Franck Bui-Huu wrote: > Currently memset() is used to fill a user space area (clear_user) or > kernel one (memset). These two functions don't have the same > prototype, the former returning the number of bytes not copied and the > latter returning the start address of the area to clear. This forces > memset() to actually returns two values in an unconventional way ie > the number of bytes not copied is given by $a2. Therefore clear_user() > needs to call memset() using inline assembly. > > Instead this patch creates __fill_user() which is the same as memset() > except it always returns the number of bytes not copied. This simplify > clear_user() and makes its definition saner. > > Also an out of line version of memset is given because gcc generates > some calls to it since builtin functions have been disabled. It allows > assembly code to call it too. > > Eventually __bzero() has been removed because it's not part of the > Linux uaccess API. And the nano-optimization it brings is not > worthing. > > Signed-off-by: Franck Bui-Huu <fbuihuu@xxxxxxxxx> > --- > arch/mips/kernel/mips_ksyms.c | 3 +- > arch/mips/lib/csum_partial.S | 2 +- > arch/mips/lib/memcpy.S | 2 +- > arch/mips/lib/memset.S | 49 ++++++++++++++++++++++++++-------------- > include/asm-mips/string.h | 7 +++++- > include/asm-mips/uaccess.h | 17 ++----------- > 6 files changed, 44 insertions(+), 36 deletions(-) > > diff --git a/arch/mips/kernel/mips_ksyms.c b/arch/mips/kernel/mips_ksyms.c > index 225755d..a801e09 100644 > --- a/arch/mips/kernel/mips_ksyms.c > +++ b/arch/mips/kernel/mips_ksyms.c > @@ -14,7 +14,6 @@ > #include <asm/pgtable.h> > #include <asm/uaccess.h> > > -extern void *__bzero(void *__s, size_t __count); > extern long __strncpy_from_user_nocheck_asm(char *__to, > const char *__from, long __len); > extern long __strncpy_from_user_asm(char *__to, const char *__from, > @@ -36,9 +35,9 @@ EXPORT_SYMBOL(kernel_thread); > /* > * Userspace access stuff. > */ > +EXPORT_SYMBOL(__fill_user); > EXPORT_SYMBOL(__copy_user); > EXPORT_SYMBOL(__copy_user_inatomic); > -EXPORT_SYMBOL(__bzero); > EXPORT_SYMBOL(__strncpy_from_user_nocheck_asm); > EXPORT_SYMBOL(__strncpy_from_user_asm); > EXPORT_SYMBOL(__strlen_user_nocheck_asm); > diff --git a/arch/mips/lib/csum_partial.S b/arch/mips/lib/csum_partial.S > index c0a77fe..8d3fa1e 100644 > --- a/arch/mips/lib/csum_partial.S > +++ b/arch/mips/lib/csum_partial.S > @@ -694,7 +694,7 @@ l_exc: > ADD dst, t0 # compute start address in a1 > SUB dst, src > /* > - * Clear len bytes starting at dst. Can't call __bzero because it > + * Clear len bytes starting at dst. Can't call memset because it > * might modify len. An inefficient loop for these rare times... > */ > beqz len, done > diff --git a/arch/mips/lib/memcpy.S b/arch/mips/lib/memcpy.S > index a526c62..425f2c3 100644 > --- a/arch/mips/lib/memcpy.S > +++ b/arch/mips/lib/memcpy.S > @@ -443,7 +443,7 @@ l_exc: > ADD dst, t0 # compute start address in a1 > SUB dst, src > /* > - * Clear len bytes starting at dst. Can't call __bzero because it > + * Clear len bytes starting at dst. Can't call memset because it > * might modify len. An inefficient loop for these rare times... > */ > beqz len, done > diff --git a/arch/mips/lib/memset.S b/arch/mips/lib/memset.S > index 3f8b8b3..cb6b83d 100644 > --- a/arch/mips/lib/memset.S > +++ b/arch/mips/lib/memset.S > @@ -46,17 +46,34 @@ > .endm > > /* > - * memset(void *s, int c, size_t n) > + * An outline version of memset, which should be used either by gcc or > + * by assembly code. > + */ > +NESTED(memset, 24, ra) > + PTR_ADDU sp, sp, -24 > + LONG_S a0, 16(sp) > + LONG_S ra, 20(sp) > + jal __fill_user > + LONG_L v0, 16(sp) > + LONG_L ra, 20(sp) > + PTR_ADDU sp, sp, 24 > + jr ra > +END(memset) This will break on 64bit kernels. Thiemo
