On 09/06/2018 02:45 AM, Palmer Dabbelt wrote:
On Sat, 01 Sep 2018 10:43:53 PDT (-0700), [email protected] wrote:
Hi Arnd,
On Fri, Apr 13, 2018 at 11:50:12AM +0200, Arnd Bergmann wrote:
We have four generations of stat() syscalls:
- the oldstat syscalls that are only used on the older architectures
- the newstat family that is used on all 64-bit architectures but
lacked support for large files on 32-bit architectures.
- the stat64 family that is used mostly on 32-bit architectures to
replace newstat
- statx() to replace all of the above, adding 64-bit timestamps among
other things.
We already compile stat64 only on those architectures that need it,
but newstat is always built, including on those that don't reference
it. This adds a new __ARCH_WANT_NEW_STAT symbol along the lines of
__ARCH_WANT_OLD_STAT and __ARCH_WANT_STAT64 to control compilation of
newstat. All architectures that need it use an explict define, the
others now get a little bit smaller, and future architecture (including
64-bit targets) won't ever see it.
This patch causes my riscv boot tests to crash in -next
Ah, thanks for running these!
sbin/init: error while loading shared libraries: libc.so.6: cannot stat shared
object: Error 38
Kernel panic - not syncing: Attempted to kill init! exitcode=0x00007f00
The following change fixes the problem for me, but of course I have no idea
if it is correct. Copying RISC-V maintainers for input.
Guenter
---
diff --git a/arch/riscv/include/asm/unistd.h b/arch/riscv/include/asm/unistd.h
index 0caea01d5cca..eff7aa9aa163 100644
--- a/arch/riscv/include/asm/unistd.h
+++ b/arch/riscv/include/asm/unistd.h
@@ -16,6 +16,7 @@
* be included multiple times. See uapi/asm/syscalls.h for more info.
*/
+#define __ARCH_WANT_NEW_STAT
#define __ARCH_WANT_SYS_CLONE
#include <uapi/asm/unistd.h>
#include <uapi/asm/syscalls.h>
I'm afraid I'm not sure what the right thing to do here is either, but from the patch description it does
seem like we should have this guarded by an "#ifdef CONFIG_32BIT" so we can keep it out of our
32-bit ABI (which isn't in glibc yet, so isn't stable) in favor of statx() (or maybe stat64()?). The one
problem here is that I can't find "newstat" anywhere in glibc to verify it's actually supposed to
be part of our 64-bit ABI, though I can find a bunch of references to "statx" that seem to indicate
it's meant to be present.
That said, assuming you don't have anything wacky going on in userspace if this
breaks the ABI then it breaks the ABI, so however newstat got into a binary we
still need to keep it around. Poking around my Fedora glibc image I see
userspace is a root file system built with buildroot (modified to support
riscv64),
using glibc 2.26. Nothing wacky, sorry.
Guenter
