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

Atish Patra
2020-07-29T23:37:08Z

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.patra@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