Merge remote-tracking branch 'at91/at91-next'

[karo-tx-linux.git] / arch / x86 / mm / dump_pagetables.c

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 71ab2d7410244f3bd3e1ec6615289a22f243b11d..1bf417e9cc1309e3353f08fee9dad6915fb34c0c 100644 (file)
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -32,6 +32,8 @@ struct pg_state {
        const struct addr_marker *marker;
        unsigned long lines;
        bool to_dmesg;
+       bool check_wx;
+       unsigned long wx_pages;
 };
 
 struct addr_marker {
@@ -214,6 +216,16 @@ static void note_page(struct seq_file *m, struct pg_state *st,
                const char *unit = units;
                unsigned long delta;
                int width = sizeof(unsigned long) * 2;
+               pgprotval_t pr = pgprot_val(st->current_prot);
+
+               if (st->check_wx && (pr & _PAGE_RW) && !(pr & _PAGE_NX)) {
+                       WARN_ONCE(1,
+                                 "x86/mm: Found insecure W+X mapping at address %p/%pS\n",
+                                 (void *)st->start_address,
+                                 (void *)st->start_address);
+                       st->wx_pages += (st->current_address -
+                                        st->start_address) / PAGE_SIZE;
+               }
 
                /*
                 * Now print the actual finished series
@@ -346,7 +358,8 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
 #define pgd_none(a)  pud_none(__pud(pgd_val(a)))
 #endif
 
-void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
+static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
+                                      bool checkwx)
 {
 #ifdef CONFIG_X86_64
        pgd_t *start = (pgd_t *) &init_level4_pgt;
@@ -362,6 +375,10 @@ void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
                st.to_dmesg = true;
        }
 
+       st.check_wx = checkwx;
+       if (checkwx)
+               st.wx_pages = 0;
+
        for (i = 0; i < PTRS_PER_PGD; i++) {
                st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
                if (!pgd_none(*start)) {
@@ -381,8 +398,26 @@ void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
        /* Flush out the last page */
        st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT);
        note_page(m, &st, __pgprot(0), 0);
+       if (!checkwx)
+               return;
+       if (st.wx_pages)
+               pr_info("x86/mm: Checked W+X mappings: FAILED, %lu W+X pages found.\n",
+                       st.wx_pages);
+       else
+               pr_info("x86/mm: Checked W+X mappings: passed, no W+X pages found.\n");
+}
+
+void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
+{
+       ptdump_walk_pgd_level_core(m, pgd, false);
 }
 
+void ptdump_walk_pgd_level_checkwx(void)
+{
+       ptdump_walk_pgd_level_core(NULL, NULL, true);
+}
+
+#ifdef CONFIG_X86_PTDUMP
 static int ptdump_show(struct seq_file *m, void *v)
 {
        ptdump_walk_pgd_level(m, NULL);
@@ -400,10 +435,13 @@ static const struct file_operations ptdump_fops = {
        .llseek         = seq_lseek,
        .release        = single_release,
 };
+#endif
 
 static int pt_dump_init(void)
 {
+#ifdef CONFIG_X86_PTDUMP
        struct dentry *pe;
+#endif
 
 #ifdef CONFIG_X86_32
        /* Not a compile-time constant on x86-32 */
@@ -415,10 +453,12 @@ static int pt_dump_init(void)
        address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
 #endif
 
+#ifdef CONFIG_X86_PTDUMP
        pe = debugfs_create_file("kernel_page_tables", 0600, NULL, NULL,
                                 &ptdump_fops);
        if (!pe)
                return -ENOMEM;
+#endif
 
        return 0;
 }