[PATCH v2] powerpc/traps: Enhance readability for trap types

[Xiongwei Song]

Michael Ellerman <mpe at ellerman.id.au> 于2021年3月31日周三 下午5:58写道：

> Xiongwei Song <sxwjean at me.com> writes:
> > From: Xiongwei Song <sxwjean at gmail.com>
> >
> > Create a new header named traps.h, define macros to list ppc exception
> > types in traps.h, replace the reference of the real trap values with
> > these macros.
>
> Personally I find the hex values easier to recognise, but I realise
> that's probably not true of other people :)
>
> I'm one of the "other people".

> ...
> > diff --git a/arch/powerpc/include/asm/traps.h
> b/arch/powerpc/include/asm/traps.h
> > new file mode 100644
> > index 000000000000..a31b6122de23
> > --- /dev/null
> > +++ b/arch/powerpc/include/asm/traps.h
> > @@ -0,0 +1,19 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_PPC_TRAPS_H
> > +#define _ASM_PPC_TRAPS_H
> > +
> > +#define TRAP_RESET   0x100 /* System reset */
> > +#define TRAP_MCE     0x200 /* Machine check */
> > +#define TRAP_DSI     0x300 /* Data storage */
> > +#define TRAP_DSEGI   0x380 /* Data segment */
> > +#define TRAP_ISI     0x400 /* Instruction storage */
> > +#define TRAP_ISEGI   0x480 /* Instruction segment */
> > +#define TRAP_ALIGN   0x600 /* Alignment */
> > +#define TRAP_PROG    0x700 /* Program */
> > +#define TRAP_DEC     0x900 /* Decrementer */
> > +#define TRAP_SYSCALL 0xc00 /* System call */
> > +#define TRAP_TRACEI  0xd00 /* Trace */
> > +#define TRAP_FPA     0xe00 /* Floating-point Assist */
> > +#define TRAP_PMI     0xf00 /* Performance monitor */
>
> I know the macro is called TRAP and the field in pt_regs is called trap,
> but the terminology in the architecture is "exception", and we already
> have many uses of that. In particular we have a lot of uses of "exc" as
> an abbreviation for "exception". So I think I'd rather we use that than
> "TRAP".
>
Ok.

>
> I think we should probably use the names from the ISA, unless they are
> really over long.
>
> Which are:
>
>   0x100   System Reset
>   0x200   Machine Check
>   0x300   Data Storage
>   0x380   Data Segment
>   0x400   Instruction Storage
>   0x480   Instruction Segment
>   0x500   External
>   0x600   Alignment
>   0x700   Program
>   0x800   Floating-Point Unavailable
>   0x900   Decrementer
>   0x980   Hypervisor Decrementer
>   0xA00   Directed Privileged Doorbell
>   0xC00   System Call
>   0xD00   Trace
>   0xE00   Hypervisor Data Storage
>   0xE20   Hypervisor Instruction Storage
>   0xE40   Hypervisor Emulation Assistance
>   0xE60   Hypervisor Maintenance
>   0xE80   Directed Hypervisor Doorbell
>   0xEA0   Hypervisor Virtualization
>   0xF00   Performance Monitor
>   0xF20   Vector Unavailable
>   0xF40   VSX Unavailable
>   0xF60   Facility Unavailable
>   0xF80   Hypervisor Facility Unavailable
>   0xFA0   Directed Ultravisor Doorbell
>
>
> So perhaps:
>
>   EXC_SYSTEM_RESET
>   EXC_MACHINE_CHECK
>   EXC_DATA_STORAGE
>   EXC_DATA_SEGMENT
>   EXC_INST_STORAGE
>   EXC_INST_SEGMENT
>   EXC_EXTERNAL_INTERRUPT
>   EXC_ALIGNMENT
>   EXC_PROGRAM_CHECK
>   EXC_FP_UNAVAILABLE
>   EXC_DECREMENTER
>   EXC_HV_DECREMENTER
>   EXC_SYSTEM_CALL
>   EXC_HV_DATA_STORAGE
>   EXC_PERF_MONITOR
>
> Thanks for the suggestions. I'm ok with the prefix. Let me change.
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