Re: [linux-next:master 8264/14724] drivers/firmware/smccc/smccc.c:141:1: error: r7 cannot be used in asm here

[Aneesh Kumar K.V <aneesh.kumar@kernel.org>]

kernel test robot <lkp@intel.com> writes:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   eea3fef32a9cf36abcb5975a5a594e4135a6b026
> commit: d8263a131bb05398faa72ac32be54a03e48fa197 [8264/14724] firmware: hwrng: arm_smccc_trng: Register as an SMCCC device
> config: arm-randconfig-1001-20261007 (https://download.01.org/0day-ci/archive/20261007/202610070641.B8hxBJcf-lkp@intel.com/config)
> compiler: arm-linux-gnueabi-gcc (GCC) 8.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261007/202610070641.B8hxBJcf-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202610070641.B8hxBJcf-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
>    drivers/firmware/smccc/smccc.c: In function 'smccc_devices_init':
>>> drivers/firmware/smccc/smccc.c:141:1: error: r7 cannot be used in asm here
>     }
>     ^
>>> drivers/firmware/smccc/smccc.c:141:1: error: r7 cannot be used in asm here
>
>
> vim +141 drivers/firmware/smccc/smccc.c
>
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  122) 
> b83c2d92be719bf Andre Przywara         2021-07-31  123  static int __init smccc_devices_init(void)
> b83c2d92be719bf Andre Przywara         2021-07-31  124  {
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  125) 	struct arm_smccc_device *sdev;
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  126) 	const struct smccc_device_info *smccc_dev;
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  127) 
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  128) 	for (int i = 0; i < ARRAY_SIZE(smccc_devices); i++) {
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  129) 		smccc_dev = &smccc_devices[i];
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  130) 
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  131) 		if (!smccc_probe_smccc_device(smccc_dev))
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  132) 			continue;
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  133) 
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  134) 		sdev = arm_smccc_device_register(smccc_dev->device_name, smccc_dev->func_id);
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  135) 		if (IS_ERR(sdev))
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  136) 			pr_err("%s: could not register device: %pe\n",
> d8263a131bb0539 Aneesh Kumar K.V (Arm  2026-09-23  137) 			       smccc_dev->device_name, sdev);
> b83c2d92be719bf Andre Przywara         2021-07-31  138  	}
> b83c2d92be719bf Andre Przywara         2021-07-31  139  
> b83c2d92be719bf Andre Przywara         2021-07-31  140  	return 0;
> b83c2d92be719bf Andre Przywara         2021-07-31 @141  }
>


This is with:

CONFIG_ARM_THUMB=y
CONFIG_ARM_THUMBEE=y

where there are restrictions on the use of r7. IMHO, this needs to be
addressed in the implementation of arm_smccc_1_1_invoke(), rather than
worked around in this patch?

-aneesh