[PATCH 1/2] x86 e820: Check for exactmap appearance when parsing first memmap option

Thomas Renninger
2013-01-22T15:20:53Z

From: Yinghai Lu <yinghai@kernel.org>

memmap=exactmap will throw away all original, but also until then
user defined (through other provided memmap= parameters) areas.
That means all memmap= boot parameters passed before a memmap=exactmap
parameter are not recognized.
Without this fix:
memmap=x@y memmap=exactmap memmap=i#k
only i#k would get recognized.

This is wrong, this fix will only throw away all original e820 areas once
when memmap=exactmap is found in the whole boot command line and before
any other memmap= option is parsed.

Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Thomas Renninger <trenn@suse.de>
---
arch/x86/kernel/e820.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index d32abea..dc0b9f0 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -835,6 +835,8 @@ static int __init parse_memopt(char *p)
}
early_param("mem", parse_memopt);

+static bool __initdata exactmap_parsed;
+
static int __init parse_memmap_one(char *p)
{
char *oldp;
@@ -844,6 +846,10 @@ static int __init parse_memmap_one(char *p)
return -EINVAL;

if (!strncmp(p, "exactmap", 8)) {
+ if (exactmap_parsed)
+ return 0;
+
+ exactmap_parsed = true;
#ifdef CONFIG_CRASH_DUMP
/*
* If we are doing a crash dump, we still need to know
@@ -879,6 +885,12 @@ static int __init parse_memmap_one(char *p)
}
static int __init parse_memmap_opt(char *str)
{
+ char *p = boot_command_line;
+
+ p = strstr(p, "exactmap");
+ if (p)
+ parse_memmap_one("exactmap");
+
while (str) {
char *k = strchr(str, ',');

--
1.7.6.1