Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763201AbcLSME6 (ORCPT ); Mon, 19 Dec 2016 07:04:58 -0500 Received: from mailapp01.imgtec.com ([195.59.15.196]:43470 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751673AbcLSME5 (ORCPT ); Mon, 19 Dec 2016 07:04:57 -0500 Subject: Re: [PATCH 19/21] MIPS memblock: Add print out method of kernel virtual memory layout To: Serge Semin , , , , , , , References: <1482113266-13207-1-git-send-email-fancer.lancer@gmail.com> <1482113266-13207-20-git-send-email-fancer.lancer@gmail.com> CC: , , , From: Matt Redfearn Message-ID: Date: Mon, 19 Dec 2016 12:04:54 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1482113266-13207-20-git-send-email-fancer.lancer@gmail.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.150.130.83] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3351 Lines: 100 Hi Serge, On 19/12/16 02:07, Serge Semin wrote: > It's useful to have some printed map of the kernel virtual memory, > at least for debugging purpose. > > Signed-off-by: Serge Semin > --- > arch/mips/mm/init.c | 47 +++++++++++++++++++++++++++++++++++ > 1 file changed, 47 insertions(+) > > diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c > index 13a032f..35e7ba8 100644 > --- a/arch/mips/mm/init.c > +++ b/arch/mips/mm/init.c > @@ -32,6 +32,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -106,6 +107,49 @@ static void __init zone_sizes_init(void) > } > > /* > + * Print out kernel memory layout > + */ > +#define MLK(b, t) b, t, ((t) - (b)) >> 10 > +#define MLM(b, t) b, t, ((t) - (b)) >> 20 > +#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K) > +static void __init mem_print_kmap_info(void) > +{ > + pr_notice("Virtual kernel memory layout:\n" > + " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" > + " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" > +#ifdef CONFIG_HIGHMEM > + " pkmap : 0x%08lx - 0x%08lx (%4ld MB)\n" > +#endif > + " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" > + " .text : 0x%p" " - 0x%p" " (%4td kB)\n" > + " .data : 0x%p" " - 0x%p" " (%4td kB)\n" > + " .init : 0x%p" " - 0x%p" " (%4td kB)\n", > + MLM(PAGE_OFFSET, (unsigned long)high_memory), > + MLM(VMALLOC_START, VMALLOC_END), > +#ifdef CONFIG_HIGHMEM > + MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP)*(PAGE_SIZE)), > +#endif > + MLK(FIXADDR_START, FIXADDR_TOP), > + MLK_ROUNDUP(_text, _etext), > + MLK_ROUNDUP(_sdata, _edata), > + MLK_ROUNDUP(__init_begin, __init_end)); Please drop printing the kernel addresses, or at least only do it if KASLR is not turned on, otherwise you're removing the advantage of KASLR, that critical kernel addresses cannot be determined easily from userspace. It may be better to merge the functionality of show_kernel_relocation http://lxr.free-electrons.com/source/arch/mips/kernel/relocate.c#L354 into this function, but only print it under the same conditions as currently, i.e. #if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO) http://lxr.free-electrons.com/source/arch/mips/kernel/setup.c#L530 Thanks, Matt > + > + /* Check some fundamental inconsistencies. May add something else? */ > +#ifdef CONFIG_HIGHMEM > + BUILD_BUG_ON(VMALLOC_END < PAGE_OFFSET); > + BUG_ON(VMALLOC_END < (unsigned long)high_memory); > +#endif > + BUILD_BUG_ON((PKMAP_BASE) + (LAST_PKMAP)*(PAGE_SIZE) < PAGE_OFFSET); > + BUG_ON((PKMAP_BASE) + (LAST_PKMAP)*(PAGE_SIZE) < > + (unsigned long)high_memory); > + BUILD_BUG_ON(FIXADDR_TOP < PAGE_OFFSET); > + BUG_ON(FIXADDR_TOP < (unsigned long)high_memory); > +} > +#undef MLK > +#undef MLM > +#undef MLK_ROUNDUP > + > +/* > * Not static inline because used by IP27 special magic initialization code > */ > void setup_zero_pages(void) > @@ -492,6 +536,9 @@ void __init mem_init(void) > /* Free highmemory registered in memblocks */ > mem_init_free_highmem(); > > + /* Print out kernel memory layout */ > + mem_print_kmap_info(); > + > /* Print out memory areas statistics */ > mem_init_print_info(NULL); >