#include <linux/of_fdt.h>
#include <linux/mm.h>
#include <linux/string_helpers.h>
+#include <linux/stop_machine.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
+#include <asm/mmu_context.h>
#include <asm/dma.h>
#include <asm/machdep.h>
#include <asm/mmu.h>
"r" (TLBIEL_INVAL_SET_LPID), "r" (0));
asm volatile("eieio; tlbsync; ptesync" : : : "memory");
trace_tlbie(0, 0, TLBIEL_INVAL_SET_LPID, 0, 2, 1, 1);
+
+ /*
+ * The init_mm context is given the first available (non-zero) PID,
+ * which is the "guard PID" and contains no page table. PIDR should
+ * never be set to zero because that duplicates the kernel address
+ * space at the 0x0... offset (quadrant 0)!
+ *
+ * An arbitrary PID that may later be allocated by the PID allocator
+ * for userspace processes must not be used either, because that
+ * would cause stale user mappings for that PID on CPUs outside of
+ * the TLB invalidation scheme (because it won't be in mm_cpumask).
+ *
+ * So permanently carve out one PID for the purpose of a guard PID.
+ */
+ init_mm.context.id = mmu_base_pid;
+ mmu_base_pid++;
}
static void __init radix_init_partition_table(void)
__pmd_index_size = RADIX_PMD_INDEX_SIZE;
__pud_index_size = RADIX_PUD_INDEX_SIZE;
__pgd_index_size = RADIX_PGD_INDEX_SIZE;
+ __pud_cache_index = RADIX_PUD_INDEX_SIZE;
__pmd_cache_index = RADIX_PMD_INDEX_SIZE;
__pte_table_size = RADIX_PTE_TABLE_SIZE;
__pmd_table_size = RADIX_PMD_TABLE_SIZE;
radix_init_iamr();
radix_init_pgtable();
-
+ /* Switch to the guard PID before turning on MMU */
+ radix__switch_mmu_context(NULL, &init_mm);
if (cpu_has_feature(CPU_FTR_HVMODE))
tlbiel_all();
}
}
radix_init_iamr();
+ radix__switch_mmu_context(NULL, &init_mm);
if (cpu_has_feature(CPU_FTR_HVMODE))
tlbiel_all();
}
pud_clear(pud);
}
+struct change_mapping_params {
+ pte_t *pte;
+ unsigned long start;
+ unsigned long end;
+ unsigned long aligned_start;
+ unsigned long aligned_end;
+};
+
+static int stop_machine_change_mapping(void *data)
+{
+ struct change_mapping_params *params =
+ (struct change_mapping_params *)data;
+
+ if (!data)
+ return -1;
+
+ spin_unlock(&init_mm.page_table_lock);
+ pte_clear(&init_mm, params->aligned_start, params->pte);
+ create_physical_mapping(params->aligned_start, params->start);
+ create_physical_mapping(params->end, params->aligned_end);
+ spin_lock(&init_mm.page_table_lock);
+ return 0;
+}
+
static void remove_pte_table(pte_t *pte_start, unsigned long addr,
unsigned long end)
{
}
}
+/*
+ * clear the pte and potentially split the mapping helper
+ */
+static void split_kernel_mapping(unsigned long addr, unsigned long end,
+ unsigned long size, pte_t *pte)
+{
+ unsigned long mask = ~(size - 1);
+ unsigned long aligned_start = addr & mask;
+ unsigned long aligned_end = addr + size;
+ struct change_mapping_params params;
+ bool split_region = false;
+
+ if ((end - addr) < size) {
+ /*
+ * We're going to clear the PTE, but not flushed
+ * the mapping, time to remap and flush. The
+ * effects if visible outside the processor or
+ * if we are running in code close to the
+ * mapping we cleared, we are in trouble.
+ */
+ if (overlaps_kernel_text(aligned_start, addr) ||
+ overlaps_kernel_text(end, aligned_end)) {
+ /*
+ * Hack, just return, don't pte_clear
+ */
+ WARN_ONCE(1, "Linear mapping %lx->%lx overlaps kernel "
+ "text, not splitting\n", addr, end);
+ return;
+ }
+ split_region = true;
+ }
+
+ if (split_region) {
+ params.pte = pte;
+ params.start = addr;
+ params.end = end;
+ params.aligned_start = addr & ~(size - 1);
+ params.aligned_end = min_t(unsigned long, aligned_end,
+ (unsigned long)__va(memblock_end_of_DRAM()));
+ stop_machine(stop_machine_change_mapping, ¶ms, NULL);
+ return;
+ }
+
+ pte_clear(&init_mm, addr, pte);
+}
+
static void remove_pmd_table(pmd_t *pmd_start, unsigned long addr,
unsigned long end)
{
continue;
if (pmd_huge(*pmd)) {
- if (!IS_ALIGNED(addr, PMD_SIZE) ||
- !IS_ALIGNED(next, PMD_SIZE)) {
- WARN_ONCE(1, "%s: unaligned range\n", __func__);
- continue;
- }
-
- pte_clear(&init_mm, addr, (pte_t *)pmd);
+ split_kernel_mapping(addr, end, PMD_SIZE, (pte_t *)pmd);
continue;
}
continue;
if (pud_huge(*pud)) {
- if (!IS_ALIGNED(addr, PUD_SIZE) ||
- !IS_ALIGNED(next, PUD_SIZE)) {
- WARN_ONCE(1, "%s: unaligned range\n", __func__);
- continue;
- }
-
- pte_clear(&init_mm, addr, (pte_t *)pud);
+ split_kernel_mapping(addr, end, PUD_SIZE, (pte_t *)pud);
continue;
}
continue;
if (pgd_huge(*pgd)) {
- if (!IS_ALIGNED(addr, PGDIR_SIZE) ||
- !IS_ALIGNED(next, PGDIR_SIZE)) {
- WARN_ONCE(1, "%s: unaligned range\n", __func__);
- continue;
- }
-
- pte_clear(&init_mm, addr, (pte_t *)pgd);
+ split_kernel_mapping(addr, end, PGDIR_SIZE, (pte_t *)pgd);
continue;
}
projects / linux.git / blobdiff