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From 34b4624b04fc8f038b2c329ca7560197320615b4 Mon Sep 17 00:00:00 2001
From: Fangrui Song <maskray@google.com>
Date: Wed, 18 Aug 2021 10:01:31 -0700
Subject: [PATCH] riscv: Drop reliance on _GLOBAL_OFFSET_TABLE_[0]
&__ehdr_start is a better way to get the load address.
This is similar to commits b37b75d269883a2c553bb7019a813094eb4e2dd1
(x86-64) and 43d06ed218fc8be58987bdfd00e21e5720f0b862 (aarch64).
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
sysdeps/riscv/dl-machine.h | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/sysdeps/riscv/dl-machine.h b/sysdeps/riscv/dl-machine.h
index aedf69f..5b07461 100644
--- a/sysdeps/riscv/dl-machine.h
+++ b/sysdeps/riscv/dl-machine.h
@@ -76,27 +76,26 @@ elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
return 1;
}
+/* Return the run-time load address of the shared object. */
+static inline ElfW(Addr)
+elf_machine_load_address (void)
+{
+ extern const ElfW(Ehdr) __ehdr_start attribute_hidden;
+ return (ElfW(Addr)) &__ehdr_start;
+}
+
/* Return the link-time address of _DYNAMIC. */
static inline ElfW(Addr)
elf_machine_dynamic (void)
{
- extern ElfW(Addr) _GLOBAL_OFFSET_TABLE_ __attribute__ ((visibility ("hidden")));
- return _GLOBAL_OFFSET_TABLE_;
+ extern ElfW(Dyn) _DYNAMIC[] attribute_hidden;
+ return (ElfW(Addr)) _DYNAMIC - elf_machine_load_address ();
}
#define STRINGXP(X) __STRING (X)
#define STRINGXV(X) STRINGV_ (X)
#define STRINGV_(...) # __VA_ARGS__
-/* Return the run-time load address of the shared object. */
-static inline ElfW(Addr)
-elf_machine_load_address (void)
-{
- ElfW(Addr) load_addr;
- asm ("lla %0, _DYNAMIC" : "=r" (load_addr));
- return load_addr - elf_machine_dynamic ();
-}
-
/* Initial entry point code for the dynamic linker.
The C function `_dl_start' is the real entry point;
its return value is the user program's entry point. */
--
1.8.3.1
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