mirror of
https://github.com/zephyrproject-rtos/zephyr
synced 2025-09-14 10:51:57 +00:00
7ef2506611
Enable us bit to check user mode more efficienly. US is read as zero in user mode. This will allow use mode sleep instructions, and it enables a form of denial-of-service attack by putting the processor in sleep mode, but since interrupt level/mask can't be set from user space that's not worse than executing a loop without yielding. Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
106 lines
2.0 KiB
ArmAsm
106 lines
2.0 KiB
ArmAsm
/*
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* Copyright (c) 2014 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Reset handler
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*
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* Reset handler that prepares the system for running C code.
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*/
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#include <toolchain.h>
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#include <linker/sections.h>
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#include <arch/cpu.h>
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GDATA(_interrupt_stack)
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GDATA(_main_stack)
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/* use one of the available interrupt stacks during init */
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#define INIT_STACK _interrupt_stack
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#define INIT_STACK_SIZE CONFIG_ISR_STACK_SIZE
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GTEXT(__reset)
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GTEXT(__start)
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/**
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*
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* @brief Reset vector
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*
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* Ran when the system comes out of reset. The processor is at supervisor level.
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*
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* Locking interrupts prevents anything from interrupting the CPU.
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*
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* When these steps are completed, jump to _PrepC(), which will finish setting
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* up the system for running C code.
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*
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* @return N/A
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*/
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SECTION_FUNC(TEXT,__reset)
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SECTION_FUNC(TEXT,__start)
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/* lock interrupts: will get unlocked when switch to main task */
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clri
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#if CONFIG_USERSPACE
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lr r0, [_ARC_V2_STATUS32]
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bset r0, r0, _ARC_V2_STATUS32_US_BIT
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kflag r0
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#endif
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mov r1, 1
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invalidate_and_disable_icache:
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lr r0, [_ARC_V2_I_CACHE_BUILD]
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and.f r0, r0, 0xff
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bz.nd invalidate_dcache
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mov_s r2, 0
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sr r2, [_ARC_V2_IC_IVIC]
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/* writing to IC_IVIC needs 3 NOPs */
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nop
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nop
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nop
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sr r1, [_ARC_V2_IC_CTRL]
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invalidate_dcache:
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lr r3, [_ARC_V2_D_CACHE_BUILD]
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and.f r3, r3, 0xff
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bz.nd done_cache_invalidate
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sr r1, [_ARC_V2_DC_IVDC]
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done_cache_invalidate:
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#if defined(CONFIG_SYS_POWER_DEEP_SLEEP) && \
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!defined(CONFIG_BOOTLOADER_CONTEXT_RESTORE)
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jl @_sys_soc_resume_from_deep_sleep
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#endif
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#ifdef CONFIG_INIT_STACKS
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/*
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* use the main stack to call memset on the interrupt stack and the
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* FIRQ stack when CONFIG_INIT_STACKS is enabled before switching to
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* one of them for the rest of the early boot
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*/
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mov sp, _main_stack
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add sp, sp, CONFIG_MAIN_STACK_SIZE
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mov_s r0, _interrupt_stack
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mov_s r1, 0xaa
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mov_s r2, CONFIG_ISR_STACK_SIZE
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jl memset
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#endif /* CONFIG_INIT_STACKS */
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mov sp, INIT_STACK
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add sp, sp, INIT_STACK_SIZE
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j @_PrepC
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