diff options
Diffstat (limited to 'arch/avr32/kernel/entry-avr32b.S')
| -rw-r--r-- | arch/avr32/kernel/entry-avr32b.S | 541 |
1 files changed, 346 insertions, 195 deletions
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S index 42657f1703b..7301f4806bb 100644 --- a/arch/avr32/kernel/entry-avr32b.S +++ b/arch/avr32/kernel/entry-avr32b.S @@ -74,50 +74,41 @@ exception_vectors: .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 + .org 0x50 .global itlb_miss itlb_miss: tlbmiss_save rjmp tlb_miss_common - .section .tlbr.ex.text,"ax",@progbits + .org 0x60 dtlb_miss_read: tlbmiss_save rjmp tlb_miss_common - .section .tlbw.ex.text,"ax",@progbits + .org 0x70 dtlb_miss_write: tlbmiss_save .global tlb_miss_common + .align 2 tlb_miss_common: mfsr r0, SYSREG_TLBEAR mfsr r1, SYSREG_PTBR - /* Is it the vmalloc space? */ - bld r0, 31 - brcs handle_vmalloc_miss - - /* First level lookup */ + /* + * First level lookup: The PGD contains virtual pointers to + * the second-level page tables, but they may be NULL if not + * present. + */ pgtbl_lookup: lsr r2, r0, PGDIR_SHIFT ld.w r3, r1[r2 << 2] bfextu r1, r0, PAGE_SHIFT, PGDIR_SHIFT - PAGE_SHIFT - bld r3, _PAGE_BIT_PRESENT - brcc page_table_not_present - - /* Translate to virtual address in P1. */ - andl r3, 0xf000 - sbr r3, 31 + cp.w r3, 0 + breq page_table_not_present /* Second level lookup */ ld.w r2, r3[r1 << 2] @@ -148,22 +139,68 @@ pgtbl_lookup: tlbmiss_restore rete -handle_vmalloc_miss: - /* Simply do the lookup in init's page table */ + /* The slow path of the TLB miss handler */ + .align 2 +page_table_not_present: + /* Do we need to synchronize with swapper_pg_dir? */ + bld r0, 31 + brcs sync_with_swapper_pg_dir + +page_not_present: + tlbmiss_restore + sub sp, 4 + stmts --sp, r0-lr + call save_full_context_ex + mfsr r12, SYSREG_ECR + mov r11, sp + call do_page_fault + rjmp ret_from_exception + + .align 2 +sync_with_swapper_pg_dir: + /* + * If swapper_pg_dir contains a non-NULL second-level page + * table pointer, copy it into the current PGD. If not, we + * must handle it as a full-blown page fault. + * + * Jumping back to pgtbl_lookup causes an unnecessary lookup, + * but it is guaranteed to be a cache hit, it won't happen + * very often, and we absolutely do not want to sacrifice any + * performance in the fast path in order to improve this. + */ mov r1, lo(swapper_pg_dir) orh r1, hi(swapper_pg_dir) + ld.w r3, r1[r2 << 2] + cp.w r3, 0 + breq page_not_present + mfsr r1, SYSREG_PTBR + st.w r1[r2 << 2], r3 rjmp pgtbl_lookup + /* + * We currently have two bytes left at this point until we + * crash into the system call handler... + * + * Don't worry, the assembler will let us know. + */ + /* --- System Call --- */ - .section .scall.text,"ax",@progbits + .org 0x100 system_call: +#ifdef CONFIG_PREEMPT + mask_interrupts +#endif pushm r12 /* r12_orig */ stmts --sp, r0-lr - zero_fp + mfsr r0, SYSREG_RAR_SUP mfsr r1, SYSREG_RSR_SUP +#ifdef CONFIG_PREEMPT + unmask_interrupts +#endif + zero_fp stm --sp, r0-r1 /* check for syscall tracing */ @@ -213,18 +250,20 @@ syscall_badsys: .global ret_from_fork ret_from_fork: - rcall schedule_tail + call schedule_tail + mov r12, 0 + rjmp syscall_return - /* 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 + .global ret_from_kernel_thread +ret_from_kernel_thread: + call schedule_tail + mov r12, r0 + mov lr, r2 /* syscall_return */ + mov pc, r1 syscall_trace_enter: pushm r8-r12 - rcall syscall_trace + call syscall_trace popm r8-r12 rjmp syscall_trace_cont @@ -232,60 +271,44 @@ syscall_exit_work: bld r1, TIF_SYSCALL_TRACE brcc 1f unmask_interrupts - rcall syscall_trace + call syscall_trace mask_interrupts ld.w r1, r0[TI_flags] 1: bld r1, TIF_NEED_RESCHED brcc 2f unmask_interrupts - rcall schedule + call schedule mask_interrupts ld.w r1, r0[TI_flags] rjmp 1b -2: mov r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK +2: mov r2, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME tst r1, r2 breq 3f unmask_interrupts mov r12, sp mov r11, r0 - rcall do_notify_resume + call 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 + rjmp enter_monitor_mode /* This function expects to find offending PC in SYSREG_RAR_EX */ + .type save_full_context_ex, @function + .align 2 save_full_context_ex: + mfsr r11, SYSREG_RAR_EX + sub r9, pc, . - debug_trampoline mfsr r8, SYSREG_RSR_EX + cp.w r9, r11 + breq 3f mov r12, r8 andh r8, (MODE_MASK >> 16), COH - mfsr r11, SYSREG_RAR_EX brne 2f 1: pushm r11, r12 /* PC and SR */ @@ -296,38 +319,109 @@ save_full_context_ex: stdsp sp[4], r10 /* replace saved SP */ rjmp 1b + /* + * The debug handler set up a trampoline to make us + * automatically enter monitor mode upon return, but since + * we're saving the full context, we must assume that the + * exception handler might want to alter the return address + * and/or status register. So we need to restore the original + * context and enter monitor mode manually after the exception + * has been handled. + */ +3: get_thread_info r8 + ld.w r11, r8[TI_rar_saved] + ld.w r12, r8[TI_rsr_saved] + rjmp 1b + .size save_full_context_ex, . - save_full_context_ex + /* Low-level exception handlers */ handle_critical: - pushm r12 + /* + * AT32AP700x errata: + * + * After a Java stack overflow or underflow trap, any CPU + * memory access may cause erratic behavior. This will happen + * when the four least significant bits of the JOSP system + * register contains any value between 9 and 15 (inclusive). + * + * Possible workarounds: + * - Don't use the Java Extension Module + * - Ensure that the stack overflow and underflow trap + * handlers do not do any memory access or trigger any + * exceptions before the overflow/underflow condition is + * cleared (by incrementing or decrementing the JOSP) + * - Make sure that JOSP does not contain any problematic + * value before doing any exception or interrupt + * processing. + * - Set up a critical exception handler which writes a + * known-to-be-safe value, e.g. 4, to JOSP before doing + * any further processing. + * + * We'll use the last workaround for now since we cannot + * guarantee that user space processes don't use Java mode. + * Non-well-behaving userland will be terminated with extreme + * prejudice. + */ +#ifdef CONFIG_CPU_AT32AP700X + /* + * There's a chance we can't touch memory, so temporarily + * borrow PTBR to save the stack pointer while we fix things + * up... + */ + mtsr SYSREG_PTBR, sp + mov sp, 4 + mtsr SYSREG_JOSP, sp + mfsr sp, SYSREG_PTBR + sub pc, -2 + + /* Push most of pt_regs on stack. We'll do the rest later */ + sub sp, 4 pushm r0-r12 - rcall save_full_context_ex + + /* PTBR mirrors current_thread_info()->task->active_mm->pgd */ + get_thread_info r0 + ld.w r1, r0[TI_task] + ld.w r2, r1[TSK_active_mm] + ld.w r3, r2[MM_pgd] + mtsr SYSREG_PTBR, r3 +#else + sub sp, 4 + pushm r0-r12 +#endif + sub r0, sp, -(14 * 4) + mov r1, lr + mfsr r2, SYSREG_RAR_EX + mfsr r3, SYSREG_RSR_EX + pushm r0-r3 + mfsr r12, SYSREG_ECR mov r11, sp - rcall do_critical_exception + call do_critical_exception /* We should never get here... */ bad_return: sub r12, pc, (. - 1f) - bral panic + lddpc pc, 2f .align 2 1: .asciz "Return from critical exception!" +2: .long panic .align 1 do_bus_error_write: sub sp, 4 stmts --sp, r0-lr - rcall save_full_context_ex + call 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 + call save_full_context_ex mov r11, 0 1: mfsr r12, SYSREG_BEAR mov r10, sp - rcall do_bus_error + call do_bus_error rjmp ret_from_exception .align 1 @@ -342,7 +436,7 @@ do_nmi_ll: 1: pushm r8, r9 /* PC and SR */ mfsr r12, SYSREG_ECR mov r11, sp - rcall do_nmi + call do_nmi popm r8-r9 mtsr SYSREG_RAR_NMI, r8 tst r0, r0 @@ -366,29 +460,29 @@ do_nmi_ll: handle_address_fault: sub sp, 4 stmts --sp, r0-lr - rcall save_full_context_ex + call save_full_context_ex mfsr r12, SYSREG_ECR mov r11, sp - rcall do_address_exception + call do_address_exception rjmp ret_from_exception handle_protection_fault: sub sp, 4 stmts --sp, r0-lr - rcall save_full_context_ex + call save_full_context_ex mfsr r12, SYSREG_ECR mov r11, sp - rcall do_page_fault + call 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 + call save_full_context_ex mfsr r12, SYSREG_ECR mov r11, sp - rcall do_illegal_opcode + call do_illegal_opcode rjmp ret_from_exception do_dtlb_modified: @@ -422,16 +516,17 @@ do_dtlb_modified: do_fpe_ll: sub sp, 4 stmts --sp, r0-lr - rcall save_full_context_ex + call save_full_context_ex unmask_interrupts mov r12, 26 mov r11, sp - rcall do_fpe + call 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 @@ -461,7 +556,7 @@ fault_resume_kernel: lddsp r4, sp[REG_SR] bld r4, SYSREG_GM_OFFSET brcs 1f - rcall preempt_schedule_irq + call preempt_schedule_irq 1: #endif @@ -490,137 +585,142 @@ fault_exit_work: bld r1, TIF_NEED_RESCHED brcc 1f unmask_interrupts - rcall schedule + call schedule mask_interrupts ld.w r1, r0[TI_flags] rjmp fault_exit_work -1: mov r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK +1: mov r2, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME tst r1, r2 breq 2f unmask_interrupts mov r12, sp mov r11, r0 - rcall do_notify_resume + call 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 */ + rjmp enter_monitor_mode + + .section .kprobes.text, "ax", @progbits + .type handle_debug, @function +handle_debug: + sub sp, 4 /* r12_orig */ + stmts --sp, r0-lr + mfsr r8, SYSREG_RAR_DBG + mfsr r9, SYSREG_RSR_DBG + unmask_exceptions + pushm r8-r9 + bfextu r9, r9, SYSREG_MODE_OFFSET, SYSREG_MODE_SIZE + brne debug_fixup_regs + +.Ldebug_fixup_cont: +#ifdef CONFIG_TRACE_IRQFLAGS + call trace_hardirqs_off +#endif + mov r12, sp + call do_debug + mov sp, r12 + + lddsp r2, sp[REG_SR] + bfextu r3, r2, SYSREG_MODE_OFFSET, SYSREG_MODE_SIZE + brne debug_resume_kernel + + get_thread_info r0 + ld.w r1, r0[TI_flags] + mov r2, _TIF_DBGWORK_MASK + tst r1, r2 + brne debug_exit_work + + bld r1, TIF_SINGLE_STEP + brcc 1f + mfdr r4, OCD_DC + sbr r4, OCD_DC_SS_BIT + mtdr OCD_DC, r4 + +1: popm r10,r11 + mask_exceptions + mtsr SYSREG_RSR_DBG, r11 + mtsr SYSREG_RAR_DBG, r10 +#ifdef CONFIG_TRACE_IRQFLAGS + call trace_hardirqs_on +1: +#endif + ldmts sp++, r0-lr + sub sp, -4 + retd + .size handle_debug, . - handle_debug + + /* Mode of the trapped context is in r9 */ + .type debug_fixup_regs, @function +debug_fixup_regs: mfsr r8, SYSREG_SR - mov r9, r8 - andh r8, hi(~MODE_MASK) - or r8, r11 + mov r10, r8 + bfins r8, r9, SYSREG_MODE_OFFSET, SYSREG_MODE_SIZE mtsr SYSREG_SR, r8 sub pc, -2 stdsp sp[REG_LR], lr - mtsr SYSREG_SR, r9 + mtsr SYSREG_SR, r10 sub pc, -2 - sub r10, sp, -FRAME_SIZE_FULL - stdsp sp[REG_SP], r10 - mov r12, sp - rcall do_debug_priv + sub r8, sp, -FRAME_SIZE_FULL + stdsp sp[REG_SP], r8 + rjmp .Ldebug_fixup_cont + .size debug_fixup_regs, . - debug_fixup_regs - /* Now, put everything back */ - ssrf SR_EM_BIT + .type debug_resume_kernel, @function +debug_resume_kernel: + mask_exceptions 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 +#ifdef CONFIG_TRACE_IRQFLAGS + bld r11, SYSREG_GM_OFFSET + brcc 1f + call trace_hardirqs_on +1: +#endif + mfsr r2, SYSREG_SR + mov r1, r2 + bfins r2, r3, SYSREG_MODE_OFFSET, SYSREG_MODE_SIZE + mtsr SYSREG_SR, r2 sub pc, -2 popm lr - mtsr SYSREG_SR, r9 + mtsr SYSREG_SR, r1 sub pc, -2 sub sp, -4 /* skip SP */ popm r0-r12 sub sp, -4 retd + .size debug_resume_kernel, . - debug_resume_kernel + .type debug_exit_work, @function +debug_exit_work: /* - * 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. + * We must return from Monitor Mode using a retd, and we must + * not schedule since that involves the D bit in SR getting + * cleared by something other than the debug hardware. This + * may cause undefined behaviour according to the Architecture + * manual. + * + * So we fix up the return address and status and return to a + * stub below in Exception mode. From there, we can follow the + * normal exception return path. + * + * The real return address and status registers are stored on + * the stack in the way the exception return path understands, + * so no need to fix anything up there. */ -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 + sub r8, pc, . - fault_exit_work + mtsr SYSREG_RAR_DBG, r8 + mov r9, 0 + orh r9, hi(SR_EM | SR_GM | MODE_EXCEPTION) + mtsr SYSREG_RSR_DBG, r9 + sub pc, -2 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 + .size debug_exit_work, . - debug_exit_work .set rsr_int0, SYSREG_RSR_INT0 .set rsr_int1, SYSREG_RSR_INT1 @@ -638,12 +738,19 @@ irq_level\level: stmts --sp,r0-lr mfsr r8, rar_int\level mfsr r9, rsr_int\level + +#ifdef CONFIG_PREEMPT + sub r11, pc, (. - system_call) + cp.w r11, r8 + breq 4f +#endif + pushm r8-r9 mov r11, sp mov r12, \level - rcall do_IRQ + call do_IRQ lddsp r4, sp[REG_SR] bfextu r4, r4, SYSREG_M0_OFFSET, 3 @@ -661,13 +768,27 @@ irq_level\level: andl r1, _TIF_WORK_MASK, COH brne irq_exit_work -1: popm r8-r9 +1: +#ifdef CONFIG_TRACE_IRQFLAGS + call trace_hardirqs_on +#endif + 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 +4: mask_interrupts + mfsr r8, rsr_int\level + sbr r8, 16 + mtsr rsr_int\level, r8 + ldmts sp++, r0-lr + sub sp, -4 /* ignore r12_orig */ + rete +#endif + 2: get_thread_info r0 ld.w r1, r0[TI_flags] bld r1, TIF_CPU_GOING_TO_SLEEP @@ -689,33 +810,13 @@ irq_level\level: lddsp r4, sp[REG_SR] bld r4, SYSREG_GM_OFFSET brcs 1b - rcall preempt_schedule_irq + call preempt_schedule_irq #endif rjmp 1b .endm .section .irq.text,"ax",@progbits -.global cpu_idle_sleep -cpu_idle_sleep: - mask_interrupts - get_thread_info r8 - ld.w r9, r8[TI_flags] - bld r9, TIF_NEED_RESCHED - brcs cpu_idle_enable_int_and_exit - sbr r9, TIF_CPU_GOING_TO_SLEEP - st.w r8[TI_flags], r9 - unmask_interrupts - sleep 0 -cpu_idle_skip_sleep: - mask_interrupts - ld.w r9, r8[TI_flags] - cbr r9, TIF_CPU_GOING_TO_SLEEP - st.w r8[TI_flags], r9 -cpu_idle_enable_int_and_exit: - unmask_interrupts - retal r12 - .global irq_level0 .global irq_level1 .global irq_level2 @@ -724,3 +825,53 @@ cpu_idle_enable_int_and_exit: IRQ_LEVEL 1 IRQ_LEVEL 2 IRQ_LEVEL 3 + + .section .kprobes.text, "ax", @progbits + .type enter_monitor_mode, @function +enter_monitor_mode: + /* + * We need to enter monitor mode to do a single step. The + * monitor code will alter the return address so that we + * return directly to the user instead of returning here. + */ + breakpoint + rjmp breakpoint_failed + + .size enter_monitor_mode, . - enter_monitor_mode + + .type debug_trampoline, @function + .global debug_trampoline +debug_trampoline: + /* + * Save the registers on the stack so that the monitor code + * can find them easily. + */ + sub sp, 4 /* r12_orig */ + stmts --sp, r0-lr + get_thread_info r0 + ld.w r8, r0[TI_rar_saved] + ld.w r9, r0[TI_rsr_saved] + pushm r8-r9 + + /* + * The monitor code will alter the return address so we don't + * return here. + */ + breakpoint + rjmp breakpoint_failed + .size debug_trampoline, . - debug_trampoline + + .type breakpoint_failed, @function +breakpoint_failed: + /* + * Something went wrong. Perhaps the debug hardware isn't + * enabled? + */ + lda.w r12, msg_breakpoint_failed + mov r11, sp + mov r10, 9 /* SIGKILL */ + call die +1: rjmp 1b + +msg_breakpoint_failed: + .asciz "Failed to enter Debug Mode" |