Em Sat, Aug 29, 2015 at 04:21:57AM +0000, Wang Nan escreveu: > From: He Kuang <heku...@huawei.com> > > arch_get_reg_info() is a helper function which converts register name > like "%rax" to offset of a register in 'struct pt_regs', which is > required by BPF prologue generator.
Is this something like: /* Query offset/name of register from its name/offset */ extern int regs_query_register_offset(const char *name); in ptrace? Can't we reuse that name and even code? Was this that was done and only a rename was made? - Arnaldo > This patch replaces original string table by a 'struct reg_info' table, > which records offset of registers according to its name. > > For x86, since there are two sub-archs (x86_32 and x86_64) but we can > only get pt_regs for the arch we are currently on, this patch fills > offset with '-1' for another sub-arch. This introduces a limitation to > perf prologue that, we are unable to generate prologue on a x86_32 > compiled perf for BPF programs targeted on x86_64 kernel. This > limitation is acceptable, because this is a very rare usecase. > > Signed-off-by: Wang Nan <wangn...@huawei.com> > Signed-off-by: He Kuang <heku...@huawei.com> > Cc: Alexei Starovoitov <a...@plumgrid.com> > Cc: Brendan Gregg <brendan.d.gr...@gmail.com> > Cc: Daniel Borkmann <dan...@iogearbox.net> > Cc: David Ahern <dsah...@gmail.com> > Cc: He Kuang <heku...@huawei.com> > Cc: Jiri Olsa <jo...@kernel.org> > Cc: Kaixu Xia <xiaka...@huawei.com> > Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> > Cc: Namhyung Kim <namhy...@kernel.org> > Cc: Paul Mackerras <pau...@samba.org> > Cc: Peter Zijlstra <a.p.zijls...@chello.nl> > Cc: Zefan Li <lize...@huawei.com> > Cc: pi3or...@163.com > Cc: Arnaldo Carvalho de Melo <a...@redhat.com> > Link: > http://lkml.kernel.org/n/1436445342-1402-34-git-send-email-wangn...@huawei.com > --- > tools/perf/arch/x86/Makefile | 1 + > tools/perf/arch/x86/util/Build | 2 + > tools/perf/arch/x86/util/dwarf-regs.c | 104 > ++++++++++++++++++++++++---------- > 3 files changed, 78 insertions(+), 29 deletions(-) > > diff --git a/tools/perf/arch/x86/Makefile b/tools/perf/arch/x86/Makefile > index 21322e0..a84a6f6f 100644 > --- a/tools/perf/arch/x86/Makefile > +++ b/tools/perf/arch/x86/Makefile > @@ -2,3 +2,4 @@ ifndef NO_DWARF > PERF_HAVE_DWARF_REGS := 1 > endif > HAVE_KVM_STAT_SUPPORT := 1 > +PERF_HAVE_ARCH_GET_REG_INFO := 1 > diff --git a/tools/perf/arch/x86/util/Build b/tools/perf/arch/x86/util/Build > index 2c55e1b..09429f6 100644 > --- a/tools/perf/arch/x86/util/Build > +++ b/tools/perf/arch/x86/util/Build > @@ -3,6 +3,8 @@ libperf-y += tsc.o > libperf-y += pmu.o > libperf-y += kvm-stat.o > > +# BPF_PROLOGUE also need dwarf-regs.o. However, if CONFIG_BPF_PROLOGUE > +# is true, CONFIG_DWARF must true. > libperf-$(CONFIG_DWARF) += dwarf-regs.o > > libperf-$(CONFIG_LIBUNWIND) += unwind-libunwind.o > diff --git a/tools/perf/arch/x86/util/dwarf-regs.c > b/tools/perf/arch/x86/util/dwarf-regs.c > index be22dd4..9928caf 100644 > --- a/tools/perf/arch/x86/util/dwarf-regs.c > +++ b/tools/perf/arch/x86/util/dwarf-regs.c > @@ -22,44 +22,67 @@ > > #include <stddef.h> > #include <dwarf-regs.h> > +#include <string.h> > +#include <linux/ptrace.h> > +#include <linux/kernel.h> /* for offsetof */ > +#include <util/bpf-loader.h> > + > +struct reg_info { > + const char *name; /* Reg string in debuginfo */ > + int offset; /* Reg offset in struct pt_regs */ > +}; > > /* > * Generic dwarf analysis helpers > */ > - > +/* > + * x86_64 compiling can't access pt_regs for x86_32, so fill offset > + * with -1. > + */ > +#ifdef __x86_64__ > +# define REG_INFO(n, f) { .name = n, .offset = -1, } > +#else > +# define REG_INFO(n, f) { .name = n, .offset = offsetof(struct pt_regs, f), } > +#endif > #define X86_32_MAX_REGS 8 > -const char *x86_32_regs_table[X86_32_MAX_REGS] = { > - "%ax", > - "%cx", > - "%dx", > - "%bx", > - "$stack", /* Stack address instead of %sp */ > - "%bp", > - "%si", > - "%di", > + > +struct reg_info x86_32_regs_table[X86_32_MAX_REGS] = { > + REG_INFO("%ax", eax), > + REG_INFO("%cx", ecx), > + REG_INFO("%dx", edx), > + REG_INFO("%bx", ebx), > + REG_INFO("$stack", esp), /* Stack address instead of %sp */ > + REG_INFO("%bp", ebp), > + REG_INFO("%si", esi), > + REG_INFO("%di", edi), > }; > > +#undef REG_INFO > +#ifdef __x86_64__ > +# define REG_INFO(n, f) { .name = n, .offset = offsetof(struct pt_regs, f), } > +#else > +# define REG_INFO(n, f) { .name = n, .offset = -1, } > +#endif > #define X86_64_MAX_REGS 16 > -const char *x86_64_regs_table[X86_64_MAX_REGS] = { > - "%ax", > - "%dx", > - "%cx", > - "%bx", > - "%si", > - "%di", > - "%bp", > - "%sp", > - "%r8", > - "%r9", > - "%r10", > - "%r11", > - "%r12", > - "%r13", > - "%r14", > - "%r15", > +struct reg_info x86_64_regs_table[X86_64_MAX_REGS] = { > + REG_INFO("%ax", rax), > + REG_INFO("%dx", rdx), > + REG_INFO("%cx", rcx), > + REG_INFO("%bx", rbx), > + REG_INFO("%si", rsi), > + REG_INFO("%di", rdi), > + REG_INFO("%bp", rbp), > + REG_INFO("%sp", rsp), > + REG_INFO("%r8", r8), > + REG_INFO("%r9", r9), > + REG_INFO("%r10", r10), > + REG_INFO("%r11", r11), > + REG_INFO("%r12", r12), > + REG_INFO("%r13", r13), > + REG_INFO("%r14", r14), > + REG_INFO("%r15", r15), > }; > > -/* TODO: switching by dwarf address size */ > #ifdef __x86_64__ > #define ARCH_MAX_REGS X86_64_MAX_REGS > #define arch_regs_table x86_64_regs_table > @@ -71,5 +94,28 @@ const char *x86_64_regs_table[X86_64_MAX_REGS] = { > /* Return architecture dependent register string (for kprobe-tracer) */ > const char *get_arch_regstr(unsigned int n) > { > - return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL; > + return (n <= ARCH_MAX_REGS) ? arch_regs_table[n].name : NULL; > } > + > +#ifdef HAVE_BPF_PROLOGUE > +int arch_get_reg_info(const char *name, int *offset) > +{ > + int i; > + struct reg_info *info; > + > + if (!name || !offset) > + return -1; > + > + for (i = 0; i < ARCH_MAX_REGS; i++) { > + info = &arch_regs_table[i]; > + if (strcmp(info->name, name) == 0) { > + if (info->offset < 0) > + return -1; > + *offset = info->offset; > + return 0; > + } > + } > + > + return -1; > +} > +#endif > -- > 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
