From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/xtensa/mm/fault.c | 256 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 256 insertions(+) create mode 100644 arch/xtensa/mm/fault.c (limited to 'arch/xtensa/mm/fault.c') diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c new file mode 100644 index 0000000000..16e11b6f6f --- /dev/null +++ b/arch/xtensa/mm/fault.c @@ -0,0 +1,256 @@ +// TODO VM_EXEC flag work-around, cache aliasing +/* + * arch/xtensa/mm/fault.c + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2001 - 2010 Tensilica Inc. + * + * Chris Zankel + * Joe Taylor + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +void bad_page_fault(struct pt_regs*, unsigned long, int); + +static void vmalloc_fault(struct pt_regs *regs, unsigned int address) +{ +#ifdef CONFIG_MMU + /* Synchronize this task's top level page-table + * with the 'reference' page table. + */ + struct mm_struct *act_mm = current->active_mm; + int index = pgd_index(address); + pgd_t *pgd, *pgd_k; + p4d_t *p4d, *p4d_k; + pud_t *pud, *pud_k; + pmd_t *pmd, *pmd_k; + pte_t *pte_k; + + if (act_mm == NULL) + goto bad_page_fault; + + pgd = act_mm->pgd + index; + pgd_k = init_mm.pgd + index; + + if (!pgd_present(*pgd_k)) + goto bad_page_fault; + + pgd_val(*pgd) = pgd_val(*pgd_k); + + p4d = p4d_offset(pgd, address); + p4d_k = p4d_offset(pgd_k, address); + if (!p4d_present(*p4d) || !p4d_present(*p4d_k)) + goto bad_page_fault; + + pud = pud_offset(p4d, address); + pud_k = pud_offset(p4d_k, address); + if (!pud_present(*pud) || !pud_present(*pud_k)) + goto bad_page_fault; + + pmd = pmd_offset(pud, address); + pmd_k = pmd_offset(pud_k, address); + if (!pmd_present(*pmd) || !pmd_present(*pmd_k)) + goto bad_page_fault; + + pmd_val(*pmd) = pmd_val(*pmd_k); + pte_k = pte_offset_kernel(pmd_k, address); + + if (!pte_present(*pte_k)) + goto bad_page_fault; + return; + +bad_page_fault: + bad_page_fault(regs, address, SIGKILL); +#else + WARN_ONCE(1, "%s in noMMU configuration\n", __func__); +#endif +} +/* + * This routine handles page faults. It determines the address, + * and the problem, and then passes it off to one of the appropriate + * routines. + * + * Note: does not handle Miss and MultiHit. + */ + +void do_page_fault(struct pt_regs *regs) +{ + struct vm_area_struct * vma; + struct mm_struct *mm = current->mm; + unsigned int exccause = regs->exccause; + unsigned int address = regs->excvaddr; + int code; + + int is_write, is_exec; + vm_fault_t fault; + unsigned int flags = FAULT_FLAG_DEFAULT; + + code = SEGV_MAPERR; + + /* We fault-in kernel-space virtual memory on-demand. The + * 'reference' page table is init_mm.pgd. + */ + if (address >= TASK_SIZE && !user_mode(regs)) { + vmalloc_fault(regs, address); + return; + } + + /* If we're in an interrupt or have no user + * context, we must not take the fault.. + */ + if (faulthandler_disabled() || !mm) { + bad_page_fault(regs, address, SIGSEGV); + return; + } + + is_write = (exccause == EXCCAUSE_STORE_CACHE_ATTRIBUTE) ? 1 : 0; + is_exec = (exccause == EXCCAUSE_ITLB_PRIVILEGE || + exccause == EXCCAUSE_ITLB_MISS || + exccause == EXCCAUSE_FETCH_CACHE_ATTRIBUTE) ? 1 : 0; + + pr_debug("[%s:%d:%08x:%d:%08lx:%s%s]\n", + current->comm, current->pid, + address, exccause, regs->pc, + is_write ? "w" : "", is_exec ? "x" : ""); + + 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.. + */ + + code = SEGV_ACCERR; + + if (is_write) { + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + flags |= FAULT_FLAG_WRITE; + } else if (is_exec) { + if (!(vma->vm_flags & VM_EXEC)) + goto bad_area; + } else /* Allow read even from write-only pages. */ + if (!(vma->vm_flags & (VM_READ | VM_WRITE))) + goto bad_area; + + /* 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)) { + if (!user_mode(regs)) + bad_page_fault(regs, address, SIGKILL); + 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)) { + force_sig_fault(SIGSEGV, code, (void *) address); + return; + } + bad_page_fault(regs, address, SIGSEGV); + return; + + + /* 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)) + bad_page_fault(regs, address, SIGKILL); + else + 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 *) address); + + /* Kernel mode? Handle exceptions or die */ + if (!user_mode(regs)) + bad_page_fault(regs, address, SIGBUS); + return; +} + + +void +bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) +{ + extern void __noreturn die(const char*, struct pt_regs*, long); + const struct exception_table_entry *entry; + + /* Are we prepared to handle this kernel fault? */ + if ((entry = search_exception_tables(regs->pc)) != NULL) { + pr_debug("%s: Exception at pc=%#010lx (%lx)\n", + current->comm, regs->pc, entry->fixup); + regs->pc = entry->fixup; + return; + } + + /* Oops. The kernel tried to access some bad page. We'll have to + * terminate things with extreme prejudice. + */ + pr_alert("Unable to handle kernel paging request at virtual " + "address %08lx\n pc = %08lx, ra = %08lx\n", + address, regs->pc, regs->areg[0]); + die("Oops", regs, sig); +} -- cgit v1.2.3