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alistair23-linux/arch/arm64/kernel/module.c
Andrey Ryabinin cb9e3c292d mm: vmalloc: pass additional vm_flags to __vmalloc_node_range() 
For instrumenting global variables KASan will shadow memory backing memory
for modules.  So on module loading we will need to allocate memory for
shadow and map it at address in shadow that corresponds to the address
allocated in module_alloc().

__vmalloc_node_range() could be used for this purpose, except it puts a
guard hole after allocated area.  Guard hole in shadow memory should be a
problem because at some future point we might need to have a shadow memory
at address occupied by guard hole.  So we could fail to allocate shadow
for module_alloc().

Now we have VM_NO_GUARD flag disabling guard page, so we need to pass into
__vmalloc_node_range().  Add new parameter 'vm_flags' to
__vmalloc_node_range() function.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:42 -08:00

416 lines
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/*
* AArch64 loadable module support.
*
* Copyright (C) 2012 ARM Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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, see <http://www.gnu.org/licenses/>.
*
* Author: Will Deacon <will.deacon@arm.com>
*/
#include <linux/bitops.h>
#include <linux/elf.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/moduleloader.h>
#include <linux/vmalloc.h>
#include <asm/alternative.h>
#include <asm/insn.h>
#include <asm/sections.h>
#define AARCH64_INSN_IMM_MOVNZ AARCH64_INSN_IMM_MAX
#define AARCH64_INSN_IMM_MOVK AARCH64_INSN_IMM_16
void *module_alloc(unsigned long size)
{
return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
GFP_KERNEL, PAGE_KERNEL_EXEC, 0,
NUMA_NO_NODE, __builtin_return_address(0));
}
enum aarch64_reloc_op {
RELOC_OP_NONE,
RELOC_OP_ABS,
RELOC_OP_PREL,
RELOC_OP_PAGE,
};
static u64 do_reloc(enum aarch64_reloc_op reloc_op, void *place, u64 val)
{
switch (reloc_op) {
case RELOC_OP_ABS:
return val;
case RELOC_OP_PREL:
return val - (u64)place;
case RELOC_OP_PAGE:
return (val & ~0xfff) - ((u64)place & ~0xfff);
case RELOC_OP_NONE:
return 0;
}
pr_err("do_reloc: unknown relocation operation %d\n", reloc_op);
return 0;
}
static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len)
{
u64 imm_mask = (1 << len) - 1;
s64 sval = do_reloc(op, place, val);
switch (len) {
case 16:
*(s16 *)place = sval;
break;
case 32:
*(s32 *)place = sval;
break;
case 64:
*(s64 *)place = sval;
break;
default:
pr_err("Invalid length (%d) for data relocation\n", len);
return 0;
}
/*
* Extract the upper value bits (including the sign bit) and
* shift them to bit 0.
*/
sval = (s64)(sval & ~(imm_mask >> 1)) >> (len - 1);
/*
* Overflow has occurred if the value is not representable in
* len bits (i.e the bottom len bits are not sign-extended and
* the top bits are not all zero).
*/
if ((u64)(sval + 1) > 2)
return -ERANGE;
return 0;
}
static int reloc_insn_movw(enum aarch64_reloc_op op, void *place, u64 val,
int lsb, enum aarch64_insn_imm_type imm_type)
{
u64 imm, limit = 0;
s64 sval;
u32 insn = le32_to_cpu(*(u32 *)place);
sval = do_reloc(op, place, val);
sval >>= lsb;
imm = sval & 0xffff;
if (imm_type == AARCH64_INSN_IMM_MOVNZ) {
/*
* For signed MOVW relocations, we have to manipulate the
* instruction encoding depending on whether or not the
* immediate is less than zero.
*/
insn &= ~(3 << 29);
if ((s64)imm >= 0) {
/* >=0: Set the instruction to MOVZ (opcode 10b). */
insn |= 2 << 29;
} else {
/*
* <0: Set the instruction to MOVN (opcode 00b).
* Since we've masked the opcode already, we
* don't need to do anything other than
* inverting the new immediate field.
*/
imm = ~imm;
}
imm_type = AARCH64_INSN_IMM_MOVK;
}
/* Update the instruction with the new encoding. */
insn = aarch64_insn_encode_immediate(imm_type, insn, imm);
*(u32 *)place = cpu_to_le32(insn);
/* Shift out the immediate field. */
sval >>= 16;
/*
* For unsigned immediates, the overflow check is straightforward.
* For signed immediates, the sign bit is actually the bit past the
* most significant bit of the field.
* The AARCH64_INSN_IMM_16 immediate type is unsigned.
*/
if (imm_type != AARCH64_INSN_IMM_16) {
sval++;
limit++;
}
/* Check the upper bits depending on the sign of the immediate. */
if ((u64)sval > limit)
return -ERANGE;
return 0;
}
static int reloc_insn_imm(enum aarch64_reloc_op op, void *place, u64 val,
int lsb, int len, enum aarch64_insn_imm_type imm_type)
{
u64 imm, imm_mask;
s64 sval;
u32 insn = le32_to_cpu(*(u32 *)place);
/* Calculate the relocation value. */
sval = do_reloc(op, place, val);
sval >>= lsb;
/* Extract the value bits and shift them to bit 0. */
imm_mask = (BIT(lsb + len) - 1) >> lsb;
imm = sval & imm_mask;
/* Update the instruction's immediate field. */
insn = aarch64_insn_encode_immediate(imm_type, insn, imm);
*(u32 *)place = cpu_to_le32(insn);
/*
* Extract the upper value bits (including the sign bit) and
* shift them to bit 0.
*/
sval = (s64)(sval & ~(imm_mask >> 1)) >> (len - 1);
/*
* Overflow has occurred if the upper bits are not all equal to
* the sign bit of the value.
*/
if ((u64)(sval + 1) >= 2)
return -ERANGE;
return 0;
}
int apply_relocate_add(Elf64_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
unsigned int relsec,
struct module *me)
{
unsigned int i;
int ovf;
bool overflow_check;
Elf64_Sym *sym;
void *loc;
u64 val;
Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* loc corresponds to P in the AArch64 ELF document. */
loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
/* sym is the ELF symbol we're referring to. */
sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+ ELF64_R_SYM(rel[i].r_info);
/* val corresponds to (S + A) in the AArch64 ELF document. */
val = sym->st_value + rel[i].r_addend;
/* Check for overflow by default. */
overflow_check = true;
/* Perform the static relocation. */
switch (ELF64_R_TYPE(rel[i].r_info)) {
/* Null relocations. */
case R_ARM_NONE:
case R_AARCH64_NONE:
ovf = 0;
break;
/* Data relocations. */
case R_AARCH64_ABS64:
overflow_check = false;
ovf = reloc_data(RELOC_OP_ABS, loc, val, 64);
break;
case R_AARCH64_ABS32:
ovf = reloc_data(RELOC_OP_ABS, loc, val, 32);
break;
case R_AARCH64_ABS16:
ovf = reloc_data(RELOC_OP_ABS, loc, val, 16);
break;
case R_AARCH64_PREL64:
overflow_check = false;
ovf = reloc_data(RELOC_OP_PREL, loc, val, 64);
break;
case R_AARCH64_PREL32:
ovf = reloc_data(RELOC_OP_PREL, loc, val, 32);
break;
case R_AARCH64_PREL16:
ovf = reloc_data(RELOC_OP_PREL, loc, val, 16);
break;
/* MOVW instruction relocations. */
case R_AARCH64_MOVW_UABS_G0_NC:
overflow_check = false;
case R_AARCH64_MOVW_UABS_G0:
ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
AARCH64_INSN_IMM_16);
break;
case R_AARCH64_MOVW_UABS_G1_NC:
overflow_check = false;
case R_AARCH64_MOVW_UABS_G1:
ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
AARCH64_INSN_IMM_16);
break;
case R_AARCH64_MOVW_UABS_G2_NC:
overflow_check = false;
case R_AARCH64_MOVW_UABS_G2:
ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
AARCH64_INSN_IMM_16);
break;
case R_AARCH64_MOVW_UABS_G3:
/* We're using the top bits so we can't overflow. */
overflow_check = false;
ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 48,
AARCH64_INSN_IMM_16);
break;
case R_AARCH64_MOVW_SABS_G0:
ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
AARCH64_INSN_IMM_MOVNZ);
break;
case R_AARCH64_MOVW_SABS_G1:
ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
AARCH64_INSN_IMM_MOVNZ);
break;
case R_AARCH64_MOVW_SABS_G2:
ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
AARCH64_INSN_IMM_MOVNZ);
break;
case R_AARCH64_MOVW_PREL_G0_NC:
overflow_check = false;
ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0,
AARCH64_INSN_IMM_MOVK);
break;
case R_AARCH64_MOVW_PREL_G0:
ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0,
AARCH64_INSN_IMM_MOVNZ);
break;
case R_AARCH64_MOVW_PREL_G1_NC:
overflow_check = false;
ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16,
AARCH64_INSN_IMM_MOVK);
break;
case R_AARCH64_MOVW_PREL_G1:
ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16,
AARCH64_INSN_IMM_MOVNZ);
break;
case R_AARCH64_MOVW_PREL_G2_NC:
overflow_check = false;
ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32,
AARCH64_INSN_IMM_MOVK);
break;
case R_AARCH64_MOVW_PREL_G2:
ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32,
AARCH64_INSN_IMM_MOVNZ);
break;
case R_AARCH64_MOVW_PREL_G3:
/* We're using the top bits so we can't overflow. */
overflow_check = false;
ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 48,
AARCH64_INSN_IMM_MOVNZ);
break;
/* Immediate instruction relocations. */
case R_AARCH64_LD_PREL_LO19:
ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19,
AARCH64_INSN_IMM_19);
break;
case R_AARCH64_ADR_PREL_LO21:
ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 0, 21,
AARCH64_INSN_IMM_ADR);
break;
case R_AARCH64_ADR_PREL_PG_HI21_NC:
overflow_check = false;
case R_AARCH64_ADR_PREL_PG_HI21:
ovf = reloc_insn_imm(RELOC_OP_PAGE, loc, val, 12, 21,
AARCH64_INSN_IMM_ADR);
break;
case R_AARCH64_ADD_ABS_LO12_NC:
case R_AARCH64_LDST8_ABS_LO12_NC:
overflow_check = false;
ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 0, 12,
AARCH64_INSN_IMM_12);
break;
case R_AARCH64_LDST16_ABS_LO12_NC:
overflow_check = false;
ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 1, 11,
AARCH64_INSN_IMM_12);
break;
case R_AARCH64_LDST32_ABS_LO12_NC:
overflow_check = false;
ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 2, 10,
AARCH64_INSN_IMM_12);
break;
case R_AARCH64_LDST64_ABS_LO12_NC:
overflow_check = false;
ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 3, 9,
AARCH64_INSN_IMM_12);
break;
case R_AARCH64_LDST128_ABS_LO12_NC:
overflow_check = false;
ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 4, 8,
AARCH64_INSN_IMM_12);
break;
case R_AARCH64_TSTBR14:
ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 14,
AARCH64_INSN_IMM_14);
break;
case R_AARCH64_CONDBR19:
ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19,
AARCH64_INSN_IMM_19);
break;
case R_AARCH64_JUMP26:
case R_AARCH64_CALL26:
ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26,
AARCH64_INSN_IMM_26);
break;
default:
pr_err("module %s: unsupported RELA relocation: %llu\n",
me->name, ELF64_R_TYPE(rel[i].r_info));
return -ENOEXEC;
}
if (overflow_check && ovf == -ERANGE)
goto overflow;
}
return 0;
overflow:
pr_err("module %s: overflow in relocation type %d val %Lx\n",
me->name, (int)ELF64_R_TYPE(rel[i].r_info), val);
return -ENOEXEC;
}
int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
const Elf_Shdr *s, *se;
const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
if (strcmp(".altinstructions", secstrs + s->sh_name) == 0) {
apply_alternatives((void *)s->sh_addr, s->sh_size);
return 0;
}
}
return 0;
}
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