Messages in this thread Patch in this message | | | Date | Fri, 3 Feb 2017 13:00:26 +0000 | From | Will Deacon <> | Subject | Re: [PATCH v2 1/3] perf tools: Use offset instead of dwarfnum in register table. |
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On Fri, Feb 03, 2017 at 11:06:05AM +0000, He Kuang wrote: > This patch changes the 'dwarfnum' to 'offset' in register table, so > the index of array becomes the dwarfnum (the index of each register > defined by DWARF) and the "offset" member means the byte-offset of the > register in (user_)pt_regs. This change makes the code consistent with > x86. > > Acked-by: Masami Hiramatsu <mhiramat@kernel.org> > Signed-off-by: He Kuang <hekuang@huawei.com> > --- > tools/perf/arch/arm64/util/dwarf-regs.c | 107 ++++++++++++++++---------------- > 1 file changed, 52 insertions(+), 55 deletions(-)
Thanks for splitting this up. Comment below.
> diff --git a/tools/perf/arch/arm64/util/dwarf-regs.c b/tools/perf/arch/arm64/util/dwarf-regs.c > index d49efeb..090f36b 100644 > --- a/tools/perf/arch/arm64/util/dwarf-regs.c > +++ b/tools/perf/arch/arm64/util/dwarf-regs.c > @@ -9,72 +9,69 @@ > */ > > #include <stddef.h> > +#include <linux/ptrace.h> /* for struct user_pt_regs */ > #include <dwarf-regs.h> > > -struct pt_regs_dwarfnum { > +struct pt_regs_offset { > const char *name; > - unsigned int dwarfnum; > + int offset; > }; > > -#define STR(s) #s > -#define REG_DWARFNUM_NAME(r, num) {.name = r, .dwarfnum = num} > -#define GPR_DWARFNUM_NAME(num) \ > - {.name = STR(%x##num), .dwarfnum = num} > -#define REG_DWARFNUM_END {.name = NULL, .dwarfnum = 0} > - > /* > * Reference: > * http://infocenter.arm.com/help/topic/com.arm.doc.ihi0057b/IHI0057B_aadwarf64.pdf > */ > -static const struct pt_regs_dwarfnum regdwarfnum_table[] = { > - GPR_DWARFNUM_NAME(0), > - GPR_DWARFNUM_NAME(1), > - GPR_DWARFNUM_NAME(2), > - GPR_DWARFNUM_NAME(3), > - GPR_DWARFNUM_NAME(4), > - GPR_DWARFNUM_NAME(5), > - GPR_DWARFNUM_NAME(6), > - GPR_DWARFNUM_NAME(7), > - GPR_DWARFNUM_NAME(8), > - GPR_DWARFNUM_NAME(9), > - GPR_DWARFNUM_NAME(10), > - GPR_DWARFNUM_NAME(11), > - GPR_DWARFNUM_NAME(12), > - GPR_DWARFNUM_NAME(13), > - GPR_DWARFNUM_NAME(14), > - GPR_DWARFNUM_NAME(15), > - GPR_DWARFNUM_NAME(16), > - GPR_DWARFNUM_NAME(17), > - GPR_DWARFNUM_NAME(18), > - GPR_DWARFNUM_NAME(19), > - GPR_DWARFNUM_NAME(20), > - GPR_DWARFNUM_NAME(21), > - GPR_DWARFNUM_NAME(22), > - GPR_DWARFNUM_NAME(23), > - GPR_DWARFNUM_NAME(24), > - GPR_DWARFNUM_NAME(25), > - GPR_DWARFNUM_NAME(26), > - GPR_DWARFNUM_NAME(27), > - GPR_DWARFNUM_NAME(28), > - GPR_DWARFNUM_NAME(29), > - REG_DWARFNUM_NAME("%lr", 30), > - REG_DWARFNUM_NAME("%sp", 31), > - REG_DWARFNUM_END, > -}; > +#define REG_OFFSET_NAME(r, num) {.name = "%" #r, \ > + .offset = offsetof(struct user_pt_regs, regs[num])}
Whilst this works in practice, this is undefined behaviour for "sp", since you'll go off the end of the regs array.
I still think you're better off sticking with the dwarfnum, then just having a dwarfnum2offset macro that multiplies by the size of a register.
Will
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