1248 lines
29 KiB
ArmAsm
1248 lines
29 KiB
ArmAsm
/*
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* linux/arch/arm/kernel/entry-armv.S
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*
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* Copyright (C) 1996,1997,1998 Russell King.
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* ARM700 fix by Matthew Godbolt (linux-user@willothewisp.demon.co.uk)
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* nommu support by Hyok S. Choi (hyok.choi@samsung.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Low-level vector interface routines
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*
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* Note: there is a StrongARM bug in the STMIA rn, {regs}^ instruction
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* that causes it to save wrong values... Be aware!
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*/
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#include <asm/memory.h>
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#include <asm/glue.h>
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#include <asm/vfpmacros.h>
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#include <mach/entry-macro.S>
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#include <asm/thread_notify.h>
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#include <asm/unwind.h>
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#include <asm/unistd.h>
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#include <asm/tls.h>
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#include "entry-header.S"
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/*
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* Interrupt handling. Preserves r7, r8, r9
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*/
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.macro irq_handler
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get_irqnr_preamble r5, lr
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1: get_irqnr_and_base r0, r6, r5, lr
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movne r1, sp
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@
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@ routine called with r0 = irq number, r1 = struct pt_regs *
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@
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adrne lr, BSYM(1b)
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bne asm_do_IRQ
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#ifdef CONFIG_SMP
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/*
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* XXX
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*
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* this macro assumes that irqstat (r6) and base (r5) are
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* preserved from get_irqnr_and_base above
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*/
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test_for_ipi r0, r6, r5, lr
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movne r0, sp
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adrne lr, BSYM(1b)
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bne do_IPI
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#ifdef CONFIG_LOCAL_TIMERS
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test_for_ltirq r0, r6, r5, lr
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movne r0, sp
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adrne lr, BSYM(1b)
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bne do_local_timer
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#endif
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#endif
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.endm
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#ifdef CONFIG_KPROBES
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.section .kprobes.text,"ax",%progbits
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#else
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.text
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#endif
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/*
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* Invalid mode handlers
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*/
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.macro inv_entry, reason
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sub sp, sp, #S_FRAME_SIZE
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ARM( stmib sp, {r1 - lr} )
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THUMB( stmia sp, {r0 - r12} )
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THUMB( str sp, [sp, #S_SP] )
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THUMB( str lr, [sp, #S_LR] )
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mov r1, #\reason
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.endm
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__pabt_invalid:
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inv_entry BAD_PREFETCH
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b common_invalid
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ENDPROC(__pabt_invalid)
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__dabt_invalid:
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inv_entry BAD_DATA
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b common_invalid
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ENDPROC(__dabt_invalid)
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__irq_invalid:
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inv_entry BAD_IRQ
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b common_invalid
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ENDPROC(__irq_invalid)
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__und_invalid:
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inv_entry BAD_UNDEFINSTR
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@
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@ XXX fall through to common_invalid
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@
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@
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@ common_invalid - generic code for failed exception (re-entrant version of handlers)
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@
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common_invalid:
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zero_fp
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ldmia r0, {r4 - r6}
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add r0, sp, #S_PC @ here for interlock avoidance
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mov r7, #-1 @ "" "" "" ""
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str r4, [sp] @ save preserved r0
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stmia r0, {r5 - r7} @ lr_<exception>,
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@ cpsr_<exception>, "old_r0"
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mov r0, sp
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b bad_mode
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ENDPROC(__und_invalid)
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/*
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* SVC mode handlers
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*/
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#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
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#define SPFIX(code...) code
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#else
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#define SPFIX(code...)
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#endif
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.macro svc_entry, stack_hole=0
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UNWIND(.fnstart )
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UNWIND(.save {r0 - pc} )
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sub sp, sp, #(S_FRAME_SIZE + \stack_hole - 4)
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#ifdef CONFIG_THUMB2_KERNEL
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SPFIX( str r0, [sp] ) @ temporarily saved
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SPFIX( mov r0, sp )
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SPFIX( tst r0, #4 ) @ test original stack alignment
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SPFIX( ldr r0, [sp] ) @ restored
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#else
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SPFIX( tst sp, #4 )
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#endif
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SPFIX( subeq sp, sp, #4 )
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stmia sp, {r1 - r12}
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ldmia r0, {r1 - r3}
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add r5, sp, #S_SP - 4 @ here for interlock avoidance
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mov r4, #-1 @ "" "" "" ""
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add r0, sp, #(S_FRAME_SIZE + \stack_hole - 4)
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SPFIX( addeq r0, r0, #4 )
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str r1, [sp, #-4]! @ save the "real" r0 copied
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@ from the exception stack
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mov r1, lr
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@
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@ We are now ready to fill in the remaining blanks on the stack:
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@
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@ r0 - sp_svc
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@ r1 - lr_svc
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@ r2 - lr_<exception>, already fixed up for correct return/restart
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@ r3 - spsr_<exception>
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@ r4 - orig_r0 (see pt_regs definition in ptrace.h)
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@
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stmia r5, {r0 - r4}
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.endm
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.align 5
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__dabt_svc:
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svc_entry
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@
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@ get ready to re-enable interrupts if appropriate
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@
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mrs r9, cpsr
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tst r3, #PSR_I_BIT
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biceq r9, r9, #PSR_I_BIT
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@
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@ Call the processor-specific abort handler:
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@
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@ r2 - aborted context pc
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@ r3 - aborted context cpsr
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@
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@ The abort handler must return the aborted address in r0, and
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@ the fault status register in r1. r9 must be preserved.
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@
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#ifdef MULTI_DABORT
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ldr r4, .LCprocfns
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mov lr, pc
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ldr pc, [r4, #PROCESSOR_DABT_FUNC]
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#else
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bl CPU_DABORT_HANDLER
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#endif
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@
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@ set desired IRQ state, then call main handler
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@
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msr cpsr_c, r9
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mov r2, sp
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bl do_DataAbort
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@
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@ IRQs off again before pulling preserved data off the stack
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@
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disable_irq_notrace
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@
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@ restore SPSR and restart the instruction
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@
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ldr r2, [sp, #S_PSR]
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svc_exit r2 @ return from exception
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UNWIND(.fnend )
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ENDPROC(__dabt_svc)
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.align 5
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__irq_svc:
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svc_entry
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#ifdef CONFIG_TRACE_IRQFLAGS
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bl trace_hardirqs_off
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#endif
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#ifdef CONFIG_PREEMPT
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get_thread_info tsk
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ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
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add r7, r8, #1 @ increment it
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str r7, [tsk, #TI_PREEMPT]
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#endif
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irq_handler
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#ifdef CONFIG_PREEMPT
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str r8, [tsk, #TI_PREEMPT] @ restore preempt count
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ldr r0, [tsk, #TI_FLAGS] @ get flags
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teq r8, #0 @ if preempt count != 0
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movne r0, #0 @ force flags to 0
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tst r0, #_TIF_NEED_RESCHED
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blne svc_preempt
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#endif
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ldr r4, [sp, #S_PSR] @ irqs are already disabled
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#ifdef CONFIG_TRACE_IRQFLAGS
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tst r4, #PSR_I_BIT
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bleq trace_hardirqs_on
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#endif
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svc_exit r4 @ return from exception
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UNWIND(.fnend )
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ENDPROC(__irq_svc)
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.ltorg
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#ifdef CONFIG_PREEMPT
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svc_preempt:
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mov r8, lr
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1: bl preempt_schedule_irq @ irq en/disable is done inside
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ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS
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tst r0, #_TIF_NEED_RESCHED
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moveq pc, r8 @ go again
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b 1b
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#endif
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.align 5
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__und_svc:
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#ifdef CONFIG_KPROBES
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@ If a kprobe is about to simulate a "stmdb sp..." instruction,
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@ it obviously needs free stack space which then will belong to
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@ the saved context.
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svc_entry 64
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#else
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svc_entry
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#endif
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@
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@ call emulation code, which returns using r9 if it has emulated
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@ the instruction, or the more conventional lr if we are to treat
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@ this as a real undefined instruction
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@
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@ r0 - instruction
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@
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#ifndef CONFIG_THUMB2_KERNEL
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ldr r0, [r2, #-4]
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#else
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ldrh r0, [r2, #-2] @ Thumb instruction at LR - 2
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and r9, r0, #0xf800
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cmp r9, #0xe800 @ 32-bit instruction if xx >= 0
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ldrhhs r9, [r2] @ bottom 16 bits
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orrhs r0, r9, r0, lsl #16
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#endif
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adr r9, BSYM(1f)
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bl call_fpe
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mov r0, sp @ struct pt_regs *regs
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bl do_undefinstr
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@
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@ IRQs off again before pulling preserved data off the stack
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@
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1: disable_irq_notrace
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@
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@ restore SPSR and restart the instruction
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@
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ldr r2, [sp, #S_PSR] @ Get SVC cpsr
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svc_exit r2 @ return from exception
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UNWIND(.fnend )
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ENDPROC(__und_svc)
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.align 5
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__pabt_svc:
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svc_entry
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@
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@ re-enable interrupts if appropriate
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@
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mrs r9, cpsr
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tst r3, #PSR_I_BIT
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biceq r9, r9, #PSR_I_BIT
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mov r0, r2 @ pass address of aborted instruction.
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#ifdef MULTI_PABORT
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ldr r4, .LCprocfns
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mov lr, pc
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ldr pc, [r4, #PROCESSOR_PABT_FUNC]
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#else
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bl CPU_PABORT_HANDLER
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#endif
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msr cpsr_c, r9 @ Maybe enable interrupts
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mov r2, sp @ regs
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bl do_PrefetchAbort @ call abort handler
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@
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@ IRQs off again before pulling preserved data off the stack
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@
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disable_irq_notrace
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@
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@ restore SPSR and restart the instruction
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@
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ldr r2, [sp, #S_PSR]
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svc_exit r2 @ return from exception
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UNWIND(.fnend )
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ENDPROC(__pabt_svc)
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.align 5
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.LCcralign:
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.word cr_alignment
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#ifdef MULTI_DABORT
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.LCprocfns:
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.word processor
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#endif
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.LCfp:
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.word fp_enter
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/*
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* User mode handlers
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*
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* EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE
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*/
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#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7)
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#error "sizeof(struct pt_regs) must be a multiple of 8"
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#endif
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.macro usr_entry
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UNWIND(.fnstart )
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UNWIND(.cantunwind ) @ don't unwind the user space
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sub sp, sp, #S_FRAME_SIZE
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ARM( stmib sp, {r1 - r12} )
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THUMB( stmia sp, {r0 - r12} )
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ldmia r0, {r1 - r3}
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add r0, sp, #S_PC @ here for interlock avoidance
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mov r4, #-1 @ "" "" "" ""
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str r1, [sp] @ save the "real" r0 copied
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@ from the exception stack
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@
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@ We are now ready to fill in the remaining blanks on the stack:
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@
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@ r2 - lr_<exception>, already fixed up for correct return/restart
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@ r3 - spsr_<exception>
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@ r4 - orig_r0 (see pt_regs definition in ptrace.h)
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@
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@ Also, separately save sp_usr and lr_usr
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@
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stmia r0, {r2 - r4}
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ARM( stmdb r0, {sp, lr}^ )
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THUMB( store_user_sp_lr r0, r1, S_SP - S_PC )
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@
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@ Enable the alignment trap while in kernel mode
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@
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alignment_trap r0
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@
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@ Clear FP to mark the first stack frame
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@
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zero_fp
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.endm
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.macro kuser_cmpxchg_check
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#if __LINUX_ARM_ARCH__ < 6 && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
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#ifndef CONFIG_MMU
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#warning "NPTL on non MMU needs fixing"
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#else
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@ Make sure our user space atomic helper is restarted
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@ if it was interrupted in a critical region. Here we
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@ perform a quick test inline since it should be false
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@ 99.9999% of the time. The rest is done out of line.
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cmp r2, #TASK_SIZE
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blhs kuser_cmpxchg_fixup
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#endif
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#endif
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.endm
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.align 5
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__dabt_usr:
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usr_entry
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kuser_cmpxchg_check
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@
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@ Call the processor-specific abort handler:
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@
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@ r2 - aborted context pc
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@ r3 - aborted context cpsr
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@
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@ The abort handler must return the aborted address in r0, and
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@ the fault status register in r1.
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@
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#ifdef MULTI_DABORT
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ldr r4, .LCprocfns
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mov lr, pc
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ldr pc, [r4, #PROCESSOR_DABT_FUNC]
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#else
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bl CPU_DABORT_HANDLER
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#endif
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@
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@ IRQs on, then call the main handler
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@
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enable_irq
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mov r2, sp
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adr lr, BSYM(ret_from_exception)
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b do_DataAbort
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UNWIND(.fnend )
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ENDPROC(__dabt_usr)
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.align 5
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__irq_usr:
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usr_entry
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kuser_cmpxchg_check
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get_thread_info tsk
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#ifdef CONFIG_PREEMPT
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ldr r8, [tsk, #TI_PREEMPT] @ get preempt count
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add r7, r8, #1 @ increment it
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str r7, [tsk, #TI_PREEMPT]
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#endif
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irq_handler
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#ifdef CONFIG_PREEMPT
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ldr r0, [tsk, #TI_PREEMPT]
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str r8, [tsk, #TI_PREEMPT]
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teq r0, r7
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ARM( strne r0, [r0, -r0] )
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THUMB( movne r0, #0 )
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THUMB( strne r0, [r0] )
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#endif
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mov why, #0
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b ret_to_user
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UNWIND(.fnend )
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ENDPROC(__irq_usr)
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.ltorg
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.align 5
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__und_usr:
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usr_entry
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@
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@ fall through to the emulation code, which returns using r9 if
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@ it has emulated the instruction, or the more conventional lr
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@ if we are to treat this as a real undefined instruction
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@
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@ r0 - instruction
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@
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adr r9, BSYM(ret_from_exception)
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adr lr, BSYM(__und_usr_unknown)
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tst r3, #PSR_T_BIT @ Thumb mode?
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itet eq @ explicit IT needed for the 1f label
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subeq r4, r2, #4 @ ARM instr at LR - 4
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subne r4, r2, #2 @ Thumb instr at LR - 2
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1: ldreqt r0, [r4]
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#ifdef CONFIG_CPU_ENDIAN_BE8
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reveq r0, r0 @ little endian instruction
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#endif
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beq call_fpe
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@ Thumb instruction
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#if __LINUX_ARM_ARCH__ >= 7
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2:
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ARM( ldrht r5, [r4], #2 )
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THUMB( ldrht r5, [r4] )
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THUMB( add r4, r4, #2 )
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and r0, r5, #0xf800 @ mask bits 111x x... .... ....
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cmp r0, #0xe800 @ 32bit instruction if xx != 0
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blo __und_usr_unknown
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3: ldrht r0, [r4]
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add r2, r2, #2 @ r2 is PC + 2, make it PC + 4
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orr r0, r0, r5, lsl #16
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#else
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b __und_usr_unknown
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#endif
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UNWIND(.fnend )
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ENDPROC(__und_usr)
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@
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@ fallthrough to call_fpe
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@
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/*
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* The out of line fixup for the ldrt above.
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*/
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.pushsection .fixup, "ax"
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4: mov pc, r9
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.popsection
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.pushsection __ex_table,"a"
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.long 1b, 4b
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#if __LINUX_ARM_ARCH__ >= 7
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.long 2b, 4b
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.long 3b, 4b
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#endif
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.popsection
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/*
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* Check whether the instruction is a co-processor instruction.
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* If yes, we need to call the relevant co-processor handler.
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*
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* Note that we don't do a full check here for the co-processor
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* instructions; all instructions with bit 27 set are well
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* defined. The only instructions that should fault are the
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* 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.
|
|
* r2 = PC+4
|
|
* r9 = normal "successful" return address
|
|
* r10 = this threads thread_info structure.
|
|
* lr = unrecognised instruction return address
|
|
*/
|
|
@
|
|
@ Fall-through from Thumb-2 __und_usr
|
|
@
|
|
#ifdef CONFIG_NEON
|
|
adr r6, .LCneon_thumb_opcodes
|
|
b 2f
|
|
#endif
|
|
call_fpe:
|
|
#ifdef CONFIG_NEON
|
|
adr r6, .LCneon_arm_opcodes
|
|
2:
|
|
ldr r7, [r6], #4 @ mask value
|
|
cmp r7, #0 @ end mask?
|
|
beq 1f
|
|
and r8, r0, r7
|
|
ldr r7, [r6], #4 @ opcode bits matching in mask
|
|
cmp r8, r7 @ NEON instruction?
|
|
bne 2b
|
|
get_thread_info r10
|
|
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
|
|
#if defined(CONFIG_CPU_ARM610) || defined(CONFIG_CPU_ARM710)
|
|
and r8, r0, #0x0f000000 @ mask out op-code bits
|
|
teqne r8, #0x0f000000 @ SWI (ARM6/7 bug)?
|
|
#endif
|
|
moveq pc, lr
|
|
get_thread_info r10 @ get current thread
|
|
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
|
|
|
|
movw_pc lr @ CP#0
|
|
W(b) do_fpe @ CP#1 (FPE)
|
|
W(b) do_fpe @ CP#2 (FPE)
|
|
movw_pc 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
|
|
movw_pc lr @ CP#4
|
|
movw_pc lr @ CP#5
|
|
movw_pc lr @ CP#6
|
|
#endif
|
|
movw_pc lr @ CP#7
|
|
movw_pc lr @ CP#8
|
|
movw_pc lr @ CP#9
|
|
#ifdef CONFIG_VFP
|
|
W(b) do_vfp @ CP#10 (VFP)
|
|
W(b) do_vfp @ CP#11 (VFP)
|
|
#else
|
|
movw_pc lr @ CP#10 (VFP)
|
|
movw_pc lr @ CP#11 (VFP)
|
|
#endif
|
|
movw_pc lr @ CP#12
|
|
movw_pc lr @ CP#13
|
|
movw_pc lr @ CP#14 (Debug)
|
|
movw_pc lr @ CP#15 (Control)
|
|
|
|
#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:
|
|
enable_irq
|
|
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)
|
|
mov pc, lr
|
|
ENDPROC(no_fp)
|
|
|
|
__und_usr_unknown:
|
|
enable_irq
|
|
mov r0, sp
|
|
adr lr, BSYM(ret_from_exception)
|
|
b do_undefinstr
|
|
ENDPROC(__und_usr_unknown)
|
|
|
|
.align 5
|
|
__pabt_usr:
|
|
usr_entry
|
|
|
|
mov r0, r2 @ pass address of aborted instruction.
|
|
#ifdef MULTI_PABORT
|
|
ldr r4, .LCprocfns
|
|
mov lr, pc
|
|
ldr pc, [r4, #PROCESSOR_PABT_FUNC]
|
|
#else
|
|
bl CPU_PABORT_HANDLER
|
|
#endif
|
|
enable_irq @ Enable interrupts
|
|
mov r2, sp @ regs
|
|
bl do_PrefetchAbort @ call abort handler
|
|
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)
|
|
|
|
/*
|
|
* 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
|
|
ldr r3, [r2, #TI_TP_VALUE]
|
|
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 )
|
|
#ifdef CONFIG_MMU
|
|
ldr r6, [r2, #TI_CPU_DOMAIN]
|
|
#endif
|
|
set_tls r3, r4, r5
|
|
#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_MMU
|
|
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.
|
|
*
|
|
* These are segment of kernel provided user code reachable from user space
|
|
* at a fixed address in kernel memory. This is used to provide user space
|
|
* with some operations which require kernel help because of unimplemented
|
|
* native feature and/or instructions in many ARM CPUs. The idea is for
|
|
* this code to be executed directly in user mode for best efficiency but
|
|
* which is too intimate with the kernel counter part to be left to user
|
|
* libraries. In fact this code might even differ from one CPU to another
|
|
* depending on the available instruction set and restrictions like on
|
|
* SMP systems. In other words, the kernel reserves the right to change
|
|
* this code as needed without warning. Only the entry points and their
|
|
* results are guaranteed to be stable.
|
|
*
|
|
* 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.
|
|
*
|
|
* User space is expected to implement those things inline when optimizing
|
|
* for a processor that has the necessary native support, but only if such
|
|
* resulting binaries are already to be incompatible with earlier ARM
|
|
* processors due to the use of unsupported instructions other than what
|
|
* is provided here. In other words don't make binaries unable to run on
|
|
* earlier processors just for the sake of not using these kernel helpers
|
|
* if your compiled code is not going to use the new instructions for other
|
|
* purpose.
|
|
*/
|
|
THUMB( .arm )
|
|
|
|
.macro usr_ret, reg
|
|
#ifdef CONFIG_ARM_THUMB
|
|
bx \reg
|
|
#else
|
|
mov pc, \reg
|
|
#endif
|
|
.endm
|
|
|
|
.align 5
|
|
.globl __kuser_helper_start
|
|
__kuser_helper_start:
|
|
|
|
/*
|
|
* Reference prototype:
|
|
*
|
|
* void __kernel_memory_barrier(void)
|
|
*
|
|
* Input:
|
|
*
|
|
* lr = return address
|
|
*
|
|
* Output:
|
|
*
|
|
* none
|
|
*
|
|
* Clobbered:
|
|
*
|
|
* none
|
|
*
|
|
* Definition and user space usage example:
|
|
*
|
|
* typedef void (__kernel_dmb_t)(void);
|
|
* #define __kernel_dmb (*(__kernel_dmb_t *)0xffff0fa0)
|
|
*
|
|
* Apply any needed memory barrier to preserve consistency with data modified
|
|
* manually and __kuser_cmpxchg usage.
|
|
*
|
|
* This could be used as follows:
|
|
*
|
|
* #define __kernel_dmb() \
|
|
* asm volatile ( "mov r0, #0xffff0fff; mov lr, pc; sub pc, r0, #95" \
|
|
* : : : "r0", "lr","cc" )
|
|
*/
|
|
|
|
__kuser_memory_barrier: @ 0xffff0fa0
|
|
smp_dmb
|
|
usr_ret lr
|
|
|
|
.align 5
|
|
|
|
/*
|
|
* Reference prototype:
|
|
*
|
|
* int __kernel_cmpxchg(int oldval, int newval, int *ptr)
|
|
*
|
|
* Input:
|
|
*
|
|
* r0 = oldval
|
|
* r1 = newval
|
|
* r2 = ptr
|
|
* lr = return address
|
|
*
|
|
* Output:
|
|
*
|
|
* r0 = returned value (zero or non-zero)
|
|
* C flag = set if r0 == 0, clear if r0 != 0
|
|
*
|
|
* Clobbered:
|
|
*
|
|
* r3, ip, flags
|
|
*
|
|
* Definition and user space usage example:
|
|
*
|
|
* typedef int (__kernel_cmpxchg_t)(int oldval, int newval, int *ptr);
|
|
* #define __kernel_cmpxchg (*(__kernel_cmpxchg_t *)0xffff0fc0)
|
|
*
|
|
* Atomically store newval in *ptr if *ptr is equal to oldval for user space.
|
|
* Return zero if *ptr was changed or non-zero if no exchange happened.
|
|
* The C flag is also set if *ptr was changed to allow for assembly
|
|
* optimization in the calling code.
|
|
*
|
|
* Notes:
|
|
*
|
|
* - This routine already includes memory barriers as needed.
|
|
*
|
|
* For example, a user space atomic_add implementation could look like this:
|
|
*
|
|
* #define atomic_add(ptr, val) \
|
|
* ({ register unsigned int *__ptr asm("r2") = (ptr); \
|
|
* register unsigned int __result asm("r1"); \
|
|
* asm volatile ( \
|
|
* "1: @ atomic_add\n\t" \
|
|
* "ldr r0, [r2]\n\t" \
|
|
* "mov r3, #0xffff0fff\n\t" \
|
|
* "add lr, pc, #4\n\t" \
|
|
* "add r1, r0, %2\n\t" \
|
|
* "add pc, r3, #(0xffff0fc0 - 0xffff0fff)\n\t" \
|
|
* "bcc 1b" \
|
|
* : "=&r" (__result) \
|
|
* : "r" (__ptr), "rIL" (val) \
|
|
* : "r0","r3","ip","lr","cc","memory" ); \
|
|
* __result; })
|
|
*/
|
|
|
|
__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_cmpxchg_fixup:
|
|
@ Called from kuser_cmpxchg_check macro.
|
|
@ r2 = address of interrupted insn (must be preserved).
|
|
@ sp = saved regs. r7 and r8 are clobbered.
|
|
@ 1b = first critical insn, 2b = last critical insn.
|
|
@ If r2 >= 1b and r2 <= 2b then saved pc_usr is set to 1b.
|
|
mov r7, #0xffff0fff
|
|
sub r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg)))
|
|
subs r8, r2, r7
|
|
rsbcss r8, r8, #(2b - 1b)
|
|
strcs r7, [sp, #S_PC]
|
|
mov pc, lr
|
|
.previous
|
|
|
|
#else
|
|
#warning "NPTL on non MMU needs fixing"
|
|
mov r0, #-1
|
|
adds r0, r0, #0
|
|
usr_ret lr
|
|
#endif
|
|
|
|
#else
|
|
|
|
smp_dmb
|
|
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 */
|
|
#ifdef CONFIG_SMP
|
|
b __kuser_memory_barrier
|
|
#else
|
|
usr_ret lr
|
|
#endif
|
|
|
|
#endif
|
|
|
|
.align 5
|
|
|
|
/*
|
|
* Reference prototype:
|
|
*
|
|
* int __kernel_get_tls(void)
|
|
*
|
|
* Input:
|
|
*
|
|
* lr = return address
|
|
*
|
|
* Output:
|
|
*
|
|
* r0 = TLS value
|
|
*
|
|
* Clobbered:
|
|
*
|
|
* none
|
|
*
|
|
* Definition and user space usage example:
|
|
*
|
|
* typedef int (__kernel_get_tls_t)(void);
|
|
* #define __kernel_get_tls (*(__kernel_get_tls_t *)0xffff0fe0)
|
|
*
|
|
* Get the TLS value as previously set via the __ARM_NR_set_tls syscall.
|
|
*
|
|
* This could be used as follows:
|
|
*
|
|
* #define __kernel_get_tls() \
|
|
* ({ register unsigned int __val asm("r0"); \
|
|
* asm( "mov r0, #0xffff0fff; mov lr, pc; sub pc, r0, #31" \
|
|
* : "=r" (__val) : : "lr","cc" ); \
|
|
* __val; })
|
|
*/
|
|
|
|
__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
|
|
.rep 4
|
|
.word 0 @ 0xffff0ff0 software TLS value, then
|
|
.endr @ pad up to __kuser_helper_version
|
|
|
|
/*
|
|
* Reference declaration:
|
|
*
|
|
* extern unsigned int __kernel_helper_version;
|
|
*
|
|
* Definition and user space usage example:
|
|
*
|
|
* #define __kernel_helper_version (*(unsigned int *)0xffff0ffc)
|
|
*
|
|
* User space may read this to determine the curent number of helpers
|
|
* available.
|
|
*/
|
|
|
|
__kuser_helper_version: @ 0xffff0ffc
|
|
.word ((__kuser_helper_end - __kuser_helper_start) >> 5)
|
|
|
|
.globl __kuser_helper_end
|
|
__kuser_helper_end:
|
|
|
|
THUMB( .thumb )
|
|
|
|
/*
|
|
* Vector stubs.
|
|
*
|
|
* This code is copied to 0xffff0200 so we can use branches in the
|
|
* vectors, rather than ldr's. Note that this code must not
|
|
* exceed 0x300 bytes.
|
|
*
|
|
* 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
|
|
|
|
.globl __stubs_start
|
|
__stubs_start:
|
|
/*
|
|
* 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
|
|
|
|
/*=============================================================================
|
|
* Undefined FIQs
|
|
*-----------------------------------------------------------------------------
|
|
* Enter in FIQ mode, spsr = ANY CPSR, lr = ANY PC
|
|
* MUST PRESERVE SVC SPSR, but need to switch to SVC mode to show our msg.
|
|
* Basically to switch modes, we *HAVE* to clobber one register... brain
|
|
* damage alert! I don't think that we can execute any code in here in any
|
|
* other mode than FIQ... Ok you can switch to another mode, but you can't
|
|
* get out of that mode without clobbering one register.
|
|
*/
|
|
vector_fiq:
|
|
disable_fiq
|
|
subs pc, lr, #4
|
|
|
|
/*=============================================================================
|
|
* 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
|
|
|
|
/*
|
|
* We group all the following data together to optimise
|
|
* for CPUs with separate I & D caches.
|
|
*/
|
|
.align 5
|
|
|
|
.LCvswi:
|
|
.word vector_swi
|
|
|
|
.globl __stubs_end
|
|
__stubs_end:
|
|
|
|
.equ stubs_offset, __vectors_start + 0x200 - __stubs_start
|
|
|
|
.globl __vectors_start
|
|
__vectors_start:
|
|
ARM( swi SYS_ERROR0 )
|
|
THUMB( svc #0 )
|
|
THUMB( nop )
|
|
W(b) vector_und + stubs_offset
|
|
W(ldr) pc, .LCvswi + stubs_offset
|
|
W(b) vector_pabt + stubs_offset
|
|
W(b) vector_dabt + stubs_offset
|
|
W(b) vector_addrexcptn + stubs_offset
|
|
W(b) vector_irq + stubs_offset
|
|
W(b) vector_fiq + stubs_offset
|
|
|
|
.globl __vectors_end
|
|
__vectors_end:
|
|
|
|
.data
|
|
|
|
.globl cr_alignment
|
|
.globl cr_no_alignment
|
|
cr_alignment:
|
|
.space 4
|
|
cr_no_alignment:
|
|
.space 4
|