lkml.org 
[lkml]   [2022]   [Mar]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v4 00/45] x86: Kernel IBT
On Tue, Mar 8, 2022 at 2:32 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Tue, Mar 08, 2022 at 11:01:04PM +0100, Peter Zijlstra wrote:
> > On Tue, Mar 08, 2022 at 12:00:52PM -0800, Alexei Starovoitov wrote:
> > > On Tue, Mar 08, 2022 at 04:30:11PM +0100, Peter Zijlstra wrote:
> > > > Hopefully last posting...
> > > >
> > > > Since last time:
> > > > - verified clang-14-rc2 works
> > > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/wip.ibt

I observed the following error when building with
CONFIG_LTO_CLANG_FULL=y enabled:

ld.lld: error: ld-temp.o <inline asm>:7:2: symbol 'ibt_selftest_ip' is
already defined
ibt_selftest_ip:
^

Seems to come from
commit a802350ba65a ("x86/ibt: Add IBT feature, MSR and #CP handling")

Commenting out the label in the inline asm, I then observed:
vmlinux.o: warning: objtool: identify_cpu()+0x6d0: sibling call from
callable instruction with modified stack frame
vmlinux.o: warning: objtool: identify_cpu()+0x6e0: stack state
mismatch: cfa1=4+64 cfa2=4+8
These seemed to disappear when I kept CONFIG_LTO_CLANG_FULL=y but then
disabled CONFIG_X86_KERNEL_IBT. (perhaps due to the way I hacked out
the ibt_selftest_ip label).

Otherwise defconfig and CONFIG_LTO_CLANG_THIN=y both built and booted
in a vm WITHOUT IBT support.

Any idea what's the status of IBT emulation in QEMU, and if it exists,
what's the necessary `-cpu` flag to enable it?
--
Thanks,
~Nick Desaulniers

\
 
 \ /
  Last update: 2022-03-10 01:31    [W:0.225 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site