Messages in this thread Patch in this message | | | Date | Tue, 7 Feb 2006 11:27:13 +1100 | From | Stephen Rothwell <> | Subject | Re: [PATCH] compat: add compat functions for *at syscalls |
| |
On Mon, 06 Feb 2006 16:01:40 -0800 (PST) "David S. Miller" <davem@davemloft.net> wrote: > > I do the sign extension with tiny stubs in arch/sparc64/kernel/sys32.S > so that the arg frobbing does not consume a stack frame, which is what > happens if you do this in C code.
In which case you need to to stubs for all the *at syscalls.
> We need to revisit this at some point and make a way for all > compat platforms to do this with a portable table of some kind > that expands a bunch of macros defined by the platform.
*If* we do get is_compat_task(), what would be you reaction to something like this:
diff --git a/fs/namei.c b/fs/namei.c index faf61c3..83d6cd1 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1877,6 +1877,8 @@ asmlinkage long sys_mkdirat(int dfd, con int error = 0; char * tmp; + if (is_compat_task()) + dfd = compat_sign_extend(dfd); tmp = getname(pathname); error = PTR_ERR(tmp); if (!IS_ERR(tmp)) { diff --git a/include/linux/compat.h b/include/linux/compat.h index f9ca534..e6c9db6 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -162,4 +162,10 @@ int get_compat_sigevent(struct sigevent const struct compat_sigevent __user *u_event); #endif /* CONFIG_COMPAT */ + +static inline int compat_sign_extend(long i) +{ + return i; +} + #endif /* _LINUX_COMPAT_H */ On powerpc64, this is sufficient to get the 32 to 64 bit sign extension we need done in place. -- Cheers, Stephen Rothwell sfr@canb.auug.org.au http://www.canb.auug.org.au/~sfr/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |