Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 28/43] x86/boot: Simplify kernel load address alignment check | Date | Mon, 16 Jul 2018 09:36:33 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Kuleshov <kuleshovmail@gmail.com>
commit a4733143085d6c782ac1e6c85778655b6bac1d4e upstream
We are using %rax as temporary register to check the kernel address alignment. We don't really have to since the TEST instruction does not clobber the destination operand.
Suggested-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Alexander Popov <alpopov@ptsecurity.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/1453531828-19291-1-git-send-email-kuleshovmail@gmail.com Link: http://lkml.kernel.org/r/1453842730-28463-11-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley@gmail.com> Reviewed-by: Alexey Makhalov <amakhalov@vmware.com> Reviewed-by: Bo Gan <ganb@vmware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> ---
arch/x86/kernel/head_64.S | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -76,9 +76,7 @@ startup_64: subq $_text - __START_KERNEL_map, %rbp /* Is the address not 2M aligned? */ - movq %rbp, %rax - andl $~PMD_PAGE_MASK, %eax - testl %eax, %eax + testl $~PMD_PAGE_MASK, %ebp jnz bad_address /*
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