From: Andy Lutomirski <[email protected]> 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 <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Borislav Petkov <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Link: https://lkml.kernel.org/r/3966a6edf6fd45deca4cf52a9b9276402499dda9.1511497875.git.l...@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 */
