Re: [PATCH v8 02/17] xen: introduce generic non-atomic test_*bit()

[Oleksii <oleksii.kurochko@xxxxxxxxx>]

On Thu, 2024-04-25 at 17:35 +0200, Jan Beulich wrote:
> >   #include <asm/bitops.h>
> >   
> > +#ifndef arch_check_bitop_size
> > +#define arch_check_bitop_size(addr)
> 
> Can this really do nothing? Passing the address of an object smaller
> than
> bitop_uint_t will read past the object in the generic__*_bit()
> functions.
It seems RISC-V isn' happy with the following generic definition:
   extern void __bitop_bad_size(void);
   
   /* --------------------- Please tidy above here --------------------
   - */
   
   #include <asm/bitops.h>
   
   #ifndef arch_check_bitop_size
   
   #define bitop_bad_size(addr) sizeof(*(addr)) < sizeof(bitop_uint_t)
   
   #define arch_check_bitop_size(addr) \
       if ( bitop_bad_size(addr) ) __bitop_bad_size();
   
   #endif /* arch_check_bitop_size */

The following errors occurs. bitop_uint_t for RISC-V is defined as
unsigned long for now:
    ./common/symbols-dummy.o -o ./.xen-syms.0
riscv64-linux-gnu-ld: prelink.o: in function `atomic_sub':
/build/xen/./arch/riscv/include/asm/atomic.h:152: undefined reference
to `__bitop_bad_size'
riscv64-linux-gnu-ld: prelink.o: in function `evtchn_check_pollers':
/build/xen/common/event_channel.c:1531: undefined reference to
`__bitop_bad_size'
riscv64-linux-gnu-ld: /build/xen/common/event_channel.c:1521: undefined
reference to `__bitop_bad_size'
riscv64-linux-gnu-ld: prelink.o: in function `evtchn_init':
/build/xen/common/event_channel.c:1541: undefined reference to
`__bitop_bad_size'
riscv64-linux-gnu-ld: prelink.o: in function `_read_lock':
/build/xen/./include/xen/rwlock.h:94: undefined reference to
`__bitop_bad_size'
riscv64-linux-gnu-ld:
prelink.o:/build/xen/./arch/riscv/include/asm/atomic.h:195: more
undefined references to `__bitop_bad_size' follow
riscv64-linux-gnu-ld: ./.xen-syms.0: hidden symbol `__bitop_bad_size'
isn't defined
riscv64-linux-gnu-ld: final link failed: bad value
make[2]: *** [arch/riscv/Makefile:15: xen-syms] Error 1

~ Oleksii