On 02/12/19 at 11:03pm, Kazuhito Hagio wrote: > > On 2/12/2019 2:59 PM, Bhupesh Sharma wrote: > > BTW, in the makedumpfile enablement patch thread for ARMv8.2 LVA > > (which I sent out for 52-bit User space VA enablement) (see [0]), Kazu > > mentioned that the changes look necessary. > > > > [0]. http://lists.infradead.org/pipermail/kexec/2019-February/022431.html > > > > > The increased 'PTRS_PER_PGD' value for such cases needs to be then > > > > calculated as is done by the underlying kernel (see > > > > 'arch/arm64/include/asm/pgtable-hwdef.h' for details): > > > > > > > > #define PTRS_PER_PGD (1 << (MAX_USER_VA_BITS - PGDIR_SHIFT)) > > Yes, this is the reason why makedumpfile needs the MAX_USER_VA_BITS. > It is used for pgd_index() also in makedumpfile to walk page tables. > > /* to find an entry in a page-table-directory */ > #define pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)) Since Dave mentioned crash tool does not need it, but crash should also travel the pg tables. If this is really necessary it would be good to describe what will happen without the patch, eg. some user visible error from an actual test etc. > > Thanks, > Kazu > > > > > > > > > Also, note that 'arch/arm64/include/asm/memory.h' defines 'MAX_USER_VA_BITS' > > > > as 'VA_BITS' in case 'CONFIG_ARM64_USER_VA_BITS_52' is set to 'n': > > > > > > > > #ifdef CONFIG_ARM64_USER_VA_BITS_52 > > > > #define MAX_USER_VA_BITS 52 > > > > #else > > > > #define MAX_USER_VA_BITS VA_BITS > > > > #endif > > > > > > > > So, makedumpfile will need this symbol exported in vmcore to make the above > > > > determination. > > > > > > > > [0]. http://lists.infradead.org/pipermail/kexec/2019-February/022425.html > > > > > > > > Thanks, > > > > Bhupesh > > > > > > Thanks > > > Dave > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
