| Message ID | 20200608125424.70198-3-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: Fix boot with some memory above MAXMEM | expand |
On Mon, Jun 08, 2020 at 03:54:24PM +0300, Kirill A. Shutemov wrote: > A 5-level paging capable machine can have memory above 46-bit in the > physical address space. This memory is only addressable in the 5-level > paging mode: we don't have enough virtual address space to create direct > mapping for such memory in the 4-level paging mode > > Teach KASLR to avoid memory regions above MAXMEM or truncate the region > if the end is above MAXMEM. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Reviewed-by: Dave Hansen <dave.hansen@intel.com> > Cc: stable@vger.kernel.org # v4.14 Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> > --- > arch/x86/boot/compressed/kaslr.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > index d7408af55738..99db18eeb40e 100644 > --- a/arch/x86/boot/compressed/kaslr.c > +++ b/arch/x86/boot/compressed/kaslr.c > @@ -695,7 +695,18 @@ static bool process_mem_region(struct mem_vector *region, > unsigned long long minimum, > unsigned long long image_size) > { > + unsigned long long end; > int i; > + > + /* Cannot access memory region above MAXMEM: skip it. */ > + if (region->start >= MAXMEM) > + return 0; > + > + /* Truncate the region if the end is above MAXMEM */ > + end = region->start + region->size; > + end = min_t(unsigned long long, end, MAXMEM - 1); > + region->size = end - region->start; > + > /* > * If no immovable memory found, or MEMORY_HOTREMOVE disabled, > * use @region directly. > -- > 2.26.2 > >
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index d7408af55738..99db18eeb40e 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -695,7 +695,18 @@ static bool process_mem_region(struct mem_vector *region, unsigned long long minimum, unsigned long long image_size) { + unsigned long long end; int i; + + /* Cannot access memory region above MAXMEM: skip it. */ + if (region->start >= MAXMEM) + return 0; + + /* Truncate the region if the end is above MAXMEM */ + end = region->start + region->size; + end = min_t(unsigned long long, end, MAXMEM - 1); + region->size = end - region->start; + /* * If no immovable memory found, or MEMORY_HOTREMOVE disabled, * use @region directly.