
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return;
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}
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/*
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* Synchronize this task's top level page-table
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* with the 'reference' page table.
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*
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* Do _not_ use "tsk" here. We might be inside
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* an interrupt in the middle of a task switch..
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*/
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offset = pgd_index(addr);
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pgd = get_pgd() + offset;
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pgd_k = init_mm.pgd + offset;
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if (!pgd_present(*pgd_k)) {
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no_context(regs, addr);
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return;
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}
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set_pgd(pgd, *pgd_k);
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pud = (pud_t *)pgd;
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pud_k = (pud_t *)pgd_k;
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if (!pud_present(*pud_k)) {
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no_context(regs, addr);
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return;
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}
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pmd = pmd_offset(pud, addr);
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pmd_k = pmd_offset(pud_k, addr);
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if (!pmd_present(*pmd_k)) {
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no_context(regs, addr);
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return;
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}
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set_pmd(pmd, *pmd_k);
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pte_k = pte_offset_kernel(pmd_k, addr);
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if (!pte_present(*pte_k)) {
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no_context(regs, addr);
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return;
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}
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flush_tlb_one(addr);
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}
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static inline bool access_error(struct pt_regs *regs, struct vm_area_struct *vma)
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{
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if (is_write(regs)) {
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if (!(vma->vm_flags & VM_WRITE))
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return true;
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} else {
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if (unlikely(!vma_is_accessible(vma)))
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return true;
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}
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return false;
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}
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/*
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* This routine handles page faults. It determines the address,
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* and the problem, and then passes it off to one of the appropriate
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* routines.
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* This routine handles page faults. It determines the address and the
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* problem, and then passes it off to one of the appropriate routines.
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*/
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asmlinkage void do_page_fault(struct pt_regs *regs)
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{
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struct vm_area_struct *vma = NULL;
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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struct task_struct *tsk;
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struct vm_area_struct *vma;
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struct mm_struct *mm;
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unsigned long addr = read_mmu_entryhi() & PAGE_MASK;
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unsigned int flags = FAULT_FLAG_DEFAULT;
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int si_code;
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int fault;
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unsigned long address = read_mmu_entryhi() & PAGE_MASK;
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int code = SEGV_MAPERR;
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vm_fault_t fault;
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tsk = current;
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mm = tsk->mm;
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csky_cmpxchg_fixup(regs);
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if (kprobe_page_fault(regs, tsk->thread.trap_no))
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return;
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si_code = SEGV_MAPERR;
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/*
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* We fault-in kernel-space virtual memory on-demand. The
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* 'reference' page table is init_mm.pgd.
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* Fault-in kernel-space virtual memory on-demand.
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* The 'reference' page table is init_mm.pgd.
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*
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* NOTE! We MUST NOT take any locks for this case. We may
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* be in an interrupt or a critical region, and should
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* only copy the information from the master page table,
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* nothing more.
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*/
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if (unlikely(address >= VMALLOC_START) &&
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unlikely(address <= VMALLOC_END)) {
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/*
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* Synchronize this task's top level page-table
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* with the 'reference' page table.
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*
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* Do _not_ use "tsk" here. We might be inside
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* an interrupt in the middle of a task switch..
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*/
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int offset = pgd_index(address);
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pgd_t *pgd, *pgd_k;
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pud_t *pud, *pud_k;
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pmd_t *pmd, *pmd_k;
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pte_t *pte_k;
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pgd = get_pgd() + offset;
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pgd_k = init_mm.pgd + offset;
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if (!pgd_present(*pgd_k))
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goto no_context;
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set_pgd(pgd, *pgd_k);
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pud = (pud_t *)pgd;
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pud_k = (pud_t *)pgd_k;
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if (!pud_present(*pud_k))
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goto no_context;
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pmd = pmd_offset(pud, address);
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pmd_k = pmd_offset(pud_k, address);
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if (!pmd_present(*pmd_k))
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goto no_context;
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set_pmd(pmd, *pmd_k);
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pte_k = pte_offset_kernel(pmd_k, address);
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if (!pte_present(*pte_k))
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goto no_context;
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flush_tlb_one(address);
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if (unlikely((addr >= VMALLOC_START) && (addr <= VMALLOC_END))) {
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vmalloc_fault(regs, code, addr);
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return;
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}
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@ -148,60 +222,65 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
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local_irq_enable();
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/*
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* If we're in an interrupt or have no user
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* context, we must not take the fault..
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* If we're in an interrupt, have no user context, or are running
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* in an atomic region, then we must not take the fault.
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*/
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if (unlikely(faulthandler_disabled() || !mm))
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goto bad_area_nosemaphore;
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if (unlikely(faulthandler_disabled() || !mm)) {
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no_context(regs, addr);
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return;
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}
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if (user_mode(regs))
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flags |= FAULT_FLAG_USER;
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
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if (is_write(regs))
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flags |= FAULT_FLAG_WRITE;
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
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retry:
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mmap_read_lock(mm);
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vma = find_vma(mm, address);
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if (!vma)
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goto bad_area;
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if (vma->vm_start <= address)
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vma = find_vma(mm, addr);
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if (unlikely(!vma)) {
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bad_area(regs, mm, code, addr);
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return;
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}
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if (likely(vma->vm_start <= addr))
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goto good_area;
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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if (expand_stack(vma, address))
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goto bad_area;
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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good_area:
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si_code = SEGV_ACCERR;
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if (is_write(regs)) {
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if (!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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} else {
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if (unlikely(!vma_is_accessible(vma)))
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goto bad_area;
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if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
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bad_area(regs, mm, code, addr);
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return;
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}
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if (unlikely(expand_stack(vma, addr))) {
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bad_area(regs, mm, code, addr);
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return;
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}
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/*
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* If for any reason at all we couldn't handle the fault,
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it.
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*/
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good_area:
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code = SEGV_ACCERR;
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if (unlikely(access_error(regs, vma))) {
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bad_area(regs, mm, code, addr);
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return;
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}
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/*
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* If for any reason at all we could not handle the fault,
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* make sure we exit gracefully rather than endlessly redo
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* the fault.
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*/
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fault = handle_mm_fault(vma, address, flags, regs);
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if (unlikely(fault & VM_FAULT_ERROR)) {
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if (fault & VM_FAULT_OOM)
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goto out_of_memory;
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else if (fault & VM_FAULT_SIGBUS)
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goto do_sigbus;
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else if (fault & VM_FAULT_SIGSEGV)
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goto bad_area;
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BUG();
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}
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fault = handle_mm_fault(vma, addr, flags, regs);
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/*
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* If we need to retry but a fatal signal is pending, handle the
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* signal first. We do not need to release the mmap_lock because it
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* would already be released in __lock_page_or_retry in mm/filemap.c.
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*/
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if (fault_signal_pending(fault, regs))
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return;
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if (unlikely((fault & VM_FAULT_RETRY) && (flags & FAULT_FLAG_ALLOW_RETRY))) {
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flags |= FAULT_FLAG_TRIED;
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@ -215,57 +294,10 @@ good_area:
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}
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mmap_read_unlock(mm);
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return;
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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bad_area:
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mmap_read_unlock(mm);
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bad_area_nosemaphore:
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/* User mode accesses just cause a SIGSEGV */
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if (user_mode(regs)) {
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tsk->thread.trap_no = trap_no(regs);
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force_sig_fault(SIGSEGV, si_code, (void __user *)address);
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if (unlikely(fault & VM_FAULT_ERROR)) {
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mm_fault_error(regs, addr, fault);
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return;
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}
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no_context:
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tsk->thread.trap_no = trap_no(regs);
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/* Are we prepared to handle this kernel fault? */
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if (fixup_exception(regs))
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return;
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/*
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* Oops. The kernel tried to access some bad page. We'll have to
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* terminate things with extreme prejudice.
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*/
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bust_spinlocks(1);
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pr_alert("Unable to handle kernel paging request at virtual "
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"address 0x%08lx, pc: 0x%08lx\n", address, regs->pc);
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die(regs, "Oops");
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out_of_memory:
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tsk->thread.trap_no = trap_no(regs);
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/*
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* We ran out of memory, call the OOM killer, and return the userspace
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* (which will retry the fault, or kill us if we got oom-killed).
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*/
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pagefault_out_of_memory();
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return;
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do_sigbus:
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tsk->thread.trap_no = trap_no(regs);
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mmap_read_unlock(mm);
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/* Kernel mode? Handle exceptions or die */
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if (!user_mode(regs))
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goto no_context;
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force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
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}
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