diff options
| author |   Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2018-02-14 14:16:53 +0300 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2018-02-14 13:11:14 +0100 |
| commit | c65e774fb3f6af212641538694b9778ff9ab4300 (patch) | |
| tree | 3c4da88dd0658874ea3fc7de3cc96ee27d711ef9 /arch/x86/kernel/cpu/mcheck | |
| parent | x86/mm: Make LDT_BASE_ADDR dynamic (diff) | |
| download | linux-dev-c65e774fb3f6af212641538694b9778ff9ab4300.tar.xz linux-dev-c65e774fb3f6af212641538694b9778ff9ab4300.zip | |
x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable
For boot-time switching between 4- and 5-level paging we need to be able
to fold p4d page table level at runtime. It requires variable
PGDIR_SHIFT and PTRS_PER_P4D.
The change doesn't affect the kernel image size much:
text data bss dec hex filename
8628091 4734304 1368064 14730459 e0c4db vmlinux.before
8628393 4734340 1368064 14730797 e0c62d vmlinux.after
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214111656.88514-7-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu/mcheck')
| -rw-r--r-- | arch/x86/kernel/cpu/mcheck/mce.c | 18 |
1 files changed, 6 insertions, 12 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 3a8e88a611eb..cbb3af721291 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -1082,19 +1082,7 @@ void arch_unmap_kpfn(unsigned long pfn) * a legal address. */ -/* - * Build time check to see if we have a spare virtual bit. Don't want - * to leave this until run time because most developers don't have a - * system that can exercise this code path. This will only become a - * problem if/when we move beyond 5-level page tables. - * - * Hard code "9" here because cpp doesn't grok ilog2(PTRS_PER_PGD) - */ -#if PGDIR_SHIFT + 9 < 63 decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63)); -#else -#error "no unused virtual bit available" -#endif if (set_memory_np(decoy_addr, 1)) pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn); @@ -2328,6 +2316,12 @@ static __init int mcheck_init_device(void) { int err; + /* + * Check if we have a spare virtual bit. This will only become + * a problem if/when we move beyond 5-level page tables. + */ + MAYBE_BUILD_BUG_ON(__VIRTUAL_MASK_SHIFT >= 63); + if (!mce_available(&boot_cpu_data)) { err = -EIO; goto err_out; |