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6cd380dd36
eXecute-Only Memory (XOM) is a protection mechanism against some ROP attacks. XOM sets the code as executable and unreadable, so the access to any data, like literal pools, in the code section causes the fault with XOM. The compiler can disable literal pools for C source files, but not for assembly files, so I use movz/movk instead of literal pools in start.S for XOM. I add MOVL macro with movz/movk instructions like movl pseudo-instruction in armasm, and use the macro instead of literal pools. * sysdeps/aarch64/start.S: Use MOVL instead of literal pools. * sysdeps/aarch64/sysdep.h (MOVL): Add MOVL macro.
163 lines
4.7 KiB
C
163 lines
4.7 KiB
C
/* Copyright (C) 1997-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _AARCH64_SYSDEP_H
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#define _AARCH64_SYSDEP_H
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#include <sysdeps/generic/sysdep.h>
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#ifdef __LP64__
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# define AARCH64_R(NAME) R_AARCH64_ ## NAME
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# define PTR_REG(n) x##n
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# define PTR_LOG_SIZE 3
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# define DELOUSE(n)
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#else
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# define AARCH64_R(NAME) R_AARCH64_P32_ ## NAME
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# define PTR_REG(n) w##n
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# define PTR_LOG_SIZE 2
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# define DELOUSE(n) mov w##n, w##n
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#endif
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#define PTR_SIZE (1<<PTR_LOG_SIZE)
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#ifdef __ASSEMBLER__
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/* Syntactic details of assembler. */
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#define ASM_SIZE_DIRECTIVE(name) .size name,.-name
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/* Define an entry point visible from C. */
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#define ENTRY(name) \
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.globl C_SYMBOL_NAME(name); \
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.type C_SYMBOL_NAME(name),%function; \
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.align 4; \
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C_LABEL(name) \
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cfi_startproc; \
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CALL_MCOUNT
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/* Define an entry point visible from C. */
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#define ENTRY_ALIGN(name, align) \
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.globl C_SYMBOL_NAME(name); \
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.type C_SYMBOL_NAME(name),%function; \
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.p2align align; \
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C_LABEL(name) \
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cfi_startproc; \
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CALL_MCOUNT
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/* Define an entry point visible from C with a specified alignment and
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pre-padding with NOPs. This can be used to ensure that a critical
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loop within a function is cache line aligned. Note this version
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does not adjust the padding if CALL_MCOUNT is defined. */
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#define ENTRY_ALIGN_AND_PAD(name, align, padding) \
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.globl C_SYMBOL_NAME(name); \
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.type C_SYMBOL_NAME(name),%function; \
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.p2align align; \
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.rep padding; \
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nop; \
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.endr; \
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C_LABEL(name) \
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cfi_startproc; \
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CALL_MCOUNT
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#undef END
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#define END(name) \
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cfi_endproc; \
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ASM_SIZE_DIRECTIVE(name)
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/* If compiled for profiling, call `mcount' at the start of each function. */
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#ifdef PROF
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# define CALL_MCOUNT \
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str x30, [sp, #-80]!; \
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cfi_adjust_cfa_offset (80); \
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cfi_rel_offset (x30, 0); \
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stp x0, x1, [sp, #16]; \
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cfi_rel_offset (x0, 16); \
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cfi_rel_offset (x1, 24); \
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stp x2, x3, [sp, #32]; \
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cfi_rel_offset (x2, 32); \
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cfi_rel_offset (x3, 40); \
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stp x4, x5, [sp, #48]; \
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cfi_rel_offset (x4, 48); \
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cfi_rel_offset (x5, 56); \
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stp x6, x7, [sp, #64]; \
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cfi_rel_offset (x6, 64); \
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cfi_rel_offset (x7, 72); \
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mov x0, x30; \
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bl mcount; \
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ldp x0, x1, [sp, #16]; \
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cfi_restore (x0); \
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cfi_restore (x1); \
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ldp x2, x3, [sp, #32]; \
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cfi_restore (x2); \
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cfi_restore (x3); \
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ldp x4, x5, [sp, #48]; \
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cfi_restore (x4); \
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cfi_restore (x5); \
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ldp x6, x7, [sp, #64]; \
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cfi_restore (x6); \
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cfi_restore (x7); \
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ldr x30, [sp], #80; \
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cfi_adjust_cfa_offset (-80); \
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cfi_restore (x30);
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#else
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# define CALL_MCOUNT /* Do nothing. */
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#endif
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/* Local label name for asm code. */
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#ifndef L
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# define L(name) .L##name
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#endif
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/* Load or store to/from a pc-relative EXPR into/from R, using T.
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Note R and T are register numbers and not register names. */
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#define LDST_PCREL(OP, R, T, EXPR) \
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adrp x##T, EXPR; \
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OP PTR_REG (R), [x##T, #:lo12:EXPR]; \
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/* Load or store to/from a got-relative EXPR into/from R, using T.
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Note R and T are register numbers and not register names. */
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#define LDST_GLOBAL(OP, R, T, EXPR) \
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adrp x##T, :got:EXPR; \
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ldr PTR_REG (T), [x##T, #:got_lo12:EXPR]; \
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OP PTR_REG (R), [x##T];
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/* Load an immediate into R.
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Note R is a register number and not a register name. */
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#ifdef __LP64__
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# define MOVL(R, NAME) \
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movz PTR_REG (R), #:abs_g3:NAME; \
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movk PTR_REG (R), #:abs_g2_nc:NAME; \
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movk PTR_REG (R), #:abs_g1_nc:NAME; \
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movk PTR_REG (R), #:abs_g0_nc:NAME;
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#else
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# define MOVL(R, NAME) \
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movz PTR_REG (R), #:abs_g1:NAME; \
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movk PTR_REG (R), #:abs_g0_nc:NAME;
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#endif
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/* Since C identifiers are not normally prefixed with an underscore
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on this system, the asm identifier `syscall_error' intrudes on the
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C name space. Make sure we use an innocuous name. */
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#define syscall_error __syscall_error
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#define mcount _mcount
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#endif /* __ASSEMBLER__ */
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#endif /* _AARCH64_SYSDEP_H */
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