| Message ID | 1414396793-9005-19-git-send-email-apinski@cavium.com |
|---|---|
| State | New |
| Headers | show |
On 27 October 2014 07:59, Andrew Pinski <apinski@cavium.com> wrote: > 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 > concating instead of string continueing. > > Also document on why this inline-asm works, it depends on the 32bit > relocation being resolved at link time. > > * sysdeps/aarch64/dl-machine.h (elf_machine_load_address): > Refactor inline-asm. Also add comment. > --- > sysdeps/aarch64/dl-machine.h | 21 ++++++++++++--------- > 1 files changed, 12 insertions(+), 9 deletions(-) This looks ok to me. > diff --git a/sysdeps/aarch64/dl-machine.h b/sysdeps/aarch64/dl-machine.h > index 6e041b1..121b178 100644 > --- a/sysdeps/aarch64/dl-machine.h > +++ b/sysdeps/aarch64/dl-machine.h > @@ -53,19 +53,22 @@ 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; > } > > -- > 1.7.2.5 >
diff --git a/sysdeps/aarch64/dl-machine.h b/sysdeps/aarch64/dl-machine.h index 6e041b1..121b178 100644 --- a/sysdeps/aarch64/dl-machine.h +++ b/sysdeps/aarch64/dl-machine.h @@ -53,19 +53,22 @@ 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; }