From 2e34bde18576a02c897ae6b699ea26301d92be1b Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 16 Mar 2009 16:51:55 +0100 Subject: 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 --- lib/dma-debug.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) (limited to 'lib/dma-debug.c') diff --git a/lib/dma-debug.c b/lib/dma-debug.c index dba02f138bd3..6022eb4a0cd0 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -29,6 +29,8 @@ #include #include +#include + #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); } -- cgit v1.2.3-59-g8ed1b