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792 lines
22 KiB
792 lines
22 KiB
/* |
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* arch/xtensa/kernel/vectors.S |
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* |
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* This file contains all exception vectors (user, kernel, and double), |
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* as well as the window vectors (overflow and underflow), and the debug |
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* vector. These are the primary vectors executed by the processor if an |
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* exception occurs. |
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* |
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* This file is subject to the terms and conditions of the GNU General |
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* Public License. See the file "COPYING" in the main directory of |
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* this archive for more details. |
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* |
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* Copyright (C) 2005 - 2008 Tensilica, Inc. |
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* |
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* Chris Zankel <chris@zankel.net> |
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* |
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*/ |
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/* |
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* We use a two-level table approach. The user and kernel exception vectors |
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* use a first-level dispatch table to dispatch the exception to a registered |
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* fast handler or the default handler, if no fast handler was registered. |
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* The default handler sets up a C-stack and dispatches the exception to a |
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* registerd C handler in the second-level dispatch table. |
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* |
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* Fast handler entry condition: |
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* |
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* a0: trashed, original value saved on stack (PT_AREG0) |
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* a1: a1 |
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* a2: new stack pointer, original value in depc |
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* a3: dispatch table |
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* depc: a2, original value saved on stack (PT_DEPC) |
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* excsave_1: a3 |
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* |
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* The value for PT_DEPC saved to stack also functions as a boolean to |
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* indicate that the exception is either a double or a regular exception: |
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* |
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* PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception |
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* < VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception |
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* |
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* Note: Neither the kernel nor the user exception handler generate literals. |
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* |
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*/ |
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#include <linux/linkage.h> |
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#include <linux/pgtable.h> |
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#include <asm/asmmacro.h> |
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#include <asm/ptrace.h> |
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#include <asm/current.h> |
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#include <asm/asm-offsets.h> |
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#include <asm/processor.h> |
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#include <asm/page.h> |
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#include <asm/thread_info.h> |
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#include <asm/vectors.h> |
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#define WINDOW_VECTORS_SIZE 0x180 |
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/* |
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* User exception vector. (Exceptions with PS.UM == 1, PS.EXCM == 0) |
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* |
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* We get here when an exception occurred while we were in userland. |
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* We switch to the kernel stack and jump to the first level handler |
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* associated to the exception cause. |
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* |
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* Note: the saved kernel stack pointer (EXC_TABLE_KSTK) is already |
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* decremented by PT_USER_SIZE. |
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*/ |
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.section .UserExceptionVector.text, "ax" |
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ENTRY(_UserExceptionVector) |
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xsr a3, excsave1 # save a3 and get dispatch table |
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wsr a2, depc # save a2 |
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l32i a2, a3, EXC_TABLE_KSTK # load kernel stack to a2 |
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s32i a0, a2, PT_AREG0 # save a0 to ESF |
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rsr a0, exccause # retrieve exception cause |
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s32i a0, a2, PT_DEPC # mark it as a regular exception |
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addx4 a0, a0, a3 # find entry in table |
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l32i a0, a0, EXC_TABLE_FAST_USER # load handler |
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xsr a3, excsave1 # restore a3 and dispatch table |
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jx a0 |
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ENDPROC(_UserExceptionVector) |
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/* |
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* Kernel exception vector. (Exceptions with PS.UM == 0, PS.EXCM == 0) |
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* |
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* We get this exception when we were already in kernel space. |
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* We decrement the current stack pointer (kernel) by PT_SIZE and |
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* jump to the first-level handler associated with the exception cause. |
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* |
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* Note: we need to preserve space for the spill region. |
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*/ |
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.section .KernelExceptionVector.text, "ax" |
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ENTRY(_KernelExceptionVector) |
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xsr a3, excsave1 # save a3, and get dispatch table |
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wsr a2, depc # save a2 |
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addi a2, a1, -16-PT_SIZE # adjust stack pointer |
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s32i a0, a2, PT_AREG0 # save a0 to ESF |
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rsr a0, exccause # retrieve exception cause |
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s32i a0, a2, PT_DEPC # mark it as a regular exception |
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addx4 a0, a0, a3 # find entry in table |
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l32i a0, a0, EXC_TABLE_FAST_KERNEL # load handler address |
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xsr a3, excsave1 # restore a3 and dispatch table |
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jx a0 |
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ENDPROC(_KernelExceptionVector) |
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/* |
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* Double exception vector (Exceptions with PS.EXCM == 1) |
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* We get this exception when another exception occurs while were are |
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* already in an exception, such as window overflow/underflow exception, |
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* or 'expected' exceptions, for example memory exception when we were trying |
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* to read data from an invalid address in user space. |
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* |
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* Note that this vector is never invoked for level-1 interrupts, because such |
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* interrupts are disabled (masked) when PS.EXCM is set. |
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* |
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* We decode the exception and take the appropriate action. However, the |
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* double exception vector is much more careful, because a lot more error |
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* cases go through the double exception vector than through the user and |
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* kernel exception vectors. |
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* |
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* Occasionally, the kernel expects a double exception to occur. This usually |
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* happens when accessing user-space memory with the user's permissions |
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* (l32e/s32e instructions). The kernel state, though, is not always suitable |
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* for immediate transfer of control to handle_double, where "normal" exception |
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* processing occurs. Also in kernel mode, TLB misses can occur if accessing |
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* vmalloc memory, possibly requiring repair in a double exception handler. |
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* |
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* The variable at TABLE_FIXUP offset from the pointer in EXCSAVE_1 doubles as |
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* a boolean variable and a pointer to a fixup routine. If the variable |
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* EXC_TABLE_FIXUP is non-zero, this handler jumps to that address. A value of |
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* zero indicates to use the default kernel/user exception handler. |
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* There is only one exception, when the value is identical to the exc_table |
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* label, the kernel is in trouble. This mechanism is used to protect critical |
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* sections, mainly when the handler writes to the stack to assert the stack |
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* pointer is valid. Once the fixup/default handler leaves that area, the |
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* EXC_TABLE_FIXUP variable is reset to the fixup handler or zero. |
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* |
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* Procedures wishing to use this mechanism should set EXC_TABLE_FIXUP to the |
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* nonzero address of a fixup routine before it could cause a double exception |
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* and reset it before it returns. |
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* |
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* Some other things to take care of when a fast exception handler doesn't |
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* specify a particular fixup handler but wants to use the default handlers: |
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* |
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* - The original stack pointer (in a1) must not be modified. The fast |
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* exception handler should only use a2 as the stack pointer. |
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* |
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* - If the fast handler manipulates the stack pointer (in a2), it has to |
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* register a valid fixup handler and cannot use the default handlers. |
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* |
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* - The handler can use any other generic register from a3 to a15, but it |
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* must save the content of these registers to stack (PT_AREG3...PT_AREGx) |
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* |
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* - These registers must be saved before a double exception can occur. |
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* |
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* - If we ever implement handling signals while in double exceptions, the |
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* number of registers a fast handler has saved (excluding a0 and a1) must |
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* be written to PT_AREG1. (1 if only a3 is used, 2 for a3 and a4, etc. ) |
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* |
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* The fixup handlers are special handlers: |
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* |
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* - Fixup entry conditions differ from regular exceptions: |
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* |
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* a0: DEPC |
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* a1: a1 |
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* a2: trashed, original value in EXC_TABLE_DOUBLE_SAVE |
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* a3: exctable |
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* depc: a0 |
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* excsave_1: a3 |
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* |
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* - When the kernel enters the fixup handler, it still assumes it is in a |
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* critical section, so EXC_TABLE_FIXUP variable is set to exc_table. |
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* The fixup handler, therefore, has to re-register itself as the fixup |
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* handler before it returns from the double exception. |
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* |
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* - Fixup handler can share the same exception frame with the fast handler. |
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* The kernel stack pointer is not changed when entering the fixup handler. |
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* |
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* - Fixup handlers can jump to the default kernel and user exception |
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* handlers. Before it jumps, though, it has to setup a exception frame |
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* on stack. Because the default handler resets the register fixup handler |
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* the fixup handler must make sure that the default handler returns to |
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* it instead of the exception address, so it can re-register itself as |
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* the fixup handler. |
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* |
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* In case of a critical condition where the kernel cannot recover, we jump |
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* to unrecoverable_exception with the following entry conditions. |
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* All registers a0...a15 are unchanged from the last exception, except: |
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* |
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* a0: last address before we jumped to the unrecoverable_exception. |
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* excsave_1: a0 |
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* |
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* |
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* See the handle_alloca_user and spill_registers routines for example clients. |
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* |
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* FIXME: Note: we currently don't allow signal handling coming from a double |
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* exception, so the item markt with (*) is not required. |
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*/ |
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.section .DoubleExceptionVector.text, "ax" |
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ENTRY(_DoubleExceptionVector) |
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xsr a3, excsave1 |
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s32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
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/* Check for kernel double exception (usually fatal). */ |
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rsr a2, ps |
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_bbsi.l a2, PS_UM_BIT, 1f |
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j .Lksp |
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.align 4 |
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.literal_position |
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1: |
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/* Check if we are currently handling a window exception. */ |
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/* Note: We don't need to indicate that we enter a critical section. */ |
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xsr a0, depc # get DEPC, save a0 |
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movi a2, WINDOW_VECTORS_VADDR |
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_bltu a0, a2, .Lfixup |
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addi a2, a2, WINDOW_VECTORS_SIZE |
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_bgeu a0, a2, .Lfixup |
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/* Window overflow/underflow exception. Get stack pointer. */ |
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l32i a2, a3, EXC_TABLE_KSTK |
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/* Check for overflow/underflow exception, jump if overflow. */ |
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bbci.l a0, 6, _DoubleExceptionVector_WindowOverflow |
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/* |
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* Restart window underflow exception. |
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* Currently: |
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* depc = orig a0, |
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* a0 = orig DEPC, |
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* a2 = new sp based on KSTK from exc_table |
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* a3 = excsave_1 |
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* excsave_1 = orig a3 |
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* |
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* We return to the instruction in user space that caused the window |
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* underflow exception. Therefore, we change window base to the value |
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* before we entered the window underflow exception and prepare the |
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* registers to return as if we were coming from a regular exception |
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* by changing depc (in a0). |
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* Note: We can trash the current window frame (a0...a3) and depc! |
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*/ |
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_DoubleExceptionVector_WindowUnderflow: |
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xsr a3, excsave1 |
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wsr a2, depc # save stack pointer temporarily |
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rsr a0, ps |
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extui a0, a0, PS_OWB_SHIFT, PS_OWB_WIDTH |
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wsr a0, windowbase |
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rsync |
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/* We are now in the previous window frame. Save registers again. */ |
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xsr a2, depc # save a2 and get stack pointer |
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s32i a0, a2, PT_AREG0 |
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xsr a3, excsave1 |
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rsr a0, exccause |
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s32i a0, a2, PT_DEPC # mark it as a regular exception |
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addx4 a0, a0, a3 |
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xsr a3, excsave1 |
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l32i a0, a0, EXC_TABLE_FAST_USER |
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jx a0 |
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/* |
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* We only allow the ITLB miss exception if we are in kernel space. |
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* All other exceptions are unexpected and thus unrecoverable! |
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*/ |
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#ifdef CONFIG_MMU |
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.extern fast_second_level_miss_double_kernel |
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.Lksp: /* a0: a0, a1: a1, a2: a2, a3: trashed, depc: depc, excsave: a3 */ |
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rsr a3, exccause |
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beqi a3, EXCCAUSE_ITLB_MISS, 1f |
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addi a3, a3, -EXCCAUSE_DTLB_MISS |
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bnez a3, .Lunrecoverable |
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1: movi a3, fast_second_level_miss_double_kernel |
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jx a3 |
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#else |
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.equ .Lksp, .Lunrecoverable |
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#endif |
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/* Critical! We can't handle this situation. PANIC! */ |
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.extern unrecoverable_exception |
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.Lunrecoverable_fixup: |
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l32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
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xsr a0, depc |
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.Lunrecoverable: |
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rsr a3, excsave1 |
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wsr a0, excsave1 |
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call0 unrecoverable_exception |
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.Lfixup:/* Check for a fixup handler or if we were in a critical section. */ |
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/* a0: depc, a1: a1, a2: trash, a3: exctable, depc: a0, excsave1: a3 */ |
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/* Enter critical section. */ |
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l32i a2, a3, EXC_TABLE_FIXUP |
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s32i a3, a3, EXC_TABLE_FIXUP |
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beq a2, a3, .Lunrecoverable_fixup # critical section |
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beqz a2, .Ldflt # no handler was registered |
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/* a0: depc, a1: a1, a2: trash, a3: exctable, depc: a0, excsave: a3 */ |
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jx a2 |
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.Ldflt: /* Get stack pointer. */ |
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l32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
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addi a2, a2, -PT_USER_SIZE |
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/* a0: depc, a1: a1, a2: kstk, a3: exctable, depc: a0, excsave: a3 */ |
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s32i a0, a2, PT_DEPC |
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l32i a0, a3, EXC_TABLE_DOUBLE_SAVE |
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xsr a0, depc |
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s32i a0, a2, PT_AREG0 |
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/* a0: avail, a1: a1, a2: kstk, a3: exctable, depc: a2, excsave: a3 */ |
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rsr a0, exccause |
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addx4 a0, a0, a3 |
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xsr a3, excsave1 |
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l32i a0, a0, EXC_TABLE_FAST_USER |
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jx a0 |
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/* |
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* Restart window OVERFLOW exception. |
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* Currently: |
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* depc = orig a0, |
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* a0 = orig DEPC, |
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* a2 = new sp based on KSTK from exc_table |
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* a3 = EXCSAVE_1 |
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* excsave_1 = orig a3 |
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* |
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* We return to the instruction in user space that caused the window |
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* overflow exception. Therefore, we change window base to the value |
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* before we entered the window overflow exception and prepare the |
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* registers to return as if we were coming from a regular exception |
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* by changing DEPC (in a0). |
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* |
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* NOTE: We CANNOT trash the current window frame (a0...a3), but we |
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* can clobber depc. |
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* |
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* The tricky part here is that overflow8 and overflow12 handlers |
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* save a0, then clobber a0. To restart the handler, we have to restore |
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* a0 if the double exception was past the point where a0 was clobbered. |
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* |
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* To keep things simple, we take advantage of the fact all overflow |
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* handlers save a0 in their very first instruction. If DEPC was past |
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* that instruction, we can safely restore a0 from where it was saved |
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* on the stack. |
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* |
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* a0: depc, a1: a1, a2: kstk, a3: exc_table, depc: a0, excsave1: a3 |
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*/ |
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_DoubleExceptionVector_WindowOverflow: |
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extui a2, a0, 0, 6 # get offset into 64-byte vector handler |
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beqz a2, 1f # if at start of vector, don't restore |
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addi a0, a0, -128 |
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bbsi.l a0, 8, 1f # don't restore except for overflow 8 and 12 |
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/* |
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* This fixup handler is for the extremely unlikely case where the |
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* overflow handler's reference thru a0 gets a hardware TLB refill |
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* that bumps out the (distinct, aliasing) TLB entry that mapped its |
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* prior references thru a9/a13, and where our reference now thru |
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* a9/a13 gets a 2nd-level miss exception (not hardware TLB refill). |
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*/ |
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movi a2, window_overflow_restore_a0_fixup |
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s32i a2, a3, EXC_TABLE_FIXUP |
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l32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
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xsr a3, excsave1 |
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bbsi.l a0, 7, 2f |
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/* |
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* Restore a0 as saved by _WindowOverflow8(). |
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*/ |
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l32e a0, a9, -16 |
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wsr a0, depc # replace the saved a0 |
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j 3f |
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2: |
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/* |
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* Restore a0 as saved by _WindowOverflow12(). |
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*/ |
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l32e a0, a13, -16 |
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wsr a0, depc # replace the saved a0 |
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3: |
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xsr a3, excsave1 |
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movi a0, 0 |
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s32i a0, a3, EXC_TABLE_FIXUP |
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s32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
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1: |
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/* |
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* Restore WindowBase while leaving all address registers restored. |
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* We have to use ROTW for this, because WSR.WINDOWBASE requires |
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* an address register (which would prevent restore). |
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* |
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* Window Base goes from 0 ... 7 (Module 8) |
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* Window Start is 8 bits; Ex: (0b1010 1010):0x55 from series of call4s |
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*/ |
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rsr a0, ps |
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extui a0, a0, PS_OWB_SHIFT, PS_OWB_WIDTH |
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rsr a2, windowbase |
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sub a0, a2, a0 |
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extui a0, a0, 0, 3 |
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l32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
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xsr a3, excsave1 |
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beqi a0, 1, .L1pane |
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beqi a0, 3, .L3pane |
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rsr a0, depc |
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rotw -2 |
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/* |
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* We are now in the user code's original window frame. |
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* Process the exception as a user exception as if it was |
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* taken by the user code. |
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* |
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* This is similar to the user exception vector, |
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* except that PT_DEPC isn't set to EXCCAUSE. |
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*/ |
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1: |
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xsr a3, excsave1 |
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wsr a2, depc |
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l32i a2, a3, EXC_TABLE_KSTK |
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s32i a0, a2, PT_AREG0 |
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rsr a0, exccause |
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s32i a0, a2, PT_DEPC |
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_DoubleExceptionVector_handle_exception: |
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addi a0, a0, -EXCCAUSE_UNALIGNED |
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beqz a0, 2f |
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addx4 a0, a0, a3 |
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l32i a0, a0, EXC_TABLE_FAST_USER + 4 * EXCCAUSE_UNALIGNED |
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xsr a3, excsave1 |
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jx a0 |
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2: |
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movi a0, user_exception |
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xsr a3, excsave1 |
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jx a0 |
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.L1pane: |
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rsr a0, depc |
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rotw -1 |
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j 1b |
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.L3pane: |
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rsr a0, depc |
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rotw -3 |
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j 1b |
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ENDPROC(_DoubleExceptionVector) |
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/* |
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* Fixup handler for TLB miss in double exception handler for window owerflow. |
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* We get here with windowbase set to the window that was being spilled and |
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* a0 trashed. a0 bit 7 determines if this is a call8 (bit clear) or call12 |
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* (bit set) window. |
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* |
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* We do the following here: |
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* - go to the original window retaining a0 value; |
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* - set up exception stack to return back to appropriate a0 restore code |
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* (we'll need to rotate window back and there's no place to save this |
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* information, use different return address for that); |
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* - handle the exception; |
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* - go to the window that was being spilled; |
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* - set up window_overflow_restore_a0_fixup as a fixup routine; |
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* - reload a0; |
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* - restore the original window; |
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* - reset the default fixup routine; |
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* - return to user. By the time we get to this fixup handler all information |
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* about the conditions of the original double exception that happened in |
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* the window overflow handler is lost, so we just return to userspace to |
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* retry overflow from start. |
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* |
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* a0: value of depc, original value in depc |
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* a2: trashed, original value in EXC_TABLE_DOUBLE_SAVE |
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* a3: exctable, original value in excsave1 |
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*/ |
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__XTENSA_HANDLER |
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.literal_position |
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ENTRY(window_overflow_restore_a0_fixup) |
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rsr a0, ps |
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extui a0, a0, PS_OWB_SHIFT, PS_OWB_WIDTH |
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rsr a2, windowbase |
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sub a0, a2, a0 |
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extui a0, a0, 0, 3 |
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l32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
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xsr a3, excsave1 |
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_beqi a0, 1, .Lhandle_1 |
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_beqi a0, 3, .Lhandle_3 |
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.macro overflow_fixup_handle_exception_pane n |
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rsr a0, depc |
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rotw -\n |
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xsr a3, excsave1 |
|
wsr a2, depc |
|
l32i a2, a3, EXC_TABLE_KSTK |
|
s32i a0, a2, PT_AREG0 |
|
|
|
movi a0, .Lrestore_\n |
|
s32i a0, a2, PT_DEPC |
|
rsr a0, exccause |
|
j _DoubleExceptionVector_handle_exception |
|
|
|
.endm |
|
|
|
overflow_fixup_handle_exception_pane 2 |
|
.Lhandle_1: |
|
overflow_fixup_handle_exception_pane 1 |
|
.Lhandle_3: |
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overflow_fixup_handle_exception_pane 3 |
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|
|
.macro overflow_fixup_restore_a0_pane n |
|
|
|
rotw \n |
|
/* Need to preserve a0 value here to be able to handle exception |
|
* that may occur on a0 reload from stack. It may occur because |
|
* TLB miss handler may not be atomic and pointer to page table |
|
* may be lost before we get here. There are no free registers, |
|
* so we need to use EXC_TABLE_DOUBLE_SAVE area. |
|
*/ |
|
xsr a3, excsave1 |
|
s32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
|
movi a2, window_overflow_restore_a0_fixup |
|
s32i a2, a3, EXC_TABLE_FIXUP |
|
l32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
|
xsr a3, excsave1 |
|
bbsi.l a0, 7, 1f |
|
l32e a0, a9, -16 |
|
j 2f |
|
1: |
|
l32e a0, a13, -16 |
|
2: |
|
rotw -\n |
|
|
|
.endm |
|
|
|
.Lrestore_2: |
|
overflow_fixup_restore_a0_pane 2 |
|
|
|
.Lset_default_fixup: |
|
xsr a3, excsave1 |
|
s32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
|
movi a2, 0 |
|
s32i a2, a3, EXC_TABLE_FIXUP |
|
l32i a2, a3, EXC_TABLE_DOUBLE_SAVE |
|
xsr a3, excsave1 |
|
rfe |
|
|
|
.Lrestore_1: |
|
overflow_fixup_restore_a0_pane 1 |
|
j .Lset_default_fixup |
|
.Lrestore_3: |
|
overflow_fixup_restore_a0_pane 3 |
|
j .Lset_default_fixup |
|
|
|
ENDPROC(window_overflow_restore_a0_fixup) |
|
|
|
/* |
|
* Debug interrupt vector |
|
* |
|
* There is not much space here, so simply jump to another handler. |
|
* EXCSAVE[DEBUGLEVEL] has been set to that handler. |
|
*/ |
|
|
|
.section .DebugInterruptVector.text, "ax" |
|
|
|
ENTRY(_DebugInterruptVector) |
|
|
|
xsr a3, SREG_EXCSAVE + XCHAL_DEBUGLEVEL |
|
s32i a0, a3, DT_DEBUG_SAVE |
|
l32i a0, a3, DT_DEBUG_EXCEPTION |
|
jx a0 |
|
|
|
ENDPROC(_DebugInterruptVector) |
|
|
|
|
|
|
|
/* |
|
* Medium priority level interrupt vectors |
|
* |
|
* Each takes less than 16 (0x10) bytes, no literals, by placing |
|
* the extra 8 bytes that would otherwise be required in the window |
|
* vectors area where there is space. With relocatable vectors, |
|
* all vectors are within ~ 4 kB range of each other, so we can |
|
* simply jump (J) to another vector without having to use JX. |
|
* |
|
* common_exception code gets current IRQ level in PS.INTLEVEL |
|
* and preserves it for the IRQ handling time. |
|
*/ |
|
|
|
.macro irq_entry_level level |
|
|
|
.if XCHAL_EXCM_LEVEL >= \level |
|
.section .Level\level\()InterruptVector.text, "ax" |
|
ENTRY(_Level\level\()InterruptVector) |
|
wsr a0, excsave2 |
|
rsr a0, epc\level |
|
wsr a0, epc1 |
|
.if \level <= LOCKLEVEL |
|
movi a0, EXCCAUSE_LEVEL1_INTERRUPT |
|
.else |
|
movi a0, EXCCAUSE_MAPPED_NMI |
|
.endif |
|
wsr a0, exccause |
|
rsr a0, eps\level |
|
# branch to user or kernel vector |
|
j _SimulateUserKernelVectorException |
|
.endif |
|
|
|
.endm |
|
|
|
irq_entry_level 2 |
|
irq_entry_level 3 |
|
irq_entry_level 4 |
|
irq_entry_level 5 |
|
irq_entry_level 6 |
|
|
|
|
|
/* Window overflow and underflow handlers. |
|
* The handlers must be 64 bytes apart, first starting with the underflow |
|
* handlers underflow-4 to underflow-12, then the overflow handlers |
|
* overflow-4 to overflow-12. |
|
* |
|
* Note: We rerun the underflow handlers if we hit an exception, so |
|
* we try to access any page that would cause a page fault early. |
|
*/ |
|
|
|
#define ENTRY_ALIGN64(name) \ |
|
.globl name; \ |
|
.align 64; \ |
|
name: |
|
|
|
.section .WindowVectors.text, "ax" |
|
|
|
|
|
/* 4-Register Window Overflow Vector (Handler) */ |
|
|
|
ENTRY_ALIGN64(_WindowOverflow4) |
|
|
|
s32e a0, a5, -16 |
|
s32e a1, a5, -12 |
|
s32e a2, a5, -8 |
|
s32e a3, a5, -4 |
|
rfwo |
|
|
|
ENDPROC(_WindowOverflow4) |
|
|
|
|
|
#if XCHAL_EXCM_LEVEL >= 2 |
|
/* Not a window vector - but a convenient location |
|
* (where we know there's space) for continuation of |
|
* medium priority interrupt dispatch code. |
|
* On entry here, a0 contains PS, and EPC2 contains saved a0: |
|
*/ |
|
.align 4 |
|
_SimulateUserKernelVectorException: |
|
addi a0, a0, (1 << PS_EXCM_BIT) |
|
#if !XTENSA_FAKE_NMI |
|
wsr a0, ps |
|
#endif |
|
bbsi.l a0, PS_UM_BIT, 1f # branch if user mode |
|
xsr a0, excsave2 # restore a0 |
|
j _KernelExceptionVector # simulate kernel vector exception |
|
1: xsr a0, excsave2 # restore a0 |
|
j _UserExceptionVector # simulate user vector exception |
|
#endif |
|
|
|
|
|
/* 4-Register Window Underflow Vector (Handler) */ |
|
|
|
ENTRY_ALIGN64(_WindowUnderflow4) |
|
|
|
l32e a0, a5, -16 |
|
l32e a1, a5, -12 |
|
l32e a2, a5, -8 |
|
l32e a3, a5, -4 |
|
rfwu |
|
|
|
ENDPROC(_WindowUnderflow4) |
|
|
|
/* 8-Register Window Overflow Vector (Handler) */ |
|
|
|
ENTRY_ALIGN64(_WindowOverflow8) |
|
|
|
s32e a0, a9, -16 |
|
l32e a0, a1, -12 |
|
s32e a2, a9, -8 |
|
s32e a1, a9, -12 |
|
s32e a3, a9, -4 |
|
s32e a4, a0, -32 |
|
s32e a5, a0, -28 |
|
s32e a6, a0, -24 |
|
s32e a7, a0, -20 |
|
rfwo |
|
|
|
ENDPROC(_WindowOverflow8) |
|
|
|
/* 8-Register Window Underflow Vector (Handler) */ |
|
|
|
ENTRY_ALIGN64(_WindowUnderflow8) |
|
|
|
l32e a1, a9, -12 |
|
l32e a0, a9, -16 |
|
l32e a7, a1, -12 |
|
l32e a2, a9, -8 |
|
l32e a4, a7, -32 |
|
l32e a3, a9, -4 |
|
l32e a5, a7, -28 |
|
l32e a6, a7, -24 |
|
l32e a7, a7, -20 |
|
rfwu |
|
|
|
ENDPROC(_WindowUnderflow8) |
|
|
|
/* 12-Register Window Overflow Vector (Handler) */ |
|
|
|
ENTRY_ALIGN64(_WindowOverflow12) |
|
|
|
s32e a0, a13, -16 |
|
l32e a0, a1, -12 |
|
s32e a1, a13, -12 |
|
s32e a2, a13, -8 |
|
s32e a3, a13, -4 |
|
s32e a4, a0, -48 |
|
s32e a5, a0, -44 |
|
s32e a6, a0, -40 |
|
s32e a7, a0, -36 |
|
s32e a8, a0, -32 |
|
s32e a9, a0, -28 |
|
s32e a10, a0, -24 |
|
s32e a11, a0, -20 |
|
rfwo |
|
|
|
ENDPROC(_WindowOverflow12) |
|
|
|
/* 12-Register Window Underflow Vector (Handler) */ |
|
|
|
ENTRY_ALIGN64(_WindowUnderflow12) |
|
|
|
l32e a1, a13, -12 |
|
l32e a0, a13, -16 |
|
l32e a11, a1, -12 |
|
l32e a2, a13, -8 |
|
l32e a4, a11, -48 |
|
l32e a8, a11, -32 |
|
l32e a3, a13, -4 |
|
l32e a5, a11, -44 |
|
l32e a6, a11, -40 |
|
l32e a7, a11, -36 |
|
l32e a9, a11, -28 |
|
l32e a10, a11, -24 |
|
l32e a11, a11, -20 |
|
rfwu |
|
|
|
ENDPROC(_WindowUnderflow12) |
|
|
|
.text
|
|
|