Commit d0aa2b43 authored by Mark Brown's avatar Mark Brown Committed by Catalin Marinas
Browse files

arm64/gcs: Provide put_user_gcs() 



In order for EL1 to write to an EL0 GCS it must use the GCSSTTR instruction
rather than a normal STTR. Provide a put_user_gcs() which does this.

Reviewed-by: default avatarThiago Jung Bauermann <thiago.bauermann@linaro.org>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-10-222b78d87eee@kernel.org


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent dad947cc

arch/arm64/include/asm/uaccess.h

+18 −0
Original line number Diff line number Diff line
@@ -522,6 +522,24 @@ static inline int gcssttr(unsigned long __user *addr, unsigned long val) 
	return err;

}



static inline void put_user_gcs(unsigned long val, unsigned long __user *addr,

				int *err)

{

	int ret;



	if (!access_ok((char __user *)addr, sizeof(u64))) {

		*err = -EFAULT;

		return;

	}



	uaccess_ttbr0_enable();

	ret = gcssttr(addr, val);

	if (ret != 0)

		*err = ret;

	uaccess_ttbr0_disable();

}





#endif /* CONFIG_ARM64_GCS */



#endif /* __ASM_UACCESS_H */