-----Original Message----- > Considering the following related commit order > > b6d00d47e81a arm64: mm: Introduce 52-bit Kernel VAs (2) > ce3aaed87344 arm64: mm: Modify calculation of VMEMMAP_SIZE > c8b6d2ccf9b1 arm64: mm: Separate out vmemmap > c812026c54cf arm64: mm: Logic to make offset_ttbr1 conditional > 5383cc6efed1 arm64: mm: Introduce vabits_actual > 90ec95cda91a arm64: mm: Introduce VA_BITS_MIN > 99426e5e8c9f arm64: dump: De-constify VA_START and KASAN_SHADOW_START > 6bd1d0be0e97 arm64: kasan: Switch to using KASAN_SHADOW_OFFSET > 14c127c957c1 arm64: mm: Flip kernel VA space (1) > > And > #define _PAGE_END(va) (-(UL(1) << ((va) - 1))) > #define PAGE_OFFSET (((0xffffffffffffffffUL) - ((1UL) << (vabits_actual - 1)) + 1)) //old > #define PAGE_OFFSET (-(1UL << vabits_actual)) //new > > before (1), SYMBOL(_text) < PAGE_OFFSET, afterward, SYMBOL(_text) > PAGE_END == "old PAGE_OFFSET" > > So the comparasion of kernel version can be replaced by > if SYMBOL(_text) > PAGE_END > info->page_offset = new PAGE_OFFSET > else > info->page_offset = old PAGE_OFFSET Oh, if we use PAGE_END(VA_BITS_MIN) here, which was actually changed in 5.11 from PAGE_END(vabits_actual), that sounds good to me. Excellent! I've been splitting and rewriting this patch of Bhupesh to remove some parts I mentioned and for easier review and adding my ideas [1], though still halfway. I'd like to try taking Pingfan's idea in. [1] https://github.com/k-hagio/makedumpfile/commits/arm64.kh.test2 BTW, we have one more challenge, for 5.4+ kernels without NUMBER(TCR_EL1_T1SZ), I'm thinking about using SYMBOL(mem_section) to get vabits_actual, because it should be an address in kernel linear space. + if (NUMBER(TCR_EL1_T1SZ) != NOT_FOUND_NUMBER) { + vabits_actual = 64 - NUMBER(TCR_EL1_T1SZ); + DEBUG_MSG("vabits_actual : %d (vmcoreinfo)\n", vabits_actual); + } else if ((info->kernel_version >= KERNEL_VERSION(5, 4, 0)) && + (va_bits == 52) && (SYMBOL(mem_section) != NOT_FOUND_SYMBOL)) { + /* + * Linux 5.4 through 5.10 have the following linear space: + * 48-bit: 0xffff000000000000 - 0xffff7fffffffffff + * 58-bit: 0xfff0000000000000 - 0xfff7ffffffffffff + */ + if (SYMBOL(mem_section) & (1UL << (52 - 1))) + vabits_actual = 48; + else + vabits_actual = 52; + } else { + vabits_actual = va_bits; + DEBUG_MSG("vabits_actual : %d (same as va_bits)\n", vabits_actual); + } This might not work with 5.11, but work through 5.10. Any comments? Thanks, Kazu _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
