From c8ef42eed100c2439e600e846caa7437da93ac17 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 19 Aug 2016 12:07:45 +0100 Subject: x32: Avoid unsigned long when installing fast tracepoint jump pads 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 * linux-x86-low.c (amd64_install_fast_tracepoint_jump_pad): Fix comment. Use memcpy instead of casting through unsigned long. --- gdb/gdbserver/ChangeLog | 5 +++++ gdb/gdbserver/linux-x86-low.c | 6 +++--- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index ed53648..f59d389 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,5 +1,10 @@ 2016-08-19 Pedro Alves + * 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 + * linux-amd64-ipa.c (alloc_jump_pad_buffer) [__ILP32__]: Try allocating around 0x80000000. diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c index d6b67c1..1ba98ba 100644 --- a/gdb/gdbserver/linux-x86-low.c +++ b/gdb/gdbserver/linux-x86-low.c @@ -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 ,%rdi */ + buf[i++] = 0x48; /* movabs ,%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); -- cgit v1.1