Messages in this thread | | | Date | Mon, 20 Mar 2017 10:26:19 +0800 | From | Wei Yang <> | Subject | Re: [PATCH] x86/mm: trivial code cleanup for memory_map_top_doown() |
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Hi, Borislav
Do you still have some concern on this change?
On Tue, Mar 14, 2017 at 11:56:39AM +0800, Wei Yang wrote: >On Mon, Mar 13, 2017 at 07:50:21PM +0100, Borislav Petkov wrote: >>On Fri, Feb 17, 2017 at 10:30:33PM +0800, Wei Yang wrote: >>> In case (last_start <= step_size), start is for sure to be 0. So, it is >> > >Hmm, I may write it more specific: > >"start" is for sure to be set to 0 with round_down(last_start - 1, step_size). > >>Well, lemme see: >> >>[ 0.000000] memory_map_top_down: entry, [0x100000:0x7ffdf000) >>[ 0.000000] memory_map_top_down: addr: 0x7fc00000, real_end: 0x7fe00000 >>[ 0.000000] memory_map_top_down: last_start: 0x40000000 <= step_size: 0x2000000000, start: 0x40000000 >> ^^^^^^^^^^ >>It doesn't look like 0 to me. >> >>--- >>diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c >>index 2193799ca800..d3b02a416df3 100644 >>--- a/arch/x86/mm/init.c >>+++ b/arch/x86/mm/init.c >>@@ -527,8 +531,13 @@ static void __init memory_map_top_down(unsigned long map_start, >> start = round_down(last_start - 1, step_size); >> if (start < map_start) >> start = map_start; >>- } else >>+ } else { >>+ pr_info("%s: last_start: 0x%lx <= step_size: 0x%lx, start: 0x%lx\n", >>+ __func__, last_start, step_size, start); >>+ > >If you change this log with the following > > pr_err("%s: last_start: 0x%lx <= step_size: 0x%lx, start: 0x%lx\n", > __func__, last_start, step_size, > round_down(last_start - 1, step_size)); > >You could see after calculation, start is 0 when (last_start <= step_size). > >-- >Wei Yang >Help you, Help me
-- Wei Yang Help you, Help me [unhandled content-type:application/pgp-signature] | |