Re: [PATCH] powerpc/fsl-booke: Work around erratum A-006958

On 07/15/2013 01:03:22 AM, Aneesh Kumar K.V wrote:

Scott Wood [off-list ref] writes:
=20
=20
=20

quoted

diff --git a/arch/powerpc/platforms/Kconfig.cputype =20

b/arch/powerpc/platforms/Kconfig.cputype

quoted

index ae0aaea..7f0e2e5 100644

--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype

@@ -165,6 +165,17 @@ config PPC_E500MC
 	  such as e5500/e6500), and must be disabled for running on
 	  e500v1 or e500v2.

+config FSL_ERRATUM_A_006958
+	bool
+	depends on PPC_E500MC && PPC64
+	default y
+	help
+	  Workaround for erratum A-006958, which says that 64-bit
+	  timebase reads are not atomic.  The workaround is to fall back
+	  to the 32-bit method of reading timebase.  Note that timebase
+	  is readable by userspace, so any non-vdso userspace accesses
+	  will need to have the workaround applied separately.
+
 config PPC_FPU
 	bool
 	default y if PPC64

=20
=20
I am completely new to this area, so ignore if it is silly. But how do
we expect to select this config ? Should that happen via .config ?

It will automatically be selected if PPC_E500MC and PPC64 are both =20
selected.

-Scott=