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Message-Id: <20200305150837.835083-1-nivedita@alum.mit.edu>
Date: Thu,  5 Mar 2020 10:08:37 -0500
From: Arvind Sankar <nivedita@...m.mit.edu>
To: Kees Cook <keescook@...omium.org>
Cc: "Tobin C . Harding" <me@...in.cc>,
	Tycho Andersen <tycho@...ho.ws>,
	kernel-hardening@...ts.openwall.com,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Michael Ellerman <mpe@...erman.id.au>,
	linuxppc-dev@...ts.ozlabs.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc/32: Stop printing the virtual memory layout

For security, don't display the kernel's virtual memory layout.

Kees Cook points out:
"These have been entirely removed on other architectures, so let's
just do the same for ia32 and remove it unconditionally."

071929dbdd86 ("arm64: Stop printing the virtual memory layout")
1c31d4e96b8c ("ARM: 8820/1: mm: Stop printing the virtual memory layout")
31833332f798 ("m68k/mm: Stop printing the virtual memory layout")
fd8d0ca25631 ("parisc: Hide virtual kernel memory layout")
adb1fe9ae2ee ("mm/page_alloc: Remove kernel address exposure in free_reserved_area()")

Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
---
 arch/powerpc/mm/mem.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index ef7b1119b2e2..df2c143b6bf7 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -331,23 +331,6 @@ void __init mem_init(void)
 #endif
 
 	mem_init_print_info(NULL);
-#ifdef CONFIG_PPC32
-	pr_info("Kernel virtual memory layout:\n");
-#ifdef CONFIG_KASAN
-	pr_info("  * 0x%08lx..0x%08lx  : kasan shadow mem\n",
-		KASAN_SHADOW_START, KASAN_SHADOW_END);
-#endif
-	pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
-#ifdef CONFIG_HIGHMEM
-	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
-		PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
-#endif /* CONFIG_HIGHMEM */
-	if (ioremap_bot != IOREMAP_TOP)
-		pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
-			ioremap_bot, IOREMAP_TOP);
-	pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
-		VMALLOC_START, VMALLOC_END);
-#endif /* CONFIG_PPC32 */
 }
 
 void free_initmem(void)
-- 
2.24.1

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