diff --git a/arch/x86/include/asm/cpu_entry_area.h b/arch/x86/include/asm/cpu_entry_area.h index dd5ea1bdf04c5fae8c4fc9af3aa592533055bca5..e2c04a5015b029912d1e1b1f775e1e37adb40ee9 100644 --- a/arch/x86/include/asm/cpu_entry_area.h +++ b/arch/x86/include/asm/cpu_entry_area.h @@ -130,10 +130,6 @@ struct cpu_entry_area { }; #define CPU_ENTRY_AREA_SIZE (sizeof(struct cpu_entry_area)) -#define CPU_ENTRY_AREA_ARRAY_SIZE (CPU_ENTRY_AREA_SIZE * NR_CPUS) - -/* Total size includes the readonly IDT mapping page as well: */ -#define CPU_ENTRY_AREA_TOTAL_SIZE (CPU_ENTRY_AREA_ARRAY_SIZE + PAGE_SIZE) DECLARE_PER_CPU(struct cpu_entry_area *, cpu_entry_area); DECLARE_PER_CPU(struct cea_exception_stacks *, cea_exception_stacks); diff --git a/arch/x86/include/asm/pgtable_areas.h b/arch/x86/include/asm/pgtable_areas.h index d34cce1b995cf133b81058c4f53808880f0efe0a..4f056fb88174bb20036a53e809a9cb4759bd4dc3 100644 --- a/arch/x86/include/asm/pgtable_areas.h +++ b/arch/x86/include/asm/pgtable_areas.h @@ -11,6 +11,12 @@ #define CPU_ENTRY_AREA_RO_IDT_VADDR ((void *)CPU_ENTRY_AREA_RO_IDT) -#define CPU_ENTRY_AREA_MAP_SIZE (CPU_ENTRY_AREA_PER_CPU + CPU_ENTRY_AREA_ARRAY_SIZE - CPU_ENTRY_AREA_BASE) +#ifdef CONFIG_X86_32 +#define CPU_ENTRY_AREA_MAP_SIZE (CPU_ENTRY_AREA_PER_CPU + \ + (CPU_ENTRY_AREA_SIZE * NR_CPUS) - \ + CPU_ENTRY_AREA_BASE) +#else +#define CPU_ENTRY_AREA_MAP_SIZE P4D_SIZE +#endif #endif /* _ASM_X86_PGTABLE_AREAS_H */ diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index 668a4a6533d923c7eddef457f3f2ebac0040a00b..bbb0f737aab1904e82a54f08e4ad41b90d435ef5 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -266,7 +266,7 @@ static inline bool within_cpu_entry(unsigned long addr, unsigned long end) /* CPU entry erea is always used for CPU entry */ if (within_area(addr, end, CPU_ENTRY_AREA_BASE, - CPU_ENTRY_AREA_TOTAL_SIZE)) + CPU_ENTRY_AREA_MAP_SIZE)) return true; /* diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 6c2f1b76a0b61028548e33f215b1eb548ad8bf01..98396a67958c4e26e26baa72b86b1576c166a576 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -5,6 +5,7 @@ #include #include #include +#include #include #include @@ -15,16 +16,57 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(struct entry_stack_page, entry_stack_storage) #ifdef CONFIG_X86_64 static DEFINE_PER_CPU_PAGE_ALIGNED(struct exception_stacks, exception_stacks); DEFINE_PER_CPU(struct cea_exception_stacks*, cea_exception_stacks); -#endif -#ifdef CONFIG_X86_32 +static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, _cea_offset); + +static __always_inline unsigned int cea_offset(unsigned int cpu) +{ + return per_cpu(_cea_offset, cpu); +} + +static __init void init_cea_offsets(void) +{ + unsigned int max_cea; + unsigned int i, j; + + max_cea = (CPU_ENTRY_AREA_MAP_SIZE - PAGE_SIZE) / CPU_ENTRY_AREA_SIZE; + + /* O(sodding terrible) */ + for_each_possible_cpu(i) { + unsigned int cea; + +again: + /* + * Directly use get_random_u32() instead of prandom_u32_max + * to avoid seed can't be generated when CONFIG_RANDOMIZE_BASE=n. + */ + cea = (u32)(((u64) get_random_u32() * max_cea) >> 32); + + for_each_possible_cpu(j) { + if (cea_offset(j) == cea) + goto again; + + if (i == j) + break; + } + + per_cpu(_cea_offset, i) = cea; + } +} +#else /* !X86_64 */ DECLARE_PER_CPU_PAGE_ALIGNED(struct doublefault_stack, doublefault_stack); + +static __always_inline unsigned int cea_offset(unsigned int cpu) +{ + return cpu; +} +static inline void init_cea_offsets(void) { } #endif /* Is called from entry code, so must be noinstr */ noinstr struct cpu_entry_area *get_cpu_entry_area(int cpu) { - unsigned long va = CPU_ENTRY_AREA_PER_CPU + cpu * CPU_ENTRY_AREA_SIZE; + unsigned long va = CPU_ENTRY_AREA_PER_CPU + cea_offset(cpu) * CPU_ENTRY_AREA_SIZE; BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0); return (struct cpu_entry_area *) va; @@ -205,7 +247,6 @@ static __init void setup_cpu_entry_area_ptes(void) /* The +1 is for the readonly IDT: */ BUILD_BUG_ON((CPU_ENTRY_AREA_PAGES+1)*PAGE_SIZE != CPU_ENTRY_AREA_MAP_SIZE); - BUILD_BUG_ON(CPU_ENTRY_AREA_TOTAL_SIZE != CPU_ENTRY_AREA_MAP_SIZE); BUG_ON(CPU_ENTRY_AREA_BASE & ~PMD_MASK); start = CPU_ENTRY_AREA_BASE; @@ -221,6 +262,8 @@ void __init setup_cpu_entry_areas(void) { unsigned int cpu; + init_cea_offsets(); + setup_cpu_entry_area_ptes(); for_each_possible_cpu(cpu)