Misc updates:

 - Remove last remaining calls to exception_enter/exception_exit() and
   simplify the entry code some more.

 - Remove force_iret()

 - Add support for "Fast Short Rep Mov", which is available starting with
   Ice Lake Intel CPUs - and make the x86 assembly version of memmove()
   use REP MOV for all sizes when FSRM is available.

 - Micro-optimize/simplify the 32-bit boot code a bit.

 - Use a more future-proof SYSRET instruction mnemonic

Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/boot: Simplify calculation of output address

Condense the calculation of decompressed kernel start a little.

Committer notes:

before:

ebp = ebx - (init_size - _end)

after:

eax = (ebx + _end) - init_size

where in both ebx contains the temporary address the kernel is moved to
for in-place decompression.

The before and after difference in register state is %eax and %ebp
but that is immaterial because the compressed image is not built with
-mregparm, i.e., all arguments of the following extract_kernel() call
are passed on the stack.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200107194436.2166846-1-nivedita@alum.mit.edu
1 file changed