diff options
Diffstat (limited to 'arch/arm64/mm/fault.c')
| -rw-r--r-- | arch/arm64/mm/fault.c | 89 |
1 files changed, 66 insertions, 23 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c7861c9864e6..89993c4be1be 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -34,6 +34,7 @@ #include <linux/hugetlb.h> #include <asm/bug.h> +#include <asm/cmpxchg.h> #include <asm/cpufeature.h> #include <asm/exception.h> #include <asm/debug-monitors.h> @@ -82,6 +83,49 @@ static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) } #endif +static void data_abort_decode(unsigned int esr) +{ + pr_alert("Data abort info:\n"); + + if (esr & ESR_ELx_ISV) { + pr_alert(" Access size = %u byte(s)\n", + 1U << ((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT)); + pr_alert(" SSE = %lu, SRT = %lu\n", + (esr & ESR_ELx_SSE) >> ESR_ELx_SSE_SHIFT, + (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT); + pr_alert(" SF = %lu, AR = %lu\n", + (esr & ESR_ELx_SF) >> ESR_ELx_SF_SHIFT, + (esr & ESR_ELx_AR) >> ESR_ELx_AR_SHIFT); + } else { + pr_alert(" ISV = 0, ISS = 0x%08lu\n", esr & ESR_ELx_ISS_MASK); + } + + pr_alert(" CM = %lu, WnR = %lu\n", + (esr & ESR_ELx_CM) >> ESR_ELx_CM_SHIFT, + (esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT); +} + +/* + * Decode mem abort information + */ +static void mem_abort_decode(unsigned int esr) +{ + pr_alert("Mem abort info:\n"); + + pr_alert(" Exception class = %s, IL = %u bits\n", + esr_get_class_string(esr), + (esr & ESR_ELx_IL) ? 32 : 16); + pr_alert(" SET = %lu, FnV = %lu\n", + (esr & ESR_ELx_SET_MASK) >> ESR_ELx_SET_SHIFT, + (esr & ESR_ELx_FnV) >> ESR_ELx_FnV_SHIFT); + pr_alert(" EA = %lu, S1PTW = %lu\n", + (esr & ESR_ELx_EA) >> ESR_ELx_EA_SHIFT, + (esr & ESR_ELx_S1PTW) >> ESR_ELx_S1PTW_SHIFT); + + if (esr_is_data_abort(esr)) + data_abort_decode(esr); +} + /* * Dump out the page tables associated with 'addr' in the currently active mm. */ @@ -139,7 +183,6 @@ void show_pte(unsigned long addr) pr_cont("\n"); } -#ifdef CONFIG_ARM64_HW_AFDBM /* * This function sets the access flags (dirty, accessed), as well as write * permission, and only to a more permissive setting. @@ -154,40 +197,33 @@ int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t entry, int dirty) { - pteval_t old_pteval; - unsigned int tmp; + pteval_t old_pteval, pteval; if (pte_same(*ptep, entry)) return 0; /* only preserve the access flags and write permission */ - pte_val(entry) &= PTE_AF | PTE_WRITE | PTE_DIRTY; - - /* - * PTE_RDONLY is cleared by default in the asm below, so set it in - * back if necessary (read-only or clean PTE). - */ - if (!pte_write(entry) || !pte_sw_dirty(entry)) - pte_val(entry) |= PTE_RDONLY; + pte_val(entry) &= PTE_RDONLY | PTE_AF | PTE_WRITE | PTE_DIRTY; /* * Setting the flags must be done atomically to avoid racing with the - * hardware update of the access/dirty state. + * hardware update of the access/dirty state. The PTE_RDONLY bit must + * be set to the most permissive (lowest value) of *ptep and entry + * (calculated as: a & b == ~(~a | ~b)). */ - asm volatile("// ptep_set_access_flags\n" - " prfm pstl1strm, %2\n" - "1: ldxr %0, %2\n" - " and %0, %0, %3 // clear PTE_RDONLY\n" - " orr %0, %0, %4 // set flags\n" - " stxr %w1, %0, %2\n" - " cbnz %w1, 1b\n" - : "=&r" (old_pteval), "=&r" (tmp), "+Q" (pte_val(*ptep)) - : "L" (~PTE_RDONLY), "r" (pte_val(entry))); + pte_val(entry) ^= PTE_RDONLY; + pteval = READ_ONCE(pte_val(*ptep)); + do { + old_pteval = pteval; + pteval ^= PTE_RDONLY; + pteval |= pte_val(entry); + pteval ^= PTE_RDONLY; + pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval); + } while (pteval != old_pteval); flush_tlb_fix_spurious_fault(vma, address); return 1; } -#endif static bool is_el1_instruction_abort(unsigned int esr) { @@ -247,6 +283,8 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg, addr); + mem_abort_decode(esr); + show_pte(addr); die("Oops", regs, esr); bust_spinlocks(0); @@ -434,8 +472,11 @@ retry: * the mmap_sem because it would already be released * in __lock_page_or_retry in mm/filemap.c. */ - if (fatal_signal_pending(current)) + if (fatal_signal_pending(current)) { + if (!user_mode(regs)) + goto no_context; return 0; + } /* * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of @@ -701,6 +742,8 @@ asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n", inf->name, esr, addr); + mem_abort_decode(esr); + info.si_signo = inf->sig; info.si_errno = 0; info.si_code = inf->code; |