/* * include/asm-xtensa/processor.h * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2008 Tensilica Inc. */ #ifndef _XTENSA_PROCESSOR_H #define _XTENSA_PROCESSOR_H #include <variant/core.h> #include <platform/hardware.h> #include <linux/compiler.h> #include <asm/ptrace.h> #include <asm/types.h> #include <asm/regs.h> /* Assertions. */ #if (XCHAL_HAVE_WINDOWED != 1) # error Linux requires the Xtensa Windowed Registers Option. #endif #define ARCH_SLAB_MINALIGN XCHAL_DATA_WIDTH /* * User space process size: 1 GB. * Windowed call ABI requires caller and callee to be located within the same * 1 GB region. The C compiler places trampoline code on the stack for sources * that take the address of a nested C function (a feature used by glibc), so * the 1 GB requirement applies to the stack as well. */ #ifdef CONFIG_MMU #define TASK_SIZE __XTENSA_UL_CONST(0x40000000) #else #define TASK_SIZE (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE) #endif #define STACK_TOP TASK_SIZE #define STACK_TOP_MAX STACK_TOP /* * General exception cause assigned to debug exceptions. Debug exceptions go * to their own vector, rather than the general exception vectors (user, * kernel, double); and their specific causes are reported via DEBUGCAUSE * rather than EXCCAUSE. However it is sometimes convenient to redirect debug * exceptions to the general exception mechanism. To do this, an otherwise * unused EXCCAUSE value was assigned to debug exceptions for this purpose. */ #define EXCCAUSE_MAPPED_DEBUG 63 /* * We use DEPC also as a flag to distinguish between double and regular * exceptions. For performance reasons, DEPC might contain the value of * EXCCAUSE for regular exceptions, so we use this definition to mark a * valid double exception address. * (Note: We use it in bgeui, so it should be 64, 128, or 256) */ #define VALID_DOUBLE_EXCEPTION_ADDRESS 64 /* LOCKLEVEL defines the interrupt level that masks all * general-purpose interrupts. */ #define LOCKLEVEL XCHAL_EXCM_LEVEL /* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE * registers */ #define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */ #define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */ #ifndef __ASSEMBLY__ /* Build a valid return address for the specified call winsize. * winsize must be 1 (call4), 2 (call8), or 3 (call12) */ #define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30) /* Convert return address to a valid pc * Note: We assume that the stack pointer is in the same 1GB ranges as the ra */ #define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000)) typedef struct { unsigned long seg; } mm_segment_t; struct thread_struct { /* kernel's return address and stack pointer for context switching */ unsigned long ra; /* kernel's a0: return address and window call size */ unsigned long sp; /* kernel's a1: stack pointer */ mm_segment_t current_ds; /* see uaccess.h for example uses */ /* struct xtensa_cpuinfo info; */ unsigned long bad_vaddr; /* last user fault */ unsigned long bad_uaddr; /* last kernel fault accessing user space */ unsigned long error_code; unsigned long ibreak[XCHAL_NUM_IBREAK]; unsigned long dbreaka[XCHAL_NUM_DBREAK]; unsigned long dbreakc[XCHAL_NUM_DBREAK]; /* Make structure 16 bytes aligned. */ int align[0] __attribute__ ((aligned(16))); }; /* * Default implementation of macro that returns current * instruction pointer ("program counter"). */ #define current_text_addr() ({ __label__ _l; _l: &&_l;}) /* This decides where the kernel will search for a free chunk of vm * space during mmap's. */ #define TASK_UNMAPPED_BASE (TASK_SIZE / 2) #define INIT_THREAD \ { \ ra: 0, \ sp: sizeof(init_stack) + (long) &init_stack, \ current_ds: {0}, \ /*info: {0}, */ \ bad_vaddr: 0, \ bad_uaddr: 0, \ error_code: 0, \ } /* * Do necessary setup to start up a newly executed thread. * Note: We set-up ps as if we did a call4 to the new pc. * set_thread_state in signal.c depends on it. */ #define USER_PS_VALUE ((1 << PS_WOE_BIT) | \ (1 << PS_CALLINC_SHIFT) | \ (USER_RING << PS_RING_SHIFT) | \ (1 << PS_UM_BIT) | \ (1 << PS_EXCM_BIT)) /* Clearing a0 terminates the backtrace. */ #define start_thread(regs, new_pc, new_sp) \ memset(regs, 0, sizeof(*regs)); \ regs->pc = new_pc; \ regs->ps = USER_PS_VALUE; \ regs->areg[1] = new_sp; \ regs->areg[0] = 0; \ regs->wmask = 1; \ regs->depc = 0; \ regs->windowbase = 0; \ regs->windowstart = 1; /* Forward declaration */ struct task_struct; struct mm_struct; /* Free all resources held by a thread. */ #define release_thread(thread) do { } while(0) /* Copy and release all segment info associated with a VM */ #define copy_segments(p, mm) do { } while(0) #define release_segments(mm) do { } while(0) #define forget_segments() do { } while (0) #define thread_saved_pc(tsk) (task_pt_regs(tsk)->pc) extern unsigned long get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1]) #define cpu_relax() barrier() #define cpu_relax_lowlatency() cpu_relax() /* Special register access. */ #define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v)); #define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v)); #define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);}) #define get_sr(sr) ({unsigned int v; RSR(v,sr); v; }) #ifndef XCHAL_HAVE_EXTERN_REGS #define XCHAL_HAVE_EXTERN_REGS 0 #endif #if XCHAL_HAVE_EXTERN_REGS static inline void set_er(unsigned long value, unsigned long addr) { asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory"); } static inline unsigned long get_er(unsigned long addr) { register unsigned long value; asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory"); return value; } #endif /* XCHAL_HAVE_EXTERN_REGS */ #endif /* __ASSEMBLY__ */ #endif /* _XTENSA_PROCESSOR_H */