[Bug target/95671] Fails to build kernel 5.7 with -march=bdver{2,3,4} workaround -mno-tbm

[ungift-ed at ya dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95671

--- Comment #4 from Maxim Britov <ungift-ed at ya dot ru> ---
(In reply to Martin Liška from comment #1)
> Can you please attach a pre-processed file for an object that fails with
> objtool?

Heh... I'm afraid I need some howto for this... :(

But I made some minimal reproducible .config for kernel 5.7

$ tar xf linux-5.7.tar.xz
$ cd linux-5.7
$ curl
https://raw.githubusercontent.com/graysky2/kernel_gcc_patch/master/enable_additional_cpu_optimizations_for_gcc_v9.1%2B_kernel_v5.7%2B.patch
| patch -p1

$ copy .config10 .config
$ make oldconfig
$ make

I will attach my .config10

For me it fails:
  CC      arch/x86/entry/vdso/vma.o
  LDS     arch/x86/entry/vdso/vdso.lds
  AS      arch/x86/entry/vdso/vdso-note.o
  CC      arch/x86/entry/vdso/vclock_gettime.o
  CC      arch/x86/entry/vdso/vgetcpu.o
  VDSO    arch/x86/entry/vdso/vdso64.so.dbg
  OBJCOPY arch/x86/entry/vdso/vdso64.so
  HOSTCC  arch/x86/entry/vdso/vdso2c
  VDSO2C  arch/x86/entry/vdso/vdso-image-64.c
  CC      arch/x86/entry/vdso/vdso-image-64.o
  AR      arch/x86/entry/vdso/built-in.a
  CC      arch/x86/entry/vsyscall/vsyscall_64.o
arch/x86/entry/vsyscall/vsyscall_64.o: warning: objtool:
emulate_vsyscall()+0x60: can't find jump dest instruction at .text+0x10a
make[3]: *** [scripts/Makefile.build:267:
arch/x86/entry/vsyscall/vsyscall_64.o] Error 255
make[3]: *** Deleting file 'arch/x86/entry/vsyscall/vsyscall_64.o'
make[2]: *** [scripts/Makefile.build:488: arch/x86/entry/vsyscall] Error 2
make[1]: *** [scripts/Makefile.build:488: arch/x86/entry] Error 2
make: *** [Makefile:1729: arch/x86] Error 2