mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-04 19:00:09 +00:00
aarch64: Move ld.so _start to separate file and drop _dl_skip_args
A separate asm file is easier to maintain than a macro that expands to inline asm. The RTLD_START macro is only needed now because _dl_start is local in rtld.c, but _start has to call it, if _dl_start was made hidden then it could be empty. _dl_skip_args is no longer needed. --- v4: - adjust commit message about _dl_skip_args. v3: - mention _dl_skip_args v2: - fix typo in commit message.
This commit is contained in:
Szabolcs Nagy
parent
3f32aa2bdd
commit
fc7beebceb
@ -33,6 +33,7 @@ tst-audit27-ENV = LD_AUDIT=$(objpfx)tst-auditmod27.so
|
||||
endif
|
||||
|
||||
ifeq ($(subdir),elf)
|
||||
sysdep-rtld-routines += dl-start
|
||||
sysdep-dl-routines += tlsdesc dl-tlsdesc
|
||||
gen-as-const-headers += dl-link.sym
|
||||
|
||||
|
||||
@ -105,81 +105,8 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
|
||||
return lazy;
|
||||
}
|
||||
|
||||
/* Initial entry point for the dynamic linker. The C function
|
||||
_dl_start is the real entry point, its return value is the user
|
||||
program's entry point */
|
||||
#ifdef __LP64__
|
||||
# define RTLD_START RTLD_START_1 ("x", "3", "sp")
|
||||
#else
|
||||
# define RTLD_START RTLD_START_1 ("w", "2", "wsp")
|
||||
#endif
|
||||
|
||||
|
||||
#define RTLD_START_1(PTR, PTR_SIZE_LOG, PTR_SP) asm ("\
|
||||
.text \n\
|
||||
.globl _start \n\
|
||||
.type _start, %function \n\
|
||||
.globl _dl_start_user \n\
|
||||
.type _dl_start_user, %function \n\
|
||||
_start: \n\
|
||||
// bti c \n\
|
||||
hint 34 \n\
|
||||
mov " PTR "0, " PTR_SP " \n\
|
||||
bl _dl_start \n\
|
||||
// returns user entry point in x0 \n\
|
||||
mov x21, x0 \n\
|
||||
_dl_start_user: \n\
|
||||
// get the original arg count \n\
|
||||
ldr " PTR "1, [sp] \n\
|
||||
// get the argv address \n\
|
||||
add " PTR "2, " PTR_SP ", #(1<<" PTR_SIZE_LOG ") \n\
|
||||
// get _dl_skip_args to see if we were \n\
|
||||
// invoked as an executable \n\
|
||||
adrp x4, _dl_skip_args \n\
|
||||
ldr w4, [x4, #:lo12:_dl_skip_args] \n\
|
||||
// do we need to adjust argc/argv \n\
|
||||
cmp w4, 0 \n\
|
||||
beq .L_done_stack_adjust \n\
|
||||
// subtract _dl_skip_args from original arg count \n\
|
||||
sub " PTR "1, " PTR "1, " PTR "4 \n\
|
||||
// store adjusted argc back to stack \n\
|
||||
str " PTR "1, [sp] \n\
|
||||
// find the first unskipped argument \n\
|
||||
mov " PTR "3, " PTR "2 \n\
|
||||
add " PTR "4, " PTR "2, " PTR "4, lsl #" PTR_SIZE_LOG " \n\
|
||||
// shuffle argv down \n\
|
||||
1: ldr " PTR "5, [x4], #(1<<" PTR_SIZE_LOG ") \n\
|
||||
str " PTR "5, [x3], #(1<<" PTR_SIZE_LOG ") \n\
|
||||
cmp " PTR "5, #0 \n\
|
||||
bne 1b \n\
|
||||
// shuffle envp down \n\
|
||||
1: ldr " PTR "5, [x4], #(1<<" PTR_SIZE_LOG ") \n\
|
||||
str " PTR "5, [x3], #(1<<" PTR_SIZE_LOG ") \n\
|
||||
cmp " PTR "5, #0 \n\
|
||||
bne 1b \n\
|
||||
// shuffle auxv down \n\
|
||||
1: ldp " PTR "0, " PTR "5, [x4, #(2<<" PTR_SIZE_LOG ")]! \n\
|
||||
stp " PTR "0, " PTR "5, [x3], #(2<<" PTR_SIZE_LOG ") \n\
|
||||
cmp " PTR "0, #0 \n\
|
||||
bne 1b \n\
|
||||
// Update _dl_argv \n\
|
||||
adrp x3, __GI__dl_argv \n\
|
||||
str " PTR "2, [x3, #:lo12:__GI__dl_argv] \n\
|
||||
.L_done_stack_adjust: \n\
|
||||
// compute envp \n\
|
||||
add " PTR "3, " PTR "2, " PTR "1, lsl #" PTR_SIZE_LOG " \n\
|
||||
add " PTR "3, " PTR "3, #(1<<" PTR_SIZE_LOG ") \n\
|
||||
adrp x16, _rtld_local \n\
|
||||
add " PTR "16, " PTR "16, #:lo12:_rtld_local \n\
|
||||
ldr " PTR "0, [x16] \n\
|
||||
bl _dl_init \n\
|
||||
// load the finalizer function \n\
|
||||
adrp x0, _dl_fini \n\
|
||||
add " PTR "0, " PTR "0, #:lo12:_dl_fini \n\
|
||||
// jump to the user_s entry point \n\
|
||||
mov x16, x21 \n\
|
||||
br x16 \n\
|
||||
");
|
||||
/* In elf/rtld.c _dl_start should be global so dl-start.S can reference it. */
|
||||
#define RTLD_START asm (".globl _dl_start");
|
||||
|
||||
#define elf_machine_type_class(type) \
|
||||
((((type) == AARCH64_R(JUMP_SLOT) \
|
||||
|
||||
53
sysdeps/aarch64/dl-start.S
Normal file
53
sysdeps/aarch64/dl-start.S
Normal file
@ -0,0 +1,53 @@
|
||||
/* ld.so _start code.
|
||||
Copyright (C) 2022 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 <sysdep.h>
|
||||
|
||||
ENTRY (_start)
|
||||
/* Create an initial frame with 0 LR and FP */
|
||||
cfi_undefined (x30)
|
||||
mov x29, #0
|
||||
mov x30, #0
|
||||
|
||||
mov x0, sp
|
||||
PTR_ARG (0)
|
||||
bl _dl_start
|
||||
/* Returns user entry point in x0. */
|
||||
mov PTR_REG (21), PTR_REG (0)
|
||||
.globl _dl_start_user
|
||||
.type _dl_start_user, %function
|
||||
_dl_start_user:
|
||||
/* Get argc. */
|
||||
ldr PTR_REG (1), [sp]
|
||||
/* Get argv. */
|
||||
add x2, sp, PTR_SIZE
|
||||
/* Compute envp. */
|
||||
add PTR_REG (3), PTR_REG (2), PTR_REG (1), lsl PTR_LOG_SIZE
|
||||
add PTR_REG (3), PTR_REG (3), PTR_SIZE
|
||||
adrp x16, _rtld_local
|
||||
add PTR_REG (16), PTR_REG (16), :lo12:_rtld_local
|
||||
ldr PTR_REG (0), [x16]
|
||||
bl _dl_init
|
||||
/* Load the finalizer function. */
|
||||
adrp x0, _dl_fini
|
||||
add PTR_REG (0), PTR_REG (0), :lo12:_dl_fini
|
||||
/* Jump to the user's entry point. */
|
||||
mov x16, x21
|
||||
br x16
|
||||
END (_start)
|
||||
Loading…
Reference in New Issue
Block a user