On 10/25/18 2:13 PM, Rob Herring wrote: > On Thu, Oct 25, 2018 at 12:30 PM Mike Rapoport <r...@linux.ibm.com> wrote: >> >> 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 <r...@linux.ibm.com> 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.faine...@gmail.com> >>>>> 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); > > BTW, I think you meant virt_to_phys() here? > >>> >>> 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. > > Here is fine yes, but I believe it was the the phys to virt in the DT > code before adjusting the linear range that was the problem.
FWIW, I am extracting the ARM implementation that parses the initrd early command line parameter and the "setup" code doing the page boundary alignment and memblock checking into a helper into lib/ that other architectures can re-use. So far, this removes the need for unicore32, arc and arm to duplicate essentially the same logic. -- Florian