After v2.6.38, is it necessary for modify_domain on ARMv7 core?
From: Li Haifeng <hidden>
Date: 2012-07-08 14:47:26
From: Li Haifeng <hidden>
Date: 2012-07-08 14:47:26
Hi Russell King. Thanks for your memory domain explanation at former email. Now I am still confusing about this topic. After 2.6.38. CONFIG_CPU_USE_DOMAINS is added. When this configuration entry is enabled, the value of DOMAIN_MANAGER is equal to DOMAIN_CLIENT, arch/arm/include/asm/domain.h: #define DOMAIN_CLIENT 1 #ifdef CONFIG_CPU_USE_DOMAINS #define DOMAIN_MANAGER 3 #else #define DOMAIN_MANAGER 1 #endif For ARMV7, because CONFIG_CPU_USE_DOMAINS is disable in Kernel, no matter the attribute of memory's domain is DOMAIN_CLIENT and DOMAIN_MANAGER, the AP will be checked while access memory. So, maybe modify_domain is unnecessary after Kernel v2.6.38. e.g. switching processes, copy_strings_kernel. Is it right?