| Message ID | 1367214005-14302-1-git-send-email-chanho.min@lge.com |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
On Mon, Apr 29, 2013 at 7:40 AM, Chanho Min <chanho.min@lge.com> wrote: > Some architectures need __clzsi2() or __clzdi2() for __builtin_clz and > It causes build failure. They can be implemented using the fls() and > overridden by linking arch-specific versions may not be implemented yet. > > Reference: https://lkml.org/lkml/2013/4/18/603 > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > Signed-off-by: Chanho Min <chanho.min@lge.com> Thanks, this fixes the link error on m68k, so Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 29 Apr 2013 14:40:05 +0900 Chanho Min <chanho.min@lge.com> wrote: > Some architectures need __clzsi2() or __clzdi2() for __builtin_clz and > It causes build failure. They can be implemented using the fls() and > overridden by linking arch-specific versions may not be implemented yet. > > Reference: https://lkml.org/lkml/2013/4/18/603 > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > Signed-off-by: Chanho Min <chanho.min@lge.com> > > ... > > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -23,7 +23,7 @@ lib-y += kobject.o klist.o > > obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ > bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \ > - gcd.o lcm.o list_sort.o uuid.o flex_array.o \ > + gcd.o lcm.o list_sort.o uuid.o flex_array.o clz.o\ > bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o > obj-y += string_helpers.o > obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o > diff --git a/lib/clz.c b/lib/clz.c > new file mode 100644 > index 0000000..5222b2d > --- /dev/null > +++ b/lib/clz.c > @@ -0,0 +1,36 @@ > +/* > + * lib/clz.c > + * > + * Copyright (C) 2013 Chanho Min <chanho.min@lge.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * __clzsi2/_clzdi2() can be overridden by linking arch-specific versions. > + */ > + > +#include <linux/export.h> > +#include <linux/kernel.h> > + > +int __weak __clzsi2(int val) > +{ > + return BITS_PER_LONG - fls(val); > +} > +EXPORT_SYMBOL(__clzsi2); > + > +#if BITS_PER_LONG == 32 > +int __weak __clzdi2(long val) > +{ > + return BITS_PER_LONG - fls((int)val); > +} > +EXPORT_SYMBOL(__clzdi2); > +#elif BITS_PER_LONG == 64 > +int __weak __clzdi2i(long val) This is a typo, surely? I'll switch it to __clzdi2. > +{ > + return BITS_PER_LONG - fls64((u64)val); > +} > +EXPORT_SYMBOL(__clzdi2); > +#else > +#error BITS_PER_LONG not 32 or 64 > +#endif -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 29 Apr 2013 09:20:25 +0200 Geert Uytterhoeven <geert@linux-m68k.org> wrote: > On Mon, Apr 29, 2013 at 7:40 AM, Chanho Min <chanho.min@lge.com> wrote: > > Some architectures need __clzsi2() or __clzdi2() for __builtin_clz and > > It causes build failure. They can be implemented using the fls() and > > overridden by linking arch-specific versions may not be implemented yet. > > > > Reference: https://lkml.org/lkml/2013/4/18/603 > > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > > Signed-off-by: Chanho Min <chanho.min@lge.com> > > Thanks, this fixes the link error on m68k, so > > Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> It doesn't work for alpha (gcc-4.4.4): ERROR: "__ctzdi2" [lib/lz4/lz4hc_compress.ko] undefined! ERROR: "__ctzdi2" [lib/lz4/lz4_compress.ko] undefined! akpm3:/usr/src/25> nm vmlinux|grep ctzd akpm3:/usr/src/25> I assume the linker threw the code away. How's about we stop using __builtin_ctz[ll]() altogether? Use N-fls()? btw, this: int __weak __clzsi2(int val) { return BITS_PER_LONG - fls(val); } looks wrong. It will give a different result for 32- and 64-bit. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Apr 30, 2013 at 11:46 PM, Andrew Morton <akpm@linux-foundation.org> wrote: > On Mon, 29 Apr 2013 09:20:25 +0200 Geert Uytterhoeven <geert@linux-m68k.org> wrote: >> On Mon, Apr 29, 2013 at 7:40 AM, Chanho Min <chanho.min@lge.com> wrote: >> > Some architectures need __clzsi2() or __clzdi2() for __builtin_clz and >> > It causes build failure. They can be implemented using the fls() and >> > overridden by linking arch-specific versions may not be implemented yet. >> > >> > Reference: https://lkml.org/lkml/2013/4/18/603 >> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> >> > Signed-off-by: Chanho Min <chanho.min@lge.com> >> >> Thanks, this fixes the link error on m68k, so >> >> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> > > It doesn't work for alpha (gcc-4.4.4): > > ERROR: "__ctzdi2" [lib/lz4/lz4hc_compress.ko] undefined! > ERROR: "__ctzdi2" [lib/lz4/lz4_compress.ko] undefined! > > akpm3:/usr/src/25> nm vmlinux|grep ctzd > akpm3:/usr/src/25> > > I assume the linker threw the code away. No, the link errors are for __ctzdi2, not __clzdi2. __ctzdi2 can be implemented using __ffs(). > How's about we stop using __builtin_ctz[ll]() altogether? Use N-fls()? That was my first suggestion ;-) > btw, this: > > int __weak __clzsi2(int val) > { > return BITS_PER_LONG - fls(val); > } > > looks wrong. It will give a different result for 32- and 64-bit. Indeed. It should be hardcoded 32. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
>No, the link errors are for __ctzdi2, not __clzdi2. >__ctzdi2 can be implemented using __ffs(). >> How's about we stop using __builtin_ctz[ll]() altogether? Use N-fls()? > >That was my first suggestion ;-) > Do we remove existing __builtin_ct[l]z? Some architecture's __builtin_clz will be more optimized than N-fls IMHO, This is not only about __builtin- but also supporting another libgcc functions in kernel. Some future user may need __clz[t]s[d]i2 symbol also. >> btw, this: >> >> int __weak __clzsi2(int val) >> { >> return BITS_PER_LONG - fls(val); >> } >> >> looks wrong. It will give a different result for 32- and 64-bit. > >Indeed. It should be hardcoded 32. > I will re-work this for 64-bit, and ctz also. Thanks Chanho Min -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/lib/Makefile b/lib/Makefile index af79e8c..e17b3ee 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -23,7 +23,7 @@ lib-y += kobject.o klist.o obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \ - gcd.o lcm.o list_sort.o uuid.o flex_array.o \ + gcd.o lcm.o list_sort.o uuid.o flex_array.o clz.o\ bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o obj-y += string_helpers.o obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o diff --git a/lib/clz.c b/lib/clz.c new file mode 100644 index 0000000..5222b2d --- /dev/null +++ b/lib/clz.c @@ -0,0 +1,36 @@ +/* + * lib/clz.c + * + * Copyright (C) 2013 Chanho Min <chanho.min@lge.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * __clzsi2/_clzdi2() can be overridden by linking arch-specific versions. + */ + +#include <linux/export.h> +#include <linux/kernel.h> + +int __weak __clzsi2(int val) +{ + return BITS_PER_LONG - fls(val); +} +EXPORT_SYMBOL(__clzsi2); + +#if BITS_PER_LONG == 32 +int __weak __clzdi2(long val) +{ + return BITS_PER_LONG - fls((int)val); +} +EXPORT_SYMBOL(__clzdi2); +#elif BITS_PER_LONG == 64 +int __weak __clzdi2i(long val) +{ + return BITS_PER_LONG - fls64((u64)val); +} +EXPORT_SYMBOL(__clzdi2); +#else +#error BITS_PER_LONG not 32 or 64 +#endif
Some architectures need __clzsi2() or __clzdi2() for __builtin_clz and It causes build failure. They can be implemented using the fls() and overridden by linking arch-specific versions may not be implemented yet. Reference: https://lkml.org/lkml/2013/4/18/603 Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Chanho Min <chanho.min@lge.com> --- lib/Makefile | 2 +- lib/clz.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+), 1 deletion(-) create mode 100644 lib/clz.c