Re: [PATCH 2/6] trace: add support for 32 bit compat syscalls on x86_64

Vaibhav Nagarnaik
2012-03-28T23:01:20Z

On Wed, Mar 28, 2012 at 2:11 PM, Vaibhav Nagarnaik
<vnagarnaik@google.com> wrote:
> Changelog:
> * Remove unmaintainable list of syscalls and use SYSCALL_DEFINEx macro
>  to define the metadata for equivalent compat syscall

This simplifies the patch significantly, but there are problems to
this approach.
* This doesn't trace compat syscalls which don't call the 64-bit
handler (e.g. sys32_stat64). They need COMPAT_SYSCALL_DEFINEx wrapper
macro where they are defined. I am planning to add them for x86.

* This will generate useless metadata for these syscalls. For e.g. it
will have metadata for compat_sys_lseek which does not generate a
trace-able event. Instead, there will be an event for sys32_lseek when
I add the corresponding metadata wrapper.

(BTW, I just found that I need a change to the check in
find_compat_syscall_meta(). Basically remove the prefixes "sys32_" and
"stub32_")

Vaibhav Nagarnaik