summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/e820.c
diff options
context:
space:
mode:
authorJan H. Schönherr <jschoenh@amazon.de>2018-02-03 02:10:20 +0300
committerIngo Molnar <mingo@kernel.org>2018-02-26 10:44:52 +0300
commitef61f8a340fd6d49df6b367785743febc47320c1 (patch)
tree010e1943bd46fcc03e8d5ddb638c0e81254a9a5b /arch/x86/kernel/e820.c
parent672c0ae09b33a11d8f31fc61526632e96301164c (diff)
downloadlinux-ef61f8a340fd6d49df6b367785743febc47320c1.tar.xz
x86/boot/e820: Implement a range manipulation operator
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 <jschoenh@amazon.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180202231020.15608-1-jschoenh@amazon.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/e820.c')
-rw-r--r--arch/x86/kernel/e820.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 71c11ad5643e..6a2cb1442e05 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);
}