| Date | Mon, 04 Dec 2017 15:07:14 +0100 | From | Thomas Gleixner <> | Subject | [patch 08/60] x86/entry/gdt: Put per-CPU GDT remaps in ascending order |
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From: Andy Lutomirski <luto@kernel.org>
We currently have CPU 0's GDT at the top of the GDT range and higher-numbered CPUs at lower addresses. This happens because the fixmap is upside down (index 0 is the top of the fixmap).
Flip it so that GDTs are in ascending order by virtual address. This will simplify a future patch that will generalize the GDT remap to contain multiple pages.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Rik van Riel <riel@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/3966a6edf6fd45deca4cf52a9b9276402499dda9.1511497875.git.luto@kernel.org
--- arch/x86/include/asm/desc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -63,7 +63,7 @@ static inline struct desc_struct *get_cu /* Get the fixmap index for a specific processor */ static inline unsigned int get_cpu_gdt_ro_index(int cpu) { - return FIX_GDT_REMAP_BEGIN + cpu; + return FIX_GDT_REMAP_END - cpu; } /* Provide the fixmap address of the remapped GDT */
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