On Sun, Jun 28, 2020 at 10:59 AM Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
>
> On Sat, 27 Jun 2020 16:20:02 +0000
> guoren@xxxxxxxxxx wrote:
>
> > From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> >
> > Unfortunately, the current code couldn't be compiled, because
> > BUILD_BUG_ON needs a static defined value, not a dynamic
> > variable with a0 regs. Just use it inline as a solution.
> >
> > CC arch/riscv/kernel/patch.o
> > In file included from ./include/linux/kernel.h:11,
> > from ./include/linux/list.h:9,
> > from ./include/linux/preempt.h:11,
> > from ./include/linux/spinlock.h:51,
> > from arch/riscv/kernel/patch.c:6:
> > In function ‘fix_to_virt’,
> > inlined from ‘patch_map’ at arch/riscv/kernel/patch.c:37:17:
> > ./include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_205’ declared with attribute error: BUILD_BUG_ON failed: idx >= __end_of_fixed_addresses
> > _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> > ^
> > ./include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
> > prefix ## suffix(); \
> > ^~~~~~
> > ./include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
> > _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> > ^~~~~~~~~~~~~~~~~~~
> > ./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
> > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> > ^~~~~~~~~~~~~~~~~~
> > ./include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
> > BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
> > ^~~~~~~~~~~~~~~~
> > ./include/asm-generic/fixmap.h:32:2: note: in expansion of macro ‘BUILD_BUG_ON’
> > BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
> > ^~~~~~~~~~~~
> >
> > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> > Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > Cc: Zong Li <zong.li@xxxxxxxxxx>
> > ---
> > arch/riscv/kernel/patch.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
> > index d4a64df..f8e84f2 100644
> > --- a/arch/riscv/kernel/patch.c
> > +++ b/arch/riscv/kernel/patch.c
> > @@ -20,7 +20,7 @@ struct patch_insn {
> > };
> >
> > #ifdef CONFIG_MMU
> > -static void *patch_map(void *addr, int fixmap)
> > +static inline void *patch_map(void *addr, int fixmap)
>
> Would we be better to use "__always_inline" as same as fix_to_virt?
Ok
> And also, could you add a comment why we need to make it inline?
I've mentioned in comment:
> > BUILD_BUG_ON needs a static defined value, not a dynamic
> > variable with a0 regs.
idx must be a const unsigned int or it will cause compile error with
BUILD_BUG_ON.
/*
* 'index to address' translation. If anyone tries to use the idx
* directly without translation, we catch the bug with a NULL-deference
* kernel oops. Illegal ranges of incoming indices are caught too.
*/
static __always_inline unsigned long fix_to_virt(const unsigned int idx)
{
BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
return __fix_to_virt(idx);
}
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
