diff options
Diffstat (limited to 'arch/x86/mm/kaiser.c')
| -rw-r--r-- | arch/x86/mm/kaiser.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c new file mode 100644 index 000000000000..cf1bb922d467 --- /dev/null +++ b/arch/x86/mm/kaiser.c @@ -0,0 +1,160 @@ + + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/bug.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/mm.h> + +#include <linux/uaccess.h> +#include <asm/pgtable.h> +#include <asm/pgalloc.h> +#include <asm/desc.h> +#ifdef CONFIG_KAISER + +__visible DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup); + +/** + * Get the real ppn from a address in kernel mapping. + * @param address The virtual adrress + * @return the physical address + */ +static inline unsigned long get_pa_from_mapping (unsigned long address) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = pgd_offset_k(address); + BUG_ON(pgd_none(*pgd) || pgd_large(*pgd)); + + pud = pud_offset(pgd, address); + BUG_ON(pud_none(*pud)); + + if (pud_large(*pud)) { + return (pud_pfn(*pud) << PAGE_SHIFT) | (address & ~PUD_PAGE_MASK); + } + + pmd = pmd_offset(pud, address); + BUG_ON(pmd_none(*pmd)); + + if (pmd_large(*pmd)) { + return (pmd_pfn(*pmd) << PAGE_SHIFT) | (address & ~PMD_PAGE_MASK); + } + + pte = pte_offset_kernel(pmd, address); + BUG_ON(pte_none(*pte)); + + return (pte_pfn(*pte) << PAGE_SHIFT) | (address & ~PAGE_MASK); +} + +void _kaiser_copy (unsigned long start_addr, unsigned long size, + unsigned long flags) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + unsigned long address; + unsigned long end_addr = start_addr + size; + unsigned long target_address; + + for (address = PAGE_ALIGN(start_addr - (PAGE_SIZE - 1)); + address < PAGE_ALIGN(end_addr); address += PAGE_SIZE) { + target_address = get_pa_from_mapping(address); + + pgd = native_get_shadow_pgd(pgd_offset_k(address)); + + BUG_ON(pgd_none(*pgd) && "All shadow pgds should be mapped at this time\n"); + BUG_ON(pgd_large(*pgd)); + + pud = pud_offset(pgd, address); + if (pud_none(*pud)) { + set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd_alloc_one(0, address)))); + } + BUG_ON(pud_large(*pud)); + + pmd = pmd_offset(pud, address); + if (pmd_none(*pmd)) { + set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte_alloc_one_kernel(0, address)))); + } + BUG_ON(pmd_large(*pmd)); + + pte = pte_offset_kernel(pmd, address); + if (pte_none(*pte)) { + set_pte(pte, __pte(flags | target_address)); + } else { + BUG_ON(__pa(pte_page(*pte)) != target_address); + } + } +} + +// at first, add a pmd for every pgd entry in the shadowmem-kernel-part of the kernel mapping +static inline void __init _kaiser_init(void) +{ + pgd_t *pgd; + int i = 0; + + pgd = native_get_shadow_pgd(pgd_offset_k((unsigned long )0)); + for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) { + set_pgd(pgd + i, __pgd(_PAGE_TABLE |__pa(pud_alloc_one(0, 0)))); + } +} + +extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[]; +spinlock_t shadow_table_lock; +void __init kaiser_init(void) +{ + int cpu; + spin_lock_init(&shadow_table_lock); + + spin_lock(&shadow_table_lock); + + _kaiser_init(); + + for_each_possible_cpu(cpu) { + // map the per cpu user variables + _kaiser_copy( + (unsigned long) (__per_cpu_user_mapped_start + per_cpu_offset(cpu)), + (unsigned long) __per_cpu_user_mapped_end - (unsigned long) __per_cpu_user_mapped_start, + __PAGE_KERNEL); + } + + // map the entry/exit text section, which is responsible to switch between user- and kernel mode + _kaiser_copy( + (unsigned long) __entry_text_start, + (unsigned long) __entry_text_end - (unsigned long) __entry_text_start, + __PAGE_KERNEL_RX); + + // the fixed map address of the idt_table + _kaiser_copy( + (unsigned long) idt_descr.address, + sizeof(gate_desc) * NR_VECTORS, + __PAGE_KERNEL_RO); + + spin_unlock(&shadow_table_lock); +} + +// add a mapping to the shadow-mapping, and synchronize the mappings +void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags) +{ + spin_lock(&shadow_table_lock); + _kaiser_copy(addr, size, flags); + spin_unlock(&shadow_table_lock); +} + +extern void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end); +void kaiser_remove_mapping(unsigned long start, unsigned long size) +{ + pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(start)); + spin_lock(&shadow_table_lock); + do { + unmap_pud_range(pgd, start, start + size); + } while (pgd++ != native_get_shadow_pgd(pgd_offset_k(start + size))); + spin_unlock(&shadow_table_lock); +} +#endif /* CONFIG_KAISER */ |