| Message ID | a82a48f72b8099c1ef6a32a63819619637797ef8.1500397441.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jul 25, 2017 at 11:55:43AM +0100, Robin Murphy wrote: > Implement the set of copy functions with guarantees of a clean cache > upon completion necessary to support the pmem driver. > > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/string.h | 4 ++++ > arch/arm64/include/asm/uaccess.h | 12 ++++++++++ > arch/arm64/lib/Makefile | 2 ++ > arch/arm64/lib/uaccess_flushcache.c | 47 +++++++++++++++++++++++++++++++++++++ > 5 files changed, 66 insertions(+) > create mode 100644 arch/arm64/lib/uaccess_flushcache.c [...] > diff --git a/arch/arm64/lib/uaccess_flushcache.c b/arch/arm64/lib/uaccess_flushcache.c > new file mode 100644 > index 000000000000..b6ceafdb8b72 > --- /dev/null > +++ b/arch/arm64/lib/uaccess_flushcache.c > @@ -0,0 +1,47 @@ > +/* > + * Copyright (C) 2017 ARM Ltd. > + * > + * 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. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/uaccess.h> > +#include <asm/barrier.h> > +#include <asm/cacheflush.h> > + > +void memcpy_flushcache(void *dst, const void *src, size_t cnt) > +{ > + /* > + * We assume this should not be called with @dst pointing to > + * non-cacheable memory, such that we don't need an explicit > + * barrier to order the cache maintenance against the memcpy. > + */ > + memcpy(dst, src, cnt); > + __clean_dcache_area_pop(dst, cnt); > +} > +EXPORT_SYMBOL_GPL(memcpy_flushcache); > + > +void memcpy_page_flushcache(char *to, struct page *page, size_t offset, > + size_t len) > +{ > + memcpy_flushcache(to, page_address(page) + offset, len); > +} > + > +unsigned long __copy_user_flushcache(void *to, const void __user *from, > + unsigned long n) > +{ > + unsigned long rc = __arch_copy_from_user(to, from, n); I'm a bit nervous calling the bare user accessor here without an access_ok check beforehand. Can we rely on the caller having done the check for us? I tried to follow the breadcrumbs back out, but I noticed that other iov iterators (such as copy_from_iter) *do* do the bounds check, whereas the pmem version (copy_from_iter_nocache) doesn't appear to check the address. Is that right? Will
On Tue, Jul 25, 2017 at 12:55 PM, Robin Murphy <robin.murphy@arm.com> wrote: > Implement the set of copy functions with guarantees of a clean cache > upon completion necessary to support the pmem driver. > > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/string.h | 4 ++++ > arch/arm64/include/asm/uaccess.h | 12 ++++++++++ > arch/arm64/lib/Makefile | 2 ++ > arch/arm64/lib/uaccess_flushcache.c | 47 +++++++++++++++++++++++++++++++++++++ > 5 files changed, 66 insertions(+) > create mode 100644 arch/arm64/lib/uaccess_flushcache.c It looks like Catalin applied part of this patch but forgot to add arch/arm64/lib/uaccess_flushcache.c Arnd
On Thu, Aug 10, 2017 at 12:58:45PM +0200, Arnd Bergmann wrote: > On Tue, Jul 25, 2017 at 12:55 PM, Robin Murphy <robin.murphy@arm.com> wrote: > > Implement the set of copy functions with guarantees of a clean cache > > upon completion necessary to support the pmem driver. > > > > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > > --- > > arch/arm64/Kconfig | 1 + > > arch/arm64/include/asm/string.h | 4 ++++ > > arch/arm64/include/asm/uaccess.h | 12 ++++++++++ > > arch/arm64/lib/Makefile | 2 ++ > > arch/arm64/lib/uaccess_flushcache.c | 47 +++++++++++++++++++++++++++++++++++++ > > 5 files changed, 66 insertions(+) > > create mode 100644 arch/arm64/lib/uaccess_flushcache.c > > It looks like Catalin applied part of this patch but forgot to add > arch/arm64/lib/uaccess_flushcache.c Added it now, thanks.
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 0b0576a54724..e43a63b3d14b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -963,6 +963,7 @@ config ARM64_UAO config ARM64_PMEM bool "Enable support for persistent memory" select ARCH_HAS_PMEM_API + select ARCH_HAS_UACCESS_FLUSHCACHE help Say Y to enable support for the persistent memory API based on the ARMv8.2 DCPoP feature. diff --git a/arch/arm64/include/asm/string.h b/arch/arm64/include/asm/string.h index d0aa42907569..dd95d33a5bd5 100644 --- a/arch/arm64/include/asm/string.h +++ b/arch/arm64/include/asm/string.h @@ -52,6 +52,10 @@ extern void *__memset(void *, int, __kernel_size_t); #define __HAVE_ARCH_MEMCMP extern int memcmp(const void *, const void *, size_t); +#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE +#define __HAVE_ARCH_MEMCPY_FLUSHCACHE +void memcpy_flushcache(void *dst, const void *src, size_t cnt); +#endif #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 8f0a1de11e4a..bb056fee297c 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -347,4 +347,16 @@ extern long strncpy_from_user(char *dest, const char __user *src, long count); extern __must_check long strnlen_user(const char __user *str, long n); +#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE +struct page; +void memcpy_page_flushcache(char *to, struct page *page, size_t offset, size_t len); +extern unsigned long __must_check __copy_user_flushcache(void *to, const void __user *from, unsigned long n); + +static inline int __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size) +{ + kasan_check_write(dst, size); + return __copy_user_flushcache(dst, src, size); +} +#endif + #endif /* __ASM_UACCESS_H */ diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index c86b7909ef31..a0abc142c92b 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile @@ -17,3 +17,5 @@ CFLAGS_atomic_ll_sc.o := -fcall-used-x0 -ffixed-x1 -ffixed-x2 \ -fcall-saved-x10 -fcall-saved-x11 -fcall-saved-x12 \ -fcall-saved-x13 -fcall-saved-x14 -fcall-saved-x15 \ -fcall-saved-x18 + +lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o diff --git a/arch/arm64/lib/uaccess_flushcache.c b/arch/arm64/lib/uaccess_flushcache.c new file mode 100644 index 000000000000..b6ceafdb8b72 --- /dev/null +++ b/arch/arm64/lib/uaccess_flushcache.c @@ -0,0 +1,47 @@ +/* + * Copyright (C) 2017 ARM Ltd. + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/uaccess.h> +#include <asm/barrier.h> +#include <asm/cacheflush.h> + +void memcpy_flushcache(void *dst, const void *src, size_t cnt) +{ + /* + * We assume this should not be called with @dst pointing to + * non-cacheable memory, such that we don't need an explicit + * barrier to order the cache maintenance against the memcpy. + */ + memcpy(dst, src, cnt); + __clean_dcache_area_pop(dst, cnt); +} +EXPORT_SYMBOL_GPL(memcpy_flushcache); + +void memcpy_page_flushcache(char *to, struct page *page, size_t offset, + size_t len) +{ + memcpy_flushcache(to, page_address(page) + offset, len); +} + +unsigned long __copy_user_flushcache(void *to, const void __user *from, + unsigned long n) +{ + unsigned long rc = __arch_copy_from_user(to, from, n); + + /* See above */ + __clean_dcache_area_pop(to, n - rc); + return rc; +}
Implement the set of copy functions with guarantees of a clean cache upon completion necessary to support the pmem driver. Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/string.h | 4 ++++ arch/arm64/include/asm/uaccess.h | 12 ++++++++++ arch/arm64/lib/Makefile | 2 ++ arch/arm64/lib/uaccess_flushcache.c | 47 +++++++++++++++++++++++++++++++++++++ 5 files changed, 66 insertions(+) create mode 100644 arch/arm64/lib/uaccess_flushcache.c