A given page of memory can only be accepted once. The kernel has a need
to accept memory both in the early decompression stage and during normal
runtime.
Use a bitmap to communicate the acceptance state of each page between
the decompression stage and normal runtime. This eliminates the
possibility of attempting to double-accept a page.
Allocate the bitmap during decompression stage and hand it over to the
main kernel image via boot_params.
In the runtime kernel, reserve the bitmap's memory to ensure nothing
overwrites it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/e820.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index bc0657f0deed..3905bd1ca41d 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1297,6 +1297,16 @@ void __init e820__memblock_setup(void)
int i;
u64 end;
+ /* Mark unaccepted memory bitmap reserved */
+ if (boot_params.unaccepted_memory) {
+ unsigned long size;
+
+ /* One bit per 2MB */
+ size = DIV_ROUND_UP(e820__end_of_ram_pfn() * PAGE_SIZE,
+ PMD_SIZE * BITS_PER_BYTE);
+ memblock_reserve(boot_params.unaccepted_memory, size);
+ }
+
/*
* The bootstrap memblock region count maximum is 128 entries
* (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
--
2.34.1
