To allow guard pages between the IST stacks each stack needs to be mapped individually.
Signed-off-by: Thomas Gleixner <[email protected]> --- arch/x86/mm/cpu_entry_area.c | 36 +++++++++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 7 deletions(-) --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -77,6 +77,33 @@ static void __init percpu_setup_debug_st #endif } +#ifdef CONFIG_X86_64 + +#define cea_map_stack(name) \ + npages = sizeof(estacks->name## _stack) / PAGE_SIZE; \ + cea_map_percpu_pages(cea->estacks.name## _stack, \ + estacks->name## _stack, npages, PAGE_KERNEL) + +static void __init percpu_setup_exception_stacks(unsigned int cpu) +{ + struct exception_stacks *estacks = per_cpu_ptr(&exception_stacks, cpu); + struct cpu_entry_area *cea = get_cpu_entry_area(cpu); + unsigned int npages; + + BUILD_BUG_ON(sizeof(exception_stacks) % PAGE_SIZE != 0); + /* + * The exceptions stack mappings in the per cpu area are protected + * by guard pages so each stack must be mapped seperately. + */ + cea_map_stack(DF); + cea_map_stack(NMI); + cea_map_stack(DB); + cea_map_stack(MCE); +} +#else +static inline void percpu_setup_exception_stacks(unsigned int cpu) {} +#endif + /* Setup the fixmap mappings only once per-processor */ static void __init setup_cpu_entry_area(unsigned int cpu) { @@ -134,13 +161,8 @@ static void __init setup_cpu_entry_area( per_cpu(cpu_entry_area, cpu) = cea; #endif -#ifdef CONFIG_X86_64 - BUILD_BUG_ON(sizeof(exception_stacks) % PAGE_SIZE != 0); - BUILD_BUG_ON(sizeof(exception_stacks) != - sizeof(((struct cpu_entry_area *)0)->estacks)); - cea_map_percpu_pages(&cea->estacks, &per_cpu(exception_stacks, cpu), - sizeof(exception_stacks) / PAGE_SIZE, PAGE_KERNEL); -#endif + percpu_setup_exception_stacks(cpu); + percpu_setup_debug_store(cpu); }
