mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-04 19:00:09 +00:00
340 lines
11 KiB
C
340 lines
11 KiB
C
/* Assembler macros for ARM.
|
|
Copyright (C) 1997-2020 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library. If not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <sysdeps/generic/sysdep.h>
|
|
#include <features.h>
|
|
|
|
#ifndef __ASSEMBLER__
|
|
# include <stdint.h>
|
|
#else
|
|
# include <arm-features.h>
|
|
#endif
|
|
|
|
/* The __ARM_ARCH define is provided by gcc 4.8. Construct it otherwise. */
|
|
#ifndef __ARM_ARCH
|
|
# ifdef __ARM_ARCH_2__
|
|
# define __ARM_ARCH 2
|
|
# elif defined (__ARM_ARCH_3__) || defined (__ARM_ARCH_3M__)
|
|
# define __ARM_ARCH 3
|
|
# elif defined (__ARM_ARCH_4__) || defined (__ARM_ARCH_4T__)
|
|
# define __ARM_ARCH 4
|
|
# elif defined (__ARM_ARCH_5__) || defined (__ARM_ARCH_5E__) \
|
|
|| defined(__ARM_ARCH_5T__) || defined(__ARM_ARCH_5TE__) \
|
|
|| defined(__ARM_ARCH_5TEJ__)
|
|
# define __ARM_ARCH 5
|
|
# elif defined (__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) \
|
|
|| defined (__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) \
|
|
|| defined (__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__)
|
|
# define __ARM_ARCH 6
|
|
# elif defined (__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) \
|
|
|| defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) \
|
|
|| defined(__ARM_ARCH_7EM__)
|
|
# define __ARM_ARCH 7
|
|
# else
|
|
# error unknown arm architecture
|
|
# endif
|
|
#endif
|
|
|
|
#if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
|
|
# define ARCH_HAS_BX
|
|
#endif
|
|
#if __ARM_ARCH > 4
|
|
# define ARCH_HAS_BLX
|
|
#endif
|
|
#if __ARM_ARCH > 6 || defined (__ARM_ARCH_6K__) || defined (__ARM_ARCH_6ZK__)
|
|
# define ARCH_HAS_HARD_TP
|
|
#endif
|
|
#if __ARM_ARCH > 6 || defined (__ARM_ARCH_6T2__)
|
|
# define ARCH_HAS_T2
|
|
#endif
|
|
|
|
#ifdef __ASSEMBLER__
|
|
|
|
/* Syntactic details of assembler. */
|
|
|
|
#define ALIGNARG(log2) log2
|
|
#define ASM_SIZE_DIRECTIVE(name) .size name,.-name
|
|
|
|
#define PLTJMP(_x) _x##(PLT)
|
|
|
|
#ifdef ARCH_HAS_BX
|
|
# define BX(R) bx R
|
|
# define BXC(C, R) bx##C R
|
|
# ifdef ARCH_HAS_BLX
|
|
# define BLX(R) blx R
|
|
# else
|
|
# define BLX(R) mov lr, pc; bx R
|
|
# endif
|
|
#else
|
|
# define BX(R) mov pc, R
|
|
# define BXC(C, R) mov##C pc, R
|
|
# define BLX(R) mov lr, pc; mov pc, R
|
|
#endif
|
|
|
|
#define DO_RET(R) BX(R)
|
|
#define RETINSTR(C, R) BXC(C, R)
|
|
|
|
/* Define an entry point visible from C. */
|
|
#define ENTRY(name) \
|
|
.globl C_SYMBOL_NAME(name); \
|
|
.type C_SYMBOL_NAME(name),%function; \
|
|
.align ALIGNARG(4); \
|
|
C_LABEL(name) \
|
|
CFI_SECTIONS; \
|
|
cfi_startproc; \
|
|
CALL_MCOUNT
|
|
|
|
#define CFI_SECTIONS \
|
|
.cfi_sections .debug_frame
|
|
|
|
#undef END
|
|
#define END(name) \
|
|
cfi_endproc; \
|
|
ASM_SIZE_DIRECTIVE(name)
|
|
|
|
/* If compiled for profiling, call `mcount' at the start of each function. */
|
|
#ifdef PROF
|
|
/* Call __gnu_mcount_nc (GCC >= 4.4). */
|
|
#define CALL_MCOUNT \
|
|
push {lr}; \
|
|
cfi_adjust_cfa_offset (4); \
|
|
cfi_rel_offset (lr, 0); \
|
|
bl PLTJMP(mcount); \
|
|
cfi_adjust_cfa_offset (-4); \
|
|
cfi_restore (lr)
|
|
#else
|
|
#define CALL_MCOUNT /* Do nothing. */
|
|
#endif
|
|
|
|
/* Since C identifiers are not normally prefixed with an underscore
|
|
on this system, the asm identifier `syscall_error' intrudes on the
|
|
C name space. Make sure we use an innocuous name. */
|
|
#define syscall_error __syscall_error
|
|
#define mcount __gnu_mcount_nc
|
|
|
|
/* Tag_ABI_align8_preserved: This code preserves 8-byte
|
|
alignment in any callee. */
|
|
.eabi_attribute 25, 1
|
|
/* Tag_ABI_align8_needed: This code may require 8-byte alignment from
|
|
the caller. */
|
|
.eabi_attribute 24, 1
|
|
|
|
/* The thumb2 encoding is reasonably complete. Unless suppressed, use it. */
|
|
.syntax unified
|
|
# if defined(__thumb2__) && !defined(NO_THUMB)
|
|
.thumb
|
|
#else
|
|
# undef __thumb__
|
|
# undef __thumb2__
|
|
.arm
|
|
# endif
|
|
|
|
/* Load or store to/from address X + Y into/from R, (maybe) using T.
|
|
X or Y can use T freely; T can be R if OP is a load. The first
|
|
version eschews the two-register addressing mode, while the
|
|
second version uses it. */
|
|
# define LDST_INDEXED_NOINDEX(OP, R, T, X, Y) \
|
|
add T, X, Y; \
|
|
OP R, [T]
|
|
# define LDST_INDEXED_INDEX(OP, R, X, Y) \
|
|
OP R, [X, Y]
|
|
|
|
# ifdef ARM_NO_INDEX_REGISTER
|
|
/* We're never using the two-register addressing mode, so this
|
|
always uses an intermediate add. */
|
|
# define LDST_INDEXED(OP, R, T, X, Y) LDST_INDEXED_NOINDEX (OP, R, T, X, Y)
|
|
# define LDST_PC_INDEXED(OP, R, T, X) LDST_INDEXED_NOINDEX (OP, R, T, pc, X)
|
|
# else
|
|
/* The two-register addressing mode is OK, except on Thumb with pc. */
|
|
# define LDST_INDEXED(OP, R, T, X, Y) LDST_INDEXED_INDEX (OP, R, X, Y)
|
|
# ifdef __thumb2__
|
|
# define LDST_PC_INDEXED(OP, R, T, X) LDST_INDEXED_NOINDEX (OP, R, T, pc, X)
|
|
# else
|
|
# define LDST_PC_INDEXED(OP, R, T, X) LDST_INDEXED_INDEX (OP, R, pc, X)
|
|
# endif
|
|
# endif
|
|
|
|
/* Load or store to/from a pc-relative EXPR into/from R, using T. */
|
|
# ifdef __thumb2__
|
|
# define LDST_PCREL(OP, R, T, EXPR) \
|
|
ldr T, 98f; \
|
|
.subsection 2; \
|
|
98: .word EXPR - 99f - PC_OFS; \
|
|
.previous; \
|
|
99: add T, T, pc; \
|
|
OP R, [T]
|
|
# elif defined (ARCH_HAS_T2) && ARM_PCREL_MOVW_OK
|
|
# define LDST_PCREL(OP, R, T, EXPR) \
|
|
movw T, #:lower16:EXPR - 99f - PC_OFS; \
|
|
movt T, #:upper16:EXPR - 99f - PC_OFS; \
|
|
99: LDST_PC_INDEXED (OP, R, T, T)
|
|
# else
|
|
# define LDST_PCREL(OP, R, T, EXPR) \
|
|
ldr T, 98f; \
|
|
.subsection 2; \
|
|
98: .word EXPR - 99f - PC_OFS; \
|
|
.previous; \
|
|
99: OP R, [pc, T]
|
|
# endif
|
|
|
|
/* Load from a global SYMBOL + CONSTANT into R, using T. */
|
|
# if defined (ARCH_HAS_T2) && !defined (PIC)
|
|
# define LDR_GLOBAL(R, T, SYMBOL, CONSTANT) \
|
|
movw T, #:lower16:SYMBOL; \
|
|
movt T, #:upper16:SYMBOL; \
|
|
ldr R, [T, $CONSTANT]
|
|
# elif defined (ARCH_HAS_T2) && defined (PIC) && ARM_PCREL_MOVW_OK
|
|
# define LDR_GLOBAL(R, T, SYMBOL, CONSTANT) \
|
|
movw R, #:lower16:_GLOBAL_OFFSET_TABLE_ - 97f - PC_OFS; \
|
|
movw T, #:lower16:99f - 98f - PC_OFS; \
|
|
movt R, #:upper16:_GLOBAL_OFFSET_TABLE_ - 97f - PC_OFS; \
|
|
movt T, #:upper16:99f - 98f - PC_OFS; \
|
|
.pushsection .rodata.cst4, "aM", %progbits, 4; \
|
|
.balign 4; \
|
|
99: .word SYMBOL##(GOT); \
|
|
.popsection; \
|
|
97: add R, R, pc; \
|
|
98: LDST_PC_INDEXED (ldr, T, T, T); \
|
|
LDST_INDEXED (ldr, R, T, R, T); \
|
|
ldr R, [R, $CONSTANT]
|
|
# else
|
|
# define LDR_GLOBAL(R, T, SYMBOL, CONSTANT) \
|
|
ldr T, 99f; \
|
|
ldr R, 100f; \
|
|
98: add T, T, pc; \
|
|
ldr T, [T, R]; \
|
|
.subsection 2; \
|
|
99: .word _GLOBAL_OFFSET_TABLE_ - 98b - PC_OFS; \
|
|
100: .word SYMBOL##(GOT); \
|
|
.previous; \
|
|
ldr R, [T, $CONSTANT]
|
|
# endif
|
|
|
|
/* This is the same as LDR_GLOBAL, but for a SYMBOL that is known to
|
|
be in the same linked object (as for one with hidden visibility).
|
|
We can avoid the GOT indirection in the PIC case. For the pure
|
|
static case, LDR_GLOBAL is already optimal. */
|
|
# ifdef PIC
|
|
# define LDR_HIDDEN(R, T, SYMBOL, CONSTANT) \
|
|
LDST_PCREL (ldr, R, T, SYMBOL + CONSTANT)
|
|
# else
|
|
# define LDR_HIDDEN(R, T, SYMBOL, CONSTANT) \
|
|
LDR_GLOBAL (R, T, SYMBOL, CONSTANT)
|
|
# endif
|
|
|
|
/* Cope with negative memory offsets, which thumb can't encode.
|
|
Use NEGOFF_ADJ_BASE to (conditionally) alter the base register,
|
|
and then NEGOFF_OFF1 to use 0 for thumb and the offset for arm,
|
|
or NEGOFF_OFF2 to use A-B for thumb and A for arm. */
|
|
# ifdef __thumb2__
|
|
# define NEGOFF_ADJ_BASE(R, OFF) add R, R, $OFF
|
|
# define NEGOFF_ADJ_BASE2(D, S, OFF) add D, S, $OFF
|
|
# define NEGOFF_OFF1(R, OFF) [R]
|
|
# define NEGOFF_OFF2(R, OFFA, OFFB) [R, $((OFFA) - (OFFB))]
|
|
# else
|
|
# define NEGOFF_ADJ_BASE(R, OFF)
|
|
# define NEGOFF_ADJ_BASE2(D, S, OFF) mov D, S
|
|
# define NEGOFF_OFF1(R, OFF) [R, $OFF]
|
|
# define NEGOFF_OFF2(R, OFFA, OFFB) [R, $OFFA]
|
|
# endif
|
|
|
|
/* Helper to get the TLS base pointer. The interface is that TMP is a
|
|
register that may be used to hold the LR, if necessary. TMP may be
|
|
LR itself to indicate that LR need not be saved. The base pointer
|
|
is returned in R0. Only R0 and TMP are modified. */
|
|
|
|
# ifdef ARCH_HAS_HARD_TP
|
|
/* If the cpu has cp15 available, use it. */
|
|
# define GET_TLS(TMP) mrc p15, 0, r0, c13, c0, 3
|
|
# else
|
|
/* At this generic level we have no tricks to pull. Call the ABI routine. */
|
|
# define GET_TLS(TMP) \
|
|
push { r1, r2, r3, lr }; \
|
|
cfi_remember_state; \
|
|
cfi_adjust_cfa_offset (16); \
|
|
cfi_rel_offset (r1, 0); \
|
|
cfi_rel_offset (r2, 4); \
|
|
cfi_rel_offset (r3, 8); \
|
|
cfi_rel_offset (lr, 12); \
|
|
bl __aeabi_read_tp; \
|
|
pop { r1, r2, r3, lr }; \
|
|
cfi_restore_state
|
|
# endif /* ARCH_HAS_HARD_TP */
|
|
|
|
/* These are the directives used for EABI unwind info.
|
|
Wrap them in macros so another configuration's sysdep.h
|
|
file can define them away if it doesn't use EABI unwind info. */
|
|
# define eabi_fnstart .fnstart
|
|
# define eabi_fnend .fnend
|
|
# define eabi_save(...) .save __VA_ARGS__
|
|
# define eabi_cantunwind .cantunwind
|
|
# define eabi_pad(n) .pad n
|
|
|
|
#endif /* __ASSEMBLER__ */
|
|
|
|
/* This number is the offset from the pc at the current location. */
|
|
#ifdef __thumb__
|
|
# define PC_OFS 4
|
|
#else
|
|
# define PC_OFS 8
|
|
#endif
|
|
|
|
/* Pointer mangling support. */
|
|
#if (IS_IN (rtld) \
|
|
|| (!defined SHARED && (IS_IN (libc) || IS_IN (libpthread))))
|
|
# ifdef __ASSEMBLER__
|
|
# define PTR_MANGLE_LOAD(guard, tmp) \
|
|
LDR_HIDDEN (guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local), 0)
|
|
# define PTR_MANGLE(dst, src, guard, tmp) \
|
|
PTR_MANGLE_LOAD(guard, tmp); \
|
|
PTR_MANGLE2(dst, src, guard)
|
|
/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
|
|
# define PTR_MANGLE2(dst, src, guard) \
|
|
eor dst, src, guard
|
|
# define PTR_DEMANGLE(dst, src, guard, tmp) \
|
|
PTR_MANGLE (dst, src, guard, tmp)
|
|
# define PTR_DEMANGLE2(dst, src, guard) \
|
|
PTR_MANGLE2 (dst, src, guard)
|
|
# else
|
|
extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
|
|
# define PTR_MANGLE(var) \
|
|
(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
|
|
# define PTR_DEMANGLE(var) PTR_MANGLE (var)
|
|
# endif
|
|
#else
|
|
# ifdef __ASSEMBLER__
|
|
# define PTR_MANGLE_LOAD(guard, tmp) \
|
|
LDR_GLOBAL (guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard), 0);
|
|
# define PTR_MANGLE(dst, src, guard, tmp) \
|
|
PTR_MANGLE_LOAD(guard, tmp); \
|
|
PTR_MANGLE2(dst, src, guard)
|
|
/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
|
|
# define PTR_MANGLE2(dst, src, guard) \
|
|
eor dst, src, guard
|
|
# define PTR_DEMANGLE(dst, src, guard, tmp) \
|
|
PTR_MANGLE (dst, src, guard, tmp)
|
|
# define PTR_DEMANGLE2(dst, src, guard) \
|
|
PTR_MANGLE2 (dst, src, guard)
|
|
# else
|
|
extern uintptr_t __pointer_chk_guard attribute_relro;
|
|
# define PTR_MANGLE(var) \
|
|
(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
|
|
# define PTR_DEMANGLE(var) PTR_MANGLE (var)
|
|
# endif
|
|
#endif
|