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ARC: entry.S: split into ARCompact ISA specific, common bits

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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2015-02-21 15:09:32 +05:30
parent c10d6969b0
commit 6d1a20b1d2
5 changed files with 711 additions and 681 deletions
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306
arch/arc/include/asm/entry-compact.h Normal file
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@ -0,0 +1,306 @@
/*
* Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
* 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: March 2009 (Supporting 2 levels of Interrupts)
* Stack switching code can no longer reliably rely on the fact that
* if we are NOT in user mode, stack is switched to kernel mode.
* e.g. L2 IRQ interrupted a L1 ISR which had not yet completed
* it's prologue including stack switching from user mode
*
* 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
* -Modified CALLEE_REG save/restore macros to handle the fact that
* r25 contains the kernel current task ptr
* - 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_COMPACT_H
#define __ASM_ARC_ENTRY_COMPACT_H
#include <asm/asm-offsets.h>
#include <asm/thread_info.h> /* For THREAD_SIZE */
/*--------------------------------------------------------------
* 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
* If CURR_IN_REG, r25 set to "current" task 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
*/
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
/* However....
* If Level 2 Interrupts enabled, we may end up with a corner case:
* 1. User Task executing
* 2. L1 IRQ taken, ISR starts (CPU auto-switched to KERNEL mode)
* 3. But before it could switch SP from USER to KERNEL stack
* a L2 IRQ "Interrupts" L1
* Thay way although L2 IRQ happened in Kernel mode, stack is still
* not switched.
* To handle this, we may need to switch stack even if in kernel mode
* provided SP has values in range of USER mode stack ( < 0x7000_0000 )
*/
brlo sp, VMALLOC_START, 88f
/* TODO: vineetg:
* We need to be a bit more cautious here. What if a kernel bug in
* L1 ISR, caused SP to go whaco (some small value which looks like
* USER stk) and then we take L2 ISR.
* Above brlo alone would treat it as a valid L1-L2 sceanrio
* instead of shouting alound
* The only feasible way is to make sure this L2 happened in
* L1 prelogue ONLY i.e. ilink2 is less than a pre-set marker in
* L1 ISR before it switches stack
*/
#endif
/* 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 66f
mov r9, sp
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
66:
#ifdef CONFIG_ARC_CURR_IN_REG
/*
* Treat r25 as scratch reg, save it on stack first
* Load it with current task pointer
*/
st r25, [r9, -4]
GET_CURR_TASK_ON_CPU r25
#endif
/* Save Pre Intr/Exception User SP on kernel stack */
st.a sp, [r9, -16] ; Make room for orig_r0, ECR, user_r25
/* 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
/* ----- 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
ld r9, [sp, PT_status32]
bic r9, r9, (STATUS_U_MASK|STATUS_DE_MASK)
bset r9, r9, STATUS_L_BIT
sr r9, [erstatus]
mov r9, 55f
sr r9, [eret]
rtie
55:
.endm
/*--------------------------------------------------------------
* For early Exception/ISR 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 pt_regs.
*-------------------------------------------------------------*/
.macro PROLOG_FREEUP_REG reg, mem
#ifdef CONFIG_SMP
sr \reg, [ARC_REG_SCRATCH_DATA0]
#else
st \reg, [\mem]
#endif
.endm
.macro PROLOG_RESTORE_REG reg, mem
#ifdef CONFIG_SMP
lr \reg, [ARC_REG_SCRATCH_DATA0]
#else
ld \reg, [\mem]
#endif
.endm
/*--------------------------------------------------------------
* Exception Entry prologue
* -Switches stack to K mode (if not already)
* -Saves the register file
*
* After this it is safe to call the "C" handlers
*-------------------------------------------------------------*/
.macro EXCEPTION_PROLOGUE
/* Need at least 1 reg to code the early exception prologue */
PROLOG_FREEUP_REG r9, @ex_saved_reg1
/* U/K mode at time of exception (stack not switched if already K) */
lr r9, [erstatus]
/* ARC700 doesn't provide auto-stack switching */
SWITCH_TO_KERNEL_STK
lr r9, [ecr]
st r9, [sp, 8] /* ECR */
st r0, [sp, 4] /* orig_r0, needed only for sys calls */
/* Restore r9 used to code the early prologue */
PROLOG_RESTORE_REG r9, @ex_saved_reg1
SAVE_R0_TO_R12
PUSH gp
PUSH fp
PUSH blink
PUSHAX eret
PUSHAX erstatus
PUSH lp_count
PUSHAX lp_end
PUSHAX lp_start
PUSHAX erbta
.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 EXCEPTION_EPILOGUE
POPAX erbta
POPAX lp_start
POPAX lp_end
POP r9
mov lp_count, r9 ;LD to lp_count is not allowed
POPAX erstatus
POPAX eret
POP blink
POP fp
POP gp
RESTORE_R12_TO_R0
ld sp, [sp] /* restore original sp */
/* orig_r0, ECR, user_r25 skipped automatically */
.endm
/* Dummy ECR values for Interrupts */
#define event_IRQ1 0x0031abcd
#define event_IRQ2 0x0032abcd
.macro INTERRUPT_PROLOGUE LVL
/* free up r9 as scratchpad */
PROLOG_FREEUP_REG r9, @int\LVL\()_saved_reg
/* Which mode (user/kernel) was the system in when intr occured */
lr r9, [status32_l\LVL\()]
SWITCH_TO_KERNEL_STK
/* restore original r9 */
PROLOG_RESTORE_REG r9, @int\LVL\()_saved_reg
/* now we are ready to save the remaining context */
st 0x003\LVL\()abcd, [sp, 8] /* Dummy ECR */
st 0, [sp, 4] /* orig_r0 , N/A for IRQ */
SAVE_R0_TO_R12
PUSH gp
PUSH fp
PUSH blink
PUSH ilink\LVL\()
PUSHAX status32_l\LVL\()
PUSH lp_count
PUSHAX lp_end
PUSHAX lp_start
PUSHAX bta_l\LVL\()
.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 INTERRUPT_EPILOGUE LVL
POPAX bta_l\LVL\()
POPAX lp_start
POPAX lp_end
POP r9
mov lp_count, r9 ;LD to lp_count is not allowed
POPAX status32_l\LVL\()
POP ilink\LVL\()
POP blink
POP fp
POP gp
RESTORE_R12_TO_R0
ld sp, [sp] /* restore original sp */
/* orig_r0, ECR, user_r25 skipped automatically */
.endm
/* Get thread_info of "current" tsk */
.macro GET_CURR_THR_INFO_FROM_SP reg
bic \reg, sp, (THREAD_SIZE - 1)
.endm
/* Get CPU-ID of this core */
.macro GET_CPU_ID reg
lr \reg, [identity]
lsr \reg, \reg, 8
bmsk \reg, \reg, 7
.endm
#endif /* __ASM_ARC_ENTRY_COMPACT_H */

300
arch/arc/include/asm/entry.h
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@ -1,45 +1,23 @@
/*
* Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
* 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: March 2009 (Supporting 2 levels of Interrupts)
* Stack switching code can no longer reliably rely on the fact that
* if we are NOT in user mode, stack is switched to kernel mode.
* e.g. L2 IRQ interrupted a L1 ISR which had not yet completed
* it's prologue including stack switching from user mode
*
* 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
* -Modified CALLEE_REG save/restore macros to handle the fact that
* r25 contains the kernel current task ptr
* - 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/processor.h> /* For VMALLOC_START */
#include <asm/thread_info.h> /* For THREAD_SIZE */
#include <asm/mmu.h>
#include <asm/entry-compact.h> /* ISA specific bits */
/* Note on the LD/ST addr modes with addr reg wback
*
* LD.a same as LD.aw
@ -240,117 +218,6 @@
.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
* If CURR_IN_REG, r25 set to "current" task 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
*/
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
/* However....
* If Level 2 Interrupts enabled, we may end up with a corner case:
* 1. User Task executing
* 2. L1 IRQ taken, ISR starts (CPU auto-switched to KERNEL mode)
* 3. But before it could switch SP from USER to KERNEL stack
* a L2 IRQ "Interrupts" L1
* Thay way although L2 IRQ happened in Kernel mode, stack is still
* not switched.
* To handle this, we may need to switch stack even if in kernel mode
* provided SP has values in range of USER mode stack ( < 0x7000_0000 )
*/
brlo sp, VMALLOC_START, 88f
/* TODO: vineetg:
* We need to be a bit more cautious here. What if a kernel bug in
* L1 ISR, caused SP to go whaco (some small value which looks like
* USER stk) and then we take L2 ISR.
* Above brlo alone would treat it as a valid L1-L2 sceanrio
* instead of shouting alound
* The only feasible way is to make sure this L2 happened in
* L1 prelogue ONLY i.e. ilink2 is less than a pre-set marker in
* L1 ISR before it switches stack
*/
#endif
/* 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 66f
mov r9, sp
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
66:
#ifdef CONFIG_ARC_CURR_IN_REG
/*
* Treat r25 as scratch reg, save it on stack first
* Load it with current task pointer
*/
st r25, [r9, -4]
GET_CURR_TASK_ON_CPU r25
#endif
/* Save Pre Intr/Exception User SP on kernel stack */
st.a sp, [r9, -16] ; Make room for orig_r0, ECR, user_r25
/* 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
/* ----- 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
ld r9, [sp, PT_status32]
bic r9, r9, (STATUS_U_MASK|STATUS_DE_MASK)
bset r9, r9, STATUS_L_BIT
sr r9, [erstatus]
mov r9, 55f
sr r9, [eret]
rtie
55:
.endm
/*
* @reg [OUT] &thread_info of "current"
*/
.macro GET_CURR_THR_INFO_FROM_SP reg
bic \reg, sp, (THREAD_SIZE - 1)
.endm
/*
* @reg [OUT] thread_info->flags of "current"
*/
@ -359,165 +226,6 @@
ld \reg, [\reg, THREAD_INFO_FLAGS]
.endm
/*--------------------------------------------------------------
* For early Exception/ISR 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 pt_regs.
*-------------------------------------------------------------*/
.macro PROLOG_FREEUP_REG reg, mem
#ifdef CONFIG_SMP
sr \reg, [ARC_REG_SCRATCH_DATA0]
#else
st \reg, [\mem]
#endif
.endm
.macro PROLOG_RESTORE_REG reg, mem
#ifdef CONFIG_SMP
lr \reg, [ARC_REG_SCRATCH_DATA0]
#else
ld \reg, [\mem]
#endif
.endm
/*--------------------------------------------------------------
* Exception Entry prologue
* -Switches stack to K mode (if not already)
* -Saves the register file
*
* After this it is safe to call the "C" handlers
*-------------------------------------------------------------*/
.macro EXCEPTION_PROLOGUE
/* Need at least 1 reg to code the early exception prologue */
PROLOG_FREEUP_REG r9, @ex_saved_reg1
/* U/K mode at time of exception (stack not switched if already K) */
lr r9, [erstatus]
/* ARC700 doesn't provide auto-stack switching */
SWITCH_TO_KERNEL_STK
lr r9, [ecr]
st r9, [sp, 8] /* ECR */
st r0, [sp, 4] /* orig_r0, needed only for sys calls */
/* Restore r9 used to code the early prologue */
PROLOG_RESTORE_REG r9, @ex_saved_reg1
SAVE_R0_TO_R12
PUSH gp
PUSH fp
PUSH blink
PUSHAX eret
PUSHAX erstatus
PUSH lp_count
PUSHAX lp_end
PUSHAX lp_start
PUSHAX erbta
.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 EXCEPTION_EPILOGUE
POPAX erbta
POPAX lp_start
POPAX lp_end
POP r9
mov lp_count, r9 ;LD to lp_count is not allowed
POPAX erstatus
POPAX eret
POP blink
POP fp
POP gp
RESTORE_R12_TO_R0
ld sp, [sp] /* restore original sp */
/* orig_r0, ECR, user_r25 skipped automatically */
.endm
/* Dummy ECR values for Interrupts */
#define event_IRQ1 0x0031abcd
#define event_IRQ2 0x0032abcd
.macro INTERRUPT_PROLOGUE LVL
/* free up r9 as scratchpad */
PROLOG_FREEUP_REG r9, @int\LVL\()_saved_reg
/* Which mode (user/kernel) was the system in when intr occurred */
lr r9, [status32_l\LVL\()]
SWITCH_TO_KERNEL_STK
/* restore original r9 */
PROLOG_RESTORE_REG r9, @int\LVL\()_saved_reg
/* now we are ready to save the remaining context */
st 0x003\LVL\()abcd, [sp, 8] /* Dummy ECR */
st 0, [sp, 4] /* orig_r0 , N/A for IRQ */
SAVE_R0_TO_R12
PUSH gp
PUSH fp
PUSH blink
PUSH ilink\LVL\()
PUSHAX status32_l\LVL\()
PUSH lp_count
PUSHAX lp_end
PUSHAX lp_start
PUSHAX bta_l\LVL\()
.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 INTERRUPT_EPILOGUE LVL
POPAX bta_l\LVL\()
POPAX lp_start
POPAX lp_end
POP r9
mov lp_count, r9 ;LD to lp_count is not allowed
POPAX status32_l\LVL\()
POP ilink\LVL\()
POP blink
POP fp
POP gp
RESTORE_R12_TO_R0
ld sp, [sp] /* restore original sp */
/* orig_r0, ECR, user_r25 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
#ifdef CONFIG_SMP
/*-------------------------------------------------
@ -586,6 +294,4 @@
#endif /* CONFIG_ARC_CURR_IN_REG */
#endif /* __ASSEMBLY__ */
#endif /* __ASM_ARC_ENTRY_H */

4
arch/arc/kernel/Makefile
View file

@ -8,9 +8,9 @@
# Pass UTS_MACHINE for user_regset definition
CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"'
obj-y := arcksyms.o setup.o irq.o time.o reset.o ptrace.o entry.o process.o
obj-y := arcksyms.o setup.o irq.o time.o reset.o ptrace.o process.o devtree.o
obj-y += signal.o traps.o sys.o troubleshoot.o stacktrace.o disasm.o clk.o
obj-y += devtree.o
obj-y += entry-compact.o
obj-$(CONFIG_MODULES) += arcksyms.o module.o
obj-$(CONFIG_SMP) += smp.o

393
arch/arc/kernel/entry-compact.S Normal file
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@ -0,0 +1,393 @@
/*
* Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARCompact ISA
*
* Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
* 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: May 2011
* -Userspace unaligned access emulation
*
* vineetg: Feb 2011 (ptrace low level code fixes)
* -traced syscall return code (r0) was not saved into pt_regs for restoring
* into user reg-file when traded task rets to user space.
* -syscalls needing arch-wrappers (mainly for passing sp as pt_regs)
* were not invoking post-syscall trace hook (jumping directly into
* ret_from_system_call)
*
* vineetg: Nov 2010:
* -Vector table jumps (@8 bytes) converted into branches (@4 bytes)
* -To maintain the slot size of 8 bytes/vector, added nop, which is
* not executed at runtime.
*
* vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK)
* -do_signal()invoked upon TIF_RESTORE_SIGMASK as well
* -Wrappers for sys_{,rt_}sigsuspend() nolonger needed as they don't
* need ptregs anymore
*
* Vineetg: Oct 2009
* -In a rare scenario, Process gets a Priv-V exception and gets scheduled
* out. Since we don't do FAKE RTIE for Priv-V, CPU excpetion state remains
* active (AE bit enabled). This causes a double fault for a subseq valid
* exception. Thus FAKE RTIE needed in low level Priv-Violation handler.
* Instr Error could also cause similar scenario, so same there as well.
*
* Vineetg: March 2009 (Supporting 2 levels of Interrupts)
*
* 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 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". Since it is Loop INHIBIT Bit,
* setting it and not clearing it clears ZOL context
*
* Vineetg: May 16th, 2008
* - r25 now contains the Current Task when in kernel
*
* Vineetg: Dec 22, 2007
* Minor Surgery of Low Level ISR to make it SMP safe
* - MMU_SCRATCH0 Reg used for freeing up r9 in Level 1 ISR
* - _current_task is made an array of NR_CPUS
* - Access of _current_task wrapped inside a macro so that if hardware
* team agrees for a dedicated reg, no other code is touched
*
* Amit Bhor, Rahul Trivedi, Kanika Nema, Sameer Dhavale : Codito Tech 2004
*/
#include <linux/errno.h>
#include <linux/linkage.h> /* {EXTRY,EXIT} */
#include <asm/entry.h>
#include <asm/irqflags.h>
.cpu A7
;############################ Vector Table #################################
.macro VECTOR lbl
#if 1 /* Just in case, build breaks */
j \lbl
#else
b \lbl
nop
#endif
.endm
.section .vector, "ax",@progbits
.align 4
/* Each entry in the vector table must occupy 2 words. Since it is a jump
* across sections (.vector to .text) we are gauranteed that 'j somewhere'
* will use the 'j limm' form of the intrsuction as long as somewhere is in
* a section other than .vector.
*/
; ********* Critical System Events **********************
VECTOR res_service ; 0x0, Restart Vector (0x0)
VECTOR mem_service ; 0x8, Mem exception (0x1)
VECTOR instr_service ; 0x10, Instrn Error (0x2)
; ******************** Device ISRs **********************
#ifdef CONFIG_ARC_IRQ3_LV2
VECTOR handle_interrupt_level2
#else
VECTOR handle_interrupt_level1
#endif
VECTOR handle_interrupt_level1
#ifdef CONFIG_ARC_IRQ5_LV2
VECTOR handle_interrupt_level2
#else
VECTOR handle_interrupt_level1
#endif
#ifdef CONFIG_ARC_IRQ6_LV2
VECTOR handle_interrupt_level2
#else
VECTOR handle_interrupt_level1
#endif
.rept 25
VECTOR handle_interrupt_level1 ; Other devices
.endr
/* FOR ARC600: timer = 0x3, uart = 0x8, emac = 0x10 */
; ******************** Exceptions **********************
VECTOR EV_MachineCheck ; 0x100, Fatal Machine check (0x20)
VECTOR EV_TLBMissI ; 0x108, Intruction TLB miss (0x21)
VECTOR EV_TLBMissD ; 0x110, Data TLB miss (0x22)
VECTOR EV_TLBProtV ; 0x118, Protection Violation (0x23)
; or Misaligned Access
VECTOR EV_PrivilegeV ; 0x120, Privilege Violation (0x24)
VECTOR EV_Trap ; 0x128, Trap exception (0x25)
VECTOR EV_Extension ; 0x130, Extn Intruction Excp (0x26)
.rept 24
VECTOR reserved ; Reserved Exceptions
.endr
;##################### Scratch Mem for IRQ stack switching #############
ARCFP_DATA int1_saved_reg
.align 32
.type int1_saved_reg, @object
.size int1_saved_reg, 4
int1_saved_reg:
.zero 4
/* Each Interrupt level needs its own scratch */
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
ARCFP_DATA int2_saved_reg
.type int2_saved_reg, @object
.size int2_saved_reg, 4
int2_saved_reg:
.zero 4
#endif
; ---------------------------------------------
.section .text, "ax",@progbits
res_service: ; processor restart
flag 0x1 ; not implemented
nop
nop
reserved: ; processor restart
rtie ; jump to processor initializations
;##################### Interrupt Handling ##############################
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
; ---------------------------------------------
; Level 2 ISR: Can interrupt a Level 1 ISR
; ---------------------------------------------
ENTRY(handle_interrupt_level2)
INTERRUPT_PROLOGUE 2
;------------------------------------------------------
; if L2 IRQ interrupted a L1 ISR, disable preemption
;------------------------------------------------------
ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
bbit0 r9, STATUS_A1_BIT, 1f ; L1 not active when L2 IRQ, so normal
; A1 is set in status32_l2
; bump thread_info->preempt_count (Disable preemption)
GET_CURR_THR_INFO_FROM_SP r10
ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
add r9, r9, 1
st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
1:
;------------------------------------------------------
; setup params for Linux common ISR and invoke it
;------------------------------------------------------
lr r0, [icause2]
and r0, r0, 0x1f
bl.d @arch_do_IRQ
mov r1, sp
mov r8,0x2
sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
b ret_from_exception
END(handle_interrupt_level2)
#endif
; ---------------------------------------------
; Level 1 ISR
; ---------------------------------------------
ENTRY(handle_interrupt_level1)
INTERRUPT_PROLOGUE 1
lr r0, [icause1]
and r0, r0, 0x1f
#ifdef CONFIG_TRACE_IRQFLAGS
; icause1 needs to be read early, before calling tracing, which
; can clobber scratch regs, hence use of stack to stash it
push r0
TRACE_ASM_IRQ_DISABLE
pop r0
#endif
bl.d @arch_do_IRQ
mov r1, sp
mov r8,0x1
sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
b ret_from_exception
END(handle_interrupt_level1)
;################### Non TLB Exception Handling #############################
; ---------------------------------------------
; Protection Violation Exception Handler
; ---------------------------------------------
ENTRY(EV_TLBProtV)
EXCEPTION_PROLOGUE
lr r2, [ecr]
lr r0, [efa] ; Faulting Data address (not part of pt_regs saved above)
; Exception auto-disables further Intr/exceptions.
; Re-enable them by pretending to return from exception
; (so rest of handler executes in pure K mode)
FAKE_RET_FROM_EXCPN
mov r1, sp ; Handle to pt_regs
;------ (5) Type of Protection Violation? ----------
;
; ProtV Hardware Exception is triggered for Access Faults of 2 types
; -Access Violaton : 00_23_(00|01|02|03)_00
; x r w r+w
; -Unaligned Access : 00_23_04_00
;
bbit1 r2, ECR_C_BIT_PROTV_MISALIG_DATA, 4f
;========= (6a) Access Violation Processing ========
bl do_page_fault
b ret_from_exception
;========== (6b) Non aligned access ============
4:
SAVE_CALLEE_SAVED_USER
mov r2, sp ; callee_regs
bl do_misaligned_access
; TBD: optimize - do this only if a callee reg was involved
; either a dst of emulated LD/ST or src with address-writeback
RESTORE_CALLEE_SAVED_USER
b ret_from_exception
END(EV_TLBProtV)
; Wrapper for Linux page fault handler called from EV_TLBMiss*
; Very similar to ProtV handler case (6a) above, but avoids the extra checks
; for Misaligned access
;
ENTRY(call_do_page_fault)
EXCEPTION_PROLOGUE
lr r0, [efa] ; Faulting Data address
mov r1, sp
FAKE_RET_FROM_EXCPN
mov blink, ret_from_exception
b do_page_fault
END(call_do_page_fault)
;############# Common Handlers for ARCompact and ARCv2 ##############
#include "entry.S"
;############# Return from Intr/Excp/Trap (ARC Specifics) ##############
;
; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap)
; IRQ shd definitely not happen between now and rtie
; All 2 entry points to here already disable interrupts
.Lrestore_regs:
TRACE_ASM_IRQ_ENABLE
lr r10, [status32]
; Restore REG File. In case multiple Events outstanding,
; use the same priorty as rtie: EXCPN, L2 IRQ, L1 IRQ, None
; Note that we use realtime STATUS32 (not pt_regs->status32) to
; decide that.
; if Returning from Exception
bbit0 r10, STATUS_AE_BIT, not_exception
EXCEPTION_EPILOGUE
rtie
; Not Exception so maybe Interrupts (Level 1 or 2)
not_exception:
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
; Level 2 interrupt return Path - from hardware standpoint
bbit0 r10, STATUS_A2_BIT, not_level2_interrupt
;------------------------------------------------------------------
; However the context returning might not have taken L2 intr itself
; e.g. Task'A' user-code -> L2 intr -> schedule -> 'B' user-code ret
; Special considerations needed for the context which took L2 intr
ld r9, [sp, PT_event] ; Ensure this is L2 intr context
brne r9, event_IRQ2, 149f
;------------------------------------------------------------------
; if L2 IRQ interrupted an L1 ISR, we'd disabled preemption earlier
; so that sched doesn't move to new task, causing L1 to be delayed
; undeterministically. Now that we've achieved that, let's reset
; things to what they were, before returning from L2 context
;----------------------------------------------------------------
ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
bbit0 r9, STATUS_A1_BIT, 149f ; L1 not active when L2 IRQ, so normal
; decrement thread_info->preempt_count (re-enable preemption)
GET_CURR_THR_INFO_FROM_SP r10
ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
; paranoid check, given A1 was active when A2 happened, preempt count
; must not be 0 because we would have incremented it.
; If this does happen we simply HALT as it means a BUG !!!
cmp r9, 0
bnz 2f
flag 1
2:
sub r9, r9, 1
st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
149:
;return from level 2
INTERRUPT_EPILOGUE 2
debug_marker_l2:
rtie
not_level2_interrupt:
#endif
bbit0 r10, STATUS_A1_BIT, not_level1_interrupt
;return from level 1
INTERRUPT_EPILOGUE 1
debug_marker_l1:
rtie
not_level1_interrupt:
;this case is for syscalls or Exceptions (with fake rtie)
EXCEPTION_EPILOGUE
debug_marker_syscall:
rtie

389
arch/arc/kernel/entry.S
View file

@ -1,60 +1,13 @@
/*
* Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARC
* Common Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARC
* (included from entry-<isa>.S
*
* Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
* 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: May 2011
* -Userspace unaligned access emulation
*
* vineetg: Feb 2011 (ptrace low level code fixes)
* -traced syscall return code (r0) was not saved into pt_regs for restoring
* into user reg-file when traded task rets to user space.
* -syscalls needing arch-wrappers (mainly for passing sp as pt_regs)
* were not invoking post-syscall trace hook (jumping directly into
* ret_from_system_call)
*
* vineetg: Nov 2010:
* -Vector table jumps (@8 bytes) converted into branches (@4 bytes)
* -To maintain the slot size of 8 bytes/vector, added nop, which is
* not executed at runtime.
*
* vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK)
* -do_signal()invoked upon TIF_RESTORE_SIGMASK as well
* -Wrappers for sys_{,rt_}sigsuspend() nolonger needed as they don't
* need ptregs anymore
*
* Vineetg: Oct 2009
* -In a rare scenario, Process gets a Priv-V exception and gets scheduled
* out. Since we don't do FAKE RTIE for Priv-V, CPU excpetion state remains
* active (AE bit enabled). This causes a double fault for a subseq valid
* exception. Thus FAKE RTIE needed in low level Priv-Violation handler.
* Instr Error could also cause similar scenario, so same there as well.
*
* Vineetg: March 2009 (Supporting 2 levels of Interrupts)
*
* 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 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". Since it is Loop INHIBIT Bit,
* setting it and not clearing it clears ZOL context
*
* Vineetg: May 16th, 2008
* - r25 now contains the Current Task when in kernel
*
* Vineetg: Dec 22, 2007
* Minor Surgery of Low Level ISR to make it SMP safe
* - MMU_SCRATCH0 Reg used for freeing up r9 in Level 1 ISR
* - _current_task is made an array of NR_CPUS
* - Access of _current_task wrapped inside a macro so that if hardware
* team agrees for a dedicated reg, no other code is touched
*
* Amit Bhor, Rahul Trivedi, Kanika Nema, Sameer Dhavale : Codito Tech 2004
*/
/*------------------------------------------------------------------
@ -67,187 +20,10 @@
* Global Pointer (gp) r26
* Frame Pointer (fp) r27
* Stack Pointer (sp) r28
* Interrupt link register (ilink1) r29
* Interrupt link register (ilink2) r30
* Branch link register (blink) r31
*------------------------------------------------------------------
*/
.cpu A7
;############################ Vector Table #################################
.macro VECTOR lbl
#if 1 /* Just in case, build breaks */
j \lbl
#else
b \lbl
nop
#endif
.endm
.section .vector, "ax",@progbits
.align 4
/* Each entry in the vector table must occupy 2 words. Since it is a jump
* across sections (.vector to .text) we are gauranteed that 'j somewhere'
* will use the 'j limm' form of the intrsuction as long as somewhere is in
* a section other than .vector.
*/
; ********* Critical System Events **********************
VECTOR res_service ; 0x0, Restart Vector (0x0)
VECTOR mem_service ; 0x8, Mem exception (0x1)
VECTOR instr_service ; 0x10, Instrn Error (0x2)
; ******************** Device ISRs **********************
#ifdef CONFIG_ARC_IRQ3_LV2
VECTOR handle_interrupt_level2
#else
VECTOR handle_interrupt_level1
#endif
VECTOR handle_interrupt_level1
#ifdef CONFIG_ARC_IRQ5_LV2
VECTOR handle_interrupt_level2
#else
VECTOR handle_interrupt_level1
#endif
#ifdef CONFIG_ARC_IRQ6_LV2
VECTOR handle_interrupt_level2
#else
VECTOR handle_interrupt_level1
#endif
.rept 25
VECTOR handle_interrupt_level1 ; Other devices
.endr
/* FOR ARC600: timer = 0x3, uart = 0x8, emac = 0x10 */
; ******************** Exceptions **********************
VECTOR EV_MachineCheck ; 0x100, Fatal Machine check (0x20)
VECTOR EV_TLBMissI ; 0x108, Intruction TLB miss (0x21)
VECTOR EV_TLBMissD ; 0x110, Data TLB miss (0x22)
VECTOR EV_TLBProtV ; 0x118, Protection Violation (0x23)
; or Misaligned Access
VECTOR EV_PrivilegeV ; 0x120, Privilege Violation (0x24)
VECTOR EV_Trap ; 0x128, Trap exception (0x25)
VECTOR EV_Extension ; 0x130, Extn Intruction Excp (0x26)
.rept 24
VECTOR reserved ; Reserved Exceptions
.endr
#include <linux/linkage.h> /* {EXTRY,EXIT} */
#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,SYS...} */
#include <asm/errno.h>
#include <asm/arcregs.h>
#include <asm/irqflags.h>
;##################### Scratch Mem for IRQ stack switching #############
ARCFP_DATA int1_saved_reg
.align 32
.type int1_saved_reg, @object
.size int1_saved_reg, 4
int1_saved_reg:
.zero 4
/* Each Interrupt level needs its own scratch */
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
ARCFP_DATA int2_saved_reg
.type int2_saved_reg, @object
.size int2_saved_reg, 4
int2_saved_reg:
.zero 4
#endif
; ---------------------------------------------
.section .text, "ax",@progbits
res_service: ; processor restart
flag 0x1 ; not implemented
nop
nop
reserved: ; processor restart
rtie ; jump to processor initializations
;##################### Interrupt Handling ##############################
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
; ---------------------------------------------
; Level 2 ISR: Can interrupt a Level 1 ISR
; ---------------------------------------------
ENTRY(handle_interrupt_level2)
INTERRUPT_PROLOGUE 2
;------------------------------------------------------
; if L2 IRQ interrupted a L1 ISR, disable preemption
;------------------------------------------------------
ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
bbit0 r9, STATUS_A1_BIT, 1f ; L1 not active when L2 IRQ, so normal
; A1 is set in status32_l2
; bump thread_info->preempt_count (Disable preemption)
GET_CURR_THR_INFO_FROM_SP r10
ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
add r9, r9, 1
st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
1:
;------------------------------------------------------
; setup params for Linux common ISR and invoke it
;------------------------------------------------------
lr r0, [icause2]
and r0, r0, 0x1f
bl.d @arch_do_IRQ
mov r1, sp
mov r8,0x2
sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
b ret_from_exception
END(handle_interrupt_level2)
#endif
; ---------------------------------------------
; Level 1 ISR
; ---------------------------------------------
ENTRY(handle_interrupt_level1)
INTERRUPT_PROLOGUE 1
lr r0, [icause1]
and r0, r0, 0x1f
#ifdef CONFIG_TRACE_IRQFLAGS
; icause1 needs to be read early, before calling tracing, which
; can clobber scratch regs, hence use of stack to stash it
push r0
TRACE_ASM_IRQ_DISABLE
pop r0
#endif
bl.d @arch_do_IRQ
mov r1, sp
mov r8,0x1
sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
b ret_from_exception
END(handle_interrupt_level1)
;################### Non TLB Exception Handling #############################
; ---------------------------------------------
@ -314,70 +90,6 @@ ENTRY(EV_MachineCheck)
END(EV_MachineCheck)
; ---------------------------------------------
; Protection Violation Exception Handler
; ---------------------------------------------
ENTRY(EV_TLBProtV)
EXCEPTION_PROLOGUE
lr r2, [ecr]
lr r0, [efa] ; Faulting Data addr (not part of pt_regs saved above)
; Exception auto-disables further Intr/exceptions.
; Re-enable them by pretending to return from exception
; (so rest of handler executes in pure K mode)
FAKE_RET_FROM_EXCPN
mov r1, sp ; Handle to pt_regs
;------ (5) Type of Protection Violation? ----------
;
; ProtV Hardware Exception is triggered for Access Faults of 2 types
; -Access Violaton : 00_23_(00|01|02|03)_00
; x r w r+w
; -Unaligned Access : 00_23_04_00
;
bbit1 r2, ECR_C_BIT_PROTV_MISALIG_DATA, 4f
;========= (6a) Access Violation Processing ========
bl do_page_fault
b ret_from_exception
;========== (6b) Non aligned access ============
4:
SAVE_CALLEE_SAVED_USER
mov r2, sp ; callee_regs
bl do_misaligned_access
; TBD: optimize - do this only if a callee reg was involved
; either a dst of emulated LD/ST or src with address-writeback
RESTORE_CALLEE_SAVED_USER
b ret_from_exception
END(EV_TLBProtV)
; Wrapper for Linux page fault handler called from EV_TLBMiss*
; Very similar to ProtV handler case (6a) above, but avoids the extra checks
; for Misaligned access
;
ENTRY(call_do_page_fault)
EXCEPTION_PROLOGUE
lr r0, [efa] ; Faulting Data address
mov r1, sp
FAKE_RET_FROM_EXCPN
mov blink, ret_from_exception
b do_page_fault
END(call_do_page_fault)
; ---------------------------------------------
; Privilege Violation Exception Handler
; ---------------------------------------------
@ -625,97 +337,7 @@ resume_kernel_mode:
; preempt_schedule_irq() always returns with IRQ disabled
#endif
; fall through
;############# Return from Intr/Excp/Trap (ARC Specifics) ##############
;
; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap)
; IRQ shd definitely not happen between now and rtie
; All 2 entry points to here already disable interrupts
.Lrestore_regs:
TRACE_ASM_IRQ_ENABLE
lr r10, [status32]
; Restore REG File. In case multiple Events outstanding,
; use the same priorty as rtie: EXCPN, L2 IRQ, L1 IRQ, None
; Note that we use realtime STATUS32 (not pt_regs->status32) to
; decide that.
; if Returning from Exception
bbit0 r10, STATUS_AE_BIT, not_exception
EXCEPTION_EPILOGUE
rtie
; Not Exception so maybe Interrupts (Level 1 or 2)
not_exception:
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
; Level 2 interrupt return Path - from hardware standpoint
bbit0 r10, STATUS_A2_BIT, not_level2_interrupt
;------------------------------------------------------------------
; However the context returning might not have taken L2 intr itself
; e.g. Task'A' user-code -> L2 intr -> schedule -> 'B' user-code ret
; Special considerations needed for the context which took L2 intr
ld r9, [sp, PT_event] ; Ensure this is L2 intr context
brne r9, event_IRQ2, 149f
;------------------------------------------------------------------
; if L2 IRQ interrupted an L1 ISR, we'd disabled preemption earlier
; so that sched doesn't move to new task, causing L1 to be delayed
; undeterministically. Now that we've achieved that, let's reset
; things to what they were, before returning from L2 context
;----------------------------------------------------------------
ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
bbit0 r9, STATUS_A1_BIT, 149f ; L1 not active when L2 IRQ, so normal
; decrement thread_info->preempt_count (re-enable preemption)
GET_CURR_THR_INFO_FROM_SP r10
ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
; paranoid check, given A1 was active when A2 happened, preempt count
; must not be 0 because we would have incremented it.
; If this does happen we simply HALT as it means a BUG !!!
cmp r9, 0
bnz 2f
flag 1
2:
sub r9, r9, 1
st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
149:
;return from level 2
INTERRUPT_EPILOGUE 2
debug_marker_l2:
rtie
not_level2_interrupt:
#endif
bbit0 r10, STATUS_A1_BIT, not_level1_interrupt
;return from level 1
INTERRUPT_EPILOGUE 1
debug_marker_l1:
rtie
not_level1_interrupt:
;this case is for syscalls or Exceptions (with fake rtie)
EXCEPTION_EPILOGUE
debug_marker_syscall:
rtie
b .Lrestore_regs
END(ret_from_exception)
ENTRY(ret_from_fork)
@ -762,4 +384,7 @@ END(sys_clone_wrapper)
; This also fixes STAR 9000487933 where the prev-workaround (objcopy --setflag)
; would not work after a clean build due to kernel build system dependencies.
.section .debug_frame, "wa",@progbits
; Reset to .text as this file is included in entry-<isa>.S
.section .text, "ax",@progbits
#endif