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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>
This commit is contained in:
Joerg Roedel 2009-03-16 16:51:55 +01:00
parent 6c132d1bcd
commit 2e34bde185
1 changed files with 25 additions and 1 deletions
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26
lib/dma-debug.c
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@ -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 @@ static void check_for_stack(struct device *dev, void *addr)
"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 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
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 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
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);
}