From caa65211bbbfd53c40c9ce1b79b97ccf2c679a52 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 22 Oct 2015 04:53:04 -0700 Subject: Add "-z call-nop=PADDING" option to ld The ld linker can transform indirect call to a locally defined function, foo, via its GOT slot, to either "NOP call foo" or "call foo NOP" where NOP is a 1-byte NOP padding. This patch adds a "-z call-nop=PADDING" option to x86 ld to control 1-byte NOP padding for x86 call instruction. PADDING is one of prefix-addr, prefix-nop, suffix-nop, prefix-NUMBER or suffix-NUMBER. bfd/ * elf32-i386.c (elf_i386_convert_load): Use call_nop_byte and check call_nop_as_suffix for 1-byte NOP padding to pad call. * elf64-x86-64.c (elf_x86_64_convert_load): Likewise. include/ * bfdlink.h (bfd_link_info): Add call_nop_as_suffix and call_nop_byte. ld/ * ld/ld.texinfo: Document "-z call-nop=PADDING" option. * emulparams/call_nop.sh: New file. * emulparams/elf_i386_be.sh: Source ${srcdir}/emulparams/call_nop.sh. * emulparams/elf_i386_chaos.sh: Likewise. * emulparams/elf_i386_ldso.sh: Likewise. * emulparams/elf_i386_vxworks.sh: Likewise. * emulparams/elf_iamcu.sh: Likewise. * emulparams/elf_k1om.sh: Likewise. * emulparams/elf_l1om.sh: Likewise. * emulparams/elf_x86_64.sh: Likewise. * emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Set link_info.call_nop_byte if $CALL_NOP_BYTE isn't empty. ld/testsuite/ * ld-i386/call3.s: New file. * ld-i386/call3a.d: Likewise. * ld-i386/call3b.d: Likewise. * ld-i386/call3c.d: Likewise. * ld-i386/call3d.d: Likewise. * ld-i386/call3e.d: Likewise. * ld-i386/call3f.d: Likewise. * ld-i386/call3g.d: Likewise. * ld-i386/call3h.d: Likewise. * ld-i386/load1-nacl.d: Likewise. * ld-x86-64/call1.s: Likewise. * ld-x86-64/call1a.d: Likewise. * ld-x86-64/call1b.d: Likewise. * ld-x86-64/call1c.d: Likewise. * ld-x86-64/call1d.d: Likewise. * ld-x86-64/call1e.d: Likewise. * ld-x86-64/call1f.d: Likewise. * ld-x86-64/call1g.d: Likewise. * ld-x86-64/call1h.d: Likewise. * ld-x86-64/call1i.d: Likewise. * ld-x86-64/load1a-nacl.d: Likewise. * ld-x86-64/load1b-nacl.d: Likewise. * ld-x86-64/load1c-nacl.d: Likewise. * ld-x86-64/load1d-nacl.d: Likewise. --- include/ChangeLog | 5 +++++ include/bfdlink.h | 6 ++++++ 2 files changed, 11 insertions(+) (limited to 'include') diff --git a/include/ChangeLog b/include/ChangeLog index 5301696..c6b8f0b 100644 --- a/include/ChangeLog +++ b/include/ChangeLog @@ -1,3 +1,8 @@ +2015-10-22 H.J. Lu + + * bfdlink.h (bfd_link_info): Add call_nop_as_suffix and + call_nop_byte. + 2015-10-07 Claudiu Zissulescu * dis-asm.h (arc_get_disassembler): Correct declaration. diff --git a/include/bfdlink.h b/include/bfdlink.h index 2ffb3d1..93abab1 100644 --- a/include/bfdlink.h +++ b/include/bfdlink.h @@ -434,6 +434,12 @@ struct bfd_link_info /* TRUE if generation of .interp/PT_INTERP should be suppressed. */ unsigned int nointerp: 1; + /* TRUE if generate a 1-byte NOP as suffix for x86 call instruction. */ + unsigned int call_nop_as_suffix : 1; + + /* The 1-byte NOP for x86 call instruction. */ + char call_nop_byte; + /* Char that may appear as the first char of a symbol, but should be skipped (like symbol_leading_char) when looking up symbols in wrap_hash. Used by PowerPC Linux for 'dot' symbols. */ -- cgit v1.1