Messages in this thread | | | Date | Fri, 22 May 2015 13:05:10 -0400 | From | David Long <> | Subject | Re: [PATCH v6 1/6] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature |
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On 05/21/15 13:55, Catalin Marinas wrote: > On Wed, May 20, 2015 at 11:29:24PM -0400, David Long wrote: >> On 05/20/15 09:39, Catalin Marinas wrote: >>> On Mon, Apr 20, 2015 at 04:19:42PM -0400, David Long wrote: >>>> diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h >>>> index 6913643..58c0223 100644 >>>> --- a/arch/arm64/include/uapi/asm/ptrace.h >>>> +++ b/arch/arm64/include/uapi/asm/ptrace.h >>>> @@ -61,6 +61,42 @@ >>>> >>>> #ifndef __ASSEMBLY__ >>>> >>>> +#define ARM_pstate pstate >>>> +#define ARM_pc pc >>>> +#define ARM_sp sp >>>> +#define ARM_lr regs[30] >>>> +#define ARM_fp regs[29] >>>> +#define ARM_x28 regs[28] >>>> +#define ARM_x27 regs[27] >>>> +#define ARM_x26 regs[26] >>>> +#define ARM_x25 regs[25] >>>> +#define ARM_x24 regs[24] >>>> +#define ARM_x23 regs[23] >>>> +#define ARM_x22 regs[22] >>>> +#define ARM_x21 regs[21] >>>> +#define ARM_x20 regs[20] >>>> +#define ARM_x19 regs[19] >>>> +#define ARM_x18 regs[18] >>>> +#define ARM_ip1 regs[17] >>>> +#define ARM_ip0 regs[16] >>>> +#define ARM_x15 regs[15] >>>> +#define ARM_x14 regs[14] >>>> +#define ARM_x13 regs[13] >>>> +#define ARM_x12 regs[12] >>>> +#define ARM_x11 regs[11] >>>> +#define ARM_x10 regs[10] >>>> +#define ARM_x9 regs[9] >>>> +#define ARM_x8 regs[8] >>>> +#define ARM_x7 regs[7] >>>> +#define ARM_x6 regs[6] >>>> +#define ARM_x5 regs[5] >>>> +#define ARM_x4 regs[4] >>>> +#define ARM_x3 regs[3] >>>> +#define ARM_x2 regs[2] >>>> +#define ARM_x1 regs[1] >>>> +#define ARM_x0 regs[0] >>>> +#define ARM_ORIG_x0 orig_x0 >>> >>> I replied some time ago on this part. I don't see the point these >>> macros. >> >> I replied belatedly on April 20 saying what I did matches (more or less) how >> it's done on various other platforms, including arm and powerpc. >> It looks like this comes from the pt_regs structure defining the >> registers as an array instead of a list of structure fields. It looks >> to me like that design choice is pretty widely depended upon now and >> would be quite disruptive to change. It also seems to me a relatively >> clean way to do it on systems with a uniform register set. > > I see why we need to cope with the regs[] array but why do we need these > definitions in a uapi file? >
I expect Sandeepa did it that way because it's the way it's done in other architectures. I see your point though, these definitions are only referenced in a macro that's defined and used only in ptrace.c. I can easily move them there.
>>>> + >>>> /* >>>> * User structures for general purpose, floating point and debug registers. >>>> */ >>>> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c >>>> index d882b83..a889f79 100644 >>>> --- a/arch/arm64/kernel/ptrace.c >>>> +++ b/arch/arm64/kernel/ptrace.c >>>> @@ -48,6 +48,122 @@ >>>> #define CREATE_TRACE_POINTS >>>> #include <trace/events/syscalls.h> >>>> >>>> +struct pt_regs_offset { >>>> + const char *name; >>>> + int offset; >>>> +}; >>>> + >>>> +#define REG_OFFSET_NAME(r) \ >>>> + {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)} >> >>> Can you not just use "offsetof(struct pt_regs, r)" here? That would be >>> the same as x86, powerpc. >> >> The registers (except for pc, pstate, and sp) are not separate structure >> fields, they are slots in a single array. To reference them the symbolic >> name has to be converted to an index (integer register number) somehow. > > Can we not keep them local to this file, say __reg_x0 etc. (something to > make it clear they are for internal use)? >
As above we can make it local to the file. Given that I don't think there's a need to chance ARM_x* to __reg_x* though, is there? Either way, no problem.
-dl
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