ARM: ptdump: Add domain to output

This adds the memory domain (on non-LPAE) to the PMD and PTE dumps. This isn't in the regular PMD bit struct because I couldn't find a clean way to fall back to retain some of the PMD bits when reporting PTE. So this is special-cased for now.

New output example:

---[ Modules ]---

0x7f000000-0x7f001000       4K DOMAIN_KERNEL      ro x  SHD MEM/CACHED/WBWA
0x7f001000-0x7f002000       4K DOMAIN_KERNEL      ro NX SHD MEM/CACHED/WBWA
0x7f002000-0x7f004000       8K DOMAIN_KERNEL      RW NX SHD MEM/CACHED/WBWA
---[ Kernel Mapping ]---
0x80000000-0x80100000       1M DOMAIN_KERNEL      RW NX SHD
0x80100000-0x80800000       7M DOMAIN_KERNEL      ro x  SHD
0x80800000-0x80b00000       3M DOMAIN_KERNEL      ro NX SHD
0x80b00000-0xa0000000     501M DOMAIN_KERNEL      RW NX SHD
...
---[ Vectors ]---
0xffff0000-0xffff1000       4K DOMAIN_VECTORS USR ro x  SHD MEM/CACHED/WBWA
0xffff1000-0xffff2000       4K DOMAIN_VECTORS     ro x  SHD MEM/CACHED/WBWA

Signed-off-by Kees Cook <[email protected]>

---
This actually works correctly now (tested by forcing different domains on portions of the Kernel Mapping. I really wanted to find a way to use the existing bit structs, but I couldn't make anything work... I'm open to ideas.

---
 arch/arm/mm/dump.c | 54 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 44 insertions(+), 10 deletions(-)

arch/arm/mm/dump.c +44 -11

index 21192d6eda40..3770d9f83bdc 100644
@@ -17,6 +17,7 @@
 #include <linux/mm.h>
 #include <linux/seq_file.h>
 
+#include <asm/domain.h>
 #include <asm/fixmap.h>
 #include <asm/memory.h>
 #include <asm/pgtable.h>

@@ -43,6 +44,7 @@ struct pg_state {
        unsigned long start_address;
        unsigned level;
        u64 current_prot;
+       const char *current_domain;
 };
 
 struct prot_bits {

@@ -216,7 +218,8 @@ static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t
        }
 }
 
-static void note_page(struct pg_state *st, unsigned long addr, unsigned level, u64 val)
+static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
+                     u64 val, const char *domain)
 {
        static const char units[] = "KMGTPE";
        u64 prot = val & pg_level[level].mask;

@@ -224,8 +227,10 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level, u
        if (!st->level) {
                st->level = level;
                st->current_prot = prot;
+               st->current_domain = domain;
                seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
        } else if (prot != st->current_prot || level != st->level ||
+                  domain != st->current_domain ||
                   addr >= st->marker[1].start_address) {
                const char *unit = units;
                unsigned long delta;

@@ -240,6 +245,8 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level, u
                                unit++;
                        }
                        seq_printf(st->seq, "%9lu%c", delta, *unit);
+                       if (st->current_domain)
+                               seq_printf(st->seq, " %s", st->current_domain);
                        if (pg_level[st->level].bits)
                                dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num);
                        seq_printf(st->seq, "\n");

@@ -251,11 +258,13 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level, u
                }
                st->start_address = addr;
                st->current_prot = prot;
+               st->current_domain = domain;
                st->level = level;
        }
 }
 
-static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
+static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start,
+                    const char *domain)
 {
        pte_t *pte = pte_offset_kernel(pmd, 0);
        unsigned long addr;

@@ -263,25 +272,50 @@ static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
 
        for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
                addr = start + i * PAGE_SIZE;
-               note_page(st, addr, 4, pte_val(*pte));
+               note_page(st, addr, 4, pte_val(*pte), domain);
        }
 }
 
+static const char *get_domain_name(pmd_t *pmd)
+{
+#ifndef CONFIG_ARM_LPAE
+       switch (pmd_val(*pmd) & PMD_DOMAIN_MASK) {
+       case PMD_DOMAIN(DOMAIN_KERNEL):
+               return "DOMAIN_KERNEL ";
+       case PMD_DOMAIN(DOMAIN_USER):
+               return "DOMAIN_USER   ";
+       case PMD_DOMAIN(DOMAIN_IO):
+               return "DOMAIN_IO     ";
+       case PMD_DOMAIN(DOMAIN_VECTORS):
+               return "DOMAIN_VECTORS";
+       default:
+               return "DOMAIN_unknown";
+       }
+#endif
+       return NULL;
+}
+
 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 {
        pmd_t *pmd = pmd_offset(pud, 0);
        unsigned long addr;
        unsigned i;
+       const char *domain;
 
        for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
                addr = start + i * PMD_SIZE;
+               domain = get_domain_name(pmd);
                if (pmd_none(*pmd) || pmd_large(*pmd) || !pmd_present(*pmd))
-                       note_page(st, addr, 3, pmd_val(*pmd));
+                       note_page(st, addr, 3, pmd_val(*pmd), domain);
                else
-                       walk_pte(st, pmd, addr);
+                       walk_pte(st, pmd, addr, domain);
 
-               if (SECTION_SIZE < PMD_SIZE && pmd_large(pmd[1]))
-                       note_page(st, addr + SECTION_SIZE, 3, pmd_val(pmd[1]));
+               if (SECTION_SIZE < PMD_SIZE && pmd_large(pmd[1])) {
+                       addr += SECTION_SIZE;
+                       pmd++;
+                       domain = get_domain_name(pmd);
+                       note_page(st, addr, 3, pmd_val(*pmd), domain);
+               }
        }
 }
 

@@ -296,7 +330,7 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
                if (!pud_none(*pud)) {
                        walk_pmd(st, pud, addr);
                } else {
-                       note_page(st, addr, 2, pud_val(*pud));
+                       note_page(st, addr, 2, pud_val(*pud), NULL);
                }
        }
 }

@@ -317,11 +351,11 @@ static void walk_pgd(struct seq_file *m)
                if (!pgd_none(*pgd)) {
                        walk_pud(&st, pgd, addr);
                } else {
-                       note_page(&st, addr, 1, pgd_val(*pgd));
+                       note_page(&st, addr, 1, pgd_val(*pgd), NULL);
                }
        }
 
-       note_page(&st, 0, 0, 0);
+       note_page(&st, 0, 0, 0, NULL);
 }
 
 static int ptdump_show(struct seq_file *m, void *v)
--

2.7.4

--
Kees Cook
Pixel Security

Quoted 3 lines

This actually works correctly now (tested by forcing different domains on portions of the Kernel Mapping. I really wanted to find a way to use the existing bit structs, but I couldn't make anything work... I'm open to ideas.

Any feedback on this? Should I submit this to the ARM patch tracker?