[coreboot-gerrit] New patch to review for coreboot: commonlib/lz4_wrapper: Use correct casts to ensure valid calculations

[Paul Menzel]

Paul Menzel ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13771

-gerrit

commit 428383ac4627c2ec522d088779e459519a16c34d
Author: Paul Menzel 
Date:   Tue Feb 23 18:59:04 2016 +0100

commonlib/lz4_wrapper: Use correct casts to ensure valid calculations

Commit 09f2921b (cbfs: Add LZ4 in-place decompression support for
    pre-RAM stages) breaks building cbfstool with gcc (Debian 4.9.2-10)
    4.9.2 in Debian 8.3 (jessie) with a 32-bit user space. It works fine
    in a 64-bit user space.

```
    /home/joey/src/coreboot/src/commonlib/lz4_wrapper.c:164:18: note: in expansion of macro 'MIN'
        size_t size = MIN((uint32_t)b.size, dst + dstn - out);
                      ^
    /home/joey/src/coreboot/src/commonlib/include/commonlib/helpers.h:29:35: error: signed and unsigned type in conditional expression [-Werror=sign-compare]
     #define MIN(a,b) ((a) < (b) ? (a) : (b))
                                       ^
    ```

The problem is arithmetic on void*, so explicitly cast to the wanted types.

Change-Id: I85bee25a69c432ef8bb934add7fd2e2e31f03662
    Signed-off-by: Paul Menzel 
---
 src/commonlib/lz4_wrapper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/commonlib/lz4_wrapper.c b/src/commonlib/lz4_wrapper.c
index ea7b90d..1a765af 100644
--- a/src/commonlib/lz4_wrapper.c
+++ b/src/commonlib/lz4_wrapper.c
@@ -161,7 +161,7 @@ size_t ulz4fn(const void *src, size_t srcn, void *dst, size_t dstn)
    	}

if (b.not_compressed) {
-			size_t size = MIN((uint32_t)b.size, dst + dstn - out);
+			size_t size = MIN((uintptr_t)b.size, (uintptr_t)dst + dstn - (uintptr_t)out);
    		memcpy(out, in, size);
    		if (size < b.size)
    			break;		/* output overrun */