Commit aa4ea675 authored Mar 22, 2017 by Andy Lutomirski Committed by Ingo Molnar Mar 23, 2017

x86/gdt: Fix setup_fixmap_gdt() to use the correct PA



__pa() cannot be used on percpu pointers because they may be
virtually mapped.  Use per_cpu_ptr_to_phys() instead.

This fixes a boot crash on a some 32-bit configurations.  I assume
this is related to which allocation strategy is chosen by the percpu
core.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 69218e47 x86: ("Remap GDT tables in the fixmap section")
Link: http://lkml.kernel.org/r/22e0069c29fba31998f193201e359eebfdac4960.1490218061.git.luto@kernel.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 65973dd3

arch/x86/include/asm/desc.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -98,6 +98,12 @@ static inline unsigned long get_current_gdt_ro_vaddr(void)
		return (unsigned long)get_current_gdt_ro();
		}

		/* Provide the physical address of the GDT page. */
		static inline phys_addr_t get_cpu_gdt_paddr(unsigned int cpu)
		{
		return per_cpu_ptr_to_phys(get_cpu_gdt_rw(cpu));
		}

		#ifdef CONFIG_X86_64

		static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,

arch/x86/kernel/cpu/common.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -461,8 +461,8 @@ pgprot_t pg_fixmap_gdt_flags = PAGE_KERNEL;
		/* Setup the fixmap mapping only once per-processor */
		static inline void setup_fixmap_gdt(int cpu)
		{
		__set_fixmap(get_cpu_gdt_ro_index(cpu),
		__pa(get_cpu_gdt_rw(cpu)), pg_fixmap_gdt_flags);
		__set_fixmap(get_cpu_gdt_ro_index(cpu), get_cpu_gdt_paddr(cpu),
		pg_fixmap_gdt_flags);
		}

		/* Load the original GDT from the per-cpu structure */