linux-stable.git/arch/x86/kernel/process.h, branch linux-4.4.y

x86/speculation: Change misspelled STIPB to STIBP

2020-06-20T08:23:17+00:00

[ Upstream commit aa77bfb354c495fc4361199e63fc5765b9e1e783 ]

STIBP stands for Single Thread Indirect Branch Predictors. The acronym,
however, can be easily mis-spelled as STIPB. It is perhaps due to the
presence of another related term - IBPB (Indirect Branch Predictor
Barrier).

Fix the mis-spelling in the code.

Signed-off-by: Waiman Long 
Signed-off-by: Borislav Petkov 
Cc: "H. Peter Anvin" 
Cc: Andi Kleen 
Cc: David Woodhouse 
Cc: Ingo Molnar 
Cc: Jiri Kosina 
Cc: Josh Poimboeuf 
Cc: KarimAllah Ahmed 
Cc: Konrad Rzeszutek Wilk 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Tim Chen 
Cc: x86-ml 
Link: https://lkml.kernel.org/r/1544039368-9009-1-git-send-email-longman@redhat.com
Signed-off-by: Sasha Levin

x86/speculation: Avoid __switch_to_xtra() calls

2019-05-16T17:45:12+00:00

commit 5635d99953f04b550738f6f4c1c532667c3fd872 upstream.

The TIF_SPEC_IB bit does not need to be evaluated in the decision to invoke
__switch_to_xtra() when:

 - CONFIG_SMP is disabled

 - The conditional STIPB mode is disabled

The TIF_SPEC_IB bit still controls IBPB in both cases so the TIF work mask
checks might invoke __switch_to_xtra() for nothing if TIF_SPEC_IB is the
only set bit in the work masks.

Optimize it out by masking the bit at compile time for CONFIG_SMP=n and at
run time when the static key controlling the conditional STIBP mode is
disabled.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Jiri Kosina 
Cc: Tom Lendacky 
Cc: Josh Poimboeuf 
Cc: Andrea Arcangeli 
Cc: David Woodhouse 
Cc: Tim Chen 
Cc: Andi Kleen 
Cc: Dave Hansen 
Cc: Casey Schaufler 
Cc: Asit Mallick 
Cc: Arjan van de Ven 
Cc: Jon Masters 
Cc: Waiman Long 
Cc: Greg KH 
Cc: Dave Stewart 
Cc: Kees Cook 
Link: https://lkml.kernel.org/r/20181125185005.374062201@linutronix.de
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

x86/process: Consolidate and simplify switch_to_xtra() code

2019-05-16T17:45:12+00:00

commit ff16701a29cba3aafa0bd1656d766813b2d0a811 upstream.

Move the conditional invocation of __switch_to_xtra() into an inline
function so the logic can be shared between 32 and 64 bit.

Remove the handthrough of the TSS pointer and retrieve the pointer directly
in the bitmap handling function. Use this_cpu_ptr() instead of the
per_cpu() indirection.

This is a preparatory change so integration of conditional indirect branch
speculation optimization happens only in one place.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Jiri Kosina 
Cc: Tom Lendacky 
Cc: Josh Poimboeuf 
Cc: Andrea Arcangeli 
Cc: David Woodhouse 
Cc: Tim Chen 
Cc: Andi Kleen 
Cc: Dave Hansen 
Cc: Casey Schaufler 
Cc: Asit Mallick 
Cc: Arjan van de Ven 
Cc: Jon Masters 
Cc: Waiman Long 
Cc: Greg KH 
Cc: Dave Stewart 
Cc: Kees Cook 
Link: https://lkml.kernel.org/r/20181125185005.280855518@linutronix.de
[bwh: Backported to 4.4:
 - Use cpu_tss instead of cpu_tss_rw
 - __switch_to() still uses the tss variable, so don't delete it
 - Adjust context]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman