Messages in this thread | | | Date | Tue, 25 Mar 2014 11:16:00 +0900 | From | AKASHI Takahiro <> | Subject | Re: [PATCH] compat_audit: allow it to work without asm/unistd32.h |
| |
On 03/25/2014 01:39 AM, Chris Metcalf wrote: > The problem is that audit_is_compat() is a dynamic test that the compiler > can't optimize away, so you end with an undefined reference to > audit_classify_compat_syscall(). > > For some reason audit_classify_compat_syscall() is declared as __weak > in <linux/audit.h>; usually the __weak tag is only provided on the definition. > But I suppose you could imagine providing a weak definition in lib/audit.c > itself.
I still believe that a function can be declared with __weak and replaced by a strong definition later on (at link time). But this is not the case anyway.
> Or there could be a CONFIG_AUDIT_COMPAT symbol that architectures need to > set if they want to have audit_is_compat() return anything other than "false", > and then just use that symbol in the #ifdef in <uapi/linux/audit.h>. In that > case the compiler would optimize away the call to audit_classify_compat_syscall(). > > My guess is that the second option is probably cleanest.
Yep, but I don't want to add new CONFIG_AUDIT_COMPAT symbol just for audit_is_compat() because it is only used in lib/audit.c(AUDIT_GENERIC). Instead, I prefer #ifdef CONFIG_AUDIT_COMPAT_GENERIC #define audit_is_compat(arch) (...) #else #define audit_is_compat(arch) false #endif
Thanks, -Takahiro AKASHI
> On 3/24/2014 12:21 PM, Eric Paris wrote: >> I don't know tilegx, but I have replaced 223b24d807610 with >> 4b58841149dcaa5. I believe adding AUDIT_ARCH_COMPAT_GENERIC was >> akashi-san's fix for this problem on mips. Is this a better fix? >> >> Thanks >> -Eric >> >> On Thu, 2014-03-20 at 11:31 -0400, Chris Metcalf wrote: >>> For architectures that use the asm-generic syscall table for both >>> 32- and 64-bit, there should be no need to provide a separate >>> <asm/unistd32.h>; just using <linux/unistd.h> is sufficient. >>> Conditionalize use of <asm/unistd32.h> on the one platform that >>> currently requires it (arm64). If another platform ends up needing >>> it we can create a suitable config flag at that point. >>> >>> This change fixes the tilegx build failure seen in linux-next. >>> >>> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> >>> --- >>> By the way - I also note that commit 223b24d807610 that introduced >>> this also put an "#ifdef COMPAT_xxx" in a UAPI header. This seems >>> like a pretty clear signal that the added code should be in >>> linux/include/audit.h, not linux/uapi/include/audit.h. But here >>> I'm just focussing on getting tilegx to continue to build... >>> >>> lib/compat_audit.c | 7 ++++++- >>> 1 file changed, 6 insertions(+), 1 deletion(-) >>> >>> diff --git a/lib/compat_audit.c b/lib/compat_audit.c >>> index 873f75b640ab..e89a84b3fbe8 100644 >>> --- a/lib/compat_audit.c >>> +++ b/lib/compat_audit.c >>> @@ -1,6 +1,11 @@ >>> #include <linux/init.h> >>> #include <linux/types.h> >>> -#include <asm/unistd32.h> >>> +#ifdef COMPAT_ARM64 >>> +/* 64-bit syscalls are generic, but 32-bit are not. */ >>> +# include <asm/unistd32.h> >>> +#else >>> +# include <linux/unistd.h> >>> +#endif >>> >>> unsigned compat_dir_class[] = { >>> #include <asm-generic/audit_dir_write.h> >> >
| |