Commit d3ab52c3 authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf dwarf-regs: Add get_dwarf_regnum_for_perf_regnum() and use for x86 unwinding 



Add a utility to map a perf register number to a DWARF register number
for a particular ELF machine type.

Create a generic unwind-libdw initial register initialization routine
that uses this function and thereby avoids arch specific
initialization. The unwind-libdw code does:

1) compute the maximum DWARF register from the set of sampled user registers,
2) allocates a set of DWARF registers,
3) copies the sample registers into the appropriate DWARF registers.

This generic solution is initially implemented for use with x86 as
only get_dwarf_regnum_for_perf_regnum() support for x86 is currently present.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Aditya Bodkhe <aditya.b1@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Haibo Xu <haibo1.xu@intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Krzysztof Łopatowski <krzysztof.m.lopatowski@gmail.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Wielaard <mark@klomp.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergei Trofimovich <slyich@gmail.com>
Cc: Shimin Guo <shimin.guo@skydio.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent c3104008

tools/perf/util/dwarf-regs-arch/dwarf-regs-x86.c

+95 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <string.h> /* for strcmp */

#include <linux/kernel.h> /* for ARRAY_SIZE */

#include <dwarf-regs.h>

#include "../../../arch/x86/include/uapi/asm/perf_regs.h"



struct dwarf_regs_idx {

	const char *name;
@@ -163,3 +164,97 @@ int __get_dwarf_regnum_x86_64(const char *name) 
{

	return get_regnum(x86_64_regidx_table, ARRAY_SIZE(x86_64_regidx_table), name);

}



int __get_dwarf_regnum_for_perf_regnum_i386(int perf_regnum)

{

	static const int dwarf_i386_regnums[] = {

		[PERF_REG_X86_AX] = 0,

		[PERF_REG_X86_BX] = 3,

		[PERF_REG_X86_CX] = 1,

		[PERF_REG_X86_DX] = 2,

		[PERF_REG_X86_SI] = 6,

		[PERF_REG_X86_DI] = 7,

		[PERF_REG_X86_BP] = 5,

		[PERF_REG_X86_SP] = 4,

		[PERF_REG_X86_IP] = 8,

		[PERF_REG_X86_FLAGS] = 9,

		[PERF_REG_X86_CS] = 41,

		[PERF_REG_X86_SS] = 42,

		[PERF_REG_X86_DS] = 43,

		[PERF_REG_X86_ES] = 40,

		[PERF_REG_X86_FS] = 44,

		[PERF_REG_X86_GS] = 45,

		[PERF_REG_X86_XMM0] = 21,

		[PERF_REG_X86_XMM1] = 22,

		[PERF_REG_X86_XMM2] = 23,

		[PERF_REG_X86_XMM3] = 24,

		[PERF_REG_X86_XMM4] = 25,

		[PERF_REG_X86_XMM5] = 26,

		[PERF_REG_X86_XMM6] = 27,

		[PERF_REG_X86_XMM7] = 28,

	};



	if (perf_regnum == 0)

		return 0;



	if (perf_regnum <  0 || perf_regnum > (int)ARRAY_SIZE(dwarf_i386_regnums) ||

	    dwarf_i386_regnums[perf_regnum] == 0)

		return -ENOENT;



	return dwarf_i386_regnums[perf_regnum];

}



int __get_dwarf_regnum_for_perf_regnum_x86_64(int perf_regnum)

{

	static const int dwarf_x86_64_regnums[] = {

		[PERF_REG_X86_AX] = 0,

		[PERF_REG_X86_BX] = 3,

		[PERF_REG_X86_CX] = 2,

		[PERF_REG_X86_DX] = 1,

		[PERF_REG_X86_SI] = 4,

		[PERF_REG_X86_DI] = 5,

		[PERF_REG_X86_BP] = 6,

		[PERF_REG_X86_SP] = 7,

		[PERF_REG_X86_IP] = 16,

		[PERF_REG_X86_FLAGS] = 49,

		[PERF_REG_X86_CS] = 51,

		[PERF_REG_X86_SS] = 52,

		[PERF_REG_X86_DS] = 53,

		[PERF_REG_X86_ES] = 50,

		[PERF_REG_X86_FS] = 54,

		[PERF_REG_X86_GS] = 55,

		[PERF_REG_X86_R8] = 8,

		[PERF_REG_X86_R9] = 9,

		[PERF_REG_X86_R10] = 10,

		[PERF_REG_X86_R11] = 11,

		[PERF_REG_X86_R12] = 12,

		[PERF_REG_X86_R13] = 13,

		[PERF_REG_X86_R14] = 14,

		[PERF_REG_X86_R15] = 15,

		[PERF_REG_X86_XMM0] = 17,

		[PERF_REG_X86_XMM1] = 18,

		[PERF_REG_X86_XMM2] = 19,

		[PERF_REG_X86_XMM3] = 20,

		[PERF_REG_X86_XMM4] = 21,

		[PERF_REG_X86_XMM5] = 22,

		[PERF_REG_X86_XMM6] = 23,

		[PERF_REG_X86_XMM7] = 24,

		[PERF_REG_X86_XMM8] = 25,

		[PERF_REG_X86_XMM9] = 26,

		[PERF_REG_X86_XMM10] = 27,

		[PERF_REG_X86_XMM11] = 28,

		[PERF_REG_X86_XMM12] = 29,

		[PERF_REG_X86_XMM13] = 30,

		[PERF_REG_X86_XMM14] = 31,

		[PERF_REG_X86_XMM15] = 32,

	};



	if (perf_regnum == 0)

		return 0;



	if (perf_regnum <  0 || perf_regnum > (int)ARRAY_SIZE(dwarf_x86_64_regnums) ||

	    dwarf_x86_64_regnums[perf_regnum] == 0)

		return -ENOENT;



	return dwarf_x86_64_regnums[perf_regnum];

}

tools/perf/util/dwarf-regs.c

+55 −0
Original line number Diff line number Diff line
@@ -103,3 +103,58 @@ int get_dwarf_regnum(const char *name, unsigned int machine, unsigned int flags 
	free(regname);

	return reg;

}



static int get_libdw_frame_nregs(unsigned int machine, unsigned int flags __maybe_unused)

{

	switch (machine) {

	case EM_X86_64:

		return 17;

	case EM_386:

		return 9;

	case EM_ARM:

		return 16;

	case EM_AARCH64:

		return 97;

	case EM_CSKY:

		return 38;

	case EM_S390:

		return 32;

	case EM_PPC:

	case EM_PPC64:

		return 145;

	case EM_RISCV:

		return 66;

	case EM_SPARC:

	case EM_SPARCV9:

		return 103;

	case EM_LOONGARCH:

		return 74;

	default:

		return 0;

	}

}



int get_dwarf_regnum_for_perf_regnum(int perf_regnum, unsigned int machine,

				     unsigned int flags, bool only_libdw_supported)

{

	int reg;



	switch (machine) {

	case EM_X86_64:

		reg = __get_dwarf_regnum_for_perf_regnum_x86_64(perf_regnum);

		break;

	case EM_386:

		reg = __get_dwarf_regnum_for_perf_regnum_i386(perf_regnum);

		break;

	default:

		pr_err("ELF MACHINE %x is not supported.\n", machine);

		return -ENOENT;

	}

	if (reg >= 0 && only_libdw_supported) {

		int nregs = get_libdw_frame_nregs(machine, flags);



		if (reg >= nregs)

			reg = -ENOENT;

	}

	return reg;

}

tools/perf/util/include/dwarf-regs.h

+8 −0
Original line number Diff line number Diff line
@@ -101,6 +101,8 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int 


int __get_dwarf_regnum_i386(const char *name);

int __get_dwarf_regnum_x86_64(const char *name);

int __get_dwarf_regnum_for_perf_regnum_i386(int perf_regnum);

int __get_dwarf_regnum_for_perf_regnum_x86_64(int perf_regnum);



/*

 * get_dwarf_regnum - Returns DWARF regnum from register name
@@ -109,6 +111,12 @@ int __get_dwarf_regnum_x86_64(const char *name); 
 */

int get_dwarf_regnum(const char *name, unsigned int machine, unsigned int flags);



/*

 * get_dwarf_regnum - Returns DWARF regnum from perf register number.

 */

int get_dwarf_regnum_for_perf_regnum(int perf_regnum, unsigned int machine, unsigned int flags,

				     bool only_libdw_supported);



void get_powerpc_regs(u32 raw_insn, int is_source, struct annotated_op_loc *op_loc);



#else /* HAVE_LIBDW_SUPPORT */

tools/perf/util/unwind-libdw-arch/Build

+0 −1
Original line number Diff line number Diff line 
perf-util-y += unwind-libdw-x86.o

perf-util-y += unwind-libdw-arm.o

perf-util-y += unwind-libdw-arm64.o

perf-util-y += unwind-libdw-csky.o

tools/perf/util/unwind-libdw-arch/unwind-libdw-x86.c

deleted100644 → 0
+0 −54
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <elfutils/libdwfl.h>

#include "../arch/x86/include/uapi/asm/perf_regs.h"

#include "util/unwind-libdw.h"

#include "util/perf_regs.h"

#include "util/sample.h"



bool libdw_set_initial_registers_x86(Dwfl_Thread *thread, void *arg)

{

	struct unwind_info *ui = arg;

	struct regs_dump *user_regs = perf_sample__user_regs(ui->sample);

	Dwarf_Word dwarf_regs[17];

	unsigned nregs;



#define REG(r) ({						\

	Dwarf_Word val = 0;					\

	perf_reg_value(&val, user_regs, PERF_REG_X86_##r);	\

	val;							\

})



	if (user_regs->abi == PERF_SAMPLE_REGS_ABI_32) {

		dwarf_regs[0] = REG(AX);

		dwarf_regs[1] = REG(CX);

		dwarf_regs[2] = REG(DX);

		dwarf_regs[3] = REG(BX);

		dwarf_regs[4] = REG(SP);

		dwarf_regs[5] = REG(BP);

		dwarf_regs[6] = REG(SI);

		dwarf_regs[7] = REG(DI);

		dwarf_regs[8] = REG(IP);

		nregs = 9;

	} else {

		dwarf_regs[0]  = REG(AX);

		dwarf_regs[1]  = REG(DX);

		dwarf_regs[2]  = REG(CX);

		dwarf_regs[3]  = REG(BX);

		dwarf_regs[4]  = REG(SI);

		dwarf_regs[5]  = REG(DI);

		dwarf_regs[6]  = REG(BP);

		dwarf_regs[7]  = REG(SP);

		dwarf_regs[8]  = REG(R8);

		dwarf_regs[9]  = REG(R9);

		dwarf_regs[10] = REG(R10);

		dwarf_regs[11] = REG(R11);

		dwarf_regs[12] = REG(R12);

		dwarf_regs[13] = REG(R13);

		dwarf_regs[14] = REG(R14);

		dwarf_regs[15] = REG(R15);

		dwarf_regs[16] = REG(IP);

		nregs = 17;

	}



	return dwfl_thread_state_registers(thread, 0, nregs, dwarf_regs);

}