Add a more versatile memmap= operator, which -- in addition to all the
things that were possible before -- allows you to:
- redeclare existing ranges -- before, you were limited to adding ranges;
- drop any range -- like a mem= for any location;
- use any e820 memory type -- not just some predefined ones.
The syntax is:
memmap=<size>%<offset>-<oldtype>+<newtype>
Size and offset work as usual. The "-<oldtype>" and "+<newtype>" are
optional and their existence determine the behavior: The command
works on the specified range of memory limited to type <oldtype>
(if specified). This memory is then configured to show up as <newtype>.
If <newtype> is not specified, the memory is removed from the e820 map.
Signed-off-by: Jan H. Schönherr <jscho...@amazon.de>
---
Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++
arch/x86/kernel/e820.c | 18 ++++++++++++++++++
2 files changed, 27 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 46b26bfee27b..94609eaff2a9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2221,6 +2221,15 @@
The memory region may be marked as e820 type 12 (0xc)
and is NVDIMM or ADR memory.
+ memmap=<size>%<offset>-<oldtype>+<newtype>
+ [KNL,ACPI] Convert memory within the specified region
+ from <oldtype> to <newtype>. If "-<oldtype>" is left
+ out, the whole region will be marked as <newtype>,
+ even if previously unavailable. If "+<newtype>" is left
+ out, matching memory will be removed. Types are
+ specified as e820 types, eg, 1==RAM, 2==reserved,
+ 3==ACPI, 12==PRAM.
+
memory_corruption_check=0/1 [X86]
Some BIOSes seem to corrupt the first 64k of
memory when doing things like suspend/resume.
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 71c11ad5643e..cd22c6a07632 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -924,6 +924,24 @@ static int __init parse_memmap_one(char *p)
} else if (*p == '!') {
start_at = memparse(p+1, &p);
e820__range_add(start_at, mem_size, E820_TYPE_PRAM);
+ } else if (*p == '%') {
+ enum e820_type from = 0, to = 0;
+
+ start_at = memparse(p + 1, &p);
+ if (*p == '-')
+ from = simple_strtoull(p + 1, &p, 0);
+ if (*p == '+')
+ to = simple_strtoull(p + 1, &p, 0);
+ if (*p != 0)
+ return -EINVAL;
+ if (from && to)
+ e820__range_update(start_at, mem_size, from, to);
+ else if (to)
+ e820__range_add(start_at, mem_size, to);
+ else if (from)
+ e820__range_remove(start_at, mem_size, from, 1);
+ else
+ e820__range_remove(start_at, mem_size, 0, 0);
} else {
e820__range_remove(mem_size, ULLONG_MAX - mem_size,
E820_TYPE_RAM, 1);
}
--
2.9.3.1.gcba166c.dirty
