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path: root/arch/x86/mm/mem_encrypt_boot.S
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2017-08-29x86/mm: Fix SME encryption stack ptr handlingBorislav Petkov
sme_encrypt_execute() stashes the stack pointer on entry into %rbp because it allocates a one-page stack in the non-encrypted area for the encryption routine to use. When the latter is done, it restores it from %rbp again, before returning. However, it uses the FRAME_* macros partially but restores %rsp from %rbp explicitly with a MOV. And this is fine as long as the macros *actually* do something. Unless, you do a !CONFIG_FRAME_POINTER build where those macros are empty. Then, we still restore %rsp from %rbp but %rbp contains *something* and this leads to a stack corruption. The manifestation being a triple-fault during early boot when testing SME. Good luck to me debugging this with the clumsy endless-loop-in-asm method and narrowing it down gradually. :-( So, long story short, open-code the frame macros so that there's no monkey business and we avoid subtly breaking SME depending on the .config. Fixes: 6ebcb060713f ("x86/mm: Add support to encrypt the kernel in-place") Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Link: http://lkml.kernel.org/r/20170827163924.25552-1-bp@alien8.de
2017-07-18x86/mm: Add support to encrypt the kernel in-placeTom Lendacky
Add the support to encrypt the kernel in-place. This is done by creating new page mappings for the kernel - a decrypted write-protected mapping and an encrypted mapping. The kernel is encrypted by copying it through a temporary buffer. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Dave Young <dyoung@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Toshimitsu Kani <toshi.kani@hpe.com> Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/c039bf9412ef95e1e6bf4fdf8facab95e00c717b.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org>