On Tue, Jul 26, 2016 at 10:37 AM, tip-bot for Borislav Petkov <tip...@zytor.com> wrote: > Commit-ID: efaad554b4ffae1840a2759e09e21325ddbc8b05 > Gitweb: http://git.kernel.org/tip/efaad554b4ffae1840a2759e09e21325ddbc8b05 > Author: Borislav Petkov <b...@suse.de> > AuthorDate: Tue, 26 Jul 2016 11:51:38 +0200 > Committer: Ingo Molnar <mi...@kernel.org> > CommitDate: Tue, 26 Jul 2016 19:32:57 +0200 > > x86/microcode/intel: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y > > CONFIG_RANDOMIZE_MEMORY=y randomizes the physical memmap and thus the > address where the initrd is located. Therefore, we need to add the > offset KASLR put us to in order to find the initrd again on the AP path. > > In the future, we will get rid of the initrd address caching and query > the address on both the BSP and AP paths but that would need more work. > > Thanks to Nicolai Stange for the good bisection and debugging work. > > Reported-and-tested-by: Nicolai Stange <nicsta...@gmail.com> > Signed-off-by: Borislav Petkov <b...@suse.de> > Cc: Kees Cook <keesc...@chromium.org> > Cc: Linus Torvalds <torva...@linux-foundation.org> > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Thomas Gleixner <t...@linutronix.de> > Link: http://lkml.kernel.org/r/20160726095138.3470-1...@alien8.de > Signed-off-by: Ingo Molnar <mi...@kernel.org> > --- > arch/x86/kernel/cpu/microcode/intel.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/cpu/microcode/intel.c > b/arch/x86/kernel/cpu/microcode/intel.c > index 6515c80..0f97ae9 100644 > --- a/arch/x86/kernel/cpu/microcode/intel.c > +++ b/arch/x86/kernel/cpu/microcode/intel.c > @@ -793,10 +793,10 @@ void __init load_ucode_intel_bsp(void) > void load_ucode_intel_ap(void) > { > struct ucode_blobs *blobs_p; > + unsigned long *ptrs, start = 0; > struct mc_saved_data *mcs; > struct ucode_cpu_info uci; > enum ucode_state ret; > - unsigned long *ptrs; > > #ifdef CONFIG_X86_32 > mcs = (struct mc_saved_data *)__pa_nodebug(&mc_saved_data); > @@ -815,8 +815,20 @@ void load_ucode_intel_ap(void) > if (!mcs->num_saved) > return; > > + if (blobs_p->valid) { > + start = blobs_p->start; > + > +#ifdef CONFIG_RANDOMIZE_MEMORY
These ifdefs aren't needed if we added a no-op __PAGE_OFFSET_BASE to the 32-bit page table headers. Then the compiler will DTRT with the start calculation. When CONFIG_RANDOMIZE_MEMORY is set, start will have a non-zero value, and when not set it'll be 0. > + /* > + * Pay attention to CONFIG_RANDOMIZE_MEMORY=y as it shuffles > + * physmem mapping too and there we have the initrd. > + */ > + start += PAGE_OFFSET - __PAGE_OFFSET_BASE; > +#endif > + } > + > collect_cpu_info_early(&uci); > - ret = load_microcode(mcs, ptrs, blobs_p->start, &uci); > + ret = load_microcode(mcs, ptrs, start, &uci); > if (ret != UCODE_OK) > return; > -- Kees Cook Chrome OS & Brillo Security
