On Thu, Aug 17, 2017 at 12:48 PM, Michal Simek <[email protected]> wrote: > On 16.8.2017 17:05, Arnd Bergmann wrote: >> On Wed, Aug 16, 2017 at 4:34 PM, Michal Simek <[email protected]> >> wrote: >> >> Looks good, just make sure you also check with sparse (make C=1) >> to ensure you have the right __le64/__le32 types everywhere. > > Are you aware about any doc where it is written that data should be > passed as little endian?
Looking at http://infocenter.arm.com/help/topic/com.arm.doc.den0028b/ARM_DEN0028B_SMC_Calling_Convention.pdf now, I think that the structure above is endian-neutral as the arguments get passed in registers rather than memory. However, if you pass pointers to data structures in memory, those data structures would have to be defined with __le32/__le64 types. > I was playing with it a little bit and this means that these 2(3 with > hvc) needs to be changed. > > asmlinkage void __arm_smccc_smc(__le64 a0, __le64 a1, __le64 a2, > __le64 a3,__le64 a4, __le64 a5, __le64 a6, __le64 a7, > struct arm_smccc_res *res, struct arm_smccc_quirk *quirk); > > struct arm_smccc_res { > - unsigned long a0; > - unsigned long a1; > - unsigned long a2; > - unsigned long a3; > + __le64 a0; > + __le64 a1; > + __le64 a2; > + __le64 a3; > }; This is clearly wrong on 32-bit machines, I think this is intentionally defined as 'unsigned long' to have register sized arguments. Arnd
