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| author | Borislav Petkov <bp@suse.de> | 2015-04-01 12:49:52 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-04-03 15:26:15 +0200 |
| commit | 78cac48c0434c82e860fade3cd0420a7a4adbb08 (patch) | |
| tree | 76e1afefb1a0f9baad05487738de9f1b4a126aa7 /Documentation/x86/boot.txt | |
| parent | 47091e3c5b072daca29a15d2a3caf40359b0d140 (diff) | |
| download | lwn-78cac48c0434c82e860fade3cd0420a7a4adbb08.tar.gz lwn-78cac48c0434c82e860fade3cd0420a7a4adbb08.zip | |
x86/mm/KASLR: Propagate KASLR status to kernel proper
Commit:
e2b32e678513 ("x86, kaslr: randomize module base load address")
made module base address randomization unconditional and didn't regard
disabled KKASLR due to CONFIG_HIBERNATION and command line option
"nokaslr". For more info see (now reverted) commit:
f47233c2d34f ("x86/mm/ASLR: Propagate base load address calculation")
In order to propagate KASLR status to kernel proper, we need a single bit
in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the
top-down allocated bits for bits supposed to be used by the bootloader.
Originally-From: Jiri Kosina <jkosina@suse.cz>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/x86/boot.txt')
| -rw-r--r-- | Documentation/x86/boot.txt | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt index a75e3adaa39d..88b85899d309 100644 --- a/Documentation/x86/boot.txt +++ b/Documentation/x86/boot.txt @@ -406,6 +406,12 @@ Protocol: 2.00+ - If 0, the protected-mode code is loaded at 0x10000. - If 1, the protected-mode code is loaded at 0x100000. + Bit 1 (kernel internal): ALSR_FLAG + - Used internally by the compressed kernel to communicate + KASLR status to kernel proper. + If 1, KASLR enabled. + If 0, KASLR disabled. + Bit 5 (write): QUIET_FLAG - If 0, print early messages. - If 1, suppress early messages. |