[PATCH] efi: arm64: add debugfs node to dump UEFI runtime page tables

Register the debugfs node 'efi_page_tables' to allow the UEFI runtime
page tables to be inspected. Note that ARM does not have 'asm/ptdump.h'
[yet] so for now, this is arm64 only.

Signed-off-by: Ard Biesheuvel <redacted>
---

This patch could be helpful in assessing the series 'arm64: avoid block
entries that we need to split later' that I sent out yesterday.

 drivers/firmware/efi/arm-runtime.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 17ccf0a8787a..4197a1da013d 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c

@@ -39,6 +39,26 @@ static struct mm_struct efi_mm = {
 	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
 };
 
+#ifdef CONFIG_ARM64
+#include <asm/ptdump.h>
+
+static struct ptdump_info efi_ptdump_info = {
+	.mm		= &efi_mm,
+	.markers	= (struct addr_marker[]){
+		{ 0,		"UEFI runtime start" },
+		{ TASK_SIZE_64,	"UEFI runtime end" }
+	},
+	.base_addr	= 0,
+};
+
+static int __init ptdump_init(void)
+{
+	return ptdump_register(&efi_ptdump_info, "efi_page_tables");
+}
+device_initcall(ptdump_init);
+
+#endif
+
 static bool __init efi_virtmap_init(void)
 {
 	efi_memory_desc_t *md;

-- 
2.7.4

On Thu, Jun 30, 2016 at 12:01:46PM +0200, Ard Biesheuvel wrote:

Register the debugfs node 'efi_page_tables' to allow the UEFI runtime
page tables to be inspected. Note that ARM does not have 'asm/ptdump.h'
[yet] so for now, this is arm64 only.

Signed-off-by: Ard Biesheuvel <redacted>
---

This patch could be helpful in assessing the series 'arm64: avoid block
entries that we need to split later' that I sent out yesterday.

It's probably worth noting that this is based on the arm64 for-next/core
branch. I don't know if/how we can orgnise branches for merging this.

If you use CONFIG_ARM64_PTDUMP for the moment, then we won't have some
unused structs lying around when the feature is unused.

Otherwise, I agree that this is a useful debuging feature. FWIW, either
way:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Thanks,
Mark.

+#include <asm/ptdump.h>
+
+static struct ptdump_info efi_ptdump_info = {
+	.mm		= &efi_mm,
+	.markers	= (struct addr_marker[]){
+		{ 0,		"UEFI runtime start" },
+		{ TASK_SIZE_64,	"UEFI runtime end" }
+	},
+	.base_addr	= 0,
+};
+
+static int __init ptdump_init(void)
+{
+	return ptdump_register(&efi_ptdump_info, "efi_page_tables");
+}
+device_initcall(ptdump_init);
+
+#endif
+
 static bool __init efi_virtmap_init(void)
 {
 	efi_memory_desc_t *md;
-- 
2.7.4

On 30 June 2016 at 16:09, Mark Rutland [off-list ref] wrote:

On Thu, Jun 30, 2016 at 12:01:46PM +0200, Ard Biesheuvel wrote:

quoted

Register the debugfs node 'efi_page_tables' to allow the UEFI runtime
page tables to be inspected. Note that ARM does not have 'asm/ptdump.h'
[yet] so for now, this is arm64 only.

Signed-off-by: Ard Biesheuvel <redacted>
---

This patch could be helpful in assessing the series 'arm64: avoid block
entries that we need to split later' that I sent out yesterday.

It's probably worth noting that this is based on the arm64 for-next/core
branch. I don't know if/how we can orgnise branches for merging this.

There's no rush, so Matt can take it for v4.9 I suppose?

quoted

 drivers/firmware/efi/arm-runtime.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 17ccf0a8787a..4197a1da013d 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c

@@ -39,6 +39,26 @@ static struct mm_struct efi_mm = {
      .mmlist                 = LIST_HEAD_INIT(efi_mm.mmlist),
 };

+#ifdef CONFIG_ARM64

If you use CONFIG_ARM64_PTDUMP for the moment, then we won't have some
unused structs lying around when the feature is unused.

I can change that

Otherwise, I agree that this is a useful debuging feature. FWIW, either
way:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Thanks.