Kernel boot parameter memmap=nn[KMG]$ss[KMG] is used to mark specific memory as
reserved. Region of memory to be used is from ss to ss+nn.
But I found the action of this parameter is not as expected.
I tried on two machines.
Machine1: bootcmdline in grub.cfg "memmap=800M$0x60bfdfff", but the result of
"cat /proc/cmdline" changed to "memmap=800M/bin/bashx60bfdfff" after system
booted.
Machine2: bootcmdline in grub.cfg "memmap=0x77ffffff$0x880000000", the result of
"cat /proc/cmdline" changed to "memmap=0x77ffffffx880000000".
I didn't find the root cause, I think maybe grub reserved "$0" as something
special.
Replace '$' with '%' in kernel boot parameter can fix this issue.
Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 6 +++---
arch/x86/kernel/e820.c | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7f9d4f5..a96c7b1 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1604,13 +1604,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
[KNL,ACPI] Mark specific memory as ACPI data.
Region of memory to be used, from ss to ss+nn.
- memmap=nn[KMG]$ss[KMG]
+ memmap=nn[KMG]%ss[KMG]
[KNL,ACPI] Mark specific memory as reserved.
Region of memory to be used, from ss to ss+nn.
Example: Exclude memory from 0x18690000-0x1869ffff
- memmap=64K$0x18690000
+ memmap=64K%0x18690000
or
- memmap=0x10000$0x18690000
+ memmap=0x10000%0x18690000
memory_corruption_check=0/1 [X86]
Some BIOSes seem to corrupt the first 64k of
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index d32abea..8483d45 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -869,7 +869,7 @@ static int __init parse_memmap_one(char *p)
} else if (*p == '#') {
start_at = memparse(p+1, &p);
e820_add_region(start_at, mem_size, E820_ACPI);
- } else if (*p == '$') {
+ } else if (*p == '%') {
start_at = memparse(p+1, &p);
e820_add_region(start_at, mem_size, E820_RESERVED);
} else
--
1.7.10.4
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