Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 14469a8d authored by Linus Torvalds's avatar Linus Torvalds Committed by H. Peter Anvin
Browse files

x86: disable static NOPLs on 32 bits 



On 32-bit, at least the generic nops are fairly reasonable, but the
default nops for 64-bit really look pretty sad, and the P6 nops really do
look better.

So I would suggest perhaps moving the static P6 nop selection into the
CONFIG_X86_64 thing.

The alternative is to just get rid of that static nop selection, and just
have two cases: 32-bit and 64-bit, and just pick obviously safe cases for
them.

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 0253398c

arch/x86/Kconfig.cpu

+8 −5
Original line number Diff line number Diff line
@@ -382,14 +382,17 @@ config X86_OOSTORE 
# P6_NOPs are a relatively minor optimization that require a family >=

# 6 processor, except that it is broken on certain VIA chips.

# Furthermore, AMD chips prefer a totally different sequence of NOPs

# (which work on all CPUs).  As a result, disallow these if we're

# compiling X86_GENERIC but not X86_64 (these NOPs do work on all

# x86-64 capable chips); the list of processors in the right-hand clause

# are the cores that benefit from this optimization.

# (which work on all CPUs).  In addition, it looks like Virtual PC

# does not understand them.

#

# As a result, disallow these if we're not compiling for X86_64 (these

# NOPs do work on all x86-64 capable chips); the list of processors in

# the right-hand clause are the cores that benefit from this optimization.

#

config X86_P6_NOP

	def_bool y

	depends on (X86_64 || !X86_GENERIC) && (M686 || MPENTIUMII || MPENTIUMIII || MPENTIUMM || MCORE2 || MPENTIUM4 || MPSC)

	depends on X86_64

	depends on (MCORE2 || MPENTIUM4 || MPSC)



config X86_TSC

	def_bool y