Re: [Crash-utility] using crash for ARM

My comment for the fix would be something like below. /* The unity-mapped region is mapped using 1MB pages, hence 1-level translation     if bit 20 is set, we are 1MB apart physically, hence we move the page_dir     in case bit 20 is set. */ if (bit(vaddr,20))     page_dir = page_dir + 1; does it make sense ? Regards, Oza. ________________________________ From: Mika Westerberg <mika.westerberg(a)iki.fi&gt; To: Dave Anderson <anderson(a)redhat.com&gt; Cc: paawan oza <paawan1982(a)yahoo.com>; "Discussion list for crash utility usage, maintenance and development" <crash-utility(a)redhat.com>; Thomas Fänge <thomas.fange(a)sonymobile.com>; jan karlsson <jan.karlsson(a)sonymobile.com&gt; Sent: Thursday, 4 October 2012 11:56 AM Subject: Re: [Crash-utility] using crash for ARM On Wed, Oct 03, 2012 at 09:45:51AM -0400, Dave Anderson wrote: The unity-mapped region is mapped using 1MB pages. However, we actually have (when using the Linux ARM 2-level translation scheme): see arch/arm/include/asm/pgtable-2level.h: #define PMD_SHIFT              21 #define PGDIR_SHIFT            21 #define PTRS_PER_PGD            2048 So we have 2048 entries in a PGD instead of 4096 making a PGD entry an array of "two pointers". Anyway as you and Paawan suggested it looks like a bug - we always use the first entry instead of the second given that bit 20 is set in the virtual address. Paawan, your fix looks sane to me but can you add a small comment describing why this is done?