linux-kernel - [PATCH v2 05/15] MIPS: KASLR: Drop relocatable fixup from reservation

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Date:   Fri,  2 Feb 2018 06:54:48 +0300
From:   Serge Semin <fancer.lancer@...il.com>
To:     ralf@...ux-mips.org, miodrag.dinic@...s.com, jhogan@...nel.org,
        goran.ferenc@...s.com, david.daney@...ium.com,
        paul.gortmaker@...driver.com, paul.burton@...s.com,
        alex.belits@...ium.com, Steven.Hill@...ium.com
Cc:     alexander.sverdlin@...ia.com, matt.redfearn@...s.com,
        kumba@...too.org, marcin.nowakowski@...s.com, James.hogan@...s.com,
        Peter.Wotton@...s.com, Sergey.Semin@...latforms.ru,
        linux-mips@...ux-mips.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 05/15] MIPS: KASLR: Drop relocatable fixup from reservation_init

From: Matt Redfearn <matt.redfearn@...s.com>

A recent change ("MIPS: memblock: Discard bootmem initialization")
removed the reservation of all memory below the kernel's _end symbol in
bootmem. This makes the call to free_bootmem unnecessary, since the
memory region is no longer marked reserved.

Additionally, ("MIPS: memblock: Print out kernel virtual mem
layout") added a display of the kernel's virtual memory layout, so
printing the relocation information at this point is redundant.

Remove this section of code.

Signed-off-by: Matt Redfearn <matt.redfearn@...s.com>
---
 arch/mips/kernel/setup.c | 23 -----------------------
 1 file changed, 23 deletions(-)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index b5fcacf71b3f..cf3674977170 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -528,29 +528,6 @@ static void __init bootmem_init(void)
 		memory_present(0, start, end);
 	}
 
-#ifdef CONFIG_RELOCATABLE
-	/*
-	 * The kernel reserves all memory below its _end symbol as bootmem,
-	 * but the kernel may now be at a much higher address. The memory
-	 * between the original and new locations may be returned to the system.
-	 */
-	if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
-		unsigned long offset;
-		extern void show_kernel_relocation(const char *level);
-
-		offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
-		free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
-
-#if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO)
-		/*
-		 * This information is necessary when debugging the kernel
-		 * But is a security vulnerability otherwise!
-		 */
-		show_kernel_relocation(KERN_INFO);
-#endif
-	}
-#endif
-
 	/*
 	 * Reserve initrd memory if needed.
 	 */
-- 
2.12.0