forked from Minki/linux
501c26e82d
Paging on xtensa architecture requires functioning exception handling because hardware cannot transparently access page tables that are not currently mapped by TLB. Exception handling is set up late in the initialization process, but working paging is needed for KASAN. Provide early_trap_init that sets up minimal exception handling sufficient for KASAN to work. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
/*
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* arch/xtensa/include/asm/traps.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) 2012 Tensilica Inc.
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*/
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#ifndef _XTENSA_TRAPS_H
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#define _XTENSA_TRAPS_H
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#include <asm/ptrace.h>
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/*
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* Per-CPU exception handling data structure.
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* EXCSAVE1 points to it.
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*/
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struct exc_table {
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/* Kernel Stack */
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void *kstk;
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/* Double exception save area for a0 */
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unsigned long double_save;
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/* Fixup handler */
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void *fixup;
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/* For passing a parameter to fixup */
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void *fixup_param;
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/* For fast syscall handler */
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unsigned long syscall_save;
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/* Fast user exception handlers */
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void *fast_user_handler[EXCCAUSE_N];
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/* Fast kernel exception handlers */
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void *fast_kernel_handler[EXCCAUSE_N];
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/* Default C-Handlers */
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void *default_handler[EXCCAUSE_N];
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};
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/*
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* handler must be either of the following:
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* void (*)(struct pt_regs *regs);
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* void (*)(struct pt_regs *regs, unsigned long exccause);
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*/
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extern void * __init trap_set_handler(int cause, void *handler);
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extern void do_unhandled(struct pt_regs *regs, unsigned long exccause);
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void fast_second_level_miss(void);
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/* Initialize minimal exc_table structure sufficient for basic paging */
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static inline void __init early_trap_init(void)
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{
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static struct exc_table exc_table __initdata = {
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.fast_kernel_handler[EXCCAUSE_DTLB_MISS] =
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fast_second_level_miss,
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};
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__asm__ __volatile__("wsr %0, excsave1\n" : : "a" (&exc_table));
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}
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void secondary_trap_init(void);
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static inline void spill_registers(void)
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{
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#if XCHAL_NUM_AREGS > 16
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__asm__ __volatile__ (
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" call8 1f\n"
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" _j 2f\n"
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" retw\n"
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" .align 4\n"
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"1:\n"
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#if XCHAL_NUM_AREGS == 32
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" _entry a1, 32\n"
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" addi a8, a0, 3\n"
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" _entry a1, 16\n"
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" mov a12, a12\n"
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" retw\n"
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#else
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" _entry a1, 48\n"
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" call12 1f\n"
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" retw\n"
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" .align 4\n"
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"1:\n"
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" .rept (" __stringify(XCHAL_NUM_AREGS) " - 16) / 12\n"
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" _entry a1, 48\n"
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" mov a12, a0\n"
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" .endr\n"
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" _entry a1, 16\n"
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#if XCHAL_NUM_AREGS % 12 == 0
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" mov a12, a12\n"
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#elif XCHAL_NUM_AREGS % 12 == 4
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" mov a4, a4\n"
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#elif XCHAL_NUM_AREGS % 12 == 8
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" mov a8, a8\n"
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#endif
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" retw\n"
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#endif
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"2:\n"
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: : : "a8", "a9", "memory");
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#else
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__asm__ __volatile__ (
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" mov a12, a12\n"
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: : : "memory");
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#endif
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}
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struct debug_table {
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/* Pointer to debug exception handler */
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void (*debug_exception)(void);
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/* Temporary register save area */
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unsigned long debug_save[1];
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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/* Save area for DBREAKC registers */
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unsigned long dbreakc_save[XCHAL_NUM_DBREAK];
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/* Saved ICOUNT register */
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unsigned long icount_save;
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/* Saved ICOUNTLEVEL register */
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unsigned long icount_level_save;
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#endif
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};
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void debug_exception(void);
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#endif /* _XTENSA_TRAPS_H */
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