x86/boot/KASLR: Limit KASLR to extract the kernel in immovable memory only

KASLR may randomly choose a range which is located in movable memory
regions. As a result, this will break memory hotplug and make the
movable memory chosen by KASLR immovable.

Therefore, limit KASLR to choose memory regions in the immovable range
after consulting the SRAT table.

 [ bp:
    - Rewrite commit message.
    - Trim comments.
 ]

Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: caoj.fnst@cn.fujitsu.com
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: indou.takao@jp.fujitsu.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: kasong@redhat.com
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: msys.mizuma@gmail.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190123110850.12433-8-fanc.fnst@cn.fujitsu.com

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 9911d11c5d09..19e8231a6fd6 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -132,6 +132,7 @@ static inline acpi_physical_address get_rsdp_addr(void) { return 0; }
 #endif
 
 #if defined(CONFIG_RANDOMIZE_BASE) && defined(CONFIG_MEMORY_HOTREMOVE)
+extern struct mem_vector immovable_mem[MAX_NUMNODES*2];
 int count_immovable_mem_regions(void);
 #else
 static inline int count_immovable_mem_regions(void) { return 0; }