Hi Bhupesh,
On Mon, May 28, 2018 at 2:33 AM, Bhupesh Sharma <[email protected]> wrote: > Hi ARM64 maintainers, [...] > > 4. Since 'memstart_addr' indicates the start of physical RAM, we > randomize the same on basis of 'memstart_offset_seed' value above. > Also the 'memstart_addr' value is available in '/proc/kallsyms' and > hence can be accessed by user-space applications to read the > 'memstart_addr' value. User space can read, only when a system has either CONFIG_DEVMEM or CONFIG_PROC_KCORE enabled. But, we can have a system which has CONFIG_RANDOMIZE_BASE enabled but none of the kernel memory access interface (other than kdump/vmcore). > > 5. Now since the PAGE_OFFSET value is also used by several user space > tools (for e.g. makedumpfile tool uses the same to determine the start > of linear region and hence to read PT_NOTE fields from /proc/kcore), I > am not sure how to read the randomized value of the same in the KASLR > enabled case. > Do we have a use case other than makedumpfile (I mean where we do not have vmcore access)? For makedumpfile, we have following information in vmcore, and I hope, that should be sufficient to find physical address of any symbol from vmcore. 358 VMCOREINFO_NUMBER(VA_BITS); 359 /* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */ 360 vmcoreinfo_append_str("NUMBER(kimage_voffset)=0x%llx\n", 361 kimage_voffset); 362 vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%llx\n", 363 PHYS_OFFSET); Regards Pratyush _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
