mirror of
https://github.com/zephyrproject-rtos/zephyr
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542a7fa25d
The IRQ handler has had a major changes to manage syscall, reschedule and interrupt from user thread and stack guard. Add userspace support: - Use a global variable to know if the current execution is user or machine. The location of this variable is read only for all user thread and read/write for kernel thread. - Memory shared is supported. - Use dynamic allocation to optimize PMP slot usage. If the area size is a power of 2, only one PMP slot is used, else 2 are used. Add stack guard support: - Use MPRV bit to force PMP rules to machine mode execution. - IRQ stack have a locked stack guard to avoid re-write PMP configuration registers for each interruption and then win some cycle. - The IRQ stack is used as "temporary" stack at the beginning of IRQ handler to save current ESF. That avoid to trigger write fault on thread stack during store ESF which that call IRQ handler to infinity. - A stack guard is also setup for privileged stack of a user thread. Thread: - A PMP setup is specific to each thread. PMP setup are saved in each thread structure to improve reschedule performance. Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com> Reviewed-by: Nicolas Royer <nroyer@baylibre.com>
63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
/*
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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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/**
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* @file
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* @brief RISCV public error handling
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*
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* RISCV-specific kernel error handling interface. Included by riscv/arch.h.
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*/
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#ifndef ZEPHYR_INCLUDE_ARCH_RISCV_ERROR_H_
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#define ZEPHYR_INCLUDE_ARCH_RISCV_ERROR_H_
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#include <arch/riscv/syscall.h>
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#include <arch/riscv/exp.h>
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifdef CONFIG_USERSPACE
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/*
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* Kernel features like canary (software stack guard) are built
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* with an argument to bypass the test before syscall (test if CPU
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* is running in user or kernel) and directly execute the function.
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* Then if this kind of code wishes to trigger a CPU exception,
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* the implemented syscall is useless because the function is directly
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* called even if the CPU is running in user (which happens during
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* sanity check). To fix that, I bypass the generated test code by writing
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* the test myself to remove the bypass ability.
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*/
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#define ARCH_EXCEPT(reason_p) do { \
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if (_is_user_context()) { \
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arch_syscall_invoke1(reason_p, \
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K_SYSCALL_USER_FAULT); \
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} else { \
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compiler_barrier(); \
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z_impl_user_fault(reason_p); \
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} \
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CODE_UNREACHABLE; \
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} while (false)
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#else
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#define ARCH_EXCEPT(reason_p) do { \
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z_impl_user_fault(reason_p); \
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} while (false)
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#endif
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__syscall void user_fault(unsigned int reason);
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#include <syscalls/error.h>
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#ifdef __cplusplus
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}
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#endif
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#endif /* ZEPHYR_INCLUDE_ARCH_RISCV_ERROR_H_ */
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