ACIL FM

Nama	Ukuran	Aksi
arch	-	Open
include	-	Open
Build	762 B	View DL Edit
builtin-check.c	7.54 MB	View DL Edit
check.c	107.67 MB	View DL Edit
elf.c	31.85 MB	View DL Edit
fixdep	14.12 MB	View DL Edit
Makefile	1.99 MB	View DL Edit
objtool	203.52 MB	View DL Edit
objtool.c	1.76 MB	View DL Edit
orc_dump.c	4.18 MB	View DL Edit
orc_gen.c	5.79 MB	View DL Edit
special.c	4.04 MB	View DL Edit
sync-check.sh	1.28 MB	View DL Edit
weak.c	558 B	View DL Edit

Edit file: /usr/src/kernels/5.14.0-611.27.1.el9_7.x86_64/tools/objtool/special.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
 */

/*
 * This file reads all the special sections which have alternate instructions
 * which can be patched in or redirected to at runtime.
 */

#include <stdlib.h>
#include <string.h>

#include <arch/special.h>
#include <objtool/builtin.h>
#include <objtool/special.h>
#include <objtool/warn.h>
#include <objtool/endianness.h>

struct special_entry {
	const char *sec;
	bool group, jump_or_nop;
	unsigned char size, orig, new;
	unsigned char orig_len, new_len; /* group only */
	unsigned char feature; /* ALTERNATIVE macro CPU feature */
	unsigned char key; /* jump_label key */
};

struct special_entry entries[] = {
	{
		.sec = ".altinstructions",
		.group = true,
		.size = ALT_ENTRY_SIZE,
		.orig = ALT_ORIG_OFFSET,
		.orig_len = ALT_ORIG_LEN_OFFSET,
		.new = ALT_NEW_OFFSET,
		.new_len = ALT_NEW_LEN_OFFSET,
		.feature = ALT_FEATURE_OFFSET,
	},
	{
		.sec = "__jump_table",
		.jump_or_nop = true,
		.size = JUMP_ENTRY_SIZE,
		.orig = JUMP_ORIG_OFFSET,
		.new = JUMP_NEW_OFFSET,
		.key = JUMP_KEY_OFFSET,
	},
	{
		.sec = "__ex_table",
		.size = EX_ENTRY_SIZE,
		.orig = EX_ORIG_OFFSET,
		.new = EX_NEW_OFFSET,
	},
	{},
};

void __weak arch_handle_alternative(unsigned short feature, struct special_alt *alt)
{
}

static void reloc_to_sec_off(struct reloc *reloc, struct section **sec,
			     unsigned long *off)
{
	*sec = reloc->sym->sec;
	*off = reloc->sym->offset + reloc->addend;
}

static int get_alt_entry(struct elf *elf, struct special_entry *entry,
			 struct section *sec, int idx,
			 struct special_alt *alt)
{
	struct reloc *orig_reloc, *new_reloc;
	unsigned long offset;

offset = idx * entry->size;

alt->group = entry->group;
	alt->jump_or_nop = entry->jump_or_nop;

if (alt->group) {
		alt->orig_len = *(unsigned char *)(sec->data->d_buf + offset +
						   entry->orig_len);
		alt->new_len = *(unsigned char *)(sec->data->d_buf + offset +
						  entry->new_len);
	}

if (entry->feature) {
		unsigned short feature;

feature = bswap_if_needed(*(unsigned short *)(sec->data->d_buf +
							      offset +
							      entry->feature));
		arch_handle_alternative(feature, alt);
	}

orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
	if (!orig_reloc) {
		WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
		return -1;
	}

reloc_to_sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off);

if (!entry->group || alt->new_len) {
		new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new);
		if (!new_reloc) {
			WARN_FUNC("can't find new reloc",
				  sec, offset + entry->new);
			return -1;
		}

reloc_to_sec_off(new_reloc, &alt->new_sec, &alt->new_off);

/* _ASM_EXTABLE_EX hack */
		if (alt->new_off >= 0x7ffffff0)
			alt->new_off -= 0x7ffffff0;
	}

if (entry->key) {
		struct reloc *key_reloc;

key_reloc = find_reloc_by_dest(elf, sec, offset + entry->key);
		if (!key_reloc) {
			WARN_FUNC("can't find key reloc",
				  sec, offset + entry->key);
			return -1;
		}
		alt->key_addend = key_reloc->addend;
	}

return 0;
}

/*
 * Read all the special sections and create a list of special_alt structs which
 * describe all the alternate instructions which can be patched in or
 * redirected to at runtime.
 */
int special_get_alts(struct elf *elf, struct list_head *alts)
{
	struct special_entry *entry;
	struct section *sec;
	unsigned int nr_entries;
	struct special_alt *alt;
	int idx, ret;

INIT_LIST_HEAD(alts);

for (entry = entries; entry->sec; entry++) {
		sec = find_section_by_name(elf, entry->sec);
		if (!sec)
			continue;

if (sec->sh.sh_size % entry->size != 0) {
			WARN("%s size not a multiple of %d",
			     sec->name, entry->size);
			return -1;
		}

nr_entries = sec->sh.sh_size / entry->size;

for (idx = 0; idx < nr_entries; idx++) {
			alt = malloc(sizeof(*alt));
			if (!alt) {
				WARN("malloc failed");
				return -1;
			}
			memset(alt, 0, sizeof(*alt));

ret = get_alt_entry(elf, entry, sec, idx, alt);
			if (ret > 0)
				continue;
			if (ret < 0)
				return ret;

list_add_tail(&alt->list, alts);
		}
	}

return 0;
}

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