On 20/05/2023 03:55, Leo Yan wrote: > Ideally, we want util/perf_regs.c to be general enough and doesn't bind > with specific architecture. > > But since util/perf_regs.c uses the macros PERF_REG_IP and PERF_REG_SP > which are defined by architecture, thus util/perf_regs.c is dependent on > architecture header (see util/perf_regs.h includes "<perf_regs.h>", here > perf_regs.h is architecture specific header). > > As a step to generalize util/perf_regs.c, this commit introduces weak > functions arch__reg_ip() and arch__reg_sp() and every architecture can > define their own functions; thus, util/perf_regs.c doesn't need to use > PERF_REG_IP and PERF_REG_SP anymore. > > This is a preparation to get rid of architecture specific header from > util/perf_regs.h. > > Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx> > --- [...] > > -#define DWARF_MINIMAL_REGS ((1ULL << PERF_REG_IP) | (1ULL << PERF_REG_SP)) > +#define DWARF_MINIMAL_REGS ((1ULL << arch__reg_ip()) | (1ULL << arch__reg_sp())) > > const char *perf_reg_name(int id, const char *arch); > int perf_reg_value(u64 *valp, struct regs_dump *regs, int id); > diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c > index bdccfc511b7e..f308f2ea512b 100644 > --- a/tools/perf/util/unwind-libdw.c > +++ b/tools/perf/util/unwind-libdw.c > @@ -252,7 +252,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, > if (!ui->dwfl) > goto out; > > - err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP); > + err = perf_reg_value(&ip, &data->user_regs, arch__reg_ip()); Shouldn't it be more like this, because the weak symbols are a compile time thing and it's supposed to support cross arch unwinding at runtime (assuming something containing the arch from the file is passed down, like we did with perf_reg_name()): char *arch = perf_env__arch(evsel__env(evsel)); err = perf_reg_value(&ip, &data->user_regs, arch__reg_ip(arch)); Now I'm wondering how cross unwinding ever worked because I see libunwind also has something hard coded too: #define LIBUNWIND__ARCH_REG_SP PERF_REG_SP
