kaslr: rename physmem_end and PHYSMEM_END to direct_map_physmem_end

For clarity.  It's increasingly hard to reason about the code, when KASLR
is moving around the boundaries.  In this case where KASLR is randomizing
the location of the kernel image within physical memory, the maximum
number of address bits for physical memory has not changed.

What has changed is the ending address of memory that is allowed to be
directly mapped by the kernel.

Let's name the variable, and the associated macro accordingly.

Also, enhance the comment above the direct_map_physmem_end definition,
to further clarify how this all works.

Link: https://lkml.kernel.org/r/20241009025024.89813-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jordan Niethe <jniethe@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
John Hubbard
2024-10-08 19:50:24 -07:00
committed by Andrew Morton
parent 01a9097aa3
commit afe789b736
9 changed files with 20 additions and 16 deletions

View File

@@ -129,7 +129,7 @@ static inline int sparse_early_nid(struct mem_section *section)
static void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
unsigned long *end_pfn)
{
unsigned long max_sparsemem_pfn = (PHYSMEM_END + 1) >> PAGE_SHIFT;
unsigned long max_sparsemem_pfn = (DIRECT_MAP_PHYSMEM_END + 1) >> PAGE_SHIFT;
/*
* Sanity checks - do not allow an architecture to pass