Re: [PATCH V2] tools/perf: Add basic support for LoongArch

[Youling Tang]

/* snip */

> > > > --- /dev/null
> > > > +++ b/tools/perf/arch/loongarch/util/dwarf-regs.c
> > > > @@ -0,0 +1,44 @@
> > > > +// SPDX-License-Identifier: GPL-2.0
> > > > +/*
> > > > + * dwarf-regs.c : Mapping of DWARF debug register numbers into
> > > > register names.
> > > > + *
> > > > + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
> > > > + */
> > > > +
> > > > +#include <stdio.h>
> > > > +#include <errno.h> /* for EINVAL */
> > > > +#include <string.h> /* for strcmp */
> > > > +#include <dwarf-regs.h>
> > > > +
> > > > +struct pt_regs_dwarfnum {
> > > > +     const char *name;
> > > > +     unsigned int dwarfnum;
> > > > +};
> > > > +
> > > > +static struct pt_regs_dwarfnum loongarch_gpr_table[] = {
> > > > +     {"$0", 0}, {"$1", 1}, {"$2", 2}, {"$3", 3},
> > > > +     {"$4", 4}, {"$5", 5}, {"$6", 6}, {"$7", 7},
> > > > +     {"$8", 8}, {"$9", 9}, {"$10", 10}, {"$11", 11},
> > > > +     {"$12", 12}, {"$13", 13}, {"$14", 14}, {"$15", 15},
> > > > +     {"$16", 16}, {"$17", 17}, {"$18", 18}, {"$19", 19},
> > > > +     {"$20", 20}, {"$21", 21}, {"$22", 22}, {"$23", 23},
> > > > +     {"$24", 24}, {"$25", 25}, {"$26", 26}, {"$27", 27},
> > > > +     {"$28", 28}, {"$29", 29}, {"$30", 30}, {"$31", 31},
> > > > +     {NULL, 0}
> > > > +};
> > > Do you need to change it to the following:
> > >
> > > #define GPR_DWARFNUM_NAME(num) {.name = __stringify($r##num), .dwarfnum
> > > = num}
> > > #define REG_DWARFNUM_END {.name = NULL, .dwarfnum = 0}
> > >
> > > 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(30),
> > >          REG_DWARFNUM_NAME(31),
> > >          REG_DWARFNUM_END,
> > > };
> > >
> > > At the same time, "$rx" is used in __perf_reg_name_loongarch and
> > > loongarch_regstr_tbl, which is consistent with assembly.
> > OK, I will use the "$rx" format, but I don't want to use macros.
> Use the "rx" format to make regs_query_register_offset consistent with
> arch/loongarch/kernel/ptrace.c (that is, the names in
> loongarch_gpr_table and regoffset_table are consistent)

If we want to be consistent with the usage of `trace probe`, we should
use "%rx".

eg:
   # echo "p:myuprobe /tmp/test:0x4194 %r4 %r5" > uprobe_events

parse_probe_arg()
         case '%': regs_query_register_offset()

Youling.
> Youling.
> > Huacai
> > > > +
> > > > +const char *get_arch_regstr(unsigned int n)
> > > > +{
> > > > +     n %= 32;
> > > > +     return loongarch_gpr_table[n].name;
> > > > +}
> > > > +
> > > > +int regs_query_register_offset(const char *name)
> > > > +{
> > > > +     const struct pt_regs_dwarfnum *roff;
> > > > +
> > > > +     for (roff = loongarch_gpr_table; roff->name != NULL; roff++)
> > > > +             if (!strcmp(roff->name, name))
> > > > +                     return roff->dwarfnum;
> > > > +     return -EINVAL;
> > > > +}