Merge branch 'x86/espfix' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next

Pull x86-64 espfix changes from Peter Anvin:
 "This is the espfix64 code, which fixes the IRET information leak as
  well as the associated functionality problem.  With this code applied,
  16-bit stack segments finally work as intended even on a 64-bit
  kernel.

  Consequently, this patchset also removes the runtime option that we
  added as an interim measure.

  To help the people working on Linux kernels for very small systems,
  this patchset also makes these compile-time configurable features"

* 'x86/espfix' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option"
  x86, espfix: Make it possible to disable 16-bit support
  x86, espfix: Make espfix64 a Kconfig option, fix UML
  x86, espfix: Fix broken header guard
  x86, espfix: Move espfix definitions into a separate header file
  x86-32, espfix: Remove filter for espfix32 due to race
  x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack

1 files changed, 33 insertions, 11 deletions

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 20621d753d5f..167ffcac16ed 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -30,12 +30,14 @@ struct pg_state {
         unsigned long start_address;
         unsigned long current_address;
         const struct addr_marker *marker;
+        unsigned long lines;
         bool to_dmesg;
 };
 
 struct addr_marker {
         unsigned long start_address;
         const char *name;
+        unsigned long max_lines;
 };
 
 /* indices for address_markers; keep sync'd w/ address_markers below */
@@ -46,6 +48,7 @@ enum address_markers_idx {
         LOW_KERNEL_NR,
         VMALLOC_START_NR,
         VMEMMAP_START_NR,
+        ESPFIX_START_NR,
         HIGH_KERNEL_NR,
         MODULES_VADDR_NR,
         MODULES_END_NR,
@@ -68,6 +71,7 @@ static struct addr_marker address_markers[] = {
         { PAGE_OFFSET,          "Low Kernel Mapping" },
         { VMALLOC_START,        "vmalloc() Area" },
         { VMEMMAP_START,        "Vmemmap" },
+        { ESPFIX_BASE_ADDR,     "ESPfix Area", 16 },
         { __START_KERNEL_map,   "High Kernel Mapping" },
         { MODULES_VADDR,        "Modules" },
         { MODULES_END,          "End Modules" },
@@ -182,7 +186,7 @@ static void note_page(struct seq_file *m, struct pg_state *st,
                       pgprot_t new_prot, int level)
 {
         pgprotval_t prot, cur;
-        static const char units[] = "KMGTPE";
+        static const char units[] = "BKMGTPE";
 
         /*
          * If we have a "break" in the series, we need to flush the state that
@@ -197,6 +201,7 @@ static void note_page(struct seq_file *m, struct pg_state *st,
                 st->current_prot = new_prot;
                 st->level = level;
                 st->marker = address_markers;
+                st->lines = 0;
                 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
                                    st->marker->name);
         } else if (prot != cur || level != st->level ||
@@ -208,17 +213,24 @@ static void note_page(struct seq_file *m, struct pg_state *st,
                 /*
                  * Now print the actual finished series
                  */
-                pt_dump_seq_printf(m, st->to_dmesg,  "0x%0*lx-0x%0*lx   ",
-                                   width, st->start_address,
-                                   width, st->current_address);
-
-                delta = (st->current_address - st->start_address) >> 10;
-                while (!(delta & 1023) && unit[1]) {
-                        delta >>= 10;
-                        unit++;
+                if (!st->marker->max_lines ||
+                    st->lines < st->marker->max_lines) {
+                        pt_dump_seq_printf(m, st->to_dmesg,
+                                           "0x%0*lx-0x%0*lx   ",
+                                           width, st->start_address,
+                                           width, st->current_address);
+
+                        delta = st->current_address - st->start_address;
+                        while (!(delta & 1023) && unit[1]) {
+                                delta >>= 10;
+                                unit++;
+                        }
+                        pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ",
+                                            delta, *unit);
+                        printk_prot(m, st->current_prot, st->level,
+                                    st->to_dmesg);
                 }
-                pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ", delta, *unit);
-                printk_prot(m, st->current_prot, st->level, st->to_dmesg);
+                st->lines++;
 
                 /*
                  * We print markers for special areas of address space,
@@ -226,7 +238,17 @@ static void note_page(struct seq_file *m, struct pg_state *st,
                  * This helps in the interpretation.
                  */
                 if (st->current_address >= st->marker[1].start_address) {
+                        if (st->marker->max_lines &&
+                            st->lines > st->marker->max_lines) {
+                                unsigned long nskip =
+                                        st->lines - st->marker->max_lines;
+                                pt_dump_seq_printf(m, st->to_dmesg,
+                                                   "... %lu entr%s skipped ... \n",
+                                                   nskip,
+                                                   nskip == 1 ? "y" : "ies");
+                        }
                         st->marker++;
+                        st->lines = 0;
                         pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
                                            st->marker->name);
                 }