diff options
Diffstat (limited to 'arch/avr32/kernel/entry-avr32b.S')
| -rw-r--r-- | arch/avr32/kernel/entry-avr32b.S | 678 |
1 files changed, 678 insertions, 0 deletions
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S new file mode 100644 index 0000000..eeb6679 --- /dev/null +++ b/arch/avr32/kernel/entry-avr32b.S @@ -0,0 +1,678 @@ +/* + * Copyright (C) 2004-2006 Atmel Corporation + * + * 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. + */ + +/* + * This file contains the low-level entry-points into the kernel, that is, + * exception handlers, debug trap handlers, interrupt handlers and the + * system call handler. + */ +#include <linux/errno.h> + +#include <asm/asm.h> +#include <asm/hardirq.h> +#include <asm/irq.h> +#include <asm/ocd.h> +#include <asm/page.h> +#include <asm/pgtable.h> +#include <asm/ptrace.h> +#include <asm/sysreg.h> +#include <asm/thread_info.h> +#include <asm/unistd.h> + +#ifdef CONFIG_PREEMPT +# define preempt_stop mask_interrupts +#else +# define preempt_stop +# define fault_resume_kernel fault_restore_all +#endif + +#define __MASK(x) ((1 << (x)) - 1) +#define IRQ_MASK ((__MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) | \ + (__MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)) + + .section .ex.text,"ax",@progbits + .align 2 +exception_vectors: + bral handle_critical + .align 2 + bral handle_critical + .align 2 + bral do_bus_error_write + .align 2 + bral do_bus_error_read + .align 2 + bral do_nmi_ll + .align 2 + bral handle_address_fault + .align 2 + bral handle_protection_fault + .align 2 + bral handle_debug + .align 2 + bral do_illegal_opcode_ll + .align 2 + bral do_illegal_opcode_ll + .align 2 + bral do_illegal_opcode_ll + .align 2 + bral do_fpe_ll + .align 2 + bral do_illegal_opcode_ll + .align 2 + bral handle_address_fault + .align 2 + bral handle_address_fault + .align 2 + bral handle_protection_fault + .align 2 + bral handle_protection_fault + .align 2 + bral do_dtlb_modified + + /* + * r0 : PGD/PT/PTE + * r1 : Offending address + * r2 : Scratch register + * r3 : Cause (5, 12 or 13) + */ +#define tlbmiss_save pushm r0-r3 +#define tlbmiss_restore popm r0-r3 + + .section .tlbx.ex.text,"ax",@progbits + .global itlb_miss +itlb_miss: + tlbmiss_save + rjmp tlb_miss_common + + .section .tlbr.ex.text,"ax",@progbits +dtlb_miss_read: + tlbmiss_save + rjmp tlb_miss_common + + .section .tlbw.ex.text,"ax",@progbits +dtlb_miss_write: + tlbmiss_save + + .global tlb_miss_common +tlb_miss_common: + mfsr r0, SYSREG_PTBR + mfsr r1, SYSREG_TLBEAR + + /* Is it the vmalloc space? */ + bld r1, 31 + brcs handle_vmalloc_miss + + /* First level lookup */ +pgtbl_lookup: + lsr r2, r1, PGDIR_SHIFT + ld.w r0, r0[r2 << 2] + bld r0, _PAGE_BIT_PRESENT + brcc page_table_not_present + + /* TODO: Check access rights on page table if necessary */ + + /* Translate to virtual address in P1. */ + andl r0, 0xf000 + sbr r0, 31 + + /* Second level lookup */ + lsl r1, (32 - PGDIR_SHIFT) + lsr r1, (32 - PGDIR_SHIFT) + PAGE_SHIFT + add r2, r0, r1 << 2 + ld.w r1, r2[0] + bld r1, _PAGE_BIT_PRESENT + brcc page_not_present + + /* Mark the page as accessed */ + sbr r1, _PAGE_BIT_ACCESSED + st.w r2[0], r1 + + /* Drop software flags */ + andl r1, _PAGE_FLAGS_HARDWARE_MASK & 0xffff + mtsr SYSREG_TLBELO, r1 + + /* Figure out which entry we want to replace */ + mfsr r0, SYSREG_TLBARLO + clz r2, r0 + brcc 1f + mov r1, -1 /* All entries have been accessed, */ + mtsr SYSREG_TLBARLO, r1 /* so reset TLBAR */ + mov r2, 0 /* and start at 0 */ +1: mfsr r1, SYSREG_MMUCR + lsl r2, 14 + andl r1, 0x3fff, COH + or r1, r2 + mtsr SYSREG_MMUCR, r1 + + tlbw + + tlbmiss_restore + rete + +handle_vmalloc_miss: + /* Simply do the lookup in init's page table */ + mov r0, lo(swapper_pg_dir) + orh r0, hi(swapper_pg_dir) + rjmp pgtbl_lookup + + + /* --- System Call --- */ + + .section .scall.text,"ax",@progbits +system_call: + pushm r12 /* r12_orig */ + stmts --sp, r0-lr + zero_fp + mfsr r0, SYSREG_RAR_SUP + mfsr r1, SYSREG_RSR_SUP + stm --sp, r0-r1 + + /* check for syscall tracing */ + get_thread_info r0 + ld.w r1, r0[TI_flags] + bld r1, TIF_SYSCALL_TRACE + brcs syscall_trace_enter + +syscall_trace_cont: + cp.w r8, NR_syscalls + brhs syscall_badsys + + lddpc lr, syscall_table_addr + ld.w lr, lr[r8 << 2] + mov r8, r5 /* 5th argument (6th is pushed by stub) */ + icall lr + + .global syscall_return +syscall_return: + get_thread_info r0 + mask_interrupts /* make sure we don't miss an interrupt + setting need_resched or sigpending + between sampling and the rets */ + + /* Store the return value so that the correct value is loaded below */ + stdsp sp[REG_R12], r12 + + ld.w r1, r0[TI_flags] + andl r1, _TIF_ALLWORK_MASK, COH + brne syscall_exit_work + +syscall_exit_cont: + popm r8-r9 + mtsr SYSREG_RAR_SUP, r8 + mtsr SYSREG_RSR_SUP, r9 + ldmts sp++, r0-lr + sub sp, -4 /* r12_orig */ + rets + + .align 2 +syscall_table_addr: + .long sys_call_table + +syscall_badsys: + mov r12, -ENOSYS + rjmp syscall_return + + .global ret_from_fork +ret_from_fork: + rcall schedule_tail + + /* check for syscall tracing */ + get_thread_info r0 + ld.w r1, r0[TI_flags] + andl r1, _TIF_ALLWORK_MASK, COH + brne syscall_exit_work + rjmp syscall_exit_cont + +syscall_trace_enter: + pushm r8-r12 + rcall syscall_trace + popm r8-r12 + rjmp syscall_trace_cont + +syscall_exit_work: + bld r1, TIF_SYSCALL_TRACE + brcc 1f + unmask_interrupts + rcall syscall_trace + mask_interrupts + ld.w r1, r0[TI_flags] + +1: bld r1, TIF_NEED_RESCHED + brcc 2f + unmask_interrupts + rcall schedule + mask_interrupts + ld.w r1, r0[TI_flags] + rjmp 1b + +2: mov r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK + tst r1, r2 + breq 3f + unmask_interrupts + mov r12, sp + mov r11, r0 + rcall do_notify_resume + mask_interrupts + ld.w r1, r0[TI_flags] + rjmp 1b + +3: bld r1, TIF_BREAKPOINT + brcc syscall_exit_cont + mfsr r3, SYSREG_TLBEHI + lddsp r2, sp[REG_PC] + andl r3, 0xff, COH + lsl r3, 1 + sbr r3, 30 + sbr r3, 0 + mtdr DBGREG_BWA2A, r2 + mtdr DBGREG_BWC2A, r3 + rjmp syscall_exit_cont + + + /* The slow path of the TLB miss handler */ +page_table_not_present: +page_not_present: + tlbmiss_restore + sub sp, 4 + stmts --sp, r0-lr + rcall save_full_context_ex + mfsr r12, SYSREG_ECR + mov r11, sp + rcall do_page_fault + rjmp ret_from_exception + + /* This function expects to find offending PC in SYSREG_RAR_EX */ +save_full_context_ex: + mfsr r8, SYSREG_RSR_EX + mov r12, r8 + andh r8, (MODE_MASK >> 16), COH + mfsr r11, SYSREG_RAR_EX + brne 2f + +1: pushm r11, r12 /* PC and SR */ + unmask_exceptions + ret r12 + +2: sub r10, sp, -(FRAME_SIZE_FULL - REG_LR) + stdsp sp[4], r10 /* replace saved SP */ + rjmp 1b + + /* Low-level exception handlers */ +handle_critical: + pushm r12 + pushm r0-r12 + rcall save_full_context_ex + mfsr r12, SYSREG_ECR + mov r11, sp + rcall do_critical_exception + + /* We should never get here... */ +bad_return: + sub r12, pc, (. - 1f) + bral panic + .align 2 +1: .asciz "Return from critical exception!" + + .align 1 +do_bus_error_write: + sub sp, 4 + stmts --sp, r0-lr + rcall save_full_context_ex + mov r11, 1 + rjmp 1f + +do_bus_error_read: + sub sp, 4 + stmts --sp, r0-lr + rcall save_full_context_ex + mov r11, 0 +1: mfsr r12, SYSREG_BEAR + mov r10, sp + rcall do_bus_error + rjmp ret_from_exception + + .align 1 +do_nmi_ll: + sub sp, 4 + stmts --sp, r0-lr + /* FIXME: Make sure RAR_NMI and RSR_NMI are pushed instead of *_EX */ + rcall save_full_context_ex + mfsr r12, SYSREG_ECR + mov r11, sp + rcall do_nmi + rjmp bad_return + +handle_address_fault: + sub sp, 4 + stmts --sp, r0-lr + rcall save_full_context_ex + mfsr r12, SYSREG_ECR + mov r11, sp + rcall do_address_exception + rjmp ret_from_exception + +handle_protection_fault: + sub sp, 4 + stmts --sp, r0-lr + rcall save_full_context_ex + mfsr r12, SYSREG_ECR + mov r11, sp + rcall do_page_fault + rjmp ret_from_exception + + .align 1 +do_illegal_opcode_ll: + sub sp, 4 + stmts --sp, r0-lr + rcall save_full_context_ex + mfsr r12, SYSREG_ECR + mov r11, sp + rcall do_illegal_opcode + rjmp ret_from_exception + +do_dtlb_modified: + pushm r0-r3 + mfsr r1, SYSREG_TLBEAR + mfsr r0, SYSREG_PTBR + lsr r2, r1, PGDIR_SHIFT + ld.w r0, r0[r2 << 2] + lsl r1, (32 - PGDIR_SHIFT) + lsr r1, (32 - PGDIR_SHIFT) + PAGE_SHIFT + + /* Translate to virtual address in P1 */ + andl r0, 0xf000 + sbr r0, 31 + add r2, r0, r1 << 2 + ld.w r3, r2[0] + sbr r3, _PAGE_BIT_DIRTY + mov r0, r3 + st.w r2[0], r3 + + /* The page table is up-to-date. Update the TLB entry as well */ + andl r0, lo(_PAGE_FLAGS_HARDWARE_MASK) + mtsr SYSREG_TLBELO, r0 + + /* MMUCR[DRP] is updated automatically, so let's go... */ + tlbw + + popm r0-r3 + rete + +do_fpe_ll: + sub sp, 4 + stmts --sp, r0-lr + rcall save_full_context_ex + unmask_interrupts + mov r12, 26 + mov r11, sp + rcall do_fpe + rjmp ret_from_exception + +ret_from_exception: + mask_interrupts + lddsp r4, sp[REG_SR] + andh r4, (MODE_MASK >> 16), COH + brne fault_resume_kernel + + get_thread_info r0 + ld.w r1, r0[TI_flags] + andl r1, _TIF_WORK_MASK, COH + brne fault_exit_work + +fault_resume_user: + popm r8-r9 + mask_exceptions + mtsr SYSREG_RAR_EX, r8 + mtsr SYSREG_RSR_EX, r9 + ldmts sp++, r0-lr + sub sp, -4 + rete + +fault_resume_kernel: +#ifdef CONFIG_PREEMPT + get_thread_info r0 + ld.w r2, r0[TI_preempt_count] + cp.w r2, 0 + brne 1f + ld.w r1, r0[TI_flags] + bld r1, TIF_NEED_RESCHED + brcc 1f + lddsp r4, sp[REG_SR] + bld r4, SYSREG_GM_OFFSET + brcs 1f + rcall preempt_schedule_irq +1: +#endif + + popm r8-r9 + mask_exceptions + mfsr r1, SYSREG_SR + mtsr SYSREG_RAR_EX, r8 + mtsr SYSREG_RSR_EX, r9 + popm lr + sub sp, -4 /* ignore SP */ + popm r0-r12 + sub sp, -4 /* ignore r12_orig */ + rete + +irq_exit_work: + /* Switch to exception mode so that we can share the same code. */ + mfsr r8, SYSREG_SR + cbr r8, SYSREG_M0_OFFSET + orh r8, hi(SYSREG_BIT(M1) | SYSREG_BIT(M2)) + mtsr SYSREG_SR, r8 + sub pc, -2 + get_thread_info r0 + ld.w r1, r0[TI_flags] + +fault_exit_work: + bld r1, TIF_NEED_RESCHED + brcc 1f + unmask_interrupts + rcall schedule + mask_interrupts + ld.w r1, r0[TI_flags] + rjmp fault_exit_work + +1: mov r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK + tst r1, r2 + breq 2f + unmask_interrupts + mov r12, sp + mov r11, r0 + rcall do_notify_resume + mask_interrupts + ld.w r1, r0[TI_flags] + rjmp fault_exit_work + +2: bld r1, TIF_BREAKPOINT + brcc fault_resume_user + mfsr r3, SYSREG_TLBEHI + lddsp r2, sp[REG_PC] + andl r3, 0xff, COH + lsl r3, 1 + sbr r3, 30 + sbr r3, 0 + mtdr DBGREG_BWA2A, r2 + mtdr DBGREG_BWC2A, r3 + rjmp fault_resume_user + + /* If we get a debug trap from privileged context we end up here */ +handle_debug_priv: + /* Fix up LR and SP in regs. r11 contains the mode we came from */ + mfsr r8, SYSREG_SR + mov r9, r8 + andh r8, hi(~MODE_MASK) + or r8, r11 + mtsr SYSREG_SR, r8 + sub pc, -2 + stdsp sp[REG_LR], lr + mtsr SYSREG_SR, r9 + sub pc, -2 + sub r10, sp, -FRAME_SIZE_FULL + stdsp sp[REG_SP], r10 + mov r12, sp + rcall do_debug_priv + + /* Now, put everything back */ + ssrf SR_EM_BIT + popm r10, r11 + mtsr SYSREG_RAR_DBG, r10 + mtsr SYSREG_RSR_DBG, r11 + mfsr r8, SYSREG_SR + mov r9, r8 + andh r8, hi(~MODE_MASK) + andh r11, hi(MODE_MASK) + or r8, r11 + mtsr SYSREG_SR, r8 + sub pc, -2 + popm lr + mtsr SYSREG_SR, r9 + sub pc, -2 + sub sp, -4 /* skip SP */ + popm r0-r12 + sub sp, -4 + retd + + /* + * At this point, everything is masked, that is, interrupts, + * exceptions and debugging traps. We might get called from + * interrupt or exception context in some rare cases, but this + * will be taken care of by do_debug(), so we're not going to + * do a 100% correct context save here. + */ +handle_debug: + sub sp, 4 /* r12_orig */ + stmts --sp, r0-lr + mfsr r10, SYSREG_RAR_DBG + mfsr r11, SYSREG_RSR_DBG + unmask_exceptions + pushm r10,r11 + andh r11, (MODE_MASK >> 16), COH + brne handle_debug_priv + + mov r12, sp + rcall do_debug + + lddsp r10, sp[REG_SR] + andh r10, (MODE_MASK >> 16), COH + breq debug_resume_user + +debug_restore_all: + popm r10,r11 + mask_exceptions + mtsr SYSREG_RSR_DBG, r11 + mtsr SYSREG_RAR_DBG, r10 + ldmts sp++, r0-lr + sub sp, -4 + retd + +debug_resume_user: + get_thread_info r0 + mask_interrupts + + ld.w r1, r0[TI_flags] + andl r1, _TIF_DBGWORK_MASK, COH + breq debug_restore_all + +1: bld r1, TIF_NEED_RESCHED + brcc 2f + unmask_interrupts + rcall schedule + mask_interrupts + ld.w r1, r0[TI_flags] + rjmp 1b + +2: mov r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK + tst r1, r2 + breq 3f + unmask_interrupts + mov r12, sp + mov r11, r0 + rcall do_notify_resume + mask_interrupts + ld.w r1, r0[TI_flags] + rjmp 1b + +3: bld r1, TIF_SINGLE_STEP + brcc debug_restore_all + mfdr r2, DBGREG_DC + sbr r2, DC_SS_BIT + mtdr DBGREG_DC, r2 + rjmp debug_restore_all + + .set rsr_int0, SYSREG_RSR_INT0 + .set rsr_int1, SYSREG_RSR_INT1 + .set rsr_int2, SYSREG_RSR_INT2 + .set rsr_int3, SYSREG_RSR_INT3 + .set rar_int0, SYSREG_RAR_INT0 + .set rar_int1, SYSREG_RAR_INT1 + .set rar_int2, SYSREG_RAR_INT2 + .set rar_int3, SYSREG_RAR_INT3 + + .macro IRQ_LEVEL level + .type irq_level\level, @function +irq_level\level: + sub sp, 4 /* r12_orig */ + stmts --sp,r0-lr + mfsr r8, rar_int\level + mfsr r9, rsr_int\level + pushm r8-r9 + + mov r11, sp + mov r12, \level + + rcall do_IRQ + + lddsp r4, sp[REG_SR] + andh r4, (MODE_MASK >> 16), COH +#ifdef CONFIG_PREEMPT + brne 2f +#else + brne 1f +#endif + + get_thread_info r0 + ld.w r1, r0[TI_flags] + andl r1, _TIF_WORK_MASK, COH + brne irq_exit_work + +1: popm r8-r9 + mtsr rar_int\level, r8 + mtsr rsr_int\level, r9 + ldmts sp++,r0-lr + sub sp, -4 /* ignore r12_orig */ + rete + +#ifdef CONFIG_PREEMPT +2: + get_thread_info r0 + ld.w r2, r0[TI_preempt_count] + cp.w r2, 0 + brne 1b + ld.w r1, r0[TI_flags] + bld r1, TIF_NEED_RESCHED + brcc 1b + lddsp r4, sp[REG_SR] + bld r4, SYSREG_GM_OFFSET + brcs 1b + rcall preempt_schedule_irq + rjmp 1b +#endif + .endm + + .section .irq.text,"ax",@progbits + + .global irq_level0 + .global irq_level1 + .global irq_level2 + .global irq_level3 + IRQ_LEVEL 0 + IRQ_LEVEL 1 + IRQ_LEVEL 2 + IRQ_LEVEL 3 |