On Thu, Oct 15, 2020 at 09:40:05AM +0200, Michael Tretter wrote: > On Wed, 14 Oct 2020 18:33:25 +0200, Ahmad Fatoum wrote: > > On 10/14/20 5:08 PM, Michael Tretter wrote: > > > If the SDRAM is mapped to address 0x0 and an image should be loaded to > > > to the SDRAM without offset, Barebox would normally trap the access as a > > > null pointer. > > > > > > However, since Linux kernel commit cfa7ede20f13 ("arm64: set TEXT_OFFSET > > > to 0x0 in preparation for removing it entirely") no offset is the > > > default for arm64. Therefore, copying the image to 0x0 of the SDRAM is > > > necessary. > > > > > > Disable the zero page trap for copying an image to address 0x0. > > > > > > Signed-off-by: Michael Tretter <m.tretter@xxxxxxxxxxxxxx> > > > --- > > > common/uimage.c | 18 ++++++++++++++++-- > > > 1 file changed, 16 insertions(+), 2 deletions(-) > > > > > > diff --git a/common/uimage.c b/common/uimage.c > > > index a84b8fddc4e7..b1e9b402e98a 100644 > > > --- a/common/uimage.c > > > +++ b/common/uimage.c > > > @@ -27,6 +27,7 @@ > > > #include <rtc.h> > > > #include <filetype.h> > > > #include <memory.h> > > > +#include <zero_page.h> > > > > > > static inline int uimage_is_multi_image(struct uimage_handle *handle) > > > { > > > @@ -359,7 +360,13 @@ static int uimage_sdram_flush(void *buf, unsigned int len) > > > } > > > } > > > > > > - memcpy(uimage_buf + uimage_size, buf, len); > > > + if (zero_page_contains((unsigned long)uimage_buf + uimage_size)) { > > > + zero_page_disable(); > > > + memcpy(uimage_buf + uimage_size, buf, len); > > > + zero_page_enable(); > > > > If this remains, please add a memcpy_notrap or something. > > Should I check the destination before calling memcpy_notrap or should I always > call the memcpy_notrap if there is a possibility to copy to 0x0 and check for > the destination within the function? > > I fear that having such a "simple" function would encourage to use it more > often. I would prefer to make the code to use it more clumsy and make it > (similar to data_abort_mask()) the responsibility of the caller to be aware > that bad things might happen when the zero_page is disabled. That's more a reason to hide that behind a function, because then you can easily catch and if necessary fix all users. Way easier than fixing all open coded places. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox