On Thu, Oct 25, 2018 at 08:15:15AM -0500, Rob Herring wrote: > +Ard > > On Thu, Oct 25, 2018 at 4:38 AM Mike Rapoport <rppt****@linux*****> wrote: > > > > On Wed, Oct 24, 2018 at 02:55:17PM -0500, Rob Herring wrote: > > > On Wed, Oct 24, 2018 at 2:33 PM Florian Fainelli <f.fai****@gmail*****> wrote: > > > > > > > > Hi all, > > > > > > > > While investigating why ARM64 required a ton of objects to be rebuilt > > > > when toggling CONFIG_DEV_BLK_INITRD, it became clear that this was > > > > because we define __early_init_dt_declare_initrd() differently and we do > > > > that in arch/arm64/include/asm/memory.h which gets included by a fair > > > > amount of other header files, and translation units as well. > > > > > > I scratch my head sometimes as to why some config options rebuild so > > > much stuff. One down, ? to go. :) > > > > > > > Changing the value of CONFIG_DEV_BLK_INITRD is a common thing with build > > > > systems that generate two kernels: one with the initramfs and one > > > > without. buildroot is one of these build systems, OpenWrt is also > > > > another one that does this. > > > > > > > > This patch series proposes adding an empty initrd.h to satisfy the need > > > > for drivers/of/fdt.c to unconditionally include that file, and moves the > > > > custom __early_init_dt_declare_initrd() definition away from > > > > asm/memory.h > > > > > > > > This cuts the number of objects rebuilds from 1920 down to 26, so a > > > > factor 73 approximately. > > > > > > > > Apologies for the long CC list, please let me know how you would go > > > > about merging that and if another approach would be preferable, e.g: > > > > introducing a CONFIG_ARCH_INITRD_BELOW_START_OK Kconfig option or > > > > something like that. > > > > > > There may be a better way as of 4.20 because bootmem is now gone and > > > only memblock is used. This should unify what each arch needs to do > > > with initrd early. We need the physical address early for memblock > > > reserving. Then later on we need the virtual address to access the > > > initrd. Perhaps we should just change initrd_start and initrd_end to > > > physical addresses (or add 2 new variables would be less invasive and > > > allow for different translation than __va()). The sanity checks and > > > memblock reserve could also perhaps be moved to a common location. > > > > > > Alternatively, given arm64 is the only oddball, I'd be fine with an > > > "if (IS_ENABLED(CONFIG_ARM64))" condition in the default > > > __early_init_dt_declare_initrd as long as we have a path to removing > > > it like the above option. > > > > I think arm64 does not have to redefine __early_init_dt_declare_initrd(). > > Something like this might be just all we need (completely untested, > > probably it won't even compile): > > > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > > index 9d9582c..e9ca238 100644 > > --- a/arch/arm64/mm/init.c > > +++ b/arch/arm64/mm/init.c > > @@ -62,6 +62,9 @@ s64 memstart_addr __ro_after_init = -1; > > phys_addr_t arm64_dma_phys_limit __ro_after_init; > > > > #ifdef CONFIG_BLK_DEV_INITRD > > + > > +static phys_addr_t initrd_start_phys, initrd_end_phys; > > + > > static int __init early_initrd(char *p) > > { > > unsigned long start, size; > > @@ -71,8 +74,8 @@ static int __init early_initrd(char *p) > > if (*endp == ',') { > > size = memparse(endp + 1, NULL); > > > > - initrd_start = start; > > - initrd_end = start + size; > > + initrd_start_phys = start; > > + initrd_end_phys = end; > > } > > return 0; > > } > > @@ -407,14 +410,27 @@ void __init arm64_memblock_init(void) > > memblock_add(__pa_symbol(_text), (u64)(_end - _text)); > > } > > > > - if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && initrd_start) { > > + if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && > > + (initrd_start || initrd_start_phys)) { > > + /* > > + * FIXME: ensure proper precendence between > > + * early_initrd and DT when both are present > > Command line takes precedence, so just reverse the order. > > > + */ > > + if (initrd_start) { > > + initrd_start_phys = __phys_to_virt(initrd_start); > > + initrd_end_phys = __phys_to_virt(initrd_end); > > AIUI, the original issue was doing the P2V translation was happening > too early and the VA could be wrong if the linear range is adjusted. > So I don't think this would work. Probably things have changed since then, but in the current code there is initrd_start = __phys_to_virt(initrd_start); and in between only the code related to CONFIG_RANDOMIZE_BASE, so I believe it's safe to use __phys_to_virt() here as well. > I suppose you could convert the VA back to a PA before any adjustments > and then back to a VA again after. But that's kind of hacky. 2 wrongs > making a right. > > > + } else if (initrd_start_phys) { > > + initrd_start = __va(initrd_start_phys); > > + initrd_end = __va(initrd_start_phys); > > + } > > + > > /* > > * Add back the memory we just removed if it results in the > > * initrd to become inaccessible via the linear mapping. > > * Otherwise, this is a no-op > > */ > > - u64 base = initrd_start & PAGE_MASK; > > - u64 size = PAGE_ALIGN(initrd_end) - base; > > + u64 base = initrd_start_phys & PAGE_MASK; > > + u64 size = PAGE_ALIGN(initrd_end_phys) - base; > > > > /* > > * We can only add back the initrd memory if we don't end up > > @@ -458,7 +474,7 @@ void __init arm64_memblock_init(void) > > * pagetables with memblock. > > */ > > memblock_reserve(__pa_symbol(_text), _end - _text); > > -#ifdef CONFIG_BLK_DEV_INITRD > > +#if 0 > > if (initrd_start) { > > memblock_reserve(initrd_start, initrd_end - initrd_start); > > > > > > > Rob > > > > > > > -- > > Sincerely yours, > > Mike. > > > -- Sincerely yours, Mike.
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