52 lines
1.2 KiB
ArmAsm
52 lines
1.2 KiB
ArmAsm
/*
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* Userspace and service handler hooks
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*
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* Copyright (c) 2020 BayLibre, SAS
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/toolchain.h>
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#include <zephyr/linker/sections.h>
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#include <offsets_short.h>
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#include <zephyr/arch/cpu.h>
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#include <zephyr/syscall.h>
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#include <zephyr/kernel_structs.h>
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#include <zephyr/arch/riscv/csr.h>
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#include "asm_macros.inc"
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/* exports */
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GTEXT(arch_user_string_nlen)
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GTEXT(z_riscv_user_string_nlen_fault_start)
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GTEXT(z_riscv_user_string_nlen_fault_end)
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GTEXT(z_riscv_user_string_nlen_fixup)
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/*
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* size_t arch_user_string_nlen(const char *s, size_t maxsize, int *err_arg)
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*/
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SECTION_FUNC(TEXT, arch_user_string_nlen)
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li a5, 0 # Counter
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sw a5, 0(a2) # Init error value to 0
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loop:
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add a4, a0, a5 # Determine character address
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z_riscv_user_string_nlen_fault_start:
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lbu a4, 0(a4) # Load string's character
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z_riscv_user_string_nlen_fault_end:
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beqz a4, exit # Test string's end of line
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bne a5, a1, continue # Check if max length is reached
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exit:
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mv a0, a5 # Return counter value (length)
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ret
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continue:
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addi a5, a5, 1 # Increment counter
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j loop
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z_riscv_user_string_nlen_fixup:
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li a4, -1 # Put error to -1
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sw a4, 0(a2)
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j exit
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