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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2021-12-30 17:08:36 +0000
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2022-05-17 10:14:03 +0100
commit1da064c015dce624cb19fcdc0bace7af2bd8caec (patch)
treed7da68d75f2cf23f909c0d97e0cbe8ea53946464 /sysdeps/aarch64/dl-start.S
parent9faf5262c77487c96da8a3e961b88c0b1879e186 (diff)
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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.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/aarch64/dl-start.S')
-rw-r--r--sysdeps/aarch64/dl-start.S53
1 files changed, 53 insertions, 0 deletions
diff --git a/sysdeps/aarch64/dl-start.S b/sysdeps/aarch64/dl-start.S
new file mode 100644
index 0000000000..a3a57bd5a1
--- /dev/null
+++ b/sysdeps/aarch64/dl-start.S
@@ -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)