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x32: Avoid unsigned long when installing fast tracepoint jump pads

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We're casting through unsigned long to write a 64-bit immediate
operand of movabs (the comment said movl, but that was incorrect).
The problem is that unsigned long is 32-bit on x32, so we were writing
fewer bytes than necessary.

Fix this by using an 8 byte memcpy like in other similar places in the
function.

gdb/gdbserver/ChangeLog:
2016-08-19  Pedro Alves  <palves@redhat.com>

	* linux-x86-low.c (amd64_install_fast_tracepoint_jump_pad): Fix
	comment.  Use memcpy instead of casting through unsigned long.
This commit is contained in:
Pedro Alves 2016-08-19 12:07:45 +01:00
parent 9c235a72a1
commit c8ef42eed1
2 changed files with 8 additions and 3 deletions
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5
gdb/gdbserver/ChangeLog
View file

@ -1,3 +1,8 @@
2016-08-19 Pedro Alves <palves@redhat.com>
* linux-x86-low.c (amd64_install_fast_tracepoint_jump_pad): Fix
comment. Use memcpy instead of casting through unsigned long.
2016-08-19 Pedro Alves <palves@redhat.com>
* linux-amd64-ipa.c (alloc_jump_pad_buffer) [__ILP32__]: Try

6
gdb/gdbserver/linux-x86-low.c
View file

@ -1092,10 +1092,10 @@ amd64_install_fast_tracepoint_jump_pad (CORE_ADDR tpoint, CORE_ADDR tpaddr,
buf[i++] = 0x41; buf[i++] = 0x51; /* push %r9 */
buf[i++] = 0x41; buf[i++] = 0x50; /* push %r8 */
buf[i++] = 0x9c; /* pushfq */
buf[i++] = 0x48; /* movl <addr>,%rdi */
buf[i++] = 0x48; /* movabs <addr>,%rdi */
buf[i++] = 0xbf;
*((unsigned long *)(buf + i)) = (unsigned long) tpaddr;
i += sizeof (unsigned long);
memcpy (buf + i, &tpaddr, 8);
i += 8;
buf[i++] = 0x57; /* push %rdi */
append_insns (&buildaddr, i, buf);