/** * Thermosphère: register access primitives * Copyright (c) Kate J. Temkin */ #ifndef __REGS_H__ #define __REGS_H__ /** * Access to system registers. */ #define WRITE_SYSREG(sysreg, val, type) \ asm volatile ("msr "#sysreg", %0\n" : : "r"((type)(val))) #define READ_SYSREG(sysreg, val, type) \ asm volatile ("mrs %0, "#sysreg"\n" : "=r"((type)(val))) #define READ_SYSREG_32(sysreg, val) READ_SYSREG(sysreg, val, uint32_t) #define WRITE_SYSREG_32(sysreg, val) WRITE_SYSREG(sysreg, val, uint32_t) #define READ_SYSREG_64(sysreg, val) READ_SYSREG(sysreg, val, uint64_t) #define WRITE_SYSREG_64(sysreg, val) WRITE_SYSREG(sysreg, val, uint64_t) /** * Returns the system's current Execution Level (EL). */ inline static uint32_t get_current_el(void) { uint32_t val; // Read the CurrentEl register, and extract the bits that tell us our EL. READ_SYSREG_32(CurrentEl, val); return val >> 2; } /** * Sets the base address of the EL2 exception table. */ inline static void set_vbar_el2(void * address) { WRITE_SYSREG_64(vbar_el2, (uint64_t)address); } /** * Sets the address to 'return to' when leaving EL2. */ inline static void set_elr_el2(void * address) { WRITE_SYSREG_64(elr_el2, (uint64_t)address); } /** * Returns the MMU status bit from the SCTLR register. */ inline static uint32_t get_el2_mmu_status(void) { uint32_t val; // Read the CurrentEl register, and extract the bits that tell us our EL. READ_SYSREG_32(sctlr_el2, val); return val & 1; } #endif