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From:   Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
To:     linux-snps-arc@lists.infradead.org,
        Vineet Gupta <vineet.gupta1@synopsys.com>
Cc:     linux-kernel@vger.kernel.org,
        Alexey Brodkin <alexey.brodkin@synopsys.com>,
        stable@vger.kernel.org,
        Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Subject: [PATCH] ARC: adjust memblock_reserve of kernel memory
Date:   Wed, 19 Dec 2018 19:16:16 +0300
Message-Id: <20181219161616.10422-1-Eugeniy.Paltsev@synopsys.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In setup_arch_memory we reserve the memory area wherein the kernel
is located. Current implementation may reserve more memory than
it actually required in case of CONFIG_LINUX_LINK_BASE is not
equal to CONFIG_LINUX_RAM_BASE. This happens because we calculate
start of the reserved region relatively to the CONFIG_LINUX_RAM_BASE
and end of the region relatively to the CONFIG_LINUX_RAM_BASE.

For example in case of HSDK board we wasted 256MiB of physical memory:
------------------->8------------------------------
Memory: 770416K/1048576K available (5496K kernel code,
    240K rwdata, 1064K rodata, 2200K init, 275K bss,
    278160K reserved, 0K cma-reserved)
------------------->8------------------------------

Fix that.

Cc: stable@vger.kernel.org
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
---
 arch/arc/mm/init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index f8fe5668b30f..a56e6a8ed259 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -137,7 +137,8 @@ void __init setup_arch_memory(void)
 	 */
 
 	memblock_add_node(low_mem_start, low_mem_sz, 0);
-	memblock_reserve(low_mem_start, __pa(_end) - low_mem_start);
+	memblock_reserve(CONFIG_LINUX_LINK_BASE,
+			 __pa(_end) - CONFIG_LINUX_LINK_BASE);
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (initrd_start)
-- 
2.14.5