Messages in this thread Patch in this message | | | Date | Wed, 23 Apr 2008 20:44:47 +0200 | From | Sam Ravnborg <> | Subject | Re: [RFC] Introduce __ARCH_WANT_SYS_SYSFS |
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On Wed, Apr 23, 2008 at 03:36:23PM +0100, Will Newton wrote: > On Tue, Apr 22, 2008 at 4:38 PM, Kyle McMartin <kyle@mcmartin.ca> wrote: > > On Tue, Apr 22, 2008 at 04:34:03PM +0100, Will Newton wrote: > > > On Tue, Apr 22, 2008 at 4:24 PM, Kyle McMartin <kyle@mcmartin.ca> wrote: > > > > On Tue, Apr 22, 2008 at 04:16:17PM +0100, Will Newton wrote: > > > > > It can be done with Kconfig. Whether it should be or not depends on > > > > > your point of view, hence RFC. Currently __ARCH_WANT macros is the way > > > > > syscalls are enabled and disabled across architectures. If there's > > > > > consensus that it should be done via Kconfig that could certainly be > > > > > implmented, but that's a different patch. > > > > > > > > > > > > > It's currently done in unistd.h for hysterical raisins. All new > > > > conditional syscalls have been done in Kconfig. > > > > > > Do you have a syscall in mind that does this in the correct way? > > > > > > > epoll is the most immediate example at hand, since it touches > > fs/compat.c similarly to how you would be touching fs/filesystem.c, and > > touches kernel/sys_ni.c and init/Kconfig in much the same way. > > I implemented the approach you suggested - Kconfig symbol and > cond_syscall definition. I think I actually like the previous approach > better: > > 1. The arch Kconfig files are quite non-uniform compared to unistd.h > so the definitions wind up at different places in the file which is a > bit messy. > 2. Changes to Kconfig may cause churn in defconfigs perhaps? > 3. There is more churn in arch Kconfig than unistd.h so getting a > cross arch patch applied is likely to be more difficult. > 4. The patch is about 4 times as many lines. > > What do you think?
If we go the Kconfig route we should use the HAVE_ semantic as expressed by the patch below. It is preferable to defining a config symbol for each arch. This also address your point 1) and 4) 2) is not an issue since the symbols are not visible.
Sam
Note: cut'n'pasted...
diff --git a/arch/Kconfig b/arch/Kconfig index 694c9af..759bd5b 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -36,3 +36,9 @@ config HAVE_KPROBES
config HAVE_KRETPROBES def_bool n + +# syscall symbols. +# archs shall select the SYMBOL if they +# implment this syscall +config HAVE_SYS_SYSFS + defbool n diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 87a693c..487310f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -24,6 +24,8 @@ config X86 select HAVE_KRETPROBES select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64) select HAVE_ARCH_KGDB + # kconfig selectable syscalls + select HAVE_SYS_SYSFS
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