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* [PATCH] MIPS: SGI-IP28: disable use of ll/sc in kernel
@ 2020-10-07 10:17 Thomas Bogendoerfer
  2020-10-08  9:19 ` Thomas Bogendoerfer
  0 siblings, 1 reply; 2+ messages in thread
From: Thomas Bogendoerfer @ 2020-10-07 10:17 UTC (permalink / raw)
  To: linux-mips, linux-kernel

SGI-IP28 systems only use broken R10k rev 2.5 CPUs, which could lock
up, if ll/sc sequences are issued in certain order. Since those systems
are all non-SMP, we can disable ll/sc usage in kernel.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
---
 arch/mips/include/asm/mach-ip28/cpu-feature-overrides.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/include/asm/mach-ip28/cpu-feature-overrides.h b/arch/mips/include/asm/mach-ip28/cpu-feature-overrides.h
index ba8b4e30b3e2..613bbc10c1f2 100644
--- a/arch/mips/include/asm/mach-ip28/cpu-feature-overrides.h
+++ b/arch/mips/include/asm/mach-ip28/cpu-feature-overrides.h
@@ -25,7 +25,7 @@
 #define cpu_has_mcheck		0
 #define cpu_has_ejtag		0
 
-#define cpu_has_llsc		1
+#define cpu_has_llsc		0
 #define cpu_has_vtag_icache	0
 #define cpu_has_dc_aliases	0 /* see probe_pcache() */
 #define cpu_has_ic_fills_f_dc	0
-- 
2.16.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] MIPS: SGI-IP28: disable use of ll/sc in kernel
  2020-10-07 10:17 [PATCH] MIPS: SGI-IP28: disable use of ll/sc in kernel Thomas Bogendoerfer
@ 2020-10-08  9:19 ` Thomas Bogendoerfer
  0 siblings, 0 replies; 2+ messages in thread
From: Thomas Bogendoerfer @ 2020-10-08  9:19 UTC (permalink / raw)
  To: linux-mips, linux-kernel

On Wed, Oct 07, 2020 at 12:17:04PM +0200, Thomas Bogendoerfer wrote:
> SGI-IP28 systems only use broken R10k rev 2.5 CPUs, which could lock
> up, if ll/sc sequences are issued in certain order. Since those systems
> are all non-SMP, we can disable ll/sc usage in kernel.
> 
> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> ---
>  arch/mips/include/asm/mach-ip28/cpu-feature-overrides.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2020-10-07 10:17 [PATCH] MIPS: SGI-IP28: disable use of ll/sc in kernel Thomas Bogendoerfer
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