diff options
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | sysdeps/sparc/sysdep.h | 25 |
2 files changed, 26 insertions, 6 deletions
@@ -1,3 +1,10 @@ +2012-05-07 David S. Miller <davem@davemloft.net> + + [BZ #14074] + * sysdeps/sparc/sysdep.h (SPARC_PIC_THUNK_CALL): New macro. + (SETUP_PIC_REG): Use it. + (SETUP_PIC_REG_LEAF): Use it. + 2012-05-07 Joseph Myers <joseph@codesourcery.com> [BZ #13885] diff --git a/sysdeps/sparc/sysdep.h b/sysdeps/sparc/sysdep.h index 2702620be6..bcffec94f0 100644 --- a/sysdeps/sparc/sysdep.h +++ b/sysdeps/sparc/sysdep.h @@ -58,21 +58,34 @@ __sparc_get_pc_thunk.reg: \ .previous; \ .endif; -/* Even when v9 we use a call sequence instead of using "rd %pc" because +/* The "-4" and "+4" offsets against _GLOBAL_OFFSET_TABLE_ are + critical since they represent the offset from the thunk call to the + instruction containing the _GLOBAL_OFFSET_TABLE_ reference. + Therefore these instructions cannot be moved around without + appropriate adjustments to those offsets. + + Furthermore, these expressions are special in another regard. When + the assembler sees a reference to _GLOBAL_OFFSET_TABLE_ inside of + a %hi() or %lo(), it emits a PC-relative relocation. This causes + R_SPARC_HI22 to turn into R_SPARC_PC22, and R_SPARC_LO10 to turn into + R_SPARC_PC10, respectively. + + Even when v9 we use a call sequence instead of using "rd %pc" because RDPC is extremely expensive and incurs a full pipeline flush. */ -#define SETUP_PIC_REG(reg) \ - SPARC_PIC_THUNK(reg) \ +#define SPARC_PIC_THUNK_CALL(reg) \ sethi %hi(_GLOBAL_OFFSET_TABLE_-4), %##reg; \ call __sparc_get_pc_thunk.reg; \ or %##reg, %lo(_GLOBAL_OFFSET_TABLE_+4), %##reg; +#define SETUP_PIC_REG(reg) \ + SPARC_PIC_THUNK(reg) \ + SPARC_PIC_THUNK_CALL(reg) + #define SETUP_PIC_REG_LEAF(reg, tmp) \ SPARC_PIC_THUNK(reg) \ - sethi %hi(_GLOBAL_OFFSET_TABLE_-4), %##reg; \ mov %o7, %##tmp; \ - call __sparc_get_pc_thunk.reg; \ - or %##reg, %lo(_GLOBAL_OFFSET_TABLE_+4), %##reg; \ + SPARC_PIC_THUNK_CALL(reg); \ mov %##tmp, %o7; #undef ENTRY |