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

From: Laura Abbott
Date: Tue Dec 19 2017 - 17:18:13 EST


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