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Diffstat (limited to 'arch/arc/include/asm/entry.h')
| -rw-r--r-- | arch/arc/include/asm/entry.h | 495 |
1 files changed, 495 insertions, 0 deletions
diff --git a/arch/arc/include/asm/entry.h b/arch/arc/include/asm/entry.h new file mode 100644 index 0000000..63705b1 --- /dev/null +++ b/arch/arc/include/asm/entry.h @@ -0,0 +1,495 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Vineetg: Aug 28th 2008: Bug #94984 + * -Zero Overhead Loop Context shd be cleared when entering IRQ/EXcp/Trap + * Normally CPU does this automatically, however when doing FAKE rtie, + * we also need to explicitly do this. The problem in macros + * FAKE_RET_FROM_EXCPN and FAKE_RET_FROM_EXCPN_LOCK_IRQ was that this bit + * was being "CLEARED" rather then "SET". Actually "SET" clears ZOL context + * + * Vineetg: May 5th 2008 + * - Defined Stack Switching Macro to be reused in all intr/excp hdlrs + * - Shaved off 11 instructions from RESTORE_ALL_INT1 by using the + * address Write back load ld.ab instead of seperate ld/add instn + * + * Amit Bhor, Sameer Dhavale: Codito Technologies 2004 + */ + +#ifndef __ASM_ARC_ENTRY_H +#define __ASM_ARC_ENTRY_H + +#ifdef __ASSEMBLY__ +#include <asm/unistd.h> /* For NR_syscalls defination */ +#include <asm/asm-offsets.h> +#include <asm/arcregs.h> +#include <asm/ptrace.h> +#include <asm/thread_info.h> /* For THREAD_SIZE */ + +/* Note on the LD/ST addr modes with addr reg wback + * + * LD.a same as LD.aw + * + * LD.a reg1, [reg2, x] => Pre Incr + * Eff Addr for load = [reg2 + x] + * + * LD.ab reg1, [reg2, x] => Post Incr + * Eff Addr for load = [reg2] + */ + +/*-------------------------------------------------------------- + * Save caller saved registers (scratch registers) ( r0 - r12 ) + * Registers are pushed / popped in the order defined in struct ptregs + * in asm/ptrace.h + *-------------------------------------------------------------*/ +.macro SAVE_CALLER_SAVED + st.a r0, [sp, -4] + st.a r1, [sp, -4] + st.a r2, [sp, -4] + st.a r3, [sp, -4] + st.a r4, [sp, -4] + st.a r5, [sp, -4] + st.a r6, [sp, -4] + st.a r7, [sp, -4] + st.a r8, [sp, -4] + st.a r9, [sp, -4] + st.a r10, [sp, -4] + st.a r11, [sp, -4] + st.a r12, [sp, -4] +.endm + +/*-------------------------------------------------------------- + * Restore caller saved registers (scratch registers) + *-------------------------------------------------------------*/ +.macro RESTORE_CALLER_SAVED + ld.ab r12, [sp, 4] + ld.ab r11, [sp, 4] + ld.ab r10, [sp, 4] + ld.ab r9, [sp, 4] + ld.ab r8, [sp, 4] + ld.ab r7, [sp, 4] + ld.ab r6, [sp, 4] + ld.ab r5, [sp, 4] + ld.ab r4, [sp, 4] + ld.ab r3, [sp, 4] + ld.ab r2, [sp, 4] + ld.ab r1, [sp, 4] + ld.ab r0, [sp, 4] +.endm + + +/*-------------------------------------------------------------- + * Save callee saved registers (non scratch registers) ( r13 - r25 ) + * on kernel stack. + * User mode callee regs need to be saved in case of + * -fork and friends for replicating from parent to child + * -before going into do_signal( ) for ptrace/core-dump + * Special case handling is required for r25 in case it is used by kernel + * for caching task ptr. Low level exception/ISR save user mode r25 + * into task->thread.user_r25. So it needs to be retrieved from there and + * saved into kernel stack with rest of callee reg-file + *-------------------------------------------------------------*/ +.macro SAVE_CALLEE_SAVED_USER + st.a r13, [sp, -4] + st.a r14, [sp, -4] + st.a r15, [sp, -4] + st.a r16, [sp, -4] + st.a r17, [sp, -4] + st.a r18, [sp, -4] + st.a r19, [sp, -4] + st.a r20, [sp, -4] + st.a r21, [sp, -4] + st.a r22, [sp, -4] + st.a r23, [sp, -4] + st.a r24, [sp, -4] + st.a r25, [sp, -4] + + /* move up by 1 word to "create" callee_regs->"stack_place_holder" */ + sub sp, sp, 4 +.endm + +/*-------------------------------------------------------------- + * Save callee saved registers (non scratch registers) ( r13 - r25 ) + * kernel mode callee regs needed to be saved in case of context switch + * If r25 is used for caching task pointer then that need not be saved + * as it can be re-created from current task global + *-------------------------------------------------------------*/ +.macro SAVE_CALLEE_SAVED_KERNEL + st.a r13, [sp, -4] + st.a r14, [sp, -4] + st.a r15, [sp, -4] + st.a r16, [sp, -4] + st.a r17, [sp, -4] + st.a r18, [sp, -4] + st.a r19, [sp, -4] + st.a r20, [sp, -4] + st.a r21, [sp, -4] + st.a r22, [sp, -4] + st.a r23, [sp, -4] + st.a r24, [sp, -4] + st.a r25, [sp, -4] + sub sp, sp, 4 +.endm + +/*-------------------------------------------------------------- + * RESTORE_CALLEE_SAVED_KERNEL: + * Loads callee (non scratch) Reg File by popping from Kernel mode stack. + * This is reverse of SAVE_CALLEE_SAVED, + * + * NOTE: + * Ideally this shd only be called in switch_to for loading + * switched-IN task's CALLEE Reg File. + * For all other cases RESTORE_CALLEE_SAVED_FAST must be used + * which simply pops the stack w/o touching regs. + *-------------------------------------------------------------*/ +.macro RESTORE_CALLEE_SAVED_KERNEL + + add sp, sp, 4 /* skip "callee_regs->stack_place_holder" */ + ld.ab r25, [sp, 4] + ld.ab r24, [sp, 4] + ld.ab r23, [sp, 4] + ld.ab r22, [sp, 4] + ld.ab r21, [sp, 4] + ld.ab r20, [sp, 4] + ld.ab r19, [sp, 4] + ld.ab r18, [sp, 4] + ld.ab r17, [sp, 4] + ld.ab r16, [sp, 4] + ld.ab r15, [sp, 4] + ld.ab r14, [sp, 4] + ld.ab r13, [sp, 4] + +.endm + +/*-------------------------------------------------------------- + * Super FAST Restore callee saved regs by simply re-adjusting SP + *-------------------------------------------------------------*/ +.macro DISCARD_CALLEE_SAVED_USER + add sp, sp, 14 * 4 +.endm + +/*-------------------------------------------------------------- + * Restore User mode r25 saved in task_struct->thread.user_r25 + *-------------------------------------------------------------*/ +.macro RESTORE_USER_R25 + ld r25, [r25, TASK_THREAD + THREAD_USER_R25] +.endm + +/*------------------------------------------------------------- + * given a tsk struct, get to the base of it's kernel mode stack + * tsk->thread_info is really a PAGE, whose bottom hoists stack + * which grows upwards towards thread_info + *------------------------------------------------------------*/ + +.macro GET_TSK_STACK_BASE tsk, out + + /* Get task->thread_info (this is essentially start of a PAGE) */ + ld \out, [\tsk, TASK_THREAD_INFO] + + /* Go to end of page where stack begins (grows upwards) */ + add2 \out, \out, (THREAD_SIZE - 4)/4 /* one word GUTTER */ + +.endm + +/*-------------------------------------------------------------- + * Switch to Kernel Mode stack if SP points to User Mode stack + * + * Entry : r9 contains pre-IRQ/exception/trap status32 + * Exit : SP is set to kernel mode stack pointer + * Clobbers: r9 + *-------------------------------------------------------------*/ + +.macro SWITCH_TO_KERNEL_STK + + /* User Mode when this happened ? Yes: Proceed to switch stack */ + bbit1 r9, STATUS_U_BIT, 88f + + /* OK we were already in kernel mode when this event happened, thus can + * assume SP is kernel mode SP. _NO_ need to do any stack switching + */ + + /* Save Pre Intr/Exception KERNEL MODE SP on kernel stack + * safe-keeping not really needed, but it keeps the epilogue code + * (SP restore) simpler/uniform. + */ + b.d 77f + + st.a sp, [sp, -12] ; Make room for orig_r0 and orig_r8 + +88: /*------Intr/Ecxp happened in user mode, "switch" stack ------ */ + + GET_CURR_TASK_ON_CPU r9 + + /* With current tsk in r9, get it's kernel mode stack base */ + GET_TSK_STACK_BASE r9, r9 + +#ifdef PT_REGS_CANARY + st 0xabcdabcd, [r9, 0] +#endif + + /* Save Pre Intr/Exception User SP on kernel stack */ + st.a sp, [r9, -12] ; Make room for orig_r0 and orig_r8 + + /* CAUTION: + * SP should be set at the very end when we are done with everything + * In case of 2 levels of interrupt we depend on value of SP to assume + * that everything else is done (loading r25 etc) + */ + + /* set SP to point to kernel mode stack */ + mov sp, r9 + +77: /* ----- Stack Switched to kernel Mode, Now save REG FILE ----- */ + +.endm + +/*------------------------------------------------------------ + * "FAKE" a rtie to return from CPU Exception context + * This is to re-enable Exceptions within exception + * Look at EV_ProtV to see how this is actually used + *-------------------------------------------------------------*/ + +.macro FAKE_RET_FROM_EXCPN reg + + ld \reg, [sp, PT_status32] + bic \reg, \reg, (STATUS_U_MASK|STATUS_DE_MASK) + bset \reg, \reg, STATUS_L_BIT + sr \reg, [erstatus] + mov \reg, 55f + sr \reg, [eret] + + rtie +55: +.endm + +/* + * @reg [OUT] &thread_info of "current" + */ +.macro GET_CURR_THR_INFO_FROM_SP reg + and \reg, sp, ~(THREAD_SIZE - 1) +.endm + +/* + * @reg [OUT] thread_info->flags of "current" + */ +.macro GET_CURR_THR_INFO_FLAGS reg + GET_CURR_THR_INFO_FROM_SP \reg + ld \reg, [\reg, THREAD_INFO_FLAGS] +.endm + +/*-------------------------------------------------------------- + * For early Exception Prologue, a core reg is temporarily needed to + * code the rest of prolog (stack switching). This is done by stashing + * it to memory (non-SMP case) or SCRATCH0 Aux Reg (SMP). + * + * Before saving the full regfile - this reg is restored back, only + * to be saved again on kernel mode stack, as part of ptregs. + *-------------------------------------------------------------*/ +.macro EXCPN_PROLOG_FREEUP_REG reg + st \reg, [@ex_saved_reg1] +.endm + +.macro EXCPN_PROLOG_RESTORE_REG reg + ld \reg, [@ex_saved_reg1] +.endm + +/*-------------------------------------------------------------- + * Save all registers used by Exceptions (TLB Miss, Prot-V, Mem err etc) + * Requires SP to be already switched to kernel mode Stack + * sp points to the next free element on the stack at exit of this macro. + * Registers are pushed / popped in the order defined in struct ptregs + * in asm/ptrace.h + * Note that syscalls are implemented via TRAP which is also a exception + * from CPU's point of view + *-------------------------------------------------------------*/ +.macro SAVE_ALL_EXCEPTION marker + + /* Restore r9 used to code the early prologue */ + EXCPN_PROLOG_RESTORE_REG r9 + + /* Save the complete regfile now */ + + /* orig_r8 marker: + * syscalls -> 1 to NR_SYSCALLS + * Exceptions -> NR_SYSCALLS + 1 + * Break-point-> NR_SYSCALLS + 2 + */ + st \marker, [sp, 8] + st r0, [sp, 4] /* orig_r0, needed only for sys calls */ + SAVE_CALLER_SAVED + st.a r26, [sp, -4] /* gp */ + st.a fp, [sp, -4] + st.a blink, [sp, -4] + lr r9, [eret] + st.a r9, [sp, -4] + lr r9, [erstatus] + st.a r9, [sp, -4] + st.a lp_count, [sp, -4] + lr r9, [lp_end] + st.a r9, [sp, -4] + lr r9, [lp_start] + st.a r9, [sp, -4] + lr r9, [erbta] + st.a r9, [sp, -4] + +#ifdef PT_REGS_CANARY + mov r9, 0xdeadbeef + st r9, [sp, -4] +#endif + + /* move up by 1 word to "create" pt_regs->"stack_place_holder" */ + sub sp, sp, 4 +.endm + +/*-------------------------------------------------------------- + * Save scratch regs for exceptions + *-------------------------------------------------------------*/ +.macro SAVE_ALL_SYS + SAVE_ALL_EXCEPTION (NR_syscalls + 1) +.endm + +/*-------------------------------------------------------------- + * Save scratch regs for sys calls + *-------------------------------------------------------------*/ +.macro SAVE_ALL_TRAP + SAVE_ALL_EXCEPTION r8 +.endm + +/*-------------------------------------------------------------- + * Restore all registers used by system call or Exceptions + * SP should always be pointing to the next free stack element + * when entering this macro. + * + * NOTE: + * + * It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg + * for memory load operations. If used in that way interrupts are deffered + * by hardware and that is not good. + *-------------------------------------------------------------*/ +.macro RESTORE_ALL_SYS + + add sp, sp, 4 /* hop over unused "pt_regs->stack_place_holder" */ + + ld.ab r9, [sp, 4] + sr r9, [erbta] + ld.ab r9, [sp, 4] + sr r9, [lp_start] + ld.ab r9, [sp, 4] + sr r9, [lp_end] + ld.ab r9, [sp, 4] + mov lp_count, r9 + ld.ab r9, [sp, 4] + sr r9, [erstatus] + ld.ab r9, [sp, 4] + sr r9, [eret] + ld.ab blink, [sp, 4] + ld.ab fp, [sp, 4] + ld.ab r26, [sp, 4] /* gp */ + RESTORE_CALLER_SAVED + + ld sp, [sp] /* restore original sp */ + /* orig_r0 and orig_r8 skipped automatically */ +.endm + + +/*-------------------------------------------------------------- + * Save all registers used by interrupt handlers. + *-------------------------------------------------------------*/ +.macro SAVE_ALL_INT1 + + /* restore original r9 , saved in int1_saved_reg + * It will be saved on stack in macro: SAVE_CALLER_SAVED + */ + ld r9, [@int1_saved_reg] + + /* now we are ready to save the remaining context :) */ + st -1, [sp, 8] /* orig_r8, -1 for interuppt level one */ + st 0, [sp, 4] /* orig_r0 , N/A for IRQ */ + SAVE_CALLER_SAVED + st.a r26, [sp, -4] /* gp */ + st.a fp, [sp, -4] + st.a blink, [sp, -4] + st.a ilink1, [sp, -4] + lr r9, [status32_l1] + st.a r9, [sp, -4] + st.a lp_count, [sp, -4] + lr r9, [lp_end] + st.a r9, [sp, -4] + lr r9, [lp_start] + st.a r9, [sp, -4] + lr r9, [bta_l1] + st.a r9, [sp, -4] + +#ifdef PT_REGS_CANARY + mov r9, 0xdeadbee1 + st r9, [sp, -4] +#endif + /* move up by 1 word to "create" pt_regs->"stack_place_holder" */ + sub sp, sp, 4 +.endm + +/*-------------------------------------------------------------- + * Restore all registers used by interrupt handlers. + * + * NOTE: + * + * It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg + * for memory load operations. If used in that way interrupts are deffered + * by hardware and that is not good. + *-------------------------------------------------------------*/ + +.macro RESTORE_ALL_INT1 + add sp, sp, 4 /* hop over unused "pt_regs->stack_place_holder" */ + + ld.ab r9, [sp, 4] /* Actual reg file */ + sr r9, [bta_l1] + ld.ab r9, [sp, 4] + sr r9, [lp_start] + ld.ab r9, [sp, 4] + sr r9, [lp_end] + ld.ab r9, [sp, 4] + mov lp_count, r9 + ld.ab r9, [sp, 4] + sr r9, [status32_l1] + ld.ab r9, [sp, 4] + mov ilink1, r9 + ld.ab blink, [sp, 4] + ld.ab fp, [sp, 4] + ld.ab r26, [sp, 4] /* gp */ + RESTORE_CALLER_SAVED + + ld sp, [sp] /* restore original sp */ + /* orig_r0 and orig_r8 skipped automatically */ +.endm + +/* Get CPU-ID of this core */ +.macro GET_CPU_ID reg + lr \reg, [identity] + lsr \reg, \reg, 8 + bmsk \reg, \reg, 7 +.endm + +.macro GET_CURR_TASK_ON_CPU reg + ld \reg, [@_current_task] +.endm + +.macro SET_CURR_TASK_ON_CPU tsk, tmp + st \tsk, [@_current_task] +.endm + +/* ------------------------------------------------------------------ + * Get the ptr to some field of Current Task at @off in task struct + */ + +.macro GET_CURR_TASK_FIELD_PTR off, reg + GET_CURR_TASK_ON_CPU \reg + add \reg, \reg, \off +.endm + +#endif /* __ASSEMBLY__ */ + +#endif /* __ASM_ARC_ENTRY_H */ |