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authorAndrew Pinski <apinski@cavium.com>2014-10-27 00:59:42 -0700
committerWill Newton <will.newton@linaro.org>2014-11-21 14:45:11 +0000
commit6d3db89b12e5c206b8848f0ab35e0632dbbf4bbf (patch)
tree1a218e6d5fe97276df204a1c5703b5064116547c
parent01194ba18d594e79e687be570d85ec3b09a5fcb2 (diff)
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AArch64: Reformat inline-asm in elf_machine_load_address
This patch reformats the inline-asm in elf_machine_load_address so it is easier to change only part of the inline-asm. That is using string concatenating instead of string continuation. Also document why this inline-asm works - it depends on the 32bit relocation being resolved at link time. ChangeLog: 2014-11-21 Will Newton <will.newton@linaro.org> Andrew Pinski <andrew.pinski@caviumnetworks.com> * sysdeps/aarch64/dl-machine.h (elf_machine_load_address): Refactor inline-asm. Also add comment.
-rw-r--r--ChangeLog3
-rw-r--r--sysdeps/aarch64/dl-machine.h21
2 files changed, 15 insertions, 9 deletions
diff --git a/ChangeLog b/ChangeLog
index 3fd0843..076c09d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,9 @@
2014-11-21 Will Newton <will.newton@linaro.org>
Andrew Pinski <andrew.pinski@caviumnetworks.com>
+ * sysdeps/aarch64/dl-machine.h (elf_machine_load_address):
+ Refactor inline-asm. Also add comment.
+
* sysdeps/aarch64/bits/link.h (la_aarch64_gnu_pltenter): Use
ElfW macro instead of hardcoded Elf64 types.
(la_aarch64_gnu_pltenter): Likewise.
diff --git a/sysdeps/aarch64/dl-machine.h b/sysdeps/aarch64/dl-machine.h
index 7f5ce2b..1294369 100644
--- a/sysdeps/aarch64/dl-machine.h
+++ b/sysdeps/aarch64/dl-machine.h
@@ -52,19 +52,22 @@ elf_machine_load_address (void)
The choice of symbol is arbitrary. The static address we obtain
by constructing a non GOT reference to the symbol, the dynamic
address of the symbol we compute using adrp/add to compute the
- symbol's address relative to the PC. */
+ symbol's address relative to the PC.
+ This depends on 32bit relocations being resolved at link time
+ and that the static address fits in the 32bits. */
ElfW(Addr) static_addr;
ElfW(Addr) dynamic_addr;
- asm (" \n\
- adrp %1, _dl_start; \n\
- add %1, %1, #:lo12:_dl_start \n\
- ldr %w0, 1f \n\
- b 2f \n\
-1: .word _dl_start \n\
-2: \n\
- " : "=r" (static_addr), "=r" (dynamic_addr));
+ asm (" \n"
+" adrp %1, _dl_start; \n"
+" add %1, %1, #:lo12:_dl_start \n"
+" ldr %w0, 1f \n"
+" b 2f \n"
+"1: \n"
+" .word _dl_start \n"
+"2: \n"
+ : "=r" (static_addr), "=r" (dynamic_addr));
return dynamic_addr - static_addr;
}