[RFT PATCH v4 9/9] RISC-V: Add page table dump support for uefi

[Atish Patra]

Extend the current page table dump support in RISC-V to include efi
pages as well.

Here is the output of efi runtime page table mappings.

---[ UEFI runtime start ]---
0x0000000020002000-0x0000000020003000 0x00000000be732000 4K PTE D A . . . W R V
0x0000000020018000-0x0000000020019000 0x00000000be738000 4K PTE D A . . . W R V
0x000000002002c000-0x000000002002d000 0x00000000be73c000 4K PTE D A . . . W R V
0x0000000020031000-0x0000000020032000 0x00000000bff61000 4K PTE D A . . X W R V
---[ UEFI runtime end ]---

Signed-off-by: Atish Patra <atish.pa...@wdc.com>
---
 arch/riscv/mm/ptdump.c | 48 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 42 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c
index 0831c2e61a8f..ace74dec7492 100644
--- a/arch/riscv/mm/ptdump.c
+++ b/arch/riscv/mm/ptdump.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2019 SiFive
  */
 
+#include <linux/efi.h>
 #include <linux/init.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
@@ -49,6 +50,14 @@ struct addr_marker {
        const char *name;
 };
 
+/* Private information for debugfs */
+struct ptd_mm_info {
+       struct mm_struct                *mm;
+       const struct addr_marker        *markers;
+       unsigned long base_addr;
+       unsigned long end;
+};
+
 static struct addr_marker address_markers[] = {
 #ifdef CONFIG_KASAN
        {KASAN_SHADOW_START,    "Kasan shadow start"},
@@ -68,6 +77,28 @@ static struct addr_marker address_markers[] = {
        {-1, NULL},
 };
 
+static struct ptd_mm_info kernel_ptd_info = {
+       .mm             = &init_mm,
+       .markers        = address_markers,
+       .base_addr      = KERN_VIRT_START,
+       .end            = ULONG_MAX,
+};
+
+#ifdef CONFIG_EFI
+static struct addr_marker efi_addr_markers[] = {
+               { 0,            "UEFI runtime start" },
+               { SZ_1G,        "UEFI runtime end" },
+               { -1,           NULL }
+};
+
+static struct ptd_mm_info efi_ptd_info = {
+       .mm             = &efi_mm,
+       .markers        = efi_addr_markers,
+       .base_addr      = 0,
+       .end            = SZ_2G,
+};
+#endif
+
 /* Page Table Entry */
 struct prot_bits {
        u64 mask;
@@ -245,22 +276,22 @@ static void note_page(struct ptdump_state *pt_st, 
unsigned long addr,
        }
 }
 
-static void ptdump_walk(struct seq_file *s)
+static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo)
 {
        struct pg_state st = {
                .seq = s,
-               .marker = address_markers,
+               .marker = pinfo->markers,
                .level = -1,
                .ptdump = {
                        .note_page = note_page,
                        .range = (struct ptdump_range[]) {
-                               {KERN_VIRT_START, ULONG_MAX},
+                               {pinfo->base_addr, pinfo->end},
                                {0, 0}
                        }
                }
        };
 
-       ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
+       ptdump_walk_pgd(&st.ptdump, pinfo->mm, NULL);
 }
 
 void ptdump_check_wx(void)
@@ -293,7 +324,7 @@ void ptdump_check_wx(void)
 
 static int ptdump_show(struct seq_file *m, void *v)
 {
-       ptdump_walk(m);
+       ptdump_walk(m, m->private);
 
        return 0;
 }
@@ -308,8 +339,13 @@ static int ptdump_init(void)
                for (j = 0; j < ARRAY_SIZE(pte_bits); j++)
                        pg_level[i].mask |= pte_bits[j].mask;
 
-       debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
+       debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info,
                            &ptdump_fops);
+#ifdef CONFIG_EFI
+       if (efi_enabled(EFI_RUNTIME_SERVICES))
+               debugfs_create_file("efi_page_tables", 0400, NULL, 
&efi_ptd_info,
+                                   &ptdump_fops);
+#endif
 
        return 0;
 }
-- 
2.24.0