Re: [PATCH] arm64: Stop printing the virtual memory layout

[Laura Abbott]

On 12/19/2017 01:04 PM, Kees Cook wrote:
> On Tue, Dec 19, 2017 at 11:28 AM, Laura Abbott <labbott@xxxxxxxxxx> wrote:
> > Printing kernel addresses should be done in limited circumstances, mostly
> > for debugging purposes. Printing out the virtual memory layout at every
> > kernel bootup doesn't really fall into this category so delete the prints.
> > There are other ways to get the same information.
>
> In looking at this patch, I wonder: is there anything listed here that
> is _missing_ from CONFIG_PTDUMP? I would expect all of these to
> already be listed there, but I thought I'd ask...

It doesn't print the .text etc. but those can be calculated other ways.

> Regardless:
>
> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
>
> -Kees
>
> > Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
> > ---
> > Follow up to my previous proposal to switch all these to %px
> > ---
> >   arch/arm64/mm/init.c | 43 -------------------------------------------
> >   1 file changed, 43 deletions(-)
> >
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 5960bef0170d..672094ed7e07 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -599,49 +599,6 @@ void __init mem_init(void)
> >
> >          mem_init_print_info(NULL);
> >
> > -#define MLK(b, t) b, t, ((t) - (b)) >> 10
> > -#define MLM(b, t) b, t, ((t) - (b)) >> 20
> > -#define MLG(b, t) b, t, ((t) - (b)) >> 30
> > -#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
> > -
> > -       pr_notice("Virtual kernel memory layout:\n");
> > -#ifdef CONFIG_KASAN
> > -       pr_notice("    kasan   : 0x%16lx - 0x%16lx   (%6ld GB)\n",
> > -               MLG(KASAN_SHADOW_START, KASAN_SHADOW_END));
> > -#endif
> > -       pr_notice("    modules : 0x%16lx - 0x%16lx   (%6ld MB)\n",
> > -               MLM(MODULES_VADDR, MODULES_END));
> > -       pr_notice("    vmalloc : 0x%16lx - 0x%16lx   (%6ld GB)\n",
> > -               MLG(VMALLOC_START, VMALLOC_END));
> > -       pr_notice("      .text : 0x%p" " - 0x%p" "   (%6ld KB)\n",
> > -               MLK_ROUNDUP(_text, _etext));
> > -       pr_notice("    .rodata : 0x%p" " - 0x%p" "   (%6ld KB)\n",
> > -               MLK_ROUNDUP(__start_rodata, __init_begin));
> > -       pr_notice("      .init : 0x%p" " - 0x%p" "   (%6ld KB)\n",
> > -               MLK_ROUNDUP(__init_begin, __init_end));
> > -       pr_notice("      .data : 0x%p" " - 0x%p" "   (%6ld KB)\n",
> > -               MLK_ROUNDUP(_sdata, _edata));
> > -       pr_notice("       .bss : 0x%p" " - 0x%p" "   (%6ld KB)\n",
> > -               MLK_ROUNDUP(__bss_start, __bss_stop));
> > -       pr_notice("    fixed   : 0x%16lx - 0x%16lx   (%6ld KB)\n",
> > -               MLK(FIXADDR_START, FIXADDR_TOP));
> > -       pr_notice("    PCI I/O : 0x%16lx - 0x%16lx   (%6ld MB)\n",
> > -               MLM(PCI_IO_START, PCI_IO_END));
> > -#ifdef CONFIG_SPARSEMEM_VMEMMAP
> > -       pr_notice("    vmemmap : 0x%16lx - 0x%16lx   (%6ld GB maximum)\n",
> > -               MLG(VMEMMAP_START, VMEMMAP_START + VMEMMAP_SIZE));
> > -       pr_notice("              0x%16lx - 0x%16lx   (%6ld MB actual)\n",
> > -               MLM((unsigned long)phys_to_page(memblock_start_of_DRAM()),
> > -                   (unsigned long)virt_to_page(high_memory)));
> > -#endif
> > -       pr_notice("    memory  : 0x%16lx - 0x%16lx   (%6ld MB)\n",
> > -               MLM(__phys_to_virt(memblock_start_of_DRAM()),
> > -                   (unsigned long)high_memory));
> > -
> > -#undef MLK
> > -#undef MLM
> > -#undef MLK_ROUNDUP
> > -
> >          /*
> >           * Check boundaries twice: Some fundamental inconsistencies can be
> >           * detected at build time already.
> > --
> > 2.14.3