[PATCH] Unhide DEBUG_RODATA if EXPERT, even if DEBUG_KERNEL=n

[PATCH] Unhide DEBUG_RODATA if EXPERT, even if DEBUG_KERNEL=n

[Josh Triplett]

CONFIG_DEBUG_RODATA defaults to y.  Embedded systems might want to
disable this to save space; however, disabling it requires enabling
CONFIG_DEBUG_KERNEL to see it.  Unhide it for CONFIG_EXPERT=y as well,
so it shows up as an option for embedded users without having to turn on
CONFIG_DEBUG_KERNEL.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
---

On a related note, I noticed while making this patch that
DEBUG_RODATA_TEST defaults to y, as of commit
72370f2a5b227bd3817593a6b15ea3f53f51dfcb; however, the description says
"If in doubt, say N".  Should the default change, or should the
description?  DEBUG_RODATA_TEST seems like the kind of thing that should
default to n.

 arch/x86/Kconfig.debug |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index c0f8a5c..8653d8b 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -81,7 +81,7 @@ config X86_PTDUMP
 config DEBUG_RODATA
 	bool "Write protect kernel read-only data structures"
 	default y
-	depends on DEBUG_KERNEL
+	depends on DEBUG_KERNEL || EXPERT
 	---help---
 	  Mark the kernel read-only data as write-protected in the pagetables,
 	  in order to catch accidental (and incorrect) writes to such const
-- 
1.7.5.3

Re: [PATCH] Unhide DEBUG_RODATA if EXPERT, even if DEBUG_KERNEL=n

[Ingo Molnar]

* Josh Triplett <josh@joshtriplett.org> wrote:

> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -81,7 +81,7 @@ config X86_PTDUMP
>  config DEBUG_RODATA
>  	bool "Write protect kernel read-only data structures"
>  	default y
> -	depends on DEBUG_KERNEL
> +	depends on DEBUG_KERNEL || EXPERT

This is doing it the wrong way around. The right solution is what i 
wrote for verbose-debug: if we select DEBUG_KERNEL from EXPERT then 
you will avoid having to expand || EXPERT conditions into every 
default-enabled debug facility ...

My suggested solution will be a lot easier to maintain as well as 
under your scheme, because with your scheme we'd have to:

  - add || EXPERT every time a debug facility is enabled by default

  - remove || EXPERT every time a debug facility is switched to 
    off-by-default

If EXPERT selects DEBUG_KERNEL then we always get the right behavior, 
without polluting debug Kconfig's with EXPERT logic ...


Thanks,

	Ingo