--- zzzz-none-000/linux-3.10.107/arch/arm/kernel/entry-header.S 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/arch/arm/kernel/entry-header.S 2021-02-04 17:41:59.000000000 +0000 @@ -5,6 +5,7 @@ #include #include #include +#include @ Bad Abort numbers @ ----------------- @@ -36,14 +37,136 @@ #endif .endm - .macro alignment_trap, rtemp #ifdef CONFIG_ALIGNMENT_TRAP - ldr \rtemp, .LCcralign - ldr \rtemp, [\rtemp] - mcr p15, 0, \rtemp, c1, c0 +#define ATRAP(x...) x +#else +#define ATRAP(x...) +#endif + + .macro alignment_trap, rtmp1, rtmp2, label +#ifdef CONFIG_ALIGNMENT_TRAP + mrc p15, 0, \rtmp2, c1, c0, 0 + ldr \rtmp1, \label + ldr \rtmp1, [\rtmp1] + teq \rtmp1, \rtmp2 + mcrne p15, 0, \rtmp1, c1, c0, 0 #endif .endm +#ifdef CONFIG_CPU_V7M +/* + * ARMv7-M exception entry/exit macros. + * + * xPSR, ReturnAddress(), LR (R14), R12, R3, R2, R1, and R0 are + * automatically saved on the current stack (32 words) before + * switching to the exception stack (SP_main). + * + * If exception is taken while in user mode, SP_main is + * empty. Otherwise, SP_main is aligned to 64 bit automatically + * (CCR.STKALIGN set). + * + * Linux assumes that the interrupts are disabled when entering an + * exception handler and it may BUG if this is not the case. Interrupts + * are disabled during entry and reenabled in the exit macro. + * + * v7m_exception_slow_exit is used when returning from SVC or PendSV. + * When returning to kernel mode, we don't return from exception. + */ + .macro v7m_exception_entry + @ determine the location of the registers saved by the core during + @ exception entry. Depending on the mode the cpu was in when the + @ exception happend that is either on the main or the process stack. + @ Bit 2 of EXC_RETURN stored in the lr register specifies which stack + @ was used. + tst lr, #EXC_RET_STACK_MASK + mrsne r12, psp + moveq r12, sp + + @ we cannot rely on r0-r3 and r12 matching the value saved in the + @ exception frame because of tail-chaining. So these have to be + @ reloaded. + ldmia r12!, {r0-r3} + + @ Linux expects to have irqs off. Do it here before taking stack space + cpsid i + + sub sp, #S_FRAME_SIZE-S_IP + stmdb sp!, {r0-r11} + + @ load saved r12, lr, return address and xPSR. + @ r0-r7 are used for signals and never touched from now on. Clobbering + @ r8-r12 is OK. + mov r9, r12 + ldmia r9!, {r8, r10-r12} + + @ calculate the original stack pointer value. + @ r9 currently points to the memory location just above the auto saved + @ xPSR. + @ The cpu might automatically 8-byte align the stack. Bit 9 + @ of the saved xPSR specifies if stack aligning took place. In this case + @ another 32-bit value is included in the stack. + + tst r12, V7M_xPSR_FRAMEPTRALIGN + addne r9, r9, #4 + + @ store saved r12 using str to have a register to hold the base for stm + str r8, [sp, #S_IP] + add r8, sp, #S_SP + @ store r13-r15, xPSR + stmia r8!, {r9-r12} + @ store old_r0 + str r0, [r8] + .endm + + /* + * PENDSV and SVCALL are configured to have the same exception + * priorities. As a kernel thread runs at SVCALL execution priority it + * can never be preempted and so we will never have to return to a + * kernel thread here. + */ + .macro v7m_exception_slow_exit ret_r0 + cpsid i + ldr lr, =EXC_RET_THREADMODE_PROCESSSTACK + + @ read original r12, sp, lr, pc and xPSR + add r12, sp, #S_IP + ldmia r12, {r1-r5} + + @ an exception frame is always 8-byte aligned. To tell the hardware if + @ the sp to be restored is aligned or not set bit 9 of the saved xPSR + @ accordingly. + tst r2, #4 + subne r2, r2, #4 + orrne r5, V7M_xPSR_FRAMEPTRALIGN + biceq r5, V7M_xPSR_FRAMEPTRALIGN + + @ ensure bit 0 is cleared in the PC, otherwise behaviour is + @ unpredictable + bic r4, #1 + + @ write basic exception frame + stmdb r2!, {r1, r3-r5} + ldmia sp, {r1, r3-r5} + .if \ret_r0 + stmdb r2!, {r0, r3-r5} + .else + stmdb r2!, {r1, r3-r5} + .endif + + @ restore process sp + msr psp, r2 + + @ restore original r4-r11 + ldmia sp!, {r0-r11} + + @ restore main sp + add sp, sp, #S_FRAME_SIZE-S_IP + + cpsie i + bx lr + .endm +#endif /* CONFIG_CPU_V7M */ + @ @ Store/load the USER SP and LR registers by switching to the SYS @ mode. Useful in Thumb-2 mode where "stm/ldm rd, {sp, lr}^" is not @@ -73,7 +196,7 @@ msr cpsr_c, \rtemp @ switch back to the SVC mode .endm -#ifndef CONFIG_THUMB2_KERNEL + .macro svc_exit, rpsr, irq = 0 .if \irq != 0 @ IRQs already off @@ -92,87 +215,120 @@ blne trace_hardirqs_off #endif .endif + uaccess_restore + +#ifndef CONFIG_THUMB2_KERNEL + @ ARM mode SVC restore msr spsr_cxsf, \rpsr -#if defined(CONFIG_CPU_V6) - ldr r0, [sp] - strex r1, r2, [sp] @ clear the exclusive monitor - ldmib sp, {r1 - pc}^ @ load r1 - pc, cpsr -#elif defined(CONFIG_CPU_32v6K) - clrex @ clear the exclusive monitor +#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K) + @ We must avoid clrex due to Cortex-A15 erratum #830321 + sub r0, sp, #4 @ uninhabited address + strex r1, r2, [r0] @ clear the exclusive monitor +#endif ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr #else - ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr + @ Thumb mode SVC restore + ldr lr, [sp, #S_SP] @ top of the stack + ldrd r0, r1, [sp, #S_LR] @ calling lr and pc + + @ We must avoid clrex due to Cortex-A15 erratum #830321 + strex r2, r1, [sp, #S_LR] @ clear the exclusive monitor + + stmdb lr!, {r0, r1, \rpsr} @ calling lr and rfe context + ldmia sp, {r0 - r12} + mov sp, lr + ldr lr, [sp], #4 + rfeia sp! #endif .endm + @ + @ svc_exit_via_fiq - like svc_exit but switches to FIQ mode before exit + @ + @ This macro acts in a similar manner to svc_exit but switches to FIQ + @ mode to restore the final part of the register state. + @ + @ We cannot use the normal svc_exit procedure because that would + @ clobber spsr_svc (FIQ could be delivered during the first few + @ instructions of vector_swi meaning its contents have not been + @ saved anywhere). + @ + @ Note that, unlike svc_exit, this macro also does not allow a caller + @ supplied rpsr. This is because the FIQ exceptions are not re-entrant + @ and the handlers cannot call into the scheduler (meaning the value + @ on the stack remains correct). + @ + .macro svc_exit_via_fiq + uaccess_restore +#ifndef CONFIG_THUMB2_KERNEL + @ ARM mode restore + mov r0, sp + ldmib r0, {r1 - r14} @ abort is deadly from here onward (it will + @ clobber state restored below) + msr cpsr_c, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT + add r8, r0, #S_PC + ldr r9, [r0, #S_PSR] + msr spsr_cxsf, r9 + ldr r0, [r0, #S_R0] + ldmia r8, {pc}^ +#else + @ Thumb mode restore + add r0, sp, #S_R2 + ldr lr, [sp, #S_LR] + ldr sp, [sp, #S_SP] @ abort is deadly from here onward (it will + @ clobber state restored below) + ldmia r0, {r2 - r12} + mov r1, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT + msr cpsr_c, r1 + sub r0, #S_R2 + add r8, r0, #S_PC + ldmia r0, {r0 - r1} + rfeia r8 +#endif + .endm + + .macro restore_user_regs, fast = 0, offset = 0 - ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr - ldr lr, [sp, #\offset + S_PC]! @ get pc + uaccess_enable r1, isb=0 +#ifndef CONFIG_THUMB2_KERNEL + @ ARM mode restore + mov r2, sp + ldr r1, [r2, #\offset + S_PSR] @ get calling cpsr + ldr lr, [r2, #\offset + S_PC]! @ get pc msr spsr_cxsf, r1 @ save in spsr_svc -#if defined(CONFIG_CPU_V6) - strex r1, r2, [sp] @ clear the exclusive monitor -#elif defined(CONFIG_CPU_32v6K) - clrex @ clear the exclusive monitor +#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K) + @ We must avoid clrex due to Cortex-A15 erratum #830321 + strex r1, r2, [r2] @ clear the exclusive monitor #endif .if \fast - ldmdb sp, {r1 - lr}^ @ get calling r1 - lr + ldmdb r2, {r1 - lr}^ @ get calling r1 - lr .else - ldmdb sp, {r0 - lr}^ @ get calling r0 - lr + ldmdb r2, {r0 - lr}^ @ get calling r0 - lr .endif mov r0, r0 @ ARMv5T and earlier require a nop @ after ldm {}^ - add sp, sp, #S_FRAME_SIZE - S_PC + add sp, sp, #\offset + S_FRAME_SIZE movs pc, lr @ return & move spsr_svc into cpsr - .endm - - .macro get_thread_info, rd - mov \rd, sp, lsr #13 - mov \rd, \rd, lsl #13 - .endm - - @ - @ 32-bit wide "mov pc, reg" - @ - .macro movw_pc, reg - mov pc, \reg - .endm -#else /* CONFIG_THUMB2_KERNEL */ - .macro svc_exit, rpsr, irq = 0 - .if \irq != 0 - @ IRQs already off -#ifdef CONFIG_TRACE_IRQFLAGS - @ The parent context IRQs must have been enabled to get here in - @ the first place, so there's no point checking the PSR I bit. - bl trace_hardirqs_on -#endif - .else - @ IRQs off again before pulling preserved data off the stack - disable_irq_notrace -#ifdef CONFIG_TRACE_IRQFLAGS - tst \rpsr, #PSR_I_BIT - bleq trace_hardirqs_on - tst \rpsr, #PSR_I_BIT - blne trace_hardirqs_off -#endif +#elif defined(CONFIG_CPU_V7M) + @ V7M restore. + @ Note that we don't need to do clrex here as clearing the local + @ monitor is part of the exception entry and exit sequence. + .if \offset + add sp, #\offset .endif - ldr lr, [sp, #S_SP] @ top of the stack - ldrd r0, r1, [sp, #S_LR] @ calling lr and pc - clrex @ clear the exclusive monitor - stmdb lr!, {r0, r1, \rpsr} @ calling lr and rfe context - ldmia sp, {r0 - r12} - mov sp, lr - ldr lr, [sp], #4 - rfeia sp! - .endm - - .macro restore_user_regs, fast = 0, offset = 0 - clrex @ clear the exclusive monitor + v7m_exception_slow_exit ret_r0 = \fast +#else + @ Thumb mode restore mov r2, sp load_user_sp_lr r2, r3, \offset + S_SP @ calling sp, lr ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr ldr lr, [sp, #\offset + S_PC] @ get pc add sp, sp, #\offset + S_SP msr spsr_cxsf, r1 @ save in spsr_svc + + @ We must avoid clrex due to Cortex-A15 erratum #830321 + strex r1, r2, [sp] @ clear the exclusive monitor + .if \fast ldmdb sp, {r1 - r12} @ get calling r1 - r12 .else @@ -180,22 +336,8 @@ .endif add sp, sp, #S_FRAME_SIZE - S_SP movs pc, lr @ return & move spsr_svc into cpsr - .endm - - .macro get_thread_info, rd - mov \rd, sp - lsr \rd, \rd, #13 - mov \rd, \rd, lsl #13 - .endm - - @ - @ 32-bit wide "mov pc, reg" - @ - .macro movw_pc, reg - mov pc, \reg - nop - .endm #endif /* !CONFIG_THUMB2_KERNEL */ + .endm /* * Context tracking subsystem. Used to instrument transitions @@ -205,10 +347,10 @@ #ifdef CONFIG_CONTEXT_TRACKING .if \save stmdb sp!, {r0-r3, ip, lr} - bl user_exit + bl context_tracking_user_exit ldmia sp!, {r0-r3, ip, lr} .else - bl user_exit + bl context_tracking_user_exit .endif #endif .endm @@ -217,10 +359,10 @@ #ifdef CONFIG_CONTEXT_TRACKING .if \save stmdb sp!, {r0-r3, ip, lr} - bl user_enter + bl context_tracking_user_enter ldmia sp!, {r0-r3, ip, lr} .else - bl user_enter + bl context_tracking_user_enter .endif #endif .endm