diff options
Diffstat (limited to 'x86_64-Simplify-elf_machine_-load_address-dynamic.patch')
| -rw-r--r-- | x86_64-Simplify-elf_machine_-load_address-dynamic.patch | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/x86_64-Simplify-elf_machine_-load_address-dynamic.patch b/x86_64-Simplify-elf_machine_-load_address-dynamic.patch new file mode 100644 index 0000000..b411a64 --- /dev/null +++ b/x86_64-Simplify-elf_machine_-load_address-dynamic.patch @@ -0,0 +1,55 @@ +From b37b75d269883a2c553bb7019a813094eb4e2dd1 Mon Sep 17 00:00:00 2001 +From: Fangrui Song <maskray@google.com> +Date: Tue, 17 Aug 2021 10:45:57 -0700 +Subject: [PATCH] x86_64: Simplify elf_machine_{load_address,dynamic} + +and drop reliance on _GLOBAL_OFFSET_TABLE_[0] being the link-time +address of _DYNAMIC. &__ehdr_start is a better way to get the load address. + +Reviewed-by: H.J. Lu <hjl.tools@gmail.com> +--- + sysdeps/x86_64/dl-machine.h | 21 +++++++-------------- + 1 file changed, 7 insertions(+), 14 deletions(-) + +diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h +index a8596aa..ceee507 100644 +--- a/sysdeps/x86_64/dl-machine.h ++++ b/sysdeps/x86_64/dl-machine.h +@@ -35,27 +35,20 @@ elf_machine_matches_host (const ElfW(Ehdr) *ehdr) + } + + +-/* Return the link-time address of _DYNAMIC. Conveniently, this is the +- first element of the GOT. This must be inlined in a function which +- uses global data. */ ++/* Return the run-time load address of the shared object. */ + static inline ElfW(Addr) __attribute__ ((unused)) +-elf_machine_dynamic (void) ++elf_machine_load_address (void) + { +- /* This produces an IP-relative reloc which is resolved at link time. */ +- extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden; +- return _GLOBAL_OFFSET_TABLE_[0]; ++ extern const ElfW(Ehdr) __ehdr_start attribute_hidden; ++ return (ElfW(Addr)) &__ehdr_start; + } + +- +-/* Return the run-time load address of the shared object. */ ++/* Return the link-time address of _DYNAMIC. */ + static inline ElfW(Addr) __attribute__ ((unused)) +-elf_machine_load_address (void) ++elf_machine_dynamic (void) + { +- /* Compute the difference between the runtime address of _DYNAMIC as seen +- by an IP-relative reference, and the link-time address found in the +- special unrelocated first GOT entry. */ + extern ElfW(Dyn) _DYNAMIC[] attribute_hidden; +- return (ElfW(Addr)) &_DYNAMIC - elf_machine_dynamic (); ++ return (ElfW(Addr)) _DYNAMIC - elf_machine_load_address (); + } + + /* Set up the loaded object described by L so its unrelocated PLT +-- +1.8.3.1 + |