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Diffstat (limited to 'arch/arm/kernel/entry-armv.S')
| -rw-r--r-- | arch/arm/kernel/entry-armv.S | 1238 |
1 files changed, 1238 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S new file mode 100644 index 000000000..570306c49 --- /dev/null +++ b/arch/arm/kernel/entry-armv.S @@ -0,0 +1,1238 @@ +/* + * linux/arch/arm/kernel/entry-armv.S + * + * Copyright (C) 1996,1997,1998 Russell King. + * ARM700 fix by Matthew Godbolt (linux-user@willothewisp.demon.co.uk) + * nommu support by Hyok S. Choi (hyok.choi@samsung.com) + * + * 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. + * + * Low-level vector interface routines + * + * Note: there is a StrongARM bug in the STMIA rn, {regs}^ instruction + * that causes it to save wrong values... Be aware! + */ + +#include <asm/assembler.h> +#include <asm/memory.h> +#include <asm/glue-df.h> +#include <asm/glue-pf.h> +#include <asm/vfpmacros.h> +#ifndef CONFIG_MULTI_IRQ_HANDLER +#include <mach/entry-macro.S> +#endif +#include <asm/thread_notify.h> +#include <asm/unwind.h> +#include <asm/unistd.h> +#include <asm/tls.h> +#include <asm/system_info.h> + +#include "entry-header.S" +#include <asm/entry-macro-multi.S> +#include <asm/probes.h> + +/* + * Interrupt handling. + */ + .macro irq_handler +#ifdef CONFIG_MULTI_IRQ_HANDLER + ldr r1, =handle_arch_irq + mov r0, sp + adr lr, BSYM(9997f) + ldr pc, [r1] +#else + arch_irq_handler_default +#endif +9997: + .endm + + .macro pabt_helper + @ PABORT handler takes pt_regs in r2, fault address in r4 and psr in r5 +#ifdef MULTI_PABORT + ldr ip, .LCprocfns + mov lr, pc + ldr pc, [ip, #PROCESSOR_PABT_FUNC] +#else + bl CPU_PABORT_HANDLER +#endif + .endm + + .macro dabt_helper + + @ + @ Call the processor-specific abort handler: + @ + @ r2 - pt_regs + @ r4 - aborted context pc + @ r5 - aborted context psr + @ + @ The abort handler must return the aborted address in r0, and + @ the fault status register in r1. r9 must be preserved. + @ +#ifdef MULTI_DABORT + ldr ip, .LCprocfns + mov lr, pc + ldr pc, [ip, #PROCESSOR_DABT_FUNC] +#else + bl CPU_DABORT_HANDLER +#endif + .endm + +#ifdef CONFIG_KPROBES + .section .kprobes.text,"ax",%progbits +#else + .text +#endif + +/* + * Invalid mode handlers + */ + .macro inv_entry, reason + sub sp, sp, #S_FRAME_SIZE + ARM( stmib sp, {r1 - lr} ) + THUMB( stmia sp, {r0 - r12} ) + THUMB( str sp, [sp, #S_SP] ) + THUMB( str lr, [sp, #S_LR] ) + mov r1, #\reason + .endm + +__pabt_invalid: + inv_entry BAD_PREFETCH + b common_invalid +ENDPROC(__pabt_invalid) + +__dabt_invalid: + inv_entry BAD_DATA + b common_invalid +ENDPROC(__dabt_invalid) + +__irq_invalid: + inv_entry BAD_IRQ + b common_invalid +ENDPROC(__irq_invalid) + +__und_invalid: + inv_entry BAD_UNDEFINSTR + + @ + @ XXX fall through to common_invalid + @ + +@ +@ common_invalid - generic code for failed exception (re-entrant version of handlers) +@ +common_invalid: + zero_fp + + ldmia r0, {r4 - r6} + add r0, sp, #S_PC @ here for interlock avoidance + mov r7, #-1 @ "" "" "" "" + str r4, [sp] @ save preserved r0 + stmia r0, {r5 - r7} @ lr_<exception>, + @ cpsr_<exception>, "old_r0" + + mov r0, sp + b bad_mode +ENDPROC(__und_invalid) + +/* + * SVC mode handlers + */ + +#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) +#define SPFIX(code...) code +#else +#define SPFIX(code...) +#endif + + .macro svc_entry, stack_hole=0, trace=1 + UNWIND(.fnstart ) + UNWIND(.save {r0 - pc} ) + sub sp, sp, #(S_FRAME_SIZE + \stack_hole - 4) +#ifdef CONFIG_THUMB2_KERNEL + SPFIX( str r0, [sp] ) @ temporarily saved + SPFIX( mov r0, sp ) + SPFIX( tst r0, #4 ) @ test original stack alignment + SPFIX( ldr r0, [sp] ) @ restored +#else + SPFIX( tst sp, #4 ) +#endif + SPFIX( subeq sp, sp, #4 ) + stmia sp, {r1 - r12} + + ldmia r0, {r3 - r5} + add r7, sp, #S_SP - 4 @ here for interlock avoidance + mov r6, #-1 @ "" "" "" "" + add r2, sp, #(S_FRAME_SIZE + \stack_hole - 4) + SPFIX( addeq r2, r2, #4 ) + str r3, [sp, #-4]! @ save the "real" r0 copied + @ from the exception stack + + mov r3, lr + + @ + @ We are now ready to fill in the remaining blanks on the stack: + @ + @ r2 - sp_svc + @ r3 - lr_svc + @ r4 - lr_<exception>, already fixed up for correct return/restart + @ r5 - spsr_<exception> + @ r6 - orig_r0 (see pt_regs definition in ptrace.h) + @ + stmia r7, {r2 - r6} + + .if \trace +#ifdef CONFIG_TRACE_IRQFLAGS + bl trace_hardirqs_off +#endif + .endif + .endm + + .align 5 +__dabt_svc: + svc_entry + mov r2, sp + dabt_helper + THUMB( ldr r5, [sp, #S_PSR] ) @ potentially updated CPSR + svc_exit r5 @ return from exception + UNWIND(.fnend ) +ENDPROC(__dabt_svc) + + .align 5 +__irq_svc: + svc_entry + irq_handler + +#ifdef CONFIG_PREEMPT + get_thread_info tsk + ldr r8, [tsk, #TI_PREEMPT] @ get preempt count + ldr r0, [tsk, #TI_FLAGS] @ get flags + teq r8, #0 @ if preempt count != 0 + movne r0, #0 @ force flags to 0 + tst r0, #_TIF_NEED_RESCHED + blne svc_preempt +#endif + + svc_exit r5, irq = 1 @ return from exception + UNWIND(.fnend ) +ENDPROC(__irq_svc) + + .ltorg + +#ifdef CONFIG_PREEMPT +svc_preempt: + mov r8, lr +1: bl preempt_schedule_irq @ irq en/disable is done inside + ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS + tst r0, #_TIF_NEED_RESCHED + reteq r8 @ go again + b 1b +#endif + +__und_fault: + @ Correct the PC such that it is pointing at the instruction + @ which caused the fault. If the faulting instruction was ARM + @ the PC will be pointing at the next instruction, and have to + @ subtract 4. Otherwise, it is Thumb, and the PC will be + @ pointing at the second half of the Thumb instruction. We + @ have to subtract 2. + ldr r2, [r0, #S_PC] + sub r2, r2, r1 + str r2, [r0, #S_PC] + b do_undefinstr +ENDPROC(__und_fault) + + .align 5 +__und_svc: +#ifdef CONFIG_KPROBES + @ If a kprobe is about to simulate a "stmdb sp..." instruction, + @ it obviously needs free stack space which then will belong to + @ the saved context. + svc_entry MAX_STACK_SIZE +#else + svc_entry +#endif + @ + @ call emulation code, which returns using r9 if it has emulated + @ the instruction, or the more conventional lr if we are to treat + @ this as a real undefined instruction + @ + @ r0 - instruction + @ +#ifndef CONFIG_THUMB2_KERNEL + ldr r0, [r4, #-4] +#else + mov r1, #2 + ldrh r0, [r4, #-2] @ Thumb instruction at LR - 2 + cmp r0, #0xe800 @ 32-bit instruction if xx >= 0 + blo __und_svc_fault + ldrh r9, [r4] @ bottom 16 bits + add r4, r4, #2 + str r4, [sp, #S_PC] + orr r0, r9, r0, lsl #16 +#endif + adr r9, BSYM(__und_svc_finish) + mov r2, r4 + bl call_fpe + + mov r1, #4 @ PC correction to apply +__und_svc_fault: + mov r0, sp @ struct pt_regs *regs + bl __und_fault + +__und_svc_finish: + ldr r5, [sp, #S_PSR] @ Get SVC cpsr + svc_exit r5 @ return from exception + UNWIND(.fnend ) +ENDPROC(__und_svc) + + .align 5 +__pabt_svc: + svc_entry + mov r2, sp @ regs + pabt_helper + svc_exit r5 @ return from exception + UNWIND(.fnend ) +ENDPROC(__pabt_svc) + + .align 5 +__fiq_svc: + svc_entry trace=0 + mov r0, sp @ struct pt_regs *regs + bl handle_fiq_as_nmi + svc_exit_via_fiq + UNWIND(.fnend ) +ENDPROC(__fiq_svc) + + .align 5 +.LCcralign: + .word cr_alignment +#ifdef MULTI_DABORT +.LCprocfns: + .word processor +#endif +.LCfp: + .word fp_enter + +/* + * Abort mode handlers + */ + +@ +@ Taking a FIQ in abort mode is similar to taking a FIQ in SVC mode +@ and reuses the same macros. However in abort mode we must also +@ save/restore lr_abt and spsr_abt to make nested aborts safe. +@ + .align 5 +__fiq_abt: + svc_entry trace=0 + + ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( msr cpsr_c, r0 ) + mov r1, lr @ Save lr_abt + mrs r2, spsr @ Save spsr_abt, abort is now safe + ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( msr cpsr_c, r0 ) + stmfd sp!, {r1 - r2} + + add r0, sp, #8 @ struct pt_regs *regs + bl handle_fiq_as_nmi + + ldmfd sp!, {r1 - r2} + ARM( msr cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( mov r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( msr cpsr_c, r0 ) + mov lr, r1 @ Restore lr_abt, abort is unsafe + msr spsr_cxsf, r2 @ Restore spsr_abt + ARM( msr cpsr_c, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( mov r0, #SVC_MODE | PSR_I_BIT | PSR_F_BIT ) + THUMB( msr cpsr_c, r0 ) + + svc_exit_via_fiq + UNWIND(.fnend ) +ENDPROC(__fiq_abt) + +/* + * User mode handlers + * + * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE + */ + +#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7) +#error "sizeof(struct pt_regs) must be a multiple of 8" +#endif + + .macro usr_entry, trace=1 + UNWIND(.fnstart ) + UNWIND(.cantunwind ) @ don't unwind the user space + sub sp, sp, #S_FRAME_SIZE + ARM( stmib sp, {r1 - r12} ) + THUMB( stmia sp, {r0 - r12} ) + + ATRAP( mrc p15, 0, r7, c1, c0, 0) + ATRAP( ldr r8, .LCcralign) + + ldmia r0, {r3 - r5} + add r0, sp, #S_PC @ here for interlock avoidance + mov r6, #-1 @ "" "" "" "" + + str r3, [sp] @ save the "real" r0 copied + @ from the exception stack + + ATRAP( ldr r8, [r8, #0]) + + @ + @ We are now ready to fill in the remaining blanks on the stack: + @ + @ r4 - lr_<exception>, already fixed up for correct return/restart + @ r5 - spsr_<exception> + @ r6 - orig_r0 (see pt_regs definition in ptrace.h) + @ + @ Also, separately save sp_usr and lr_usr + @ + stmia r0, {r4 - r6} + ARM( stmdb r0, {sp, lr}^ ) + THUMB( store_user_sp_lr r0, r1, S_SP - S_PC ) + + @ Enable the alignment trap while in kernel mode + ATRAP( teq r8, r7) + ATRAP( mcrne p15, 0, r8, c1, c0, 0) + + @ + @ Clear FP to mark the first stack frame + @ + zero_fp + + .if \trace +#ifdef CONFIG_IRQSOFF_TRACER + bl trace_hardirqs_off +#endif + ct_user_exit save = 0 + .endif + .endm + + .macro kuser_cmpxchg_check +#if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS) && \ + !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) +#ifndef CONFIG_MMU +#warning "NPTL on non MMU needs fixing" +#else + @ Make sure our user space atomic helper is restarted + @ if it was interrupted in a critical region. Here we + @ perform a quick test inline since it should be false + @ 99.9999% of the time. The rest is done out of line. + cmp r4, #TASK_SIZE + blhs kuser_cmpxchg64_fixup +#endif +#endif + .endm + + .align 5 +__dabt_usr: + usr_entry + kuser_cmpxchg_check + mov r2, sp + dabt_helper + b ret_from_exception + UNWIND(.fnend ) +ENDPROC(__dabt_usr) + + .align 5 +__irq_usr: + usr_entry + kuser_cmpxchg_check + irq_handler + get_thread_info tsk + mov why, #0 + b ret_to_user_from_irq + UNWIND(.fnend ) +ENDPROC(__irq_usr) + + .ltorg + + .align 5 +__und_usr: + usr_entry + + mov r2, r4 + mov r3, r5 + + @ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the + @ faulting instruction depending on Thumb mode. + @ r3 = regs->ARM_cpsr + @ + @ The emulation code returns using r9 if it has emulated the + @ instruction, or the more conventional lr if we are to treat + @ this as a real undefined instruction + @ + adr r9, BSYM(ret_from_exception) + + @ IRQs must be enabled before attempting to read the instruction from + @ user space since that could cause a page/translation fault if the + @ page table was modified by another CPU. + enable_irq + + tst r3, #PSR_T_BIT @ Thumb mode? + bne __und_usr_thumb + sub r4, r2, #4 @ ARM instr at LR - 4 +1: ldrt r0, [r4] + ARM_BE8(rev r0, r0) @ little endian instruction + + @ r0 = 32-bit ARM instruction which caused the exception + @ r2 = PC value for the following instruction (:= regs->ARM_pc) + @ r4 = PC value for the faulting instruction + @ lr = 32-bit undefined instruction function + adr lr, BSYM(__und_usr_fault_32) + b call_fpe + +__und_usr_thumb: + @ Thumb instruction + sub r4, r2, #2 @ First half of thumb instr at LR - 2 +#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 +/* + * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms + * can never be supported in a single kernel, this code is not applicable at + * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be + * made about .arch directives. + */ +#if __LINUX_ARM_ARCH__ < 7 +/* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */ +#define NEED_CPU_ARCHITECTURE + ldr r5, .LCcpu_architecture + ldr r5, [r5] + cmp r5, #CPU_ARCH_ARMv7 + blo __und_usr_fault_16 @ 16bit undefined instruction +/* + * The following code won't get run unless the running CPU really is v7, so + * coding round the lack of ldrht on older arches is pointless. Temporarily + * override the assembler target arch with the minimum required instead: + */ + .arch armv6t2 +#endif +2: ldrht r5, [r4] +ARM_BE8(rev16 r5, r5) @ little endian instruction + cmp r5, #0xe800 @ 32bit instruction if xx != 0 + blo __und_usr_fault_16 @ 16bit undefined instruction +3: ldrht r0, [r2] +ARM_BE8(rev16 r0, r0) @ little endian instruction + add r2, r2, #2 @ r2 is PC + 2, make it PC + 4 + str r2, [sp, #S_PC] @ it's a 2x16bit instr, update + orr r0, r0, r5, lsl #16 + adr lr, BSYM(__und_usr_fault_32) + @ r0 = the two 16-bit Thumb instructions which caused the exception + @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc) + @ r4 = PC value for the first 16-bit Thumb instruction + @ lr = 32bit undefined instruction function + +#if __LINUX_ARM_ARCH__ < 7 +/* If the target arch was overridden, change it back: */ +#ifdef CONFIG_CPU_32v6K + .arch armv6k +#else + .arch armv6 +#endif +#endif /* __LINUX_ARM_ARCH__ < 7 */ +#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */ + b __und_usr_fault_16 +#endif + UNWIND(.fnend) +ENDPROC(__und_usr) + +/* + * The out of line fixup for the ldrt instructions above. + */ + .pushsection .text.fixup, "ax" + .align 2 +4: str r4, [sp, #S_PC] @ retry current instruction + ret r9 + .popsection + .pushsection __ex_table,"a" + .long 1b, 4b +#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 + .long 2b, 4b + .long 3b, 4b +#endif + .popsection + +/* + * Check whether the instruction is a co-processor instruction. + * If yes, we need to call the relevant co-processor handler. + * + * Note that we don't do a full check here for the co-processor + * instructions; all instructions with bit 27 set are well + * defined. The only instructions that should fault are the + * co-processor instructions. However, we have to watch out + * for the ARM6/ARM7 SWI bug. + * + * NEON is a special case that has to be handled here. Not all + * NEON instructions are co-processor instructions, so we have + * to make a special case of checking for them. Plus, there's + * five groups of them, so we have a table of mask/opcode pairs + * to check against, and if any match then we branch off into the + * NEON handler code. + * + * Emulators may wish to make use of the following registers: + * r0 = instruction opcode (32-bit ARM or two 16-bit Thumb) + * r2 = PC value to resume execution after successful emulation + * r9 = normal "successful" return address + * r10 = this threads thread_info structure + * lr = unrecognised instruction return address + * IRQs enabled, FIQs enabled. + */ + @ + @ Fall-through from Thumb-2 __und_usr + @ +#ifdef CONFIG_NEON + get_thread_info r10 @ get current thread + adr r6, .LCneon_thumb_opcodes + b 2f +#endif +call_fpe: + get_thread_info r10 @ get current thread +#ifdef CONFIG_NEON + adr r6, .LCneon_arm_opcodes +2: ldr r5, [r6], #4 @ mask value + ldr r7, [r6], #4 @ opcode bits matching in mask + cmp r5, #0 @ end mask? + beq 1f + and r8, r0, r5 + cmp r8, r7 @ NEON instruction? + bne 2b + mov r7, #1 + strb r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used + strb r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used + b do_vfp @ let VFP handler handle this +1: +#endif + tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27 + tstne r0, #0x04000000 @ bit 26 set on both ARM and Thumb-2 + reteq lr + and r8, r0, #0x00000f00 @ mask out CP number + THUMB( lsr r8, r8, #8 ) + mov r7, #1 + add r6, r10, #TI_USED_CP + ARM( strb r7, [r6, r8, lsr #8] ) @ set appropriate used_cp[] + THUMB( strb r7, [r6, r8] ) @ set appropriate used_cp[] +#ifdef CONFIG_IWMMXT + @ Test if we need to give access to iWMMXt coprocessors + ldr r5, [r10, #TI_FLAGS] + rsbs r7, r8, #(1 << 8) @ CP 0 or 1 only + movcss r7, r5, lsr #(TIF_USING_IWMMXT + 1) + bcs iwmmxt_task_enable +#endif + ARM( add pc, pc, r8, lsr #6 ) + THUMB( lsl r8, r8, #2 ) + THUMB( add pc, r8 ) + nop + + ret.w lr @ CP#0 + W(b) do_fpe @ CP#1 (FPE) + W(b) do_fpe @ CP#2 (FPE) + ret.w lr @ CP#3 +#ifdef CONFIG_CRUNCH + b crunch_task_enable @ CP#4 (MaverickCrunch) + b crunch_task_enable @ CP#5 (MaverickCrunch) + b crunch_task_enable @ CP#6 (MaverickCrunch) +#else + ret.w lr @ CP#4 + ret.w lr @ CP#5 + ret.w lr @ CP#6 +#endif + ret.w lr @ CP#7 + ret.w lr @ CP#8 + ret.w lr @ CP#9 +#ifdef CONFIG_VFP + W(b) do_vfp @ CP#10 (VFP) + W(b) do_vfp @ CP#11 (VFP) +#else + ret.w lr @ CP#10 (VFP) + ret.w lr @ CP#11 (VFP) +#endif + ret.w lr @ CP#12 + ret.w lr @ CP#13 + ret.w lr @ CP#14 (Debug) + ret.w lr @ CP#15 (Control) + +#ifdef NEED_CPU_ARCHITECTURE + .align 2 +.LCcpu_architecture: + .word __cpu_architecture +#endif + +#ifdef CONFIG_NEON + .align 6 + +.LCneon_arm_opcodes: + .word 0xfe000000 @ mask + .word 0xf2000000 @ opcode + + .word 0xff100000 @ mask + .word 0xf4000000 @ opcode + + .word 0x00000000 @ mask + .word 0x00000000 @ opcode + +.LCneon_thumb_opcodes: + .word 0xef000000 @ mask + .word 0xef000000 @ opcode + + .word 0xff100000 @ mask + .word 0xf9000000 @ opcode + + .word 0x00000000 @ mask + .word 0x00000000 @ opcode +#endif + +do_fpe: + ldr r4, .LCfp + add r10, r10, #TI_FPSTATE @ r10 = workspace + ldr pc, [r4] @ Call FP module USR entry point + +/* + * The FP module is called with these registers set: + * r0 = instruction + * r2 = PC+4 + * r9 = normal "successful" return address + * r10 = FP workspace + * lr = unrecognised FP instruction return address + */ + + .pushsection .data +ENTRY(fp_enter) + .word no_fp + .popsection + +ENTRY(no_fp) + ret lr +ENDPROC(no_fp) + +__und_usr_fault_32: + mov r1, #4 + b 1f +__und_usr_fault_16: + mov r1, #2 +1: mov r0, sp + adr lr, BSYM(ret_from_exception) + b __und_fault +ENDPROC(__und_usr_fault_32) +ENDPROC(__und_usr_fault_16) + + .align 5 +__pabt_usr: + usr_entry + mov r2, sp @ regs + pabt_helper + UNWIND(.fnend ) + /* fall through */ +/* + * This is the return code to user mode for abort handlers + */ +ENTRY(ret_from_exception) + UNWIND(.fnstart ) + UNWIND(.cantunwind ) + get_thread_info tsk + mov why, #0 + b ret_to_user + UNWIND(.fnend ) +ENDPROC(__pabt_usr) +ENDPROC(ret_from_exception) + + .align 5 +__fiq_usr: + usr_entry trace=0 + kuser_cmpxchg_check + mov r0, sp @ struct pt_regs *regs + bl handle_fiq_as_nmi + get_thread_info tsk + restore_user_regs fast = 0, offset = 0 + UNWIND(.fnend ) +ENDPROC(__fiq_usr) + +/* + * Register switch for ARMv3 and ARMv4 processors + * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info + * previous and next are guaranteed not to be the same. + */ +ENTRY(__switch_to) + UNWIND(.fnstart ) + UNWIND(.cantunwind ) + add ip, r1, #TI_CPU_SAVE + ARM( stmia ip!, {r4 - sl, fp, sp, lr} ) @ Store most regs on stack + THUMB( stmia ip!, {r4 - sl, fp} ) @ Store most regs on stack + THUMB( str sp, [ip], #4 ) + THUMB( str lr, [ip], #4 ) + ldr r4, [r2, #TI_TP_VALUE] + ldr r5, [r2, #TI_TP_VALUE + 4] +#ifdef CONFIG_CPU_USE_DOMAINS + ldr r6, [r2, #TI_CPU_DOMAIN] +#endif + switch_tls r1, r4, r5, r3, r7 +#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) + ldr r7, [r2, #TI_TASK] + ldr r8, =__stack_chk_guard + ldr r7, [r7, #TSK_STACK_CANARY] +#endif +#ifdef CONFIG_CPU_USE_DOMAINS + mcr p15, 0, r6, c3, c0, 0 @ Set domain register +#endif + mov r5, r0 + add r4, r2, #TI_CPU_SAVE + ldr r0, =thread_notify_head + mov r1, #THREAD_NOTIFY_SWITCH + bl atomic_notifier_call_chain +#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) + str r7, [r8] +#endif + THUMB( mov ip, r4 ) + mov r0, r5 + ARM( ldmia r4, {r4 - sl, fp, sp, pc} ) @ Load all regs saved previously + THUMB( ldmia ip!, {r4 - sl, fp} ) @ Load all regs saved previously + THUMB( ldr sp, [ip], #4 ) + THUMB( ldr pc, [ip] ) + UNWIND(.fnend ) +ENDPROC(__switch_to) + + __INIT + +/* + * User helpers. + * + * Each segment is 32-byte aligned and will be moved to the top of the high + * vector page. New segments (if ever needed) must be added in front of + * existing ones. This mechanism should be used only for things that are + * really small and justified, and not be abused freely. + * + * See Documentation/arm/kernel_user_helpers.txt for formal definitions. + */ + THUMB( .arm ) + + .macro usr_ret, reg +#ifdef CONFIG_ARM_THUMB + bx \reg +#else + ret \reg +#endif + .endm + + .macro kuser_pad, sym, size + .if (. - \sym) & 3 + .rept 4 - (. - \sym) & 3 + .byte 0 + .endr + .endif + .rept (\size - (. - \sym)) / 4 + .word 0xe7fddef1 + .endr + .endm + +#ifdef CONFIG_KUSER_HELPERS + .align 5 + .globl __kuser_helper_start +__kuser_helper_start: + +/* + * Due to the length of some sequences, __kuser_cmpxchg64 spans 2 regular + * kuser "slots", therefore 0xffff0f80 is not used as a valid entry point. + */ + +__kuser_cmpxchg64: @ 0xffff0f60 + +#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) + + /* + * Poor you. No fast solution possible... + * The kernel itself must perform the operation. + * A special ghost syscall is used for that (see traps.c). + */ + stmfd sp!, {r7, lr} + ldr r7, 1f @ it's 20 bits + swi __ARM_NR_cmpxchg64 + ldmfd sp!, {r7, pc} +1: .word __ARM_NR_cmpxchg64 + +#elif defined(CONFIG_CPU_32v6K) + + stmfd sp!, {r4, r5, r6, r7} + ldrd r4, r5, [r0] @ load old val + ldrd r6, r7, [r1] @ load new val + smp_dmb arm +1: ldrexd r0, r1, [r2] @ load current val + eors r3, r0, r4 @ compare with oldval (1) + eoreqs r3, r1, r5 @ compare with oldval (2) + strexdeq r3, r6, r7, [r2] @ store newval if eq + teqeq r3, #1 @ success? + beq 1b @ if no then retry + smp_dmb arm + rsbs r0, r3, #0 @ set returned val and C flag + ldmfd sp!, {r4, r5, r6, r7} + usr_ret lr + +#elif !defined(CONFIG_SMP) + +#ifdef CONFIG_MMU + + /* + * The only thing that can break atomicity in this cmpxchg64 + * implementation is either an IRQ or a data abort exception + * causing another process/thread to be scheduled in the middle of + * the critical sequence. The same strategy as for cmpxchg is used. + */ + stmfd sp!, {r4, r5, r6, lr} + ldmia r0, {r4, r5} @ load old val + ldmia r1, {r6, lr} @ load new val +1: ldmia r2, {r0, r1} @ load current val + eors r3, r0, r4 @ compare with oldval (1) + eoreqs r3, r1, r5 @ compare with oldval (2) +2: stmeqia r2, {r6, lr} @ store newval if eq + rsbs r0, r3, #0 @ set return val and C flag + ldmfd sp!, {r4, r5, r6, pc} + + .text +kuser_cmpxchg64_fixup: + @ Called from kuser_cmpxchg_fixup. + @ r4 = address of interrupted insn (must be preserved). + @ sp = saved regs. r7 and r8 are clobbered. + @ 1b = first critical insn, 2b = last critical insn. + @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. + mov r7, #0xffff0fff + sub r7, r7, #(0xffff0fff - (0xffff0f60 + (1b - __kuser_cmpxchg64))) + subs r8, r4, r7 + rsbcss r8, r8, #(2b - 1b) + strcs r7, [sp, #S_PC] +#if __LINUX_ARM_ARCH__ < 6 + bcc kuser_cmpxchg32_fixup +#endif + ret lr + .previous + +#else +#warning "NPTL on non MMU needs fixing" + mov r0, #-1 + adds r0, r0, #0 + usr_ret lr +#endif + +#else +#error "incoherent kernel configuration" +#endif + + kuser_pad __kuser_cmpxchg64, 64 + +__kuser_memory_barrier: @ 0xffff0fa0 + smp_dmb arm + usr_ret lr + + kuser_pad __kuser_memory_barrier, 32 + +__kuser_cmpxchg: @ 0xffff0fc0 + +#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) + + /* + * Poor you. No fast solution possible... + * The kernel itself must perform the operation. + * A special ghost syscall is used for that (see traps.c). + */ + stmfd sp!, {r7, lr} + ldr r7, 1f @ it's 20 bits + swi __ARM_NR_cmpxchg + ldmfd sp!, {r7, pc} +1: .word __ARM_NR_cmpxchg + +#elif __LINUX_ARM_ARCH__ < 6 + +#ifdef CONFIG_MMU + + /* + * The only thing that can break atomicity in this cmpxchg + * implementation is either an IRQ or a data abort exception + * causing another process/thread to be scheduled in the middle + * of the critical sequence. To prevent this, code is added to + * the IRQ and data abort exception handlers to set the pc back + * to the beginning of the critical section if it is found to be + * within that critical section (see kuser_cmpxchg_fixup). + */ +1: ldr r3, [r2] @ load current val + subs r3, r3, r0 @ compare with oldval +2: streq r1, [r2] @ store newval if eq + rsbs r0, r3, #0 @ set return val and C flag + usr_ret lr + + .text +kuser_cmpxchg32_fixup: + @ Called from kuser_cmpxchg_check macro. + @ r4 = address of interrupted insn (must be preserved). + @ sp = saved regs. r7 and r8 are clobbered. + @ 1b = first critical insn, 2b = last critical insn. + @ If r4 >= 1b and r4 <= 2b then saved pc_usr is set to 1b. + mov r7, #0xffff0fff + sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg))) + subs r8, r4, r7 + rsbcss r8, r8, #(2b - 1b) + strcs r7, [sp, #S_PC] + ret lr + .previous + +#else +#warning "NPTL on non MMU needs fixing" + mov r0, #-1 + adds r0, r0, #0 + usr_ret lr +#endif + +#else + + smp_dmb arm +1: ldrex r3, [r2] + subs r3, r3, r0 + strexeq r3, r1, [r2] + teqeq r3, #1 + beq 1b + rsbs r0, r3, #0 + /* beware -- each __kuser slot must be 8 instructions max */ + ALT_SMP(b __kuser_memory_barrier) + ALT_UP(usr_ret lr) + +#endif + + kuser_pad __kuser_cmpxchg, 32 + +__kuser_get_tls: @ 0xffff0fe0 + ldr r0, [pc, #(16 - 8)] @ read TLS, set in kuser_get_tls_init + usr_ret lr + mrc p15, 0, r0, c13, c0, 3 @ 0xffff0fe8 hardware TLS code + kuser_pad __kuser_get_tls, 16 + .rep 3 + .word 0 @ 0xffff0ff0 software TLS value, then + .endr @ pad up to __kuser_helper_version + +__kuser_helper_version: @ 0xffff0ffc + .word ((__kuser_helper_end - __kuser_helper_start) >> 5) + + .globl __kuser_helper_end +__kuser_helper_end: + +#endif + + THUMB( .thumb ) + +/* + * Vector stubs. + * + * This code is copied to 0xffff1000 so we can use branches in the + * vectors, rather than ldr's. Note that this code must not exceed + * a page size. + * + * Common stub entry macro: + * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC + * + * SP points to a minimal amount of processor-private memory, the address + * of which is copied into r0 for the mode specific abort handler. + */ + .macro vector_stub, name, mode, correction=0 + .align 5 + +vector_\name: + .if \correction + sub lr, lr, #\correction + .endif + + @ + @ Save r0, lr_<exception> (parent PC) and spsr_<exception> + @ (parent CPSR) + @ + stmia sp, {r0, lr} @ save r0, lr + mrs lr, spsr + str lr, [sp, #8] @ save spsr + + @ + @ Prepare for SVC32 mode. IRQs remain disabled. + @ + mrs r0, cpsr + eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE) + msr spsr_cxsf, r0 + + @ + @ the branch table must immediately follow this code + @ + and lr, lr, #0x0f + THUMB( adr r0, 1f ) + THUMB( ldr lr, [r0, lr, lsl #2] ) + mov r0, sp + ARM( ldr lr, [pc, lr, lsl #2] ) + movs pc, lr @ branch to handler in SVC mode +ENDPROC(vector_\name) + + .align 2 + @ handler addresses follow this label +1: + .endm + + .section .stubs, "ax", %progbits +__stubs_start: + @ This must be the first word + .word vector_swi + +vector_rst: + ARM( swi SYS_ERROR0 ) + THUMB( svc #0 ) + THUMB( nop ) + b vector_und + +/* + * Interrupt dispatcher + */ + vector_stub irq, IRQ_MODE, 4 + + .long __irq_usr @ 0 (USR_26 / USR_32) + .long __irq_invalid @ 1 (FIQ_26 / FIQ_32) + .long __irq_invalid @ 2 (IRQ_26 / IRQ_32) + .long __irq_svc @ 3 (SVC_26 / SVC_32) + .long __irq_invalid @ 4 + .long __irq_invalid @ 5 + .long __irq_invalid @ 6 + .long __irq_invalid @ 7 + .long __irq_invalid @ 8 + .long __irq_invalid @ 9 + .long __irq_invalid @ a + .long __irq_invalid @ b + .long __irq_invalid @ c + .long __irq_invalid @ d + .long __irq_invalid @ e + .long __irq_invalid @ f + +/* + * Data abort dispatcher + * Enter in ABT mode, spsr = USR CPSR, lr = USR PC + */ + vector_stub dabt, ABT_MODE, 8 + + .long __dabt_usr @ 0 (USR_26 / USR_32) + .long __dabt_invalid @ 1 (FIQ_26 / FIQ_32) + .long __dabt_invalid @ 2 (IRQ_26 / IRQ_32) + .long __dabt_svc @ 3 (SVC_26 / SVC_32) + .long __dabt_invalid @ 4 + .long __dabt_invalid @ 5 + .long __dabt_invalid @ 6 + .long __dabt_invalid @ 7 + .long __dabt_invalid @ 8 + .long __dabt_invalid @ 9 + .long __dabt_invalid @ a + .long __dabt_invalid @ b + .long __dabt_invalid @ c + .long __dabt_invalid @ d + .long __dabt_invalid @ e + .long __dabt_invalid @ f + +/* + * Prefetch abort dispatcher + * Enter in ABT mode, spsr = USR CPSR, lr = USR PC + */ + vector_stub pabt, ABT_MODE, 4 + + .long __pabt_usr @ 0 (USR_26 / USR_32) + .long __pabt_invalid @ 1 (FIQ_26 / FIQ_32) + .long __pabt_invalid @ 2 (IRQ_26 / IRQ_32) + .long __pabt_svc @ 3 (SVC_26 / SVC_32) + .long __pabt_invalid @ 4 + .long __pabt_invalid @ 5 + .long __pabt_invalid @ 6 + .long __pabt_invalid @ 7 + .long __pabt_invalid @ 8 + .long __pabt_invalid @ 9 + .long __pabt_invalid @ a + .long __pabt_invalid @ b + .long __pabt_invalid @ c + .long __pabt_invalid @ d + .long __pabt_invalid @ e + .long __pabt_invalid @ f + +/* + * Undef instr entry dispatcher + * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC + */ + vector_stub und, UND_MODE + + .long __und_usr @ 0 (USR_26 / USR_32) + .long __und_invalid @ 1 (FIQ_26 / FIQ_32) + .long __und_invalid @ 2 (IRQ_26 / IRQ_32) + .long __und_svc @ 3 (SVC_26 / SVC_32) + .long __und_invalid @ 4 + .long __und_invalid @ 5 + .long __und_invalid @ 6 + .long __und_invalid @ 7 + .long __und_invalid @ 8 + .long __und_invalid @ 9 + .long __und_invalid @ a + .long __und_invalid @ b + .long __und_invalid @ c + .long __und_invalid @ d + .long __und_invalid @ e + .long __und_invalid @ f + + .align 5 + +/*============================================================================= + * Address exception handler + *----------------------------------------------------------------------------- + * These aren't too critical. + * (they're not supposed to happen, and won't happen in 32-bit data mode). + */ + +vector_addrexcptn: + b vector_addrexcptn + +/*============================================================================= + * FIQ "NMI" handler + *----------------------------------------------------------------------------- + * Handle a FIQ using the SVC stack allowing FIQ act like NMI on x86 + * systems. + */ + vector_stub fiq, FIQ_MODE, 4 + + .long __fiq_usr @ 0 (USR_26 / USR_32) + .long __fiq_svc @ 1 (FIQ_26 / FIQ_32) + .long __fiq_svc @ 2 (IRQ_26 / IRQ_32) + .long __fiq_svc @ 3 (SVC_26 / SVC_32) + .long __fiq_svc @ 4 + .long __fiq_svc @ 5 + .long __fiq_svc @ 6 + .long __fiq_abt @ 7 + .long __fiq_svc @ 8 + .long __fiq_svc @ 9 + .long __fiq_svc @ a + .long __fiq_svc @ b + .long __fiq_svc @ c + .long __fiq_svc @ d + .long __fiq_svc @ e + .long __fiq_svc @ f + + .globl vector_fiq_offset + .equ vector_fiq_offset, vector_fiq + + .section .vectors, "ax", %progbits +__vectors_start: + W(b) vector_rst + W(b) vector_und + W(ldr) pc, __vectors_start + 0x1000 + W(b) vector_pabt + W(b) vector_dabt + W(b) vector_addrexcptn + W(b) vector_irq + W(b) vector_fiq + + .data + + .globl cr_alignment +cr_alignment: + .space 4 + +#ifdef CONFIG_MULTI_IRQ_HANDLER + .globl handle_arch_irq +handle_arch_irq: + .space 4 +#endif |