Message ID | 1293015862-3678-1-git-send-email-holler@ahsoftware.de |
---|---|
State | Changes Requested |
Headers | show |
On 22.12.2010 12:04, Alexander Holler wrote: > 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. > > I haven't add the definitions which are using a memory barrier because I haven't found > a place in the kernel where they were actually enabled (CONFIG_ARM_DMA_MEM_BUFFERABLE). > > Signed-off-by: Alexander Holler<holler@ahsoftware.de> This patch seems to be the same as the proposal from Wolfgang http://lists.denx.de/pipermail/u-boot/2010-December/084122.html So we shouldn't drop his Signed-off-by: Wolfgang Denk <wd@denx.de> Besides of this Acked-by: Dirk Behme <dirk.behme@googlemail.com> Thanks Dirk > --- > arch/arm/include/asm/io.h | 20 ++++++++++++++------ > 1 files changed, 14 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > index ff1518e..068ed17 100644 > --- a/arch/arm/include/asm/io.h > +++ b/arch/arm/include/asm/io.h > @@ -125,13 +125,21 @@ extern inline void __raw_readsl(unsigned int addr, void *data, int longlen) > #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) do { __iowmb(); __arch_putb(v,c); } while (0) > +#define writew(v,c) do { __iowmb(); __arch_putw(v,c); } while (0) > +#define writel(v,c) do { __iowmb(); __arch_putl(v,c); } while (0) > > -#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
Hello, Am 22.12.2010 15:50, schrieb Dirk Behme: > This patch seems to be the same as the proposal from Wolfgang > > http://lists.denx.de/pipermail/u-boot/2010-December/084122.html > Exactly. > So we shouldn't drop his > > Signed-off-by: Wolfgang Denk <wd@denx.de> > Sorry, I haven't seen that Signed-Off and I have not seen that the message includes a complete patch. I've only seen the fix for write* while (quickly) reading the msg and doing the tests afterwards. > Besides of this > > Acked-by: Dirk Behme <dirk.behme@googlemail.com> > And that I haven't added because the patch changed. Should I send a new message with that Singed-Off and Acked-by? Regards, Alexander
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index ff1518e..068ed17 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -125,13 +125,21 @@ extern inline void __raw_readsl(unsigned int addr, void *data, int longlen) #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) do { __iowmb(); __arch_putb(v,c); } while (0) +#define writew(v,c) do { __iowmb(); __arch_putw(v,c); } while (0) +#define writel(v,c) do { __iowmb(); __arch_putl(v,c); } while (0) -#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
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. I haven't add the definitions which are using a memory barrier because I haven't found a place in the kernel where they were actually enabled (CONFIG_ARM_DMA_MEM_BUFFERABLE). Signed-off-by: Alexander Holler <holler@ahsoftware.de> --- arch/arm/include/asm/io.h | 20 ++++++++++++++------ 1 files changed, 14 insertions(+), 6 deletions(-)