b1c4ba4ab6
Due to the ABI we are using we have to use the earm architecture moniker for the build system to behave correctly. This involves then some headers to move around. There is also a few related Makefile updates as well as minor source code corrections.
295 lines
6.9 KiB
ArmAsm
295 lines
6.9 KiB
ArmAsm
/* This file is part of the lowest layer of the MINIX kernel. (The other part
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* is "proc.c".) The lowest layer does process switching and message handling.
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*
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* Kernel is entered either because of kernel-calls, ipc-calls, interrupts or
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* exceptions. TSS is set so that the kernel stack is loaded. The user context is
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* saved to the proc table and the handler of the event is called. Once the
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* handler is done, switch_to_user() function is called to pick a new process,
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* finish what needs to be done for the next process to run, sets its context
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* and switch to userspace.
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*/
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#include "kernel/kernel.h" /* configures the kernel */
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/* sections */
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#include <machine/vm.h>
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#include "kernel/kernel.h"
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#include <minix/config.h>
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#include <minix/const.h>
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#include <minix/com.h>
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#include <machine/asm.h>
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#include <machine/interrupt.h>
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#include "archconst.h"
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#include "kernel/const.h"
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#include "kernel/proc.h"
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#include "sconst.h"
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#include <machine/multiboot.h>
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#include <machine/ipcconst.h>
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#include <machine/cpu.h>
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#include "omap_intr.h"
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#include "arch_proto.h" /* K_STACK_SIZE */
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IMPORT(svc_stack)
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/*
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* Adjust lr, switch to SVC mode, and push pc/psr when exception triggered
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* The 'lr_offset' argument holds the adjustment. It differs based on
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* which mode the CPU is in.
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*/
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.macro switch_to_svc lr_offset
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sub lr, lr, #\lr_offset
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srsdb #MODE_SVC!
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cps #MODE_SVC
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.endm
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/*
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* Test if the exception/interrupt occured in the kernel.
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* Jump to 'label' argument if it occurred in the kernel.
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*
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* NOTE: switch_to_svc must be called first
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*/
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.macro test_int_in_kernel, label
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push {r3}
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ldr r3, [sp, #8] /* spsr */
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and r3, r3, #PSR_MODE_MASK
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cmp r3, #MODE_USR
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pop {r3}
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bne \label /* In-kernel handling */
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.endm
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/* Save the register context to the proc structure */
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.macro save_process_ctx
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push {lr}
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ldr lr, [sp, #12] /* proc ptr */
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stm lr, {r0-r14}^
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ldr r12, [sp, #8]
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str r12, [lr, #PSREG]
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ldr r12, [sp, #4]
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str r12, [lr, #PCREG]
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pop {lr}
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add sp, sp, #8
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.endm
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.macro exception_handler exc_name, exc_num, lr_offset
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ENTRY(\exc_name\()_entry)
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switch_to_svc \lr_offset
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test_int_in_kernel \exc_name\()_entry_nested
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\exc_name\()entry_from_user:
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save_process_ctx
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/* save the pointer to the current process */
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ldr fp, [sp]
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/* save the exception pc (saved lr_user) */
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ldr r4, [fp, #PCREG]
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/* stop user process cycles */
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mov r0, fp /* first param: caller proc ptr */
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mov fp, #0 /* for stack trace */
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bl _C_LABEL(context_stop)
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/*
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* push a pointer to the interrupt state pushed by the cpu and the
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* vector number pushed by the vector handler just before calling
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* exception_entry and call the exception handler.
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*/
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mov r0, #0 /* it's not a nested exception */
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mov r1, r4 /* saved lr */
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mov r2, #\exc_num /* vector number */
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bl _C_LABEL(exception_handler)
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b _C_LABEL(switch_to_user)
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\exc_name\()_entry_nested:
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push {r0-r12, lr}
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mov r0, #1 /* it's a nested exception */
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add r1, sp, #56 /* saved lr */
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mov r2, #\exc_num /* vector number */
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bl _C_LABEL(exception_handler)
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pop {r0-r12, lr}
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rfeia sp!
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.endm
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/* Exception handlers */
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exception_handler data_abort DATA_ABORT_VECTOR 8
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exception_handler prefetch_abort PREFETCH_ABORT_VECTOR 4
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exception_handler undefined_inst UNDEFINED_INST_VECTOR 4
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ENTRY(irq_entry)
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switch_to_svc 4
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test_int_in_kernel irq_entry_from_kernel
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irq_entry_from_user:
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save_process_ctx
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/* save the pointer to the current process */
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ldr fp, [sp]
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push {fp} /* save caller proc ptr */
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/* stop user process cycles */
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mov r0, fp /* first param: caller proc ptr */
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mov fp, #0 /* for stack trace */
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bl _C_LABEL(context_stop)
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/* get irq num */
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ldr r3, =OMAP3_INTR_SIR_IRQ
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ldr r0, [r3]
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and r0, r0, #OMAP3_INTR_ACTIVEIRQ_MASK /* irq */
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/* call handler */
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bl _C_LABEL(irq_handle) /* irq_handle(irq) */
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pop {fp} /* caller proc ptr */
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/* allow new interrupts */
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mov r1, #OMAP3_INTR_NEWIRQAGR
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ldr r3, =OMAP3_INTR_CONTROL
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str r1, [r3]
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/* data synchronization barrier */
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dsb
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b _C_LABEL(switch_to_user)
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irq_entry_from_kernel:
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push {r0-r12, lr}
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bl _C_LABEL(context_stop_idle)
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/* get irq num */
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ldr r3, =OMAP3_INTR_SIR_IRQ
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ldr r0, [r3]
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and r0, r0, #OMAP3_INTR_ACTIVEIRQ_MASK /* irq */
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/* call handler */
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bl _C_LABEL(irq_handle) /* irq_handle(irq) */
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/* allow new interrupts */
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mov r1, #OMAP3_INTR_NEWIRQAGR
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ldr r3, =OMAP3_INTR_CONTROL
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str r1, [r3]
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/* data synchronization barrier */
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dsb
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pop {r0-r12, lr}
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rfeia sp!
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/*
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* supervisor call (SVC) kernel entry point
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*/
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ENTRY(svc_entry)
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srsdb #MODE_SVC!
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save_process_ctx
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/* save the pointer to the current process */
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ldr fp, [sp]
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cmp r3, #KERVEC
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beq kernel_call_entry
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cmp r3, #IPCVEC
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beq ipc_entry
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b invalid_svc
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/*
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* kernel call is only from a process to kernel
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*/
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ENTRY(kernel_call_entry)
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/*
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* pass the syscall arguments from userspace to the handler.
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* save_process_ctx() does not clobber these registers, they are still
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* set as the userspace has set them
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*/
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push {fp} /* save caller proc ptr */
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push {r0} /* save msg ptr so it's not clobbered */
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/* stop user process cycles */
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mov r0, fp /* first param: caller proc ptr */
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mov fp, #0 /* for stack trace */
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bl _C_LABEL(context_stop)
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pop {r0} /* first param: msg ptr */
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pop {r1} /* second param: caller proc ptr */
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bl _C_LABEL(kernel_call)
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b _C_LABEL(switch_to_user)
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/*
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* IPC is only from a process to kernel
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*/
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ENTRY(ipc_entry)
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/*
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* pass the syscall arguments from userspace to the handler.
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* save_process_ctx() does not clobber these registers, they are still
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* set as the userspace have set them
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*/
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push {fp} /* save caller proc ptr */
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push {r0-r2} /* save regs so they're not clobbered */
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/* stop user process cycles */
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mov r0, fp /* first param: caller proc ptr */
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mov fp, #0 /* for stack trace */
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bl _C_LABEL(context_stop)
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pop {r0-r2} /* restore regs */
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bl _C_LABEL(do_ipc)
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/* restore the current process pointer and save the return value */
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pop {fp} /* caller proc ptr */
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str r0, [fp, #REG0]
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b _C_LABEL(switch_to_user)
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ENTRY(invalid_svc)
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b .
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ENTRY(restore_user_context)
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/* sp holds the proc ptr */
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mov sp, r0
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/* Set SPSR and LR for return */
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ldr r0, [sp, #PSREG]
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msr spsr_fsxc, r0
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ldr lr, [sp, #PCREG]
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/* Restore user-mode registers from proc struct */
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ldm sp, {r0-r14}^
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ldr sp, =_C_LABEL(svc_stack)
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ldr sp, [sp]
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/* To user mode! */
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movs pc, lr
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/*===========================================================================*/
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/* data */
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/*===========================================================================*/
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.data
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.short 0x526F /* this must be the first data entry (magic #) */
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.bss
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.data
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.balign 4
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k_initial_stack:
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.space K_STACK_SIZE
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LABEL(__k_unpaged_k_initial_stktop)
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/*
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* the kernel stack
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*/
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k_boot_stack:
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.space K_STACK_SIZE /* kernel stack */ /* FIXME use macro here */
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LABEL(k_boot_stktop) /* top of kernel stack */
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.balign K_STACK_SIZE
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LABEL(k_stacks_start)
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/* two pages for each stack, one for data, other as a sandbox */
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.space 2 * (K_STACK_SIZE * CONFIG_MAX_CPUS)
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LABEL(k_stacks_end)
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/* top of kernel stack */
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