From 09e61a779e7f171c50325e6d7108a593afb2e5d4 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 14 Feb 2018 14:16:55 +0300 Subject: x86/mm: Make __VIRTUAL_MASK_SHIFT dynamic For boot-time switching between paging modes, we need to be able to adjust virtual mask shifts. The change doesn't affect the kernel image size much: text data bss dec hex filename 8628892 4734340 1368064 14731296 e0c820 vmlinux.before 8628966 4734340 1368064 14731370 e0c86a vmlinux.after Signed-off-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180214111656.88514-9-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/entry/entry_64.S | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86/entry/entry_64.S') diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 30c8c5344c4a..2c06348b7807 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -274,8 +274,20 @@ GLOBAL(entry_SYSCALL_64_after_hwframe) * Change top bits to match most significant bit (47th or 56th bit * depending on paging mode) in the address. */ +#ifdef CONFIG_X86_5LEVEL + testl $1, pgtable_l5_enabled(%rip) + jz 1f + shl $(64 - 57), %rcx + sar $(64 - 57), %rcx + jmp 2f +1: + shl $(64 - 48), %rcx + sar $(64 - 48), %rcx +2: +#else shl $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx sar $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx +#endif /* If this changed %rcx, it was not canonical */ cmpq %rcx, %r11 -- cgit v1.2.3