Zero-length arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace zero-length array with flexible-array
member in struct memmap.
Address the following warning found after building (with GCC-13) mips64
with decstation_64_defconfig:
In function 'rex_setup_memory_region',
inlined from 'prom_meminit' at arch/mips/dec/prom/memory.c:91:3:
arch/mips/dec/prom/memory.c:72:31: error: array subscript i is outside array bounds of 'unsigned char[0]' [-Werror=array-bounds=]
72 | if (bm->bitmap[i] == 0xff)
| ~~~~~~~~~~^~~
In file included from arch/mips/dec/prom/memory.c:16:
./arch/mips/include/asm/dec/prom.h: In function 'prom_meminit':
./arch/mips/include/asm/dec/prom.h:73:23: note: while referencing 'bitmap'
73 | unsigned char bitmap[0];
This helps with the ongoing efforts to globally enable -Warray-bounds.
This results in no differences in binary output.
Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/323
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
arch/mips/include/asm/dec/prom.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/dec/prom.h b/arch/mips/include/asm/dec/prom.h
index 1e1247add1cf..908e96e3a311 100644
--- a/arch/mips/include/asm/dec/prom.h
+++ b/arch/mips/include/asm/dec/prom.h
@@ -70,7 +70,7 @@ static inline bool prom_is_rex(u32 magic)
*/
typedef struct {
int pagesize;
- unsigned char bitmap[0];
+ unsigned char bitmap[];
} memmap;
--
2.34.1
On Thu, Jun 22, 2023 at 05:43:57PM -0600, Gustavo A. R. Silva wrote:
> Zero-length arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace zero-length array with flexible-array
> member in struct memmap.
>
> Address the following warning found after building (with GCC-13) mips64
> with decstation_64_defconfig:
> In function 'rex_setup_memory_region',
> inlined from 'prom_meminit' at arch/mips/dec/prom/memory.c:91:3:
> arch/mips/dec/prom/memory.c:72:31: error: array subscript i is outside array bounds of 'unsigned char[0]' [-Werror=array-bounds=]
> 72 | if (bm->bitmap[i] == 0xff)
> | ~~~~~~~~~~^~~
> In file included from arch/mips/dec/prom/memory.c:16:
> ./arch/mips/include/asm/dec/prom.h: In function 'prom_meminit':
> ./arch/mips/include/asm/dec/prom.h:73:23: note: while referencing 'bitmap'
> 73 | unsigned char bitmap[0];
>
> This helps with the ongoing efforts to globally enable -Warray-bounds.
>
> This results in no differences in binary output.
>
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/323
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> arch/mips/include/asm/dec/prom.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/mips/include/asm/dec/prom.h b/arch/mips/include/asm/dec/prom.h
> index 1e1247add1cf..908e96e3a311 100644
> --- a/arch/mips/include/asm/dec/prom.h
> +++ b/arch/mips/include/asm/dec/prom.h
> @@ -70,7 +70,7 @@ static inline bool prom_is_rex(u32 magic)
> */
> typedef struct {
> int pagesize;
> - unsigned char bitmap[0];
> + unsigned char bitmap[];
> } memmap;
>
>
> --
> 2.34.1
applied to mips-next.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
On Fri, 23 Jun 2023, Thomas Bogendoerfer wrote:
> > Zero-length arrays are deprecated, and we are replacing them with flexible
> > array members instead. So, replace zero-length array with flexible-array
> > member in struct memmap.
Technically it is a semantics bug fix actually, as the TURBOchannel
firmware specification (from Jan 1993) says it's:
typedef struct{ int pagesize; unsigned char bitmap[];}memmap;
int getbitmap(memmap *map);
(formatting preserved as in the document) so it should have always been a
flexible array member. Maybe old (2.x) GCC versions had an issue with it
or something, as otherwise I can't imagine why whoever added our typedef
did it differently from the spec.
> applied to mips-next.
Not sure if you can retrofit it, but:
Acked-by: Maciej W. Rozycki <[email protected]>
Maciej
On 6/23/23 07:41, Maciej W. Rozycki wrote:
> On Fri, 23 Jun 2023, Thomas Bogendoerfer wrote:
>
>>> Zero-length arrays are deprecated, and we are replacing them with flexible
>>> array members instead. So, replace zero-length array with flexible-array
>>> member in struct memmap.
>
> Technically it is a semantics bug fix actually, as the TURBOchannel
> firmware specification (from Jan 1993) says it's:
>
> typedef struct{ int pagesize; unsigned char bitmap[];}memmap;
> int getbitmap(memmap *map);
>
> (formatting preserved as in the document) so it should have always been a
> flexible array member. Maybe old (2.x) GCC versions had an issue with it
> or something, as otherwise I can't imagine why whoever added our typedef
> did it differently from the spec.
Apparently, flexible-array members were supported in some 2.x versions as an
extension to the language; and it was not until GCC 3.0 that they were fully
supported by the compiler.
>
>> applied to mips-next.
>
> Not sure if you can retrofit it, but:
>
> Acked-by: Maciej W. Rozycki <[email protected]>
Thanks!
--
Gustavo