dma-debug: add checks for kernel text and rodata
Impact: get notified if a device dma maps illegal areas
This patch adds a check to print a warning message when a device driver
tries to map a memory area from the kernel text segment or rodata.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index dba02f1..6022eb4 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -29,6 +29,8 @@
#include <linux/list.h>
#include <linux/slab.h>
+#include <asm/sections.h>
+
#define HASH_SIZE 1024ULL
#define HASH_FN_SHIFT 13
#define HASH_FN_MASK (HASH_SIZE - 1)
@@ -549,6 +551,24 @@
"stack [addr=%p]\n", addr);
}
+static inline bool overlap(void *addr, u64 size, void *start, void *end)
+{
+ void *addr2 = (char *)addr + size;
+
+ return ((addr >= start && addr < end) ||
+ (addr2 >= start && addr2 < end) ||
+ ((addr < start) && (addr2 >= end)));
+}
+
+static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
+{
+ if (overlap(addr, size, _text, _etext) ||
+ overlap(addr, size, __start_rodata, __end_rodata))
+ err_printk(dev, NULL, "DMA-API: device driver maps "
+ "memory from kernel text or rodata "
+ "[addr=%p] [size=%llu]\n", addr, size);
+}
+
static void check_sync(struct device *dev, dma_addr_t addr,
u64 size, u64 offset, int direction, bool to_cpu)
{
@@ -645,8 +665,11 @@
entry->direction = direction;
if (map_single) {
+ void *addr = ((char *)page_address(page)) + offset;
+
entry->type = dma_debug_single;
- check_for_stack(dev, page_address(page) + offset);
+ check_for_stack(dev, addr);
+ check_for_illegal_area(dev, addr, size);
}
add_dma_entry(entry);
@@ -699,6 +722,7 @@
entry->sg_mapped_ents = mapped_ents;
check_for_stack(dev, sg_virt(s));
+ check_for_illegal_area(dev, sg_virt(s), s->length);
add_dma_entry(entry);
}