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?
> >>+
> >> /*
> >> * 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)?
--
Catalin
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