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426 lines
11 KiB
426 lines
11 KiB
/* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file "COPYING" in the main directory of this archive |
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* for more details. |
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* |
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* |
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* Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle |
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* Copyright 1999 SuSE GmbH (Philipp Rumpf, [email protected]) |
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* Copyright 1999 Hewlett Packard Co. |
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* |
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*/ |
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#include <linux/mm.h> |
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#include <linux/ptrace.h> |
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#include <linux/sched.h> |
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#include <linux/sched/debug.h> |
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#include <linux/interrupt.h> |
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#include <linux/extable.h> |
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#include <linux/uaccess.h> |
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#include <linux/hugetlb.h> |
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#include <linux/perf_event.h> |
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#include <asm/traps.h> |
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/* Various important other fields */ |
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#define bit22set(x) (x & 0x00000200) |
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#define bits23_25set(x) (x & 0x000001c0) |
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#define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80) |
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/* extended opcode is 0x6a */ |
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#define BITSSET 0x1c0 /* for identifying LDCW */ |
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int show_unhandled_signals = 1; |
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/* |
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* parisc_acctyp(unsigned int inst) -- |
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* Given a PA-RISC memory access instruction, determine if the |
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* the instruction would perform a memory read or memory write |
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* operation. |
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* |
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* This function assumes that the given instruction is a memory access |
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* instruction (i.e. you should really only call it if you know that |
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* the instruction has generated some sort of a memory access fault). |
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* |
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* Returns: |
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* VM_READ if read operation |
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* VM_WRITE if write operation |
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* VM_EXEC if execute operation |
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*/ |
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static unsigned long |
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parisc_acctyp(unsigned long code, unsigned int inst) |
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{ |
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if (code == 6 || code == 16) |
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return VM_EXEC; |
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switch (inst & 0xf0000000) { |
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case 0x40000000: /* load */ |
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case 0x50000000: /* new load */ |
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return VM_READ; |
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case 0x60000000: /* store */ |
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case 0x70000000: /* new store */ |
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return VM_WRITE; |
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case 0x20000000: /* coproc */ |
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case 0x30000000: /* coproc2 */ |
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if (bit22set(inst)) |
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return VM_WRITE; |
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fallthrough; |
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case 0x0: /* indexed/memory management */ |
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if (bit22set(inst)) { |
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/* |
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* Check for the 'Graphics Flush Read' instruction. |
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* It resembles an FDC instruction, except for bits |
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* 20 and 21. Any combination other than zero will |
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* utilize the block mover functionality on some |
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* older PA-RISC platforms. The case where a block |
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* move is performed from VM to graphics IO space |
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* should be treated as a READ. |
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* |
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* The significance of bits 20,21 in the FDC |
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* instruction is: |
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* |
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* 00 Flush data cache (normal instruction behavior) |
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* 01 Graphics flush write (IO space -> VM) |
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* 10 Graphics flush read (VM -> IO space) |
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* 11 Graphics flush read/write (VM <-> IO space) |
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*/ |
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if (isGraphicsFlushRead(inst)) |
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return VM_READ; |
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return VM_WRITE; |
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} else { |
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/* |
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* Check for LDCWX and LDCWS (semaphore instructions). |
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* If bits 23 through 25 are all 1's it is one of |
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* the above two instructions and is a write. |
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* |
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* Note: With the limited bits we are looking at, |
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* this will also catch PROBEW and PROBEWI. However, |
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* these should never get in here because they don't |
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* generate exceptions of the type: |
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* Data TLB miss fault/data page fault |
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* Data memory protection trap |
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*/ |
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if (bits23_25set(inst) == BITSSET) |
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return VM_WRITE; |
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} |
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return VM_READ; /* Default */ |
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} |
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return VM_READ; /* Default */ |
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} |
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#undef bit22set |
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#undef bits23_25set |
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#undef isGraphicsFlushRead |
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#undef BITSSET |
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#if 0 |
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/* This is the treewalk to find a vma which is the highest that has |
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* a start < addr. We're using find_vma_prev instead right now, but |
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* we might want to use this at some point in the future. Probably |
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* not, but I want it committed to CVS so I don't lose it :-) |
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*/ |
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while (tree != vm_avl_empty) { |
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if (tree->vm_start > addr) { |
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tree = tree->vm_avl_left; |
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} else { |
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prev = tree; |
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if (prev->vm_next == NULL) |
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break; |
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if (prev->vm_next->vm_start > addr) |
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break; |
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tree = tree->vm_avl_right; |
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} |
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} |
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#endif |
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int fixup_exception(struct pt_regs *regs) |
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{ |
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const struct exception_table_entry *fix; |
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fix = search_exception_tables(regs->iaoq[0]); |
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if (fix) { |
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/* |
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* Fix up get_user() and put_user(). |
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* ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant |
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* bit in the relative address of the fixup routine to indicate |
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* that %r8 should be loaded with -EFAULT to report a userspace |
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* access error. |
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*/ |
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if (fix->fixup & 1) { |
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regs->gr[8] = -EFAULT; |
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/* zero target register for get_user() */ |
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if (parisc_acctyp(0, regs->iir) == VM_READ) { |
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int treg = regs->iir & 0x1f; |
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BUG_ON(treg == 0); |
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regs->gr[treg] = 0; |
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} |
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} |
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regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup; |
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regs->iaoq[0] &= ~3; |
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/* |
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* NOTE: In some cases the faulting instruction |
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* may be in the delay slot of a branch. We |
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* don't want to take the branch, so we don't |
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* increment iaoq[1], instead we set it to be |
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* iaoq[0]+4, and clear the B bit in the PSW |
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*/ |
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regs->iaoq[1] = regs->iaoq[0] + 4; |
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regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */ |
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return 1; |
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} |
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return 0; |
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} |
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/* |
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* parisc hardware trap list |
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* |
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* Documented in section 3 "Addressing and Access Control" of the |
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* "PA-RISC 1.1 Architecture and Instruction Set Reference Manual" |
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* https://parisc.wiki.kernel.org/index.php/File:Pa11_acd.pdf |
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* |
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* For implementation see handle_interruption() in traps.c |
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*/ |
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static const char * const trap_description[] = { |
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[1] "High-priority machine check (HPMC)", |
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[2] "Power failure interrupt", |
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[3] "Recovery counter trap", |
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[5] "Low-priority machine check", |
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[6] "Instruction TLB miss fault", |
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[7] "Instruction access rights / protection trap", |
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[8] "Illegal instruction trap", |
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[9] "Break instruction trap", |
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[10] "Privileged operation trap", |
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[11] "Privileged register trap", |
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[12] "Overflow trap", |
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[13] "Conditional trap", |
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[14] "FP Assist Exception trap", |
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[15] "Data TLB miss fault", |
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[16] "Non-access ITLB miss fault", |
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[17] "Non-access DTLB miss fault", |
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[18] "Data memory protection/unaligned access trap", |
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[19] "Data memory break trap", |
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[20] "TLB dirty bit trap", |
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[21] "Page reference trap", |
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[22] "Assist emulation trap", |
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[25] "Taken branch trap", |
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[26] "Data memory access rights trap", |
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[27] "Data memory protection ID trap", |
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[28] "Unaligned data reference trap", |
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}; |
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const char *trap_name(unsigned long code) |
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{ |
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const char *t = NULL; |
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if (code < ARRAY_SIZE(trap_description)) |
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t = trap_description[code]; |
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return t ? t : "Unknown trap"; |
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} |
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/* |
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* Print out info about fatal segfaults, if the show_unhandled_signals |
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* sysctl is set: |
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*/ |
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static inline void |
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show_signal_msg(struct pt_regs *regs, unsigned long code, |
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unsigned long address, struct task_struct *tsk, |
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struct vm_area_struct *vma) |
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{ |
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if (!unhandled_signal(tsk, SIGSEGV)) |
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return; |
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if (!printk_ratelimit()) |
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return; |
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pr_warn("\n"); |
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pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx", |
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tsk->comm, code, address); |
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print_vma_addr(KERN_CONT " in ", regs->iaoq[0]); |
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pr_cont("\ntrap #%lu: %s%c", code, trap_name(code), |
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vma ? ',':'\n'); |
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if (vma) |
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pr_cont(" vm_start = 0x%08lx, vm_end = 0x%08lx\n", |
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vma->vm_start, vma->vm_end); |
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show_regs(regs); |
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} |
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void do_page_fault(struct pt_regs *regs, unsigned long code, |
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unsigned long address) |
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{ |
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struct vm_area_struct *vma, *prev_vma; |
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struct task_struct *tsk; |
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struct mm_struct *mm; |
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unsigned long acc_type; |
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vm_fault_t fault = 0; |
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unsigned int flags; |
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if (faulthandler_disabled()) |
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goto no_context; |
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tsk = current; |
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mm = tsk->mm; |
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if (!mm) |
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goto no_context; |
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flags = FAULT_FLAG_DEFAULT; |
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if (user_mode(regs)) |
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flags |= FAULT_FLAG_USER; |
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acc_type = parisc_acctyp(code, regs->iir); |
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if (acc_type & VM_WRITE) |
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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_prev(mm, address, &prev_vma); |
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if (!vma || address < vma->vm_start) |
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goto check_expansion; |
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/* |
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* Ok, we have a good vm_area for this memory access. We still need to |
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* check the access permissions. |
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*/ |
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good_area: |
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if ((vma->vm_flags & acc_type) != acc_type) |
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goto bad_area; |
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/* |
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* If for any reason at all we couldn't handle the fault, make |
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* sure we exit gracefully rather than endlessly redo the |
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* fault. |
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*/ |
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fault = handle_mm_fault(vma, address, flags, regs); |
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if (fault_signal_pending(fault, regs)) |
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return; |
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if (unlikely(fault & VM_FAULT_ERROR)) { |
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/* |
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* We hit a shared mapping outside of the file, or some |
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* other thing happened to us that made us unable to |
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* handle the page fault gracefully. |
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*/ |
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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_SIGSEGV) |
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goto bad_area; |
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else if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON| |
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VM_FAULT_HWPOISON_LARGE)) |
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goto bad_area; |
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BUG(); |
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} |
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if (flags & FAULT_FLAG_ALLOW_RETRY) { |
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if (fault & VM_FAULT_RETRY) { |
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/* |
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* No need to mmap_read_unlock(mm) as we would |
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* have already released it in __lock_page_or_retry |
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* in mm/filemap.c. |
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*/ |
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flags |= FAULT_FLAG_TRIED; |
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goto retry; |
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} |
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} |
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mmap_read_unlock(mm); |
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return; |
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check_expansion: |
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vma = prev_vma; |
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if (vma && (expand_stack(vma, address) == 0)) |
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goto good_area; |
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/* |
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* Something tried to access memory that isn't in our memory map.. |
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*/ |
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bad_area: |
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mmap_read_unlock(mm); |
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if (user_mode(regs)) { |
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int signo, si_code; |
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switch (code) { |
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case 15: /* Data TLB miss fault/Data page fault */ |
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/* send SIGSEGV when outside of vma */ |
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if (!vma || |
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address < vma->vm_start || address >= vma->vm_end) { |
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signo = SIGSEGV; |
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si_code = SEGV_MAPERR; |
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break; |
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} |
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/* send SIGSEGV for wrong permissions */ |
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if ((vma->vm_flags & acc_type) != acc_type) { |
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signo = SIGSEGV; |
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si_code = SEGV_ACCERR; |
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break; |
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} |
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/* probably address is outside of mapped file */ |
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fallthrough; |
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case 17: /* NA data TLB miss / page fault */ |
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case 18: /* Unaligned access - PCXS only */ |
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signo = SIGBUS; |
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si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR; |
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break; |
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case 16: /* Non-access instruction TLB miss fault */ |
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case 26: /* PCXL: Data memory access rights trap */ |
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default: |
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signo = SIGSEGV; |
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si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR; |
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break; |
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} |
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#ifdef CONFIG_MEMORY_FAILURE |
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if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) { |
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unsigned int lsb = 0; |
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printk(KERN_ERR |
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"MCE: Killing %s:%d due to hardware memory corruption fault at %08lx\n", |
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tsk->comm, tsk->pid, address); |
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/* |
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* Either small page or large page may be poisoned. |
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* In other words, VM_FAULT_HWPOISON_LARGE and |
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* VM_FAULT_HWPOISON are mutually exclusive. |
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*/ |
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if (fault & VM_FAULT_HWPOISON_LARGE) |
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lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); |
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else if (fault & VM_FAULT_HWPOISON) |
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lsb = PAGE_SHIFT; |
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force_sig_mceerr(BUS_MCEERR_AR, (void __user *) address, |
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lsb); |
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return; |
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} |
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#endif |
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show_signal_msg(regs, code, address, tsk, vma); |
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force_sig_fault(signo, si_code, (void __user *) address); |
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return; |
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} |
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no_context: |
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if (!user_mode(regs) && fixup_exception(regs)) { |
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return; |
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} |
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parisc_terminate("Bad Address (null pointer deref?)", regs, code, address); |
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out_of_memory: |
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mmap_read_unlock(mm); |
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if (!user_mode(regs)) |
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goto no_context; |
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pagefault_out_of_memory(); |
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}
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