1 files changed, 153 insertions, 0 deletions

diff --git a/arch/x86/mm/kmemcheck/shadow.c b/arch/x86/mm/kmemcheck/shadow.c
new file mode 100644
index 000000000000..5544d3600877
--- /dev/null
+++ b/arch/x86/mm/kmemcheck/shadow.c
@@ -0,0 +1,153 @@
+#include <linux/kmemcheck.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+#include "pte.h"
+#include "shadow.h"
+
+/*
+ * Return the shadow address for the given address. Returns NULL if the
+ * address is not tracked.
+ *
+ * We need to be extremely careful not to follow any invalid pointers,
+ * because this function can be called for *any* possible address.
+ */
+void *kmemcheck_shadow_lookup(unsigned long address)
+{
+        pte_t *pte;
+        struct page *page;
+
+        if (!virt_addr_valid(address))
+                return NULL;
+
+        pte = kmemcheck_pte_lookup(address);
+        if (!pte)
+                return NULL;
+
+        page = virt_to_page(address);
+        if (!page->shadow)
+                return NULL;
+        return page->shadow + (address & (PAGE_SIZE - 1));
+}
+
+static void mark_shadow(void *address, unsigned int n,
+        enum kmemcheck_shadow status)
+{
+        unsigned long addr = (unsigned long) address;
+        unsigned long last_addr = addr + n - 1;
+        unsigned long page = addr & PAGE_MASK;
+        unsigned long last_page = last_addr & PAGE_MASK;
+        unsigned int first_n;
+        void *shadow;
+
+        /* If the memory range crosses a page boundary, stop there. */
+        if (page == last_page)
+                first_n = n;
+        else
+                first_n = page + PAGE_SIZE - addr;
+
+        shadow = kmemcheck_shadow_lookup(addr);
+        if (shadow)
+                memset(shadow, status, first_n);
+
+        addr += first_n;
+        n -= first_n;
+
+        /* Do full-page memset()s. */
+        while (n >= PAGE_SIZE) {
+                shadow = kmemcheck_shadow_lookup(addr);
+                if (shadow)
+                        memset(shadow, status, PAGE_SIZE);
+
+                addr += PAGE_SIZE;
+                n -= PAGE_SIZE;
+        }
+
+        /* Do the remaining page, if any. */
+        if (n > 0) {
+                shadow = kmemcheck_shadow_lookup(addr);
+                if (shadow)
+                        memset(shadow, status, n);
+        }
+}
+
+void kmemcheck_mark_unallocated(void *address, unsigned int n)
+{
+        mark_shadow(address, n, KMEMCHECK_SHADOW_UNALLOCATED);
+}
+
+void kmemcheck_mark_uninitialized(void *address, unsigned int n)
+{
+        mark_shadow(address, n, KMEMCHECK_SHADOW_UNINITIALIZED);
+}
+
+/*
+ * Fill the shadow memory of the given address such that the memory at that
+ * address is marked as being initialized.
+ */
+void kmemcheck_mark_initialized(void *address, unsigned int n)
+{
+        mark_shadow(address, n, KMEMCHECK_SHADOW_INITIALIZED);
+}
+EXPORT_SYMBOL_GPL(kmemcheck_mark_initialized);
+
+void kmemcheck_mark_freed(void *address, unsigned int n)
+{
+        mark_shadow(address, n, KMEMCHECK_SHADOW_FREED);
+}
+
+void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n)
+{
+        unsigned int i;
+
+        for (i = 0; i < n; ++i)
+                kmemcheck_mark_unallocated(page_address(&p[i]), PAGE_SIZE);
+}
+
+void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n)
+{
+        unsigned int i;
+
+        for (i = 0; i < n; ++i)
+                kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE);
+}
+
+enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)
+{
+        uint8_t *x;
+        unsigned int i;
+
+        x = shadow;
+
+#ifdef CONFIG_KMEMCHECK_PARTIAL_OK
+        /*
+         * Make sure _some_ bytes are initialized. Gcc frequently generates
+         * code to access neighboring bytes.
+         */
+        for (i = 0; i < size; ++i) {
+                if (x[i] == KMEMCHECK_SHADOW_INITIALIZED)
+                        return x[i];
+        }
+#else
+        /* All bytes must be initialized. */
+        for (i = 0; i < size; ++i) {
+                if (x[i] != KMEMCHECK_SHADOW_INITIALIZED)
+                        return x[i];
+        }
+#endif
+
+        return x[0];
+}
+
+void kmemcheck_shadow_set(void *shadow, unsigned int size)
+{
+        uint8_t *x;
+        unsigned int i;
+
+        x = shadow;
+        for (i = 0; i < size; ++i)
+                x[i] = KMEMCHECK_SHADOW_INITIALIZED;
+}