This is the mail archive of the binutils@sources.redhat.com mailing list for the binutils project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: RFC: PATCH: PR x86_64/584: Detect call on protected symbol

On Wed, Jan 19, 2005 at 07:17:09PM -0800, H. J. Lu wrote:
> On Thu, Jan 20, 2005 at 12:25:19PM +1030, Alan Modra wrote:
> > On Wed, Jan 19, 2005 at 04:40:32PM -0800, H. J. Lu wrote:
> > > Can we be sure that contents[r_offset - 1] == 0xe8 will be call?
> > 
> > Not if the PC32 reloc happens to be in data.  Also, I suspect some of
> 
> We can check if the input section is executable. The worst case is that
> you may get a runtime error instead of a linktime one.
> 
> > the possible load/store insns might have a sib byte of 0xE8.
> 
> I think 0xe8 SIB is [RAX + RIP * 8], which can't have R_X86_64_PC32.

Ah, no disp field.  A modrm of 0xE8 won't have the PC32 reloc either.
So the only problem is when people put things like jump tables in .text.

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre
Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]