diff options
-rw-r--r-- | arch/parisc/include/asm/traps.h | 1 | ||||
-rw-r--r-- | arch/parisc/kernel/traps.c | 2 | ||||
-rw-r--r-- | arch/parisc/mm/fault.c | 89 |
3 files changed, 92 insertions, 0 deletions
diff --git a/arch/parisc/include/asm/traps.h b/arch/parisc/include/asm/traps.h index 8ecc1f0c0483..d0e090a2c000 100644 --- a/arch/parisc/include/asm/traps.h +++ b/arch/parisc/include/asm/traps.h @@ -17,6 +17,7 @@ void die_if_kernel(char *str, struct pt_regs *regs, long err); const char *trap_name(unsigned long code); void do_page_fault(struct pt_regs *regs, unsigned long code, unsigned long address); +int handle_nadtlb_fault(struct pt_regs *regs); #endif #endif diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c index afe8b902a8fc..6fe5a3e98edc 100644 --- a/arch/parisc/kernel/traps.c +++ b/arch/parisc/kernel/traps.c @@ -661,6 +661,8 @@ void notrace handle_interruption(int code, struct pt_regs *regs) by hand. Technically we need to emulate: fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw */ + if (code == 17 && handle_nadtlb_fault(regs)) + return; fault_address = regs->ior; fault_space = regs->isr; break; diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index 716960f5d92e..5faa3cff4738 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -424,3 +424,92 @@ no_context: goto no_context; pagefault_out_of_memory(); } + +/* Handle non-access data TLB miss faults. + * + * For probe instructions, accesses to userspace are considered allowed + * if they lie in a valid VMA and the access type matches. We are not + * allowed to handle MM faults here so there may be situations where an + * actual access would fail even though a probe was successful. + */ +int +handle_nadtlb_fault(struct pt_regs *regs) +{ + unsigned long insn = regs->iir; + int breg, treg, xreg, val = 0; + struct vm_area_struct *vma, *prev_vma; + struct task_struct *tsk; + struct mm_struct *mm; + unsigned long address; + unsigned long acc_type; + + switch (insn & 0x380) { + case 0x280: + /* FDC instruction */ + fallthrough; + case 0x380: + /* PDC and FIC instructions */ + if (printk_ratelimit()) { + pr_warn("BUG: nullifying cache flush/purge instruction\n"); + show_regs(regs); + } + if (insn & 0x20) { + /* Base modification */ + breg = (insn >> 21) & 0x1f; + xreg = (insn >> 16) & 0x1f; + if (breg && xreg) + regs->gr[breg] += regs->gr[xreg]; + } + regs->gr[0] |= PSW_N; + return 1; + + case 0x180: + /* PROBE instruction */ + treg = insn & 0x1f; + if (regs->isr) { + tsk = current; + mm = tsk->mm; + if (mm) { + /* Search for VMA */ + address = regs->ior; + mmap_read_lock(mm); + vma = find_vma_prev(mm, address, &prev_vma); + mmap_read_unlock(mm); + + /* + * Check if access to the VMA is okay. + * We don't allow for stack expansion. + */ + acc_type = (insn & 0x40) ? VM_WRITE : VM_READ; + if (vma + && address >= vma->vm_start + && (vma->vm_flags & acc_type) == acc_type) + val = 1; + } + } + if (treg) + regs->gr[treg] = val; + regs->gr[0] |= PSW_N; + return 1; + + case 0x300: + /* LPA instruction */ + if (insn & 0x20) { + /* Base modification */ + breg = (insn >> 21) & 0x1f; + xreg = (insn >> 16) & 0x1f; + if (breg && xreg) + regs->gr[breg] += regs->gr[xreg]; + } + treg = insn & 0x1f; + if (treg) + regs->gr[treg] = 0; + regs->gr[0] |= PSW_N; + return 1; + + default: + break; + } + + return 0; +} |