/* $NetBSD: exception.S,v 1.13 2003/10/31 16:30:15 scw Exp $ */ /*- * Copyright (c) 1994-1997 Mark Brinicombe. * Copyright (c) 1994 Brini. * All rights reserved. * * This code is derived from software written for Brini by Mark Brinicombe * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Brini. * 4. The name of the company nor the name of the author may be used to * endorse or promote products derived from this software without specific * prior written permission. * * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * RiscBSD kernel project * * exception.S * * Low level handlers for exception vectors * * Created : 24/09/94 * * Based on kate/display/abort.s * */ #include "assym.inc" #include <machine/asm.h> #include <machine/armreg.h> #include <machine/asmacros.h> #include <machine/trap.h> #include <sys/intr.h> #ifdef KDTRACE_HOOKS .bss .align 4 .global _C_LABEL(dtrace_invop_jump_addr) _C_LABEL(dtrace_invop_jump_addr): .word 0 .word 0 #endif .text .align 2 /* * ASM macros for pushing and pulling trapframes from the stack * * These macros are used to handle the irqframe and trapframe structures * defined above. */ /* * PUSHFRAME - macro to push a trap frame on the stack in the current mode * Since the current mode is used, the SVC lr field is not defined. */ #define PUSHFRAME \ sub sp, sp, #4; /* Align the stack */ \ str lr, [sp, #-4]!; /* Push the return address */ \ sub sp, sp, #(4*17); /* Adjust the stack pointer */ \ stmia sp, {r0-r12}; /* Push the user mode registers */ \ add r0, sp, #(4*13); /* Adjust the stack pointer */ \ stmia r0, {r13-r14}^; /* Push the user mode registers */ \ mov r0, r0; /* NOP for previous instruction */ \ mrs r0, spsr; /* Put the SPSR on the stack */ \ str r0, [sp, #-4]!; /* * PULLFRAME - macro to pull a trap frame from the stack in the current mode * Since the current mode is used, the SVC lr field is ignored. */ #define PULLFRAME \ ldr r0, [sp], #4 ; /* Get the SPSR from stack */ \ msr spsr_fsxc, r0; \ clrex; \ ldmia sp, {r0-r14}^; /* Restore registers (usr mode) */ \ mov r0, r0; /* NOP for previous instruction */ \ add sp, sp, #(4*17); /* Adjust the stack pointer */ \ ldr lr, [sp], #4; /* Pull the return address */ \ add sp, sp, #4 /* Align the stack */ /* * PUSHFRAMEINSVC - macro to push a trap frame on the stack in SVC32 mode * This should only be used if the processor is not currently in SVC32 * mode. The processor mode is switched to SVC mode and the trap frame is * stored. The SVC lr field is used to store the previous value of * lr in SVC mode. */ #define PUSHFRAMEINSVC \ stmdb sp, {r0-r3}; /* Save 4 registers */ \ mov r0, lr; /* Save xxx32 r14 */ \ mov r1, sp; /* Save xxx32 sp */ \ mrs r3, spsr; /* Save xxx32 spsr */ \ mrs r2, cpsr; /* Get the CPSR */ \ bic r2, r2, #(PSR_MODE); /* Fix for SVC mode */ \ orr r2, r2, #(PSR_SVC32_MODE); \ msr cpsr_c, r2; /* Punch into SVC mode */ \ mov r2, sp; /* Save SVC sp */ \ bic sp, sp, #7; /* Align sp to an 8-byte addrress */ \ sub sp, sp, #(4 * 17); /* Pad trapframe to keep alignment */ \ /* and for dtrace to emulate push/pop */ \ str r0, [sp, #-4]!; /* Push return address */ \ str lr, [sp, #-4]!; /* Push SVC lr */ \ str r2, [sp, #-4]!; /* Push SVC sp */ \ msr spsr_fsxc, r3; /* Restore correct spsr */ \ ldmdb r1, {r0-r3}; /* Restore 4 regs from xxx mode */ \ sub sp, sp, #(4*15); /* Adjust the stack pointer */ \ stmia sp, {r0-r12}; /* Push the user mode registers */ \ add r0, sp, #(4*13); /* Adjust the stack pointer */ \ stmia r0, {r13-r14}^; /* Push the user mode registers */ \ mov r0, r0; /* NOP for previous instruction */ \ mrs r0, spsr; /* Put the SPSR on the stack */ \ str r0, [sp, #-4]! /* * PULLFRAMEFROMSVCANDEXIT - macro to pull a trap frame from the stack * in SVC32 mode and restore the saved processor mode and PC. * This should be used when the SVC lr register needs to be restored on * exit. */ #define PULLFRAMEFROMSVCANDEXIT \ ldr r0, [sp], #4; /* Get the SPSR from stack */ \ msr spsr_fsxc, r0; /* restore SPSR */ \ clrex; \ ldmia sp, {r0-r14}^; /* Restore registers (usr mode) */ \ mov r0, r0; /* NOP for previous instruction */ \ add sp, sp, #(4*15); /* Adjust the stack pointer */ \ ldmia sp, {sp, lr, pc}^ /* Restore lr and exit */ /* * Unwind hints so we can unwind past functions that use * PULLFRAMEFROMSVCANDEXIT. They are run in reverse order. * As the last thing we do is restore the stack pointer * we can ignore the padding at the end of struct trapframe. */ #define UNWINDSVCFRAME \ .save {r13-r15}; /* Restore sp, lr, pc */ \ .pad #(2*4); /* Skip user sp and lr */ \ .save {r0-r12}; /* Restore r0-r12 */ \ .pad #(4) /* Skip spsr */ #define DO_AST \ ldr r0, [sp]; /* Get the SPSR from stack */ \ mrs r4, cpsr; /* save CPSR */ \ orr r1, r4, #(PSR_I); \ msr cpsr_c, r1; /* Disable interrupts */ \ and r0, r0, #(PSR_MODE); /* Returning to USR mode? */ \ teq r0, #(PSR_USR32_MODE); \ bne 2f; /* Nope, get out now */ \ bic r4, r4, #(PSR_I); \ 1: GET_CURTHREAD_PTR(r5); \ ldr r1, [r5, #(TD_AST)]; \ teq r1, #0; \ beq 2f; /* Nope. Just bail */ \ msr cpsr_c, r4; /* Restore interrupts */ \ mov r0, sp; \ bl _C_LABEL(ast); /* ast(frame) */ \ orr r0, r4, #(PSR_I); \ msr cpsr_c, r0; \ b 1b; \ 2: /* * Entry point for a Software Interrupt (SWI). * * The hardware switches to svc32 mode on a swi, so we're already on the * right stack; just build a trapframe and call the handler. */ ASENTRY_NP(swi_entry) PUSHFRAME /* Build the trapframe on the */ mov r0, sp /* scv32 stack, pass it to the */ bl _C_LABEL(swi_handler) /* swi handler. */ /* * The fork_trampoline() code in swtch.S aranges for the MI fork_exit() * to return to swi_exit here, to return to userland. The net effect is * that a newly created thread appears to return from a SWI just like * the parent thread that created it. */ ASEENTRY_NP(swi_exit) DO_AST /* Handle pending signals. */ PULLFRAME /* Deallocate trapframe. */ movs pc, lr /* Return to userland. */ STOP_UNWINDING /* Don't unwind into user mode. */ EEND(swi_exit) END(swi_entry) /* * Standard exception exit handler. * * This is used to return from all exceptions except SWI. It uses DO_AST and * PULLFRAMEFROMSVCANDEXIT and can only be called if the exception entry code * used PUSHFRAMEINSVC. * * If the return is to user mode, this uses DO_AST to deliver any pending * signals and/or handle TDF_NEEDRESCHED first. */ ASENTRY_NP(exception_exit) DO_AST /* Handle pending signals. */ PULLFRAMEFROMSVCANDEXIT /* Return. */ UNWINDSVCFRAME /* Special unwinding for exceptions. */ END(exception_exit) /* * Entry point for a Prefetch Abort exception. * * The hardware switches to the abort mode stack; we switch to svc32 before * calling the handler, then return directly to the original mode/stack * on exit (without transitioning back through the abort mode stack). */ ASENTRY_NP(prefetch_abort_entry) sub lr, lr, #4 /* Adjust the lr. Transition to scv32 */ PUSHFRAMEINSVC /* mode stack, build trapframe there. */ adr lr, exception_exit /* Return from handler via standard */ mov r0, sp /* exception exit routine. Pass the */ mov r1, #1 /* Type flag */ b _C_LABEL(abort_handler) END(prefetch_abort_entry) /* * Entry point for a Data Abort exception. * * The hardware switches to the abort mode stack; we switch to svc32 before * calling the handler, then return directly to the original mode/stack * on exit (without transitioning back through the abort mode stack). */ ASENTRY_NP(data_abort_entry) sub lr, lr, #8 /* Adjust the lr. Transition to scv32 */ PUSHFRAMEINSVC /* mode stack, build trapframe there. */ adr lr, exception_exit /* Exception exit routine */ mov r0, sp /* Trapframe to the handler */ mov r1, #0 /* Type flag */ b _C_LABEL(abort_handler) END(data_abort_entry) /* * Entry point for an Undefined Instruction exception. * * The hardware switches to the undefined mode stack; we switch to svc32 before * calling the handler, then return directly to the original mode/stack * on exit (without transitioning back through the undefined mode stack). */ ASENTRY_NP(undefined_entry) PUSHFRAMEINSVC /* mode stack, build trapframe there. */ mov r4, r0 /* R0 contains SPSR */ adr lr, exception_exit /* Return from handler via standard */ mov r0, sp /* exception exit routine. pass frame */ ldr r2, [sp, #(TF_PC)] /* load pc */ tst r4, #(PSR_T) /* test if PSR_T */ subne r2, r2, #(THUMB_INSN_SIZE) subeq r2, r2, #(INSN_SIZE) str r2, [sp, #TF_PC] /* store pc */ #ifdef KDTRACE_HOOKS /* Check if dtrace is enabled */ ldr r1, =_C_LABEL(dtrace_invop_jump_addr) ldr r3, [r1] cmp r3, #0 beq undefinedinstruction and r4, r4, #(PSR_MODE) /* Mask out unneeded bits */ cmp r4, #(PSR_USR32_MODE) /* Check if we came from usermode */ beq undefinedinstruction ldr r4, [r2] /* load instrution */ ldr r1, =FBT_BREAKPOINT /* load fbt inv op */ cmp r1, r4 bne undefinedinstruction bx r3 /* call invop_jump_addr */ #endif b undefinedinstruction /* call stadnard handler */ END(undefined_entry) /* * Entry point for a normal IRQ. * * The hardware switches to the IRQ mode stack; we switch to svc32 before * calling the handler, then return directly to the original mode/stack * on exit (without transitioning back through the IRQ mode stack). */ ASENTRY_NP(irq_entry) sub lr, lr, #4 /* Adjust the lr. Transition to scv32 */ PUSHFRAMEINSVC /* mode stack, build trapframe there. */ adr lr, exception_exit /* Return from handler via standard */ mov r0, sp /* exception exit routine. Pass the */ mov r1, #INTR_ROOT_IRQ /* trapframe and PIC root to the handler. */ b _C_LABEL(intr_irq_handler) END(irq_entry) /* * Entry point for an Address Exception exception. * This is an arm26 exception that should never happen. */ ASENTRY_NP(addr_exception_entry) mov r3, lr mrs r2, spsr mrs r1, cpsr adr r0, Laddr_exception_msg b _C_LABEL(panic) Laddr_exception_msg: .asciz "Address Exception CPSR=0x%08x SPSR=0x%08x LR=0x%08x\n" .balign 4 END(addr_exception_entry) /* * Entry point for the system Reset vector. * This should never happen, so panic. */ ASENTRY_NP(reset_entry) mov r1, lr adr r0, Lreset_panicmsg b _C_LABEL(panic) /* NOTREACHED */ Lreset_panicmsg: .asciz "Reset vector called, LR = 0x%08x" .balign 4 END(reset_entry) /* * page0 and page0_data -- An image of the ARM vectors which is copied to * the ARM vectors page (high or low) as part of CPU initialization. The * code that does the copy assumes that page0_data holds one 32-bit word * of data for each of the predefined ARM vectors. It also assumes that * page0_data follows the vectors in page0, but other stuff can appear * between the two. We currently leave room between the two for some fiq * handler code to be copied in. */ .global _C_LABEL(page0), _C_LABEL(page0_data) _C_LABEL(page0): ldr pc, .Lreset_entry ldr pc, .Lundefined_entry ldr pc, .Lswi_entry ldr pc, .Lprefetch_abort_entry ldr pc, .Ldata_abort_entry ldr pc, .Laddr_exception_entry ldr pc, .Lirq_entry _C_LABEL(page0_data): .Lreset_entry: .word reset_entry .Lundefined_entry: .word undefined_entry .Lswi_entry: .word swi_entry .Lprefetch_abort_entry: .word prefetch_abort_entry .Ldata_abort_entry: .word data_abort_entry .Laddr_exception_entry: .word addr_exception_entry .Lirq_entry: .word irq_entry
