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SubjectRe: [tip:x86/boot] ACPI/NUMA: Add warning message if the padding size for KASLR is not enough
On Tue, Oct 02, 2018 at 05:05:18PM +0200, Borislav Petkov wrote:
> On Tue, Oct 02, 2018 at 03:18:41AM -0700, tip-bot for Masayoshi Mizuma wrote:
> > Commit-ID: 3b054ca88c4f4dd5f516a12d4b6d6bd0ae826f41
> > Gitweb: https://git.kernel.org/tip/3b054ca88c4f4dd5f516a12d4b6d6bd0ae826f41
> > Author: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> > AuthorDate: Mon, 1 Oct 2018 10:08:42 -0400
> > Committer: Ingo Molnar <mingo@kernel.org>
> > CommitDate: Tue, 2 Oct 2018 11:47:21 +0200
> >
> > ACPI/NUMA: Add warning message if the padding size for KASLR is not enough
> >
> > Add warning message if the padding size for KASLR,
> > rand_mem_physical_padding, is not enough. The message also
> > says the suitable padding size.
> >
> > Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> > Cc: Baoquan He <bhe@redhat.com>
> > Cc: Borislav Petkov <bp@alien8.de>
> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
> > Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Link: http://lkml.kernel.org/r/20181001140843.26137-3-msys.mizuma@gmail.com
> > Signed-off-by: Ingo Molnar <mingo@kernel.org>
> > ---
> > arch/x86/include/asm/setup.h | 2 ++
> > drivers/acpi/numa.c | 14 ++++++++++++++
> > 2 files changed, 16 insertions(+)
> >
> > diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
> > index ae13bc974416..65a5bf8f6aba 100644
> > --- a/arch/x86/include/asm/setup.h
> > +++ b/arch/x86/include/asm/setup.h
> > @@ -80,6 +80,8 @@ static inline unsigned long kaslr_offset(void)
> > return (unsigned long)&_text - __START_KERNEL;
> > }
> >
> > +extern int rand_mem_physical_padding;
> > +
> > /*
> > * Do NOT EVER look at the BIOS memory size location.
> > * It does not work on many machines.
> > diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
> > index 85167603b9c9..3d69834c692f 100644
> > --- a/drivers/acpi/numa.c
> > +++ b/drivers/acpi/numa.c
> > @@ -32,6 +32,7 @@
> > #include <linux/numa.h>
> > #include <linux/nodemask.h>
> > #include <linux/topology.h>
> > +#include <asm/setup.h>
> >
> > static nodemask_t nodes_found_map = NODE_MASK_NONE;
> >
> > @@ -435,6 +436,7 @@ acpi_table_parse_srat(enum acpi_srat_type id,
> > int __init acpi_numa_init(void)
> > {
> > int cnt = 0;
> > + u64 max_possible_phys, max_actual_phys, threshold;
> >
> > if (acpi_disabled)
> > return -EINVAL;
> > @@ -463,6 +465,18 @@ int __init acpi_numa_init(void)
> >
> > cnt = acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
> > acpi_parse_memory_affinity, 0);
> > +
> > + /* check the padding size for KASLR is enough. */
> > + if (parsed_numa_memblks && kaslr_enabled()) {
> > + max_actual_phys = roundup(PFN_PHYS(max_pfn), 1ULL << 40);
> > + max_possible_phys = roundup(PFN_PHYS(max_possible_pfn), 1ULL << 40);
> > + threshold = max_actual_phys + ((u64)rand_mem_physical_padding << 40);
>
> Nope, not really:
>
> ld: drivers/acpi/numa.o: in function `acpi_numa_init':
> /home/boris/kernel/linux/drivers/acpi/numa.c:473: undefined reference to `rand_mem_physical_padding'
> make: *** [Makefile:1030: vmlinux] Error 1
>
> due to CONFIG_RANDOMIZE_MEMORY=n in my .config.
>
> You need to add a fix ontop which adds a function
> get_rand_mem_physical_padding() which is defined in CONFIG_RANDOMIZE_MEMORY=y
> and outside returns 0.
>
> And then make that rand_mem_physical_padding static and do not export it
> to anything outside of kaslr.c but use the accessor.

Thank you for the report and suggetions!
I'll fix it and resubmit soon.

Thanks,
Masa

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