mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-06 00:36:40 +07:00
d06063cc22
This allows the callers to now pass down the full set of FAULT_FLAG_xyz flags to handle_mm_fault(). All callers have been (mechanically) converted to the new calling convention, there's almost certainly room for architectures to clean up their code and then add FAULT_FLAG_RETRY when that support is added. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
252 lines
5.9 KiB
C
252 lines
5.9 KiB
C
/*
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/hardirq.h>
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#include <asm/current.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include "arch.h"
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#include "as-layout.h"
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#include "kern_util.h"
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#include "os.h"
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#include "skas.h"
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#include "sysdep/sigcontext.h"
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/*
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* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by
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* segv().
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*/
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int handle_page_fault(unsigned long address, unsigned long ip,
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int is_write, int is_user, int *code_out)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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int err = -EFAULT;
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*code_out = SEGV_MAPERR;
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/*
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* If the fault was during atomic operation, don't take the fault, just
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* fail.
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*/
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if (in_atomic())
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goto out_nosemaphore;
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, address);
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if (!vma)
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goto out;
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else if (vma->vm_start <= address)
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goto good_area;
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else if (!(vma->vm_flags & VM_GROWSDOWN))
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goto out;
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else if (is_user && !ARCH_IS_STACKGROW(address))
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goto out;
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else if (expand_stack(vma, address))
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goto out;
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good_area:
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*code_out = SEGV_ACCERR;
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if (is_write && !(vma->vm_flags & VM_WRITE))
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goto out;
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/* Don't require VM_READ|VM_EXEC for write faults! */
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if (!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC)))
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goto out;
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do {
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int fault;
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fault = handle_mm_fault(mm, vma, address, is_write ? FAULT_FLAG_WRITE : 0);
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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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err = -EACCES;
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goto out;
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}
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BUG();
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}
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if (fault & VM_FAULT_MAJOR)
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current->maj_flt++;
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else
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current->min_flt++;
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pgd = pgd_offset(mm, address);
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pud = pud_offset(pgd, address);
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pmd = pmd_offset(pud, address);
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pte = pte_offset_kernel(pmd, address);
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} while (!pte_present(*pte));
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err = 0;
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/*
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* The below warning was added in place of
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* pte_mkyoung(); if (is_write) pte_mkdirty();
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* If it's triggered, we'd see normally a hang here (a clean pte is
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* marked read-only to emulate the dirty bit).
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* However, the generic code can mark a PTE writable but clean on a
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* concurrent read fault, triggering this harmlessly. So comment it out.
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*/
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#if 0
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WARN_ON(!pte_young(*pte) || (is_write && !pte_dirty(*pte)));
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#endif
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flush_tlb_page(vma, address);
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out:
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up_read(&mm->mmap_sem);
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out_nosemaphore:
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return err;
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out_of_memory:
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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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up_read(&mm->mmap_sem);
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pagefault_out_of_memory();
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return 0;
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}
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static void bad_segv(struct faultinfo fi, unsigned long ip)
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{
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struct siginfo si;
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si.si_signo = SIGSEGV;
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si.si_code = SEGV_ACCERR;
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si.si_addr = (void __user *) FAULT_ADDRESS(fi);
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current->thread.arch.faultinfo = fi;
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force_sig_info(SIGSEGV, &si, current);
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}
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void fatal_sigsegv(void)
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{
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force_sigsegv(SIGSEGV, current);
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do_signal();
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/*
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* This is to tell gcc that we're not returning - do_signal
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* can, in general, return, but in this case, it's not, since
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* we just got a fatal SIGSEGV queued.
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*/
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os_dump_core();
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}
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void segv_handler(int sig, struct uml_pt_regs *regs)
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{
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struct faultinfo * fi = UPT_FAULTINFO(regs);
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if (UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)) {
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bad_segv(*fi, UPT_IP(regs));
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return;
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}
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segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
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}
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/*
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* We give a *copy* of the faultinfo in the regs to segv.
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* This must be done, since nesting SEGVs could overwrite
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* the info in the regs. A pointer to the info then would
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* give us bad data!
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*/
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unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
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struct uml_pt_regs *regs)
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{
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struct siginfo si;
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jmp_buf *catcher;
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int err;
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int is_write = FAULT_WRITE(fi);
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unsigned long address = FAULT_ADDRESS(fi);
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if (!is_user && (address >= start_vm) && (address < end_vm)) {
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flush_tlb_kernel_vm();
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return 0;
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}
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else if (current->mm == NULL) {
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show_regs(container_of(regs, struct pt_regs, regs));
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panic("Segfault with no mm");
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}
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if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi))
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err = handle_page_fault(address, ip, is_write, is_user,
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&si.si_code);
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else {
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err = -EFAULT;
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/*
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* A thread accessed NULL, we get a fault, but CR2 is invalid.
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* This code is used in __do_copy_from_user() of TT mode.
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* XXX tt mode is gone, so maybe this isn't needed any more
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*/
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address = 0;
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}
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catcher = current->thread.fault_catcher;
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if (!err)
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return 0;
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else if (catcher != NULL) {
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current->thread.fault_addr = (void *) address;
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UML_LONGJMP(catcher, 1);
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}
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else if (current->thread.fault_addr != NULL)
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panic("fault_addr set but no fault catcher");
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else if (!is_user && arch_fixup(ip, regs))
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return 0;
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if (!is_user) {
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show_regs(container_of(regs, struct pt_regs, regs));
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panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
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address, ip);
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}
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if (err == -EACCES) {
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si.si_signo = SIGBUS;
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si.si_errno = 0;
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si.si_code = BUS_ADRERR;
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si.si_addr = (void __user *)address;
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current->thread.arch.faultinfo = fi;
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force_sig_info(SIGBUS, &si, current);
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} else {
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BUG_ON(err != -EFAULT);
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si.si_signo = SIGSEGV;
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si.si_addr = (void __user *) address;
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current->thread.arch.faultinfo = fi;
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force_sig_info(SIGSEGV, &si, current);
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}
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return 0;
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}
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void relay_signal(int sig, struct uml_pt_regs *regs)
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{
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if (!UPT_IS_USER(regs)) {
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if (sig == SIGBUS)
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printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
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"mount likely just ran out of space\n");
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panic("Kernel mode signal %d", sig);
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}
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arch_examine_signal(sig, regs);
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current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
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force_sig(sig, current);
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}
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void bus_handler(int sig, struct uml_pt_regs *regs)
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{
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if (current->thread.fault_catcher != NULL)
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UML_LONGJMP(current->thread.fault_catcher, 1);
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else relay_signal(sig, regs);
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}
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void winch(int sig, struct uml_pt_regs *regs)
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{
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do_IRQ(WINCH_IRQ, regs);
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}
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void trap_init(void)
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{
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}
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