Re: [patch 3/8] Immediate Values - Kconfig menu in EMBEDDED

From: Andi Kleen
Date: Fri Sep 07 2007 - 02:50:16 EST


> +config IMMEDIATE
> + default y if !DISABLE_IMMEDIATE

It's still unclear to me why DISABLE_IMMEDIATE is needed. It would
be better to make it just the default.

> +config DISABLE_IMMEDIATE
> + default y if EMBEDDED
> + bool "Disable immediate values" if EMBEDDED
> + depends on X86_32 || PPC || PPC64
> + help
> + Disable code patching based immediate values for embedded systems. It
> + consumes slightly more memory and requires to modify the instruction
> + stream each time a variable is updated.

> Should really be disabled for
> + embedded systems with read-only text.

There are no such on x86 at least And for other architectures like
PPC it would be better to have a high level CONFIG_READ_ONLY_TEXT
then that does the necessary changes internally. But I'm not sure it's even
supporting r/o text.

-Andi
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