diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-09-05 12:30:14 -0400 |
---|---|---|
committer | H. Peter Anvin <hpa@zytor.com> | 2008-09-08 14:35:43 -0400 |
commit | 14469a8dd23677921db5e7354a602c98d9c6300f (patch) | |
tree | 87aab243efb6dea0a8fb38fe6207764b24b82e6b /arch | |
parent | 0253398ca1df7e1d2bfbb452175c964a0862482c (diff) |
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: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/Kconfig.cpu | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index 2c518fbc52ec..b225219c448c 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu | |||
@@ -382,14 +382,17 @@ config X86_OOSTORE | |||
382 | # P6_NOPs are a relatively minor optimization that require a family >= | 382 | # P6_NOPs are a relatively minor optimization that require a family >= |
383 | # 6 processor, except that it is broken on certain VIA chips. | 383 | # 6 processor, except that it is broken on certain VIA chips. |
384 | # Furthermore, AMD chips prefer a totally different sequence of NOPs | 384 | # Furthermore, AMD chips prefer a totally different sequence of NOPs |
385 | # (which work on all CPUs). As a result, disallow these if we're | 385 | # (which work on all CPUs). In addition, it looks like Virtual PC |
386 | # compiling X86_GENERIC but not X86_64 (these NOPs do work on all | 386 | # does not understand them. |
387 | # x86-64 capable chips); the list of processors in the right-hand clause | 387 | # |
388 | # are the cores that benefit from this optimization. | 388 | # As a result, disallow these if we're not compiling for X86_64 (these |
389 | # NOPs do work on all x86-64 capable chips); the list of processors in | ||
390 | # the right-hand clause are the cores that benefit from this optimization. | ||
389 | # | 391 | # |
390 | config X86_P6_NOP | 392 | config X86_P6_NOP |
391 | def_bool y | 393 | def_bool y |
392 | depends on (X86_64 || !X86_GENERIC) && (M686 || MPENTIUMII || MPENTIUMIII || MPENTIUMM || MCORE2 || MPENTIUM4 || MPSC) | 394 | depends on X86_64 |
395 | depends on (MCORE2 || MPENTIUM4 || MPSC) | ||
393 | 396 | ||
394 | config X86_TSC | 397 | config X86_TSC |
395 | def_bool y | 398 | def_bool y |