[ Upstream commit e3de1e291fa58a1ab0f471a4b458eff2514e4b5f ] In commit bf13718bc57a ("powerpc: show registers when unwinding interrupt frames") we changed our stack dumping logic to show the full registers whenever we find an interrupt frame on the stack. However we didn't notice that on 64-bit this doesn't show the final frame, ie. the interrupt that brought us in from userspace, whereas on 32-bit it does. That is due to confusion about the size of that last frame. The code in show_stack() calls validate_sp(), passing it STACK_INT_FRAME_SIZE to check the sp is at least that far below the top of the stack. However on 64-bit that size is too large for the final frame, because it includes the red zone, but we don't allocate a red zone for the first frame. So add a new define that encodes the correct size for 32-bit and 64-bit, and use it in show_stack(). This results in the full trace being shown on 64-bit, eg: sysrq: Trigger a crash Kernel panic - not syncing: sysrq triggered crash CPU: 0 PID: 83 Comm: sh Not tainted 5.11.0-rc2-gcc-8.2.0-00188-g571abcb96b10-dirty #649 Call Trace: [c00000000a1c3ac0] [c000000000897b70] dump_stack+0xc4/0x114 (unreliable) [c00000000a1c3b00] [c00000000014334c] panic+0x178/0x41c [c00000000a1c3ba0] [c00000000094e600] sysrq_handle_crash+0x40/0x50 [c00000000a1c3c00] [c00000000094ef98] __handle_sysrq+0xd8/0x210 [c00000000a1c3ca0] [c00000000094f820] write_sysrq_trigger+0x100/0x188 [c00000000a1c3ce0] [c0000000005559dc] proc_reg_write+0x10c/0x1b0 [c00000000a1c3d10] [c000000000479950] vfs_write+0xf0/0x360 [c00000000a1c3d60] [c000000000479d9c] ksys_write+0x7c/0x140 [c00000000a1c3db0] [c00000000002bf5c] system_call_exception+0x19c/0x2c0 [c00000000a1c3e10] [c00000000000d35c] system_call_common+0xec/0x278 --- interrupt: c00 at 0x7fff9fbab428 NIP: 00007fff9fbab428 LR: 000000001000b724 CTR: 0000000000000000 REGS: c00000000a1c3e80 TRAP: 0c00 Not tainted (5.11.0-rc2-gcc-8.2.0-00188-g571abcb96b10-dirty) MSR: 900000000280f033 <SF,HV,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE> CR: 22002884 XER: 00000000 IRQMASK: 0 GPR00: 0000000000000004 00007fffc3cb8960 00007fff9fc59900 0000000000000001 GPR04: 000000002a4b32d0 0000000000000002 0000000000000063 0000000000000063 GPR08: 000000002a4b32d0 0000000000000000 0000000000000000 0000000000000000 GPR12: 0000000000000000 00007fff9fcca9a0 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 00000000100b8fd0 GPR20: 000000002a4b3485 00000000100b8f90 0000000000000000 0000000000000000 GPR24: 000000002a4b0440 00000000100e77b8 0000000000000020 000000002a4b32d0 GPR28: 0000000000000001 0000000000000002 000000002a4b32d0 0000000000000001 NIP [00007fff9fbab428] 0x7fff9fbab428 LR [000000001000b724] 0x1000b724 --- interrupt: c00 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210209141627.2898485-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin <sashal@kernel.org>
290 lines
8.1 KiB
C
290 lines
8.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2001 PPC64 Team, IBM Corp
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*
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* This struct defines the way the registers are stored on the
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* kernel stack during a system call or other kernel entry.
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*
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* this should only contain volatile regs
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* since we can keep non-volatile in the thread_struct
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* should set this up when only volatiles are saved
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* by intr code.
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*
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* Since this is going on the stack, *CARE MUST BE TAKEN* to insure
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* that the overall structure is a multiple of 16 bytes in length.
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*
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* Note that the offsets of the fields in this struct correspond with
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* the PT_* values below. This simplifies arch/powerpc/kernel/ptrace.c.
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*/
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#ifndef _ASM_POWERPC_PTRACE_H
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#define _ASM_POWERPC_PTRACE_H
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#include <uapi/asm/ptrace.h>
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#include <asm/asm-const.h>
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#ifndef __ASSEMBLY__
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struct pt_regs
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{
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union {
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struct user_pt_regs user_regs;
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struct {
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unsigned long gpr[32];
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unsigned long nip;
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unsigned long msr;
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unsigned long orig_gpr3;
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unsigned long ctr;
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unsigned long link;
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unsigned long xer;
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unsigned long ccr;
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#ifdef CONFIG_PPC64
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unsigned long softe;
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#else
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unsigned long mq;
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#endif
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unsigned long trap;
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unsigned long dar;
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unsigned long dsisr;
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unsigned long result;
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};
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};
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union {
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struct {
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#ifdef CONFIG_PPC64
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unsigned long ppr;
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#endif
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#ifdef CONFIG_PPC_KUAP
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unsigned long kuap;
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#endif
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};
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unsigned long __pad[2]; /* Maintain 16 byte interrupt stack alignment */
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};
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};
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#endif
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#define STACK_FRAME_WITH_PT_REGS (STACK_FRAME_OVERHEAD + sizeof(struct pt_regs))
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#ifdef __powerpc64__
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/*
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* Size of redzone that userspace is allowed to use below the stack
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* pointer. This is 288 in the 64-bit big-endian ELF ABI, and 512 in
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* the new ELFv2 little-endian ABI, so we allow the larger amount.
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*
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* For kernel code we allow a 288-byte redzone, in order to conserve
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* kernel stack space; gcc currently only uses 288 bytes, and will
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* hopefully allow explicit control of the redzone size in future.
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*/
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#define USER_REDZONE_SIZE 512
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#define KERNEL_REDZONE_SIZE 288
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#define STACK_FRAME_OVERHEAD 112 /* size of minimum stack frame */
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#define STACK_FRAME_LR_SAVE 2 /* Location of LR in stack frame */
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#define STACK_FRAME_REGS_MARKER ASM_CONST(0x7265677368657265)
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#define STACK_INT_FRAME_SIZE (sizeof(struct pt_regs) + \
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STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
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#define STACK_FRAME_MARKER 12
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#ifdef PPC64_ELF_ABI_v2
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#define STACK_FRAME_MIN_SIZE 32
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#else
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#define STACK_FRAME_MIN_SIZE STACK_FRAME_OVERHEAD
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#endif
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/* Size of dummy stack frame allocated when calling signal handler. */
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#define __SIGNAL_FRAMESIZE 128
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#define __SIGNAL_FRAMESIZE32 64
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#else /* __powerpc64__ */
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#define USER_REDZONE_SIZE 0
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#define KERNEL_REDZONE_SIZE 0
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#define STACK_FRAME_OVERHEAD 16 /* size of minimum stack frame */
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#define STACK_FRAME_LR_SAVE 1 /* Location of LR in stack frame */
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#define STACK_FRAME_REGS_MARKER ASM_CONST(0x72656773)
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#define STACK_INT_FRAME_SIZE (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
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#define STACK_FRAME_MARKER 2
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#define STACK_FRAME_MIN_SIZE STACK_FRAME_OVERHEAD
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/* Size of stack frame allocated when calling signal handler. */
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#define __SIGNAL_FRAMESIZE 64
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#endif /* __powerpc64__ */
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#ifndef __ASSEMBLY__
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static inline unsigned long instruction_pointer(struct pt_regs *regs)
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{
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return regs->nip;
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}
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static inline void instruction_pointer_set(struct pt_regs *regs,
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unsigned long val)
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{
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regs->nip = val;
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}
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static inline unsigned long user_stack_pointer(struct pt_regs *regs)
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{
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return regs->gpr[1];
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}
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static inline unsigned long frame_pointer(struct pt_regs *regs)
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{
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return 0;
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}
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#ifdef CONFIG_SMP
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extern unsigned long profile_pc(struct pt_regs *regs);
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#else
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#define profile_pc(regs) instruction_pointer(regs)
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#endif
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#define kernel_stack_pointer(regs) ((regs)->gpr[1])
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static inline int is_syscall_success(struct pt_regs *regs)
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{
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return !(regs->ccr & 0x10000000);
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}
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static inline long regs_return_value(struct pt_regs *regs)
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{
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if (is_syscall_success(regs))
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return regs->gpr[3];
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else
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return -regs->gpr[3];
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}
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static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
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{
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regs->gpr[3] = rc;
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}
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#ifdef __powerpc64__
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#define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1)
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#else
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#define user_mode(regs) (((regs)->msr & MSR_PR) != 0)
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#endif
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#define force_successful_syscall_return() \
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do { \
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set_thread_flag(TIF_NOERROR); \
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} while(0)
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struct task_struct;
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extern int ptrace_get_reg(struct task_struct *task, int regno,
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unsigned long *data);
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extern int ptrace_put_reg(struct task_struct *task, int regno,
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unsigned long data);
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#define current_pt_regs() \
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((struct pt_regs *)((unsigned long)task_stack_page(current) + THREAD_SIZE) - 1)
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/*
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* We use the least-significant bit of the trap field to indicate
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* whether we have saved the full set of registers, or only a
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* partial set. A 1 there means the partial set.
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* On 4xx we use the next bit to indicate whether the exception
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* is a critical exception (1 means it is).
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*/
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#define FULL_REGS(regs) (((regs)->trap & 1) == 0)
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#ifndef __powerpc64__
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#define IS_CRITICAL_EXC(regs) (((regs)->trap & 2) != 0)
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#define IS_MCHECK_EXC(regs) (((regs)->trap & 4) != 0)
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#define IS_DEBUG_EXC(regs) (((regs)->trap & 8) != 0)
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#endif /* ! __powerpc64__ */
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#define TRAP(regs) ((regs)->trap & ~0xF)
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#ifdef __powerpc64__
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#define NV_REG_POISON 0xdeadbeefdeadbeefUL
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#define CHECK_FULL_REGS(regs) BUG_ON(regs->trap & 1)
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#else
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#define NV_REG_POISON 0xdeadbeef
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#define CHECK_FULL_REGS(regs) \
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do { \
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if ((regs)->trap & 1) \
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printk(KERN_CRIT "%s: partial register set\n", __func__); \
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} while (0)
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#endif /* __powerpc64__ */
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#define arch_has_single_step() (1)
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#ifndef CONFIG_PPC_BOOK3S_601
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#define arch_has_block_step() (true)
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#else
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#define arch_has_block_step() (false)
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#endif
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#define ARCH_HAS_USER_SINGLE_STEP_REPORT
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/*
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* kprobe-based event tracer support
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*/
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#include <linux/stddef.h>
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#include <linux/thread_info.h>
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extern int regs_query_register_offset(const char *name);
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extern const char *regs_query_register_name(unsigned int offset);
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#define MAX_REG_OFFSET (offsetof(struct pt_regs, dsisr))
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/**
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* regs_get_register() - get register value from its offset
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* @regs: pt_regs from which register value is gotten
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* @offset: offset number of the register.
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*
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* regs_get_register returns the value of a register whose offset from @regs.
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* The @offset is the offset of the register in struct pt_regs.
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* If @offset is bigger than MAX_REG_OFFSET, this returns 0.
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*/
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static inline unsigned long regs_get_register(struct pt_regs *regs,
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unsigned int offset)
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{
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if (unlikely(offset > MAX_REG_OFFSET))
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return 0;
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return *(unsigned long *)((unsigned long)regs + offset);
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}
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/**
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* regs_within_kernel_stack() - check the address in the stack
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* @regs: pt_regs which contains kernel stack pointer.
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* @addr: address which is checked.
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*
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* regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
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* If @addr is within the kernel stack, it returns true. If not, returns false.
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*/
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static inline bool regs_within_kernel_stack(struct pt_regs *regs,
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unsigned long addr)
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{
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return ((addr & ~(THREAD_SIZE - 1)) ==
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(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
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}
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/**
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* regs_get_kernel_stack_nth() - get Nth entry of the stack
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* @regs: pt_regs which contains kernel stack pointer.
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* @n: stack entry number.
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*
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* regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
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* is specified by @regs. If the @n th entry is NOT in the kernel stack,
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* this returns 0.
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*/
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static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
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unsigned int n)
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{
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unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
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addr += n;
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if (regs_within_kernel_stack(regs, (unsigned long)addr))
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return *addr;
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else
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return 0;
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}
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#endif /* __ASSEMBLY__ */
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#ifndef __powerpc64__
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#else /* __powerpc64__ */
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#define PT_FPSCR32 (PT_FPR0 + 2*32 + 1) /* each FP reg occupies 2 32-bit userspace slots */
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#define PT_VR0_32 164 /* each Vector reg occupies 4 slots in 32-bit */
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#define PT_VSCR_32 (PT_VR0 + 32*4 + 3)
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#define PT_VRSAVE_32 (PT_VR0 + 33*4)
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#define PT_VSR0_32 300 /* each VSR reg occupies 4 slots in 32-bit */
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#endif /* __powerpc64__ */
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#endif /* _ASM_POWERPC_PTRACE_H */
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