Hi Cody, I just tried building this with gcc 4.5, which failed with the following warning (treated as an error):
cc1: warnings being treated as errors arch/powerpc/perf/hv-24x7.c: In function 'single_24x7_request': arch/powerpc/perf/hv-24x7.c:346:1: error: the frame size of 8192 bytes is larger than 2048 bytes make[3]: *** [arch/powerpc/perf/hv-24x7.o] Error 1 make[2]: *** [arch/powerpc/perf] Error 2 My .config has CONFIG_FRAME_WARN=2048 (default on 64bit), but the alignment constraints in this function may require 8K on the stack - possibly a bit large? Notably for some reason this warning no longer seems to trigger on gcc 4.8 (or at least somewhere between 4.5-4.8), though the assembly does still show it aligning the buffers. Excerpts from Cody P Schafer's message of 2014-03-06 11:01:08 +1100: > +static unsigned long single_24x7_request(u8 domain, u32 offset, u16 ix, <snip> > + /* > + * request_buffer and result_buffer are not required to be 4k aligned, > + * but are not allowed to cross any 4k boundary. Aligning them to 4k is > + * the simplest way to ensure that. > + */ > + struct reqb { > + struct hv_24x7_request_buffer buf; > + struct hv_24x7_request req; > + } __packed __aligned(4096) request_buffer = { <snip> > + struct resb { > + struct hv_24x7_data_result_buffer buf; > + struct hv_24x7_result res; > + struct hv_24x7_result_element elem; > + __be64 result; > + } __packed __aligned(4096) result_buffer = {}; <snip> Cheers, -Ian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/