Re: [PATCH 2/2] perf tools: Introduce regs_query_register_offset() for arm64

From: Arnaldo Carvalho de Melo
Date: Tue Jan 24 2017 - 14:09:22 EST


Em Tue, Jan 24, 2017 at 06:25:18PM +0000, Will Deacon escreveu:
> On Tue, Jan 24, 2017 at 10:30:15AM +0000, He Kuang wrote:
> > Since HAVE_KPROBES can be enabled in arm64, this patch introduces
> > regs_query_register_offset() to convert register name to offset for
> > arm64, so the BPF prologue feature is ready to use.
> >
> > This patch also changes the 'dwarfnum' to 'offset' in register table,
> > so the related functions are consistent with x86.
> >
> > Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>

> It would've been nice to have been cc'd on this. In future, please at least
> cc linux-arm-kernel for patches directly changing arm/arm64 code.

> > + GPR_OFFSET_NAME(30),
> > + {.name = "lr", .offset = offsetof(struct user_pt_regs, regs[30])},
> > + REG_OFFSET_NAME(sp),

> Don't sp and lr need the leading '%'?

> > + REG_OFFSET_NAME(pc),
> > + REG_OFFSET_NAME(pstate),

> The AArch64 DWARF spec says that DWARF register 32 is "RESERVED" and
> register 33 is the ELR, so these pc/pstate entries are wrong.

> However, with those changes, I think this patch can simply be ignored and
> mainline is doing the right thing.

Ok, thanks for checking, dropping this patch then.

- Arnaldo