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From:   Chen Zhou <chenzhou10@huawei.com>
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        John Donnelly <John.p.donnelly@oracle.com>
Subject: [PATCH v13 3/8] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel()
Date:   Sat, 31 Oct 2020 15:44:32 +0800
Message-ID: <20201031074437.168008-4-chenzhou10@huawei.com>
In-Reply-To: <20201031074437.168008-1-chenzhou10@huawei.com>
References: <20201031074437.168008-1-chenzhou10@huawei.com>
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To make the functions reserve_crashkernel() as generic,
replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d1599449a001..1289f079ad5f 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -491,8 +491,9 @@ static void __init reserve_crashkernel(void)
 	if (!crash_base) {
 		/*
 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over 4G, also allocates
-		 * 256M extra low memory for DMA buffers and swiotlb.
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
 		 * But the extra memory is not required for all machines.
 		 * So try low memory first and fall back to high memory
 		 * unless "crashkernel=size[KMG],high" is specified.
@@ -520,7 +521,7 @@ static void __init reserve_crashkernel(void)
 		}
 	}
 
-	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
 		memblock_free(crash_base, crash_size);
 		return;
 	}
-- 
2.20.1