Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH 2/7] x86/gdt: Fix setup_fixmap_gdt() to use the correct PA | Date | Wed, 22 Mar 2017 14:32:30 -0700 |
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__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.
Fixes: 69218e47994d x86: ("Remap GDT tables in the fixmap section") Signed-off-by: Andy Lutomirski <luto@kernel.org> --- arch/x86/include/asm/desc.h | 6 ++++++ arch/x86/kernel/cpu/common.c | 4 ++-- 2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index ec05f9c1a62c..bde11696b893 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -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, diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index f8e22dbad86c..f6e20e2dbfa5 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -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 */ -- 2.9.3
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