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e5083a63b6
Add support for !CONFIG_MMU setups. Signed-off-by: Johannes Weiner <jw@emlix.com> Signed-off-by: Chris Zankel <chris@zankel.net>
202 lines
5.9 KiB
C
202 lines
5.9 KiB
C
/*
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* include/asm-xtensa/processor.h
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2001 - 2005 Tensilica Inc.
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*/
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#ifndef _XTENSA_PROCESSOR_H
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#define _XTENSA_PROCESSOR_H
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#include <variant/core.h>
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#include <asm/coprocessor.h>
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#include <platform/hardware.h>
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#include <linux/compiler.h>
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#include <asm/ptrace.h>
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#include <asm/types.h>
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#include <asm/regs.h>
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/* Assertions. */
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#if (XCHAL_HAVE_WINDOWED != 1)
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# error Linux requires the Xtensa Windowed Registers Option.
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#endif
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#define ARCH_SLAB_MINALIGN XCHAL_DATA_WIDTH
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/*
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* User space process size: 1 GB.
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* Windowed call ABI requires caller and callee to be located within the same
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* 1 GB region. The C compiler places trampoline code on the stack for sources
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* that take the address of a nested C function (a feature used by glibc), so
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* the 1 GB requirement applies to the stack as well.
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*/
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#ifdef CONFIG_MMU
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#define TASK_SIZE __XTENSA_UL_CONST(0x40000000)
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#else
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#define TASK_SIZE (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE)
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#endif
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#define STACK_TOP TASK_SIZE
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#define STACK_TOP_MAX STACK_TOP
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/*
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* General exception cause assigned to debug exceptions. Debug exceptions go
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* to their own vector, rather than the general exception vectors (user,
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* kernel, double); and their specific causes are reported via DEBUGCAUSE
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* rather than EXCCAUSE. However it is sometimes convenient to redirect debug
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* exceptions to the general exception mechanism. To do this, an otherwise
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* unused EXCCAUSE value was assigned to debug exceptions for this purpose.
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*/
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#define EXCCAUSE_MAPPED_DEBUG 63
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/*
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* We use DEPC also as a flag to distinguish between double and regular
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* exceptions. For performance reasons, DEPC might contain the value of
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* EXCCAUSE for regular exceptions, so we use this definition to mark a
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* valid double exception address.
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* (Note: We use it in bgeui, so it should be 64, 128, or 256)
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*/
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#define VALID_DOUBLE_EXCEPTION_ADDRESS 64
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/* LOCKLEVEL defines the interrupt level that masks all
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* general-purpose interrupts.
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*/
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#define LOCKLEVEL 1
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/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
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* registers
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*/
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#define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */
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#define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
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#ifndef __ASSEMBLY__
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/* Build a valid return address for the specified call winsize.
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* winsize must be 1 (call4), 2 (call8), or 3 (call12)
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*/
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#define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30)
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/* Convert return address to a valid pc
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* Note: We assume that the stack pointer is in the same 1GB ranges as the ra
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*/
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#define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
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typedef struct {
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unsigned long seg;
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} mm_segment_t;
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struct thread_struct {
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/* kernel's return address and stack pointer for context switching */
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unsigned long ra; /* kernel's a0: return address and window call size */
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unsigned long sp; /* kernel's a1: stack pointer */
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mm_segment_t current_ds; /* see uaccess.h for example uses */
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/* struct xtensa_cpuinfo info; */
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unsigned long bad_vaddr; /* last user fault */
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unsigned long bad_uaddr; /* last kernel fault accessing user space */
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unsigned long error_code;
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unsigned long ibreak[XCHAL_NUM_IBREAK];
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unsigned long dbreaka[XCHAL_NUM_DBREAK];
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unsigned long dbreakc[XCHAL_NUM_DBREAK];
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/* Make structure 16 bytes aligned. */
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int align[0] __attribute__ ((aligned(16)));
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};
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/*
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* Default implementation of macro that returns current
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* instruction pointer ("program counter").
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*/
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#define current_text_addr() ({ __label__ _l; _l: &&_l;})
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/* This decides where the kernel will search for a free chunk of vm
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* space during mmap's.
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*/
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#define TASK_UNMAPPED_BASE (TASK_SIZE / 2)
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#define INIT_THREAD \
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{ \
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ra: 0, \
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sp: sizeof(init_stack) + (long) &init_stack, \
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current_ds: {0}, \
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/*info: {0}, */ \
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bad_vaddr: 0, \
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bad_uaddr: 0, \
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error_code: 0, \
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}
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/*
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* Do necessary setup to start up a newly executed thread.
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* Note: We set-up ps as if we did a call4 to the new pc.
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* set_thread_state in signal.c depends on it.
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*/
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#define USER_PS_VALUE ((1 << PS_WOE_BIT) | \
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(1 << PS_CALLINC_SHIFT) | \
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(USER_RING << PS_RING_SHIFT) | \
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(1 << PS_UM_BIT) | \
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(1 << PS_EXCM_BIT))
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/* Clearing a0 terminates the backtrace. */
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#define start_thread(regs, new_pc, new_sp) \
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regs->pc = new_pc; \
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regs->ps = USER_PS_VALUE; \
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regs->areg[1] = new_sp; \
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regs->areg[0] = 0; \
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regs->wmask = 1; \
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regs->depc = 0; \
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regs->windowbase = 0; \
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regs->windowstart = 1;
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/* Forward declaration */
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struct task_struct;
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struct mm_struct;
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/* Free all resources held by a thread. */
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#define release_thread(thread) do { } while(0)
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/* Prepare to copy thread state - unlazy all lazy status */
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extern void prepare_to_copy(struct task_struct*);
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/* Create a kernel thread without removing it from tasklists */
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extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
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/* Copy and release all segment info associated with a VM */
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#define copy_segments(p, mm) do { } while(0)
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#define release_segments(mm) do { } while(0)
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#define forget_segments() do { } while (0)
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#define thread_saved_pc(tsk) (task_pt_regs(tsk)->pc)
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extern unsigned long get_wchan(struct task_struct *p);
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#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
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#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
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#define cpu_relax() barrier()
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/* Special register access. */
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#define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v));
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#define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v));
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#define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);})
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#define get_sr(sr) ({unsigned int v; RSR(v,sr); v; })
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#endif /* __ASSEMBLY__ */
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#endif /* _XTENSA_PROCESSOR_H */
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