lkml.org 
[lkml]   [2021]   [Oct]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] arm64: ptdump: Support userspace page tables
Date
The kernel_page_tables debugfs file can be used to examine the page
table entries for mappings in kernel space but there is currently no
easy way to check userspace mappings. /proc/*/pagemap provides some
information but it does not include architecture-specific details such
as the memory type (Normal, Device etc).

Add a user_page_tables debugfs file to dump out the userspace page
tables for the current process. This is enabled by the same config
options as kernel_page_tables.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
---

Notes:
v2: Reworded commit message.

arch/arm64/mm/ptdump.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
index 1c403536c9bb..91a62f07eae2 100644
--- a/arch/arm64/mm/ptdump.c
+++ b/arch/arm64/mm/ptdump.c
@@ -309,6 +309,7 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,

void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
{
+ struct mm_struct *mm = info->mm ?: current->mm;
unsigned long end = ~0UL;
struct pg_state st;

@@ -328,7 +329,7 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
}
};

- ptdump_walk_pgd(&st.ptdump, info->mm, NULL);
+ ptdump_walk_pgd(&st.ptdump, mm, NULL);
}

static void __init ptdump_initialize(void)
@@ -347,6 +348,16 @@ static struct ptdump_info kernel_ptdump_info = {
.base_addr = PAGE_OFFSET,
};

+static struct addr_marker user_address_markers[] = {
+ { 0, "Userspace memory start" },
+ { 0 /* TASK_SIZE_64 */, "Userspace memory end" },
+ { -1, NULL },
+};
+
+static struct ptdump_info user_ptdump_info = {
+ .markers = user_address_markers,
+};
+
void ptdump_check_wx(void)
{
struct pg_state st = {
@@ -381,8 +392,10 @@ static int __init ptdump_init(void)
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
address_markers[KASAN_START_NR].start_address = KASAN_SHADOW_START;
#endif
+ user_address_markers[1].start_address = TASK_SIZE_64;
ptdump_initialize();
ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables");
+ ptdump_debugfs_register(&user_ptdump_info, "user_page_tables");
return 0;
}
device_initcall(ptdump_init);
--
2.28.0
\
 
 \ /
  Last update: 2021-10-14 10:14    [W:0.028 / U:0.900 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site