1a59d1b8e0
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
116 lines
3.6 KiB
C
116 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* dwarf-regs.c : Mapping of DWARF debug register numbers into register names.
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* Extracted from probe-finder.c
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*
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* Written by Masami Hiramatsu <mhiramat@redhat.com>
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*/
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#include <stddef.h>
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#include <errno.h> /* for EINVAL */
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#include <string.h> /* for strcmp */
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#include <linux/ptrace.h> /* for struct pt_regs */
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#include <linux/kernel.h> /* for offsetof */
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#include <dwarf-regs.h>
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/*
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* See arch/x86/kernel/ptrace.c.
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* Different from it:
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*
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* - Since struct pt_regs is defined differently for user and kernel,
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* but we want to use 'ax, bx' instead of 'rax, rbx' (which is struct
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* field name of user's pt_regs), we make REG_OFFSET_NAME to accept
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* both string name and reg field name.
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*
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* - Since accessing x86_32's pt_regs from x86_64 building is difficult
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* and vise versa, we simply fill offset with -1, so
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* get_arch_regstr() still works but regs_query_register_offset()
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* returns error.
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* The only inconvenience caused by it now is that we are not allowed
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* to generate BPF prologue for a x86_64 kernel if perf is built for
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* x86_32. This is really a rare usecase.
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*
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* - Order is different from kernel's ptrace.c for get_arch_regstr(). Use
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* the order defined by dwarf.
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*/
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struct pt_regs_offset {
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const char *name;
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int offset;
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};
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#define REG_OFFSET_END {.name = NULL, .offset = 0}
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#ifdef __x86_64__
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# define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)}
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# define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = -1}
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#else
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# define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = -1}
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# define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)}
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#endif
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/* TODO: switching by dwarf address size */
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#ifndef __x86_64__
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static const struct pt_regs_offset x86_32_regoffset_table[] = {
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REG_OFFSET_NAME_32("%ax", eax),
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REG_OFFSET_NAME_32("%cx", ecx),
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REG_OFFSET_NAME_32("%dx", edx),
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REG_OFFSET_NAME_32("%bx", ebx),
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REG_OFFSET_NAME_32("$stack", esp), /* Stack address instead of %sp */
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REG_OFFSET_NAME_32("%bp", ebp),
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REG_OFFSET_NAME_32("%si", esi),
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REG_OFFSET_NAME_32("%di", edi),
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REG_OFFSET_END,
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};
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#define regoffset_table x86_32_regoffset_table
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#else
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static const struct pt_regs_offset x86_64_regoffset_table[] = {
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REG_OFFSET_NAME_64("%ax", rax),
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REG_OFFSET_NAME_64("%dx", rdx),
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REG_OFFSET_NAME_64("%cx", rcx),
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REG_OFFSET_NAME_64("%bx", rbx),
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REG_OFFSET_NAME_64("%si", rsi),
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REG_OFFSET_NAME_64("%di", rdi),
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REG_OFFSET_NAME_64("%bp", rbp),
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REG_OFFSET_NAME_64("%sp", rsp),
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REG_OFFSET_NAME_64("%r8", r8),
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REG_OFFSET_NAME_64("%r9", r9),
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REG_OFFSET_NAME_64("%r10", r10),
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REG_OFFSET_NAME_64("%r11", r11),
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REG_OFFSET_NAME_64("%r12", r12),
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REG_OFFSET_NAME_64("%r13", r13),
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REG_OFFSET_NAME_64("%r14", r14),
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REG_OFFSET_NAME_64("%r15", r15),
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REG_OFFSET_END,
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};
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#define regoffset_table x86_64_regoffset_table
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#endif
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/* Minus 1 for the ending REG_OFFSET_END */
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#define ARCH_MAX_REGS ((sizeof(regoffset_table) / sizeof(regoffset_table[0])) - 1)
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/* Return architecture dependent register string (for kprobe-tracer) */
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const char *get_arch_regstr(unsigned int n)
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{
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return (n < ARCH_MAX_REGS) ? regoffset_table[n].name : NULL;
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}
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/* Reuse code from arch/x86/kernel/ptrace.c */
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/**
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* regs_query_register_offset() - query register offset from its name
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* @name: the name of a register
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*
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* regs_query_register_offset() returns the offset of a register in struct
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* pt_regs from its name. If the name is invalid, this returns -EINVAL;
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*/
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int regs_query_register_offset(const char *name)
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{
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const struct pt_regs_offset *roff;
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for (roff = regoffset_table; roff->name != NULL; roff++)
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if (!strcmp(roff->name, name))
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return roff->offset;
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return -EINVAL;
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}
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