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authorBorislav Petkov <bp@suse.de>2015-04-01 12:49:52 +0200
committerIngo Molnar <mingo@kernel.org>2015-04-03 15:26:15 +0200
commit78cac48c0434c82e860fade3cd0420a7a4adbb08 (patch)
tree76e1afefb1a0f9baad05487738de9f1b4a126aa7 /arch/x86/include/asm/setup.h
parentx86/asm/entry: Drop now unused ENABLE_INTERRUPTS_SYSEXIT32 (diff)
downloadlinux-78cac48c0434c82e860fade3cd0420a7a4adbb08.tar.xz
linux-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 'arch/x86/include/asm/setup.h')
-rw-r--r--arch/x86/include/asm/setup.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index ff4e7b236e21..f69e06b283fb 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -66,6 +66,11 @@ static inline void x86_ce4100_early_setup(void) { }
*/
extern struct boot_params boot_params;
+static inline bool kaslr_enabled(void)
+{
+ return !!(boot_params.hdr.loadflags & KASLR_FLAG);
+}
+
/*
* Do NOT EVER look at the BIOS memory size location.
* It does not work on many machines.