Commit-ID: a4af767ae59cc579569bbfe49513a0037d5989ee Gitweb: https://git.kernel.org/tip/a4af767ae59cc579569bbfe49513a0037d5989ee Author: Thomas Gleixner <[email protected]> AuthorDate: Sun, 14 Apr 2019 17:59:48 +0200 Committer: Borislav Petkov <[email protected]> CommitDate: Wed, 17 Apr 2019 12:58:21 +0200
x86/cpu_entry_area: Prepare for IST guard pages To allow guard pages between the IST stacks each stack needs to be mapped individually. Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: x86-ml <[email protected]> Link: https://lkml.kernel.org/r/[email protected] --- arch/x86/mm/cpu_entry_area.c | 37 ++++++++++++++++++++++++++++++------- 1 file changed, 30 insertions(+), 7 deletions(-) diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 6a09b84c13fe..2b1407662a6d 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -77,6 +77,34 @@ static void __init percpu_setup_debug_store(unsigned int cpu) #endif } +#ifdef CONFIG_X86_64 + +#define cea_map_stack(name) do { \ + npages = sizeof(estacks->name## _stack) / PAGE_SIZE; \ + cea_map_percpu_pages(cea->estacks.name## _stack, \ + estacks->name## _stack, npages, PAGE_KERNEL); \ + } while (0) + +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 separately. + */ + 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 +162,8 @@ static void __init setup_cpu_entry_area(unsigned int cpu) 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); }
