Message ID | 1294611584-6098-1-git-send-email-wd@denx.de |
---|---|
State | Accepted |
Commit | 3c0659b535b075be124c3d2a0714e55e65c46737 |
Delegated to: | Albert ARIBAUD |
Headers | show |
Am 09.01.2011 23:19, schrieb Wolfgang Denk: > From: Alexander Holler <holler@ahsoftware.de> > > gcc 4.5.1 seems to ignore (at least some) volatile definitions, > avoid that as done in the kernel. > > Reading C99 6.7.3 8 and the comment 114) there, I think it is a bug of that > gcc version to ignore the volatile type qualifier used e.g. in __arch_getl(). > Anyway, using a definition as in the kernel headers avoids such optimizations when > gcc 4.5.1 is used. > > Maybe the headers as used in the current linux-kernel should be used, > but to avoid large changes, I've just added a small change to the current headers. > > Signed-off-by: Alexander Holler <holler@ahsoftware.de> > Signed-off-by: Dirk Behme <dirk.behme@googlemail.com> > Signed-off-by: Wolfgang Denk <wd@denx.de> > Cc: Alessandro Rubini <rubini-list@gnudd.com> > --- > arch/arm/include/asm/io.h | 32 ++++++++++++++++++++------------ > 1 files changed, 20 insertions(+), 12 deletions(-) > > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > index ff1518e..3886f15 100644 > --- a/arch/arm/include/asm/io.h > +++ b/arch/arm/include/asm/io.h > @@ -117,21 +117,29 @@ extern inline void __raw_readsl(unsigned int addr, void *data, int longlen) > *buf++ = __arch_getl(addr); > } > > -#define __raw_writeb(v,a) __arch_putb(v,a) > -#define __raw_writew(v,a) __arch_putw(v,a) > -#define __raw_writel(v,a) __arch_putl(v,a) > +#define __raw_writeb(v,a) __arch_putb(v,a) > +#define __raw_writew(v,a) __arch_putw(v,a) > +#define __raw_writel(v,a) __arch_putl(v,a) > > -#define __raw_readb(a) __arch_getb(a) > -#define __raw_readw(a) __arch_getw(a) > -#define __raw_readl(a) __arch_getl(a) > +#define __raw_readb(a) __arch_getb(a) > +#define __raw_readw(a) __arch_getw(a) > +#define __raw_readl(a) __arch_getl(a) > > -#define writeb(v,a) __arch_putb(v,a) > -#define writew(v,a) __arch_putw(v,a) > -#define writel(v,a) __arch_putl(v,a) > +/* > + * TODO: The kernel offers some more advanced versions of barriers, it might > + * have some advantages to use them instead of the simple one here. > + */ > +#define dmb() __asm__ __volatile__ ("" : : : "memory") > +#define __iormb() dmb() > +#define __iowmb() dmb() > + > +#define writeb(v,c) ({ __iowmb(); __arch_putb(v,c); v; }) > +#define writew(v,c) ({ __iowmb(); __arch_putw(v,c); v; }) > +#define writel(v,c) ({ __iowmb(); __arch_putl(v,c); v; }) > > -#define readb(a) __arch_getb(a) > -#define readw(a) __arch_getw(a) > -#define readl(a) __arch_getl(a) > +#define readb(c) ({ u8 __v = __arch_getb(c); __iormb(); __v; }) > +#define readw(c) ({ u16 __v = __arch_getw(c); __iormb(); __v; }) > +#define readl(c) ({ u32 __v = __arch_getl(c); __iormb(); __v; }) > > /* > * The compiler seems to be incapable of optimising constants Tested-by: Thomas Weber <weber@corscience.de> on Devkit8000 with codesourcery arm2010.09 (gcc4.5.1) and arm2010q1 (gcc 4.4.1)
Am 09.01.2011 23:19, schrieb Wolfgang Denk: > gcc 4.5.1 seems to ignore (at least some) volatile definitions, > avoid that as done in the kernel. Have had a look at the asm generated by gcc 4.5.1, looks good. The wrong optimization in arch/arm/cpu/armv7/omap3/clock.c is gone and the writeb in drivers/mtd/nand/omap_gpmc.c doesn't have the problem as the v1-patch. Reagards, Alexander
Dear Alexander Holler, In message <4D2DCB18.20409@ahsoftware.de> you wrote: > Am 09.01.2011 23:19, schrieb Wolfgang Denk: > > > gcc 4.5.1 seems to ignore (at least some) volatile definitions, > > avoid that as done in the kernel. > > Have had a look at the asm generated by gcc 4.5.1, looks good. > > The wrong optimization in arch/arm/cpu/armv7/omap3/clock.c is gone and > the writeb in drivers/mtd/nand/omap_gpmc.c doesn't have the problem as > the v1-patch. Thanks - but please send a formal Acked-by: and/or Tested-by: . Best regards, Wolfgang Denk
Am 12.01.2011 17:40, schrieb Wolfgang Denk: > Dear Alexander Holler, > > In message<4D2DCB18.20409@ahsoftware.de> you wrote: >> Am 09.01.2011 23:19, schrieb Wolfgang Denk: >> >>> gcc 4.5.1 seems to ignore (at least some) volatile definitions, >>> avoid that as done in the kernel. >> >> Have had a look at the asm generated by gcc 4.5.1, looks good. >> >> The wrong optimization in arch/arm/cpu/armv7/omap3/clock.c is gone and >> the writeb in drivers/mtd/nand/omap_gpmc.c doesn't have the problem as >> the v1-patch. > > Thanks - but please send a formal Acked-by: and/or Tested-by: . Oh, as I'm still listed as the author, I thought that isn't necessary. I don't know if I should paste the whole patch (this is my first ack ;) ), but here are both: Acked-by: Alexander Holler <holler@ahsoftware.de> Tested-by: Alexander Holler <holler@ahsoftware.de> Regards, Alexander
Le 12/01/2011 17:49, Alexander Holler a écrit : >>>> Signed-off-by: Alexander Holler <holler@ahsoftware.de> >>>> Signed-off-by: Dirk Behme <dirk.behme@googlemail.com> >>>> Signed-off-by: Wolfgang Denk <wd@denx.de> >>> Tested-by: Thomas Weber <weber@corscience.de> > Acked-by: Alexander Holler<holler@ahsoftware.de> > Tested-by: Alexander Holler<holler@ahsoftware.de> Applied to u-boot-arm, thanks. Amicalement,
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index ff1518e..3886f15 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -117,21 +117,29 @@ extern inline void __raw_readsl(unsigned int addr, void *data, int longlen) *buf++ = __arch_getl(addr); } -#define __raw_writeb(v,a) __arch_putb(v,a) -#define __raw_writew(v,a) __arch_putw(v,a) -#define __raw_writel(v,a) __arch_putl(v,a) +#define __raw_writeb(v,a) __arch_putb(v,a) +#define __raw_writew(v,a) __arch_putw(v,a) +#define __raw_writel(v,a) __arch_putl(v,a) -#define __raw_readb(a) __arch_getb(a) -#define __raw_readw(a) __arch_getw(a) -#define __raw_readl(a) __arch_getl(a) +#define __raw_readb(a) __arch_getb(a) +#define __raw_readw(a) __arch_getw(a) +#define __raw_readl(a) __arch_getl(a) -#define writeb(v,a) __arch_putb(v,a) -#define writew(v,a) __arch_putw(v,a) -#define writel(v,a) __arch_putl(v,a) +/* + * TODO: The kernel offers some more advanced versions of barriers, it might + * have some advantages to use them instead of the simple one here. + */ +#define dmb() __asm__ __volatile__ ("" : : : "memory") +#define __iormb() dmb() +#define __iowmb() dmb() + +#define writeb(v,c) ({ __iowmb(); __arch_putb(v,c); v; }) +#define writew(v,c) ({ __iowmb(); __arch_putw(v,c); v; }) +#define writel(v,c) ({ __iowmb(); __arch_putl(v,c); v; }) -#define readb(a) __arch_getb(a) -#define readw(a) __arch_getw(a) -#define readl(a) __arch_getl(a) +#define readb(c) ({ u8 __v = __arch_getb(c); __iormb(); __v; }) +#define readw(c) ({ u16 __v = __arch_getw(c); __iormb(); __v; }) +#define readl(c) ({ u32 __v = __arch_getl(c); __iormb(); __v; }) /* * The compiler seems to be incapable of optimising constants