zephyr/arch/riscv/core/swap.S

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arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
/*
* Copyright (c) 2016 Jean-Paul Etienne <fractalclone@gmail.com>
*
* SPDX-License-Identifier: Apache-2.0
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
*/
headers: Refactor kernel and arch headers. This commit refactors kernel and arch headers to establish a boundary between private and public interface headers. The refactoring strategy used in this commit is detailed in the issue This commit introduces the following major changes: 1. Establish a clear boundary between private and public headers by removing "kernel/include" and "arch/*/include" from the global include paths. Ideally, only kernel/ and arch/*/ source files should reference the headers in these directories. If these headers must be used by a component, these include paths shall be manually added to the CMakeLists.txt file of the component. This is intended to discourage applications from including private kernel and arch headers either knowingly and unknowingly. - kernel/include/ (PRIVATE) This directory contains the private headers that provide private kernel definitions which should not be visible outside the kernel and arch source code. All public kernel definitions must be added to an appropriate header located under include/. - arch/*/include/ (PRIVATE) This directory contains the private headers that provide private architecture-specific definitions which should not be visible outside the arch and kernel source code. All public architecture- specific definitions must be added to an appropriate header located under include/arch/*/. - include/ AND include/sys/ (PUBLIC) This directory contains the public headers that provide public kernel definitions which can be referenced by both kernel and application code. - include/arch/*/ (PUBLIC) This directory contains the public headers that provide public architecture-specific definitions which can be referenced by both kernel and application code. 2. Split arch_interface.h into "kernel-to-arch interface" and "public arch interface" divisions. - kernel/include/kernel_arch_interface.h * provides private "kernel-to-arch interface" definition. * includes arch/*/include/kernel_arch_func.h to ensure that the interface function implementations are always available. * includes sys/arch_interface.h so that public arch interface definitions are automatically included when including this file. - arch/*/include/kernel_arch_func.h * provides architecture-specific "kernel-to-arch interface" implementation. * only the functions that will be used in kernel and arch source files are defined here. - include/sys/arch_interface.h * provides "public arch interface" definition. * includes include/arch/arch_inlines.h to ensure that the architecture-specific public inline interface function implementations are always available. - include/arch/arch_inlines.h * includes architecture-specific arch_inlines.h in include/arch/*/arch_inline.h. - include/arch/*/arch_inline.h * provides architecture-specific "public arch interface" inline function implementation. * supersedes include/sys/arch_inline.h. 3. Refactor kernel and the existing architecture implementations. - Remove circular dependency of kernel and arch headers. The following general rules should be observed: * Never include any private headers from public headers * Never include kernel_internal.h in kernel_arch_data.h * Always include kernel_arch_data.h from kernel_arch_func.h * Never include kernel.h from kernel_struct.h either directly or indirectly. Only add the kernel structures that must be referenced from public arch headers in this file. - Relocate syscall_handler.h to include/ so it can be used in the public code. This is necessary because many user-mode public codes reference the functions defined in this header. - Relocate kernel_arch_thread.h to include/arch/*/thread.h. This is necessary to provide architecture-specific thread definition for 'struct k_thread' in kernel.h. - Remove any private header dependencies from public headers using the following methods: * If dependency is not required, simply omit * If dependency is required, - Relocate a portion of the required dependencies from the private header to an appropriate public header OR - Relocate the required private header to make it public. This commit supersedes #20047, addresses #19666, and fixes #3056. Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2019-10-24 23:08:21 +08:00
#include <toolchain.h>
#include <linker/sections.h>
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
#include <offsets_short.h>
headers: Refactor kernel and arch headers. This commit refactors kernel and arch headers to establish a boundary between private and public interface headers. The refactoring strategy used in this commit is detailed in the issue This commit introduces the following major changes: 1. Establish a clear boundary between private and public headers by removing "kernel/include" and "arch/*/include" from the global include paths. Ideally, only kernel/ and arch/*/ source files should reference the headers in these directories. If these headers must be used by a component, these include paths shall be manually added to the CMakeLists.txt file of the component. This is intended to discourage applications from including private kernel and arch headers either knowingly and unknowingly. - kernel/include/ (PRIVATE) This directory contains the private headers that provide private kernel definitions which should not be visible outside the kernel and arch source code. All public kernel definitions must be added to an appropriate header located under include/. - arch/*/include/ (PRIVATE) This directory contains the private headers that provide private architecture-specific definitions which should not be visible outside the arch and kernel source code. All public architecture- specific definitions must be added to an appropriate header located under include/arch/*/. - include/ AND include/sys/ (PUBLIC) This directory contains the public headers that provide public kernel definitions which can be referenced by both kernel and application code. - include/arch/*/ (PUBLIC) This directory contains the public headers that provide public architecture-specific definitions which can be referenced by both kernel and application code. 2. Split arch_interface.h into "kernel-to-arch interface" and "public arch interface" divisions. - kernel/include/kernel_arch_interface.h * provides private "kernel-to-arch interface" definition. * includes arch/*/include/kernel_arch_func.h to ensure that the interface function implementations are always available. * includes sys/arch_interface.h so that public arch interface definitions are automatically included when including this file. - arch/*/include/kernel_arch_func.h * provides architecture-specific "kernel-to-arch interface" implementation. * only the functions that will be used in kernel and arch source files are defined here. - include/sys/arch_interface.h * provides "public arch interface" definition. * includes include/arch/arch_inlines.h to ensure that the architecture-specific public inline interface function implementations are always available. - include/arch/arch_inlines.h * includes architecture-specific arch_inlines.h in include/arch/*/arch_inline.h. - include/arch/*/arch_inline.h * provides architecture-specific "public arch interface" inline function implementation. * supersedes include/sys/arch_inline.h. 3. Refactor kernel and the existing architecture implementations. - Remove circular dependency of kernel and arch headers. The following general rules should be observed: * Never include any private headers from public headers * Never include kernel_internal.h in kernel_arch_data.h * Always include kernel_arch_data.h from kernel_arch_func.h * Never include kernel.h from kernel_struct.h either directly or indirectly. Only add the kernel structures that must be referenced from public arch headers in this file. - Relocate syscall_handler.h to include/ so it can be used in the public code. This is necessary because many user-mode public codes reference the functions defined in this header. - Relocate kernel_arch_thread.h to include/arch/*/thread.h. This is necessary to provide architecture-specific thread definition for 'struct k_thread' in kernel.h. - Remove any private header dependencies from public headers using the following methods: * If dependency is not required, simply omit * If dependency is required, - Relocate a portion of the required dependencies from the private header to an appropriate public header OR - Relocate the required private header to make it public. This commit supersedes #20047, addresses #19666, and fixes #3056. Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2019-10-24 23:08:21 +08:00
#include <arch/cpu.h>
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
/* exports */
GTEXT(z_arch_swap)
GTEXT(z_thread_entry_wrapper)
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
/* Use ABI name of registers for the sake of simplicity */
/*
* unsigned int z_arch_swap(unsigned int key)
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
*
* Always called with interrupts locked
* key is stored in a0 register
*/
SECTION_FUNC(exception.other, z_arch_swap)
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
/* Make a system call to perform context switch */
#ifdef CONFIG_EXECUTION_BENCHMARKING
addi sp, sp, -__z_arch_esf_t_SIZEOF
RV_OP_STOREREG ra, __z_arch_esf_t_ra_OFFSET(sp)
RV_OP_STOREREG gp, __z_arch_esf_t_gp_OFFSET(sp)
RV_OP_STOREREG tp, __z_arch_esf_t_tp_OFFSET(sp)
RV_OP_STOREREG t0, __z_arch_esf_t_t0_OFFSET(sp)
RV_OP_STOREREG t1, __z_arch_esf_t_t1_OFFSET(sp)
RV_OP_STOREREG t2, __z_arch_esf_t_t2_OFFSET(sp)
RV_OP_STOREREG t3, __z_arch_esf_t_t3_OFFSET(sp)
RV_OP_STOREREG t4, __z_arch_esf_t_t4_OFFSET(sp)
RV_OP_STOREREG t5, __z_arch_esf_t_t5_OFFSET(sp)
RV_OP_STOREREG t6, __z_arch_esf_t_t6_OFFSET(sp)
RV_OP_STOREREG a0, __z_arch_esf_t_a0_OFFSET(sp)
RV_OP_STOREREG a1, __z_arch_esf_t_a1_OFFSET(sp)
RV_OP_STOREREG a2, __z_arch_esf_t_a2_OFFSET(sp)
RV_OP_STOREREG a3, __z_arch_esf_t_a3_OFFSET(sp)
RV_OP_STOREREG a4, __z_arch_esf_t_a4_OFFSET(sp)
RV_OP_STOREREG a5, __z_arch_esf_t_a5_OFFSET(sp)
RV_OP_STOREREG a6, __z_arch_esf_t_a6_OFFSET(sp)
RV_OP_STOREREG a7, __z_arch_esf_t_a7_OFFSET(sp)
call read_timer_start_of_swap
RV_OP_LOADREG ra, __z_arch_esf_t_ra_OFFSET(sp)
RV_OP_LOADREG gp, __z_arch_esf_t_gp_OFFSET(sp)
RV_OP_LOADREG tp, __z_arch_esf_t_tp_OFFSET(sp)
RV_OP_LOADREG t0, __z_arch_esf_t_t0_OFFSET(sp)
RV_OP_LOADREG t1, __z_arch_esf_t_t1_OFFSET(sp)
RV_OP_LOADREG t2, __z_arch_esf_t_t2_OFFSET(sp)
RV_OP_LOADREG t3, __z_arch_esf_t_t3_OFFSET(sp)
RV_OP_LOADREG t4, __z_arch_esf_t_t4_OFFSET(sp)
RV_OP_LOADREG t5, __z_arch_esf_t_t5_OFFSET(sp)
RV_OP_LOADREG t6, __z_arch_esf_t_t6_OFFSET(sp)
RV_OP_LOADREG a0, __z_arch_esf_t_a0_OFFSET(sp)
RV_OP_LOADREG a1, __z_arch_esf_t_a1_OFFSET(sp)
RV_OP_LOADREG a2, __z_arch_esf_t_a2_OFFSET(sp)
RV_OP_LOADREG a3, __z_arch_esf_t_a3_OFFSET(sp)
RV_OP_LOADREG a4, __z_arch_esf_t_a4_OFFSET(sp)
RV_OP_LOADREG a5, __z_arch_esf_t_a5_OFFSET(sp)
RV_OP_LOADREG a6, __z_arch_esf_t_a6_OFFSET(sp)
RV_OP_LOADREG a7, __z_arch_esf_t_a7_OFFSET(sp)
/* Release stack space */
addi sp, sp, __z_arch_esf_t_SIZEOF
#endif
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
ecall
/*
* when thread is rescheduled, unlock irq and return.
* Restored register a0 contains IRQ lock state of thread.
*
* Prior to unlocking irq, load return value of
* z_arch_swap to temp register t2 (from
* _thread_offset_to_swap_return_value). Normally, it should be -EAGAIN,
* unless someone has previously called z_arch_thread_return_value_set(..).
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
*/
la t0, _kernel
/* Get pointer to _kernel.current */
RV_OP_LOADREG t1, _kernel_offset_to_current(t0)
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
/* Load return value of z_arch_swap function in temp register t2 */
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
lw t2, _thread_offset_to_swap_return_value(t1)
/*
* Unlock irq, following IRQ lock state in a0 register.
* Use atomic instruction csrrs to do so.
*/
andi a0, a0, SOC_MSTATUS_IEN
csrrs t0, mstatus, a0
/* Set value of return register a0 to value of register t2 */
addi a0, t2, 0
/* Return */
jalr x0, ra
/*
* void z_thread_entry_wrapper(k_thread_entry_t, void *, void *, void *)
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
*/
SECTION_FUNC(TEXT, z_thread_entry_wrapper)
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
/*
* z_thread_entry_wrapper is called for every new thread upon the return
* of z_arch_swap or ISR. Its address, as well as its input function
* arguments thread_entry_t, void *, void *, void * are restored from
* the thread stack (initialized via function _thread).
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
* In this case, thread_entry_t, * void *, void * and void * are stored
* in registers a0, a1, a2 and a3. These registers are used as arguments
* to function z_thread_entry. Hence, just call z_thread_entry with
arch: added support for the riscv32 architecture RISC-V is an open-source instruction set architecture. Added support for the 32bit version of RISC-V to Zephyr. 1) exceptions/interrupts/faults are handled at the architecture level via the __irq_wrapper handler. Context saving/restoring of registers can be handled at both architecture and SOC levels. If SOC-specific registers need to be saved, SOC level needs to provide __soc_save_context and __soc_restore_context functions that shall be accounted by the architecture level, when corresponding config variable RISCV_SOC_CONTEXT_SAVE is set. 2) As RISC-V architecture does not provide a clear ISA specification about interrupt handling, each RISC-V SOC handles it in its own way. Hence, at the architecture level, the __irq_wrapper handler expects the following functions to be provided by the SOC level: __soc_is_irq: to check if the exception is the result of an interrupt or not. __soc_handle_irq: handle pending IRQ at SOC level (ex: clear pending IRQ in SOC-specific IRQ register) 3) Thread/task scheduling, as well as IRQ offloading are handled via the RISC-V system call ("ecall"), which is also handled via the __irq_wrapper handler. The _Swap asm function just calls "ecall" to generate an exception. 4) As there is no conventional way of handling CPU power save in RISC-V, the default nano_cpu_idle and nano_cpu_atomic_idle functions just unlock interrupts and return to the caller, without issuing any CPU power saving instruction. Nonetheless, to allow SOC-level to implement proper CPU power save, nano_cpu_idle and nano_cpu_atomic_idle functions are defined as __weak at the architecture level. Change-Id: I980a161d0009f3f404ad22b226a6229fbb492389 Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-01-11 07:24:30 +08:00
* return address set to 0 to indicate a non-returning function call.
*/
jal x0, z_thread_entry