With ARMv8.2-LVA and LPA architecture extensions, arm64 hardware which supports these extensions can support upto 52-bit virtual and 52-bit physical addresses respectively. Since at the moment we enable the support of these extensions via CONFIG flags, e.g. - LPA via CONFIG_ARM64_PA_BITS_52 there are no clear mechanisms in user-space right now to deteremine these CONFIG flag values and also determine the PARange and VARange address values. User-space tools like 'makedumpfile' and 'crash-utility' can instead use the 'MAX_USER_VA_BITS' and 'MAX_PHYSMEM_BITS' values to determine the maximum virtual address and physical address (respectively) supported by underlying kernel. A reference 'makedumpfile' implementation which uses this approach to determining the maximum physical address is available in [0]. [0]. https://github.com/bhupesh-sharma/makedumpfile/blob/52-bit-pa-support-via-vmcore-v1/arch/arm64.c#L490 Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: James Morse <james.morse@xxxxxxx> Signed-off-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> --- arch/arm64/kernel/crash_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kernel/crash_core.c b/arch/arm64/kernel/crash_core.c index ca4c3e12d8c5..ad231be5c0d8 100644 --- a/arch/arm64/kernel/crash_core.c +++ b/arch/arm64/kernel/crash_core.c @@ -10,6 +10,8 @@ void arch_crash_save_vmcoreinfo(void) { VMCOREINFO_NUMBER(VA_BITS); + VMCOREINFO_NUMBER(MAX_USER_VA_BITS); + VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS); /* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */ vmcoreinfo_append_str("NUMBER(kimage_voffset)=0x%llx\n", kimage_voffset); -- 2.7.4 _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
