[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v7 09/12] xen: add runtime parameter access support to hypfs
On 14/04/2020 10:31, Jan Beulich wrote: Both are valid with one difference though. If tomorrow someone send a patch to add a 64-bit in the structure, what are the chance one won't notice the alignment change? It is quite high.On 14.04.2020 11:29, Julien Grall wrote:On 03/04/2020 16:31, Jürgen Groß wrote:On 03.04.20 16:51, Jan Beulich wrote:On 02.04.2020 17:46, Juergen Gross wrote:V7: - fine tune some parameter initializations (Jan Beulich) - call custom_runtime_set_var() after updating the value - modify alignment in Arm linker script to 4 (Jan Beulich)I didn't ask for this to be unilaterally 4 - I don't think this would work on Arm64, seeing that there are pointers inside the struct. This wants to be pointer size, i.e. 4 for Arm32 but 8 for Arm64.We don't allow unaligned access on Arm32, so if your structure happen to have a 64-bit value in it then you will get a crash at runtime. For safety, it should neither be POINTER_ALIGN or 4, but 8. This is going to make your linker more robust.Would you mind explaining to me why POINTER_ALIGN would be wrong when the most strictly aligned field in a structure is a pointer? If you align the section to 8, then you make your code more robust at the expense of possibly adding an extra 4-bytes in your binary. Cheers, -- Julien Grall
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |