| /optee_os/core/arch/riscv/include/kernel/ |
| H A D | thread_arch.h | 09653bca94ae052074ccc7d6a5b3e44408057828 Mon Oct 23 09:28:17 UTC 2023 Alvin Chang <alvinga@andestech.com> core: riscv: Apply exception return to resume thread
In current implementation, the thread is resumed by function return. It
is not suitable for all scenarios, especially when the thread should be
resumed to user mode. The kernel mode can not return to user mode by
pure function return.
This commit applies exception return to resume the thread. The EPC and
IE are added into thread context. The xstatus_for_xret() helper function
is added to prepare the value of CSR STATUS for exception return.
Currently we only consider PIE(previous interrupt-enable) and
PP(previous privilege mode) for exception return.
We clear thread context when the context is reinitialized, enable native
interrupt, and setup kernel GP/TP. The thread_resume() now takes care of
restoring CSR EPC, STATUS, IE, SCRATCH and all general-purpose
registers. Finally it executes exception return to target privilege mode
encoded in CSR STATUS. The registers GP and TP are also restored since
user mode may use them.
This commit also modify the usage of CSR SCRATCH. In current
implementation the SCRATCH is used to save kernel stack pointer when the
thread is in user mode. The value of TP, which stores thread_core_local
structure, is saved into kernel stack before entering user mode. The
trap handler can then get TP(thread_core_local) from kernel stack. This
is not suitable for SMP system, since the thread might be resumed to
another core, and that core gets wrong TP from kernel stack. Fix it by
directly storing TP into CSR SCRATCH.
Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Marouene Boubakri <marouene.boubakri@nxp.com>
Tested-by: Marouene Boubakri <marouene.boubakri@nxp.com>
|
| H A D | thread_private_arch.h | 09653bca94ae052074ccc7d6a5b3e44408057828 Mon Oct 23 09:28:17 UTC 2023 Alvin Chang <alvinga@andestech.com> core: riscv: Apply exception return to resume thread
In current implementation, the thread is resumed by function return. It
is not suitable for all scenarios, especially when the thread should be
resumed to user mode. The kernel mode can not return to user mode by
pure function return.
This commit applies exception return to resume the thread. The EPC and
IE are added into thread context. The xstatus_for_xret() helper function
is added to prepare the value of CSR STATUS for exception return.
Currently we only consider PIE(previous interrupt-enable) and
PP(previous privilege mode) for exception return.
We clear thread context when the context is reinitialized, enable native
interrupt, and setup kernel GP/TP. The thread_resume() now takes care of
restoring CSR EPC, STATUS, IE, SCRATCH and all general-purpose
registers. Finally it executes exception return to target privilege mode
encoded in CSR STATUS. The registers GP and TP are also restored since
user mode may use them.
This commit also modify the usage of CSR SCRATCH. In current
implementation the SCRATCH is used to save kernel stack pointer when the
thread is in user mode. The value of TP, which stores thread_core_local
structure, is saved into kernel stack before entering user mode. The
trap handler can then get TP(thread_core_local) from kernel stack. This
is not suitable for SMP system, since the thread might be resumed to
another core, and that core gets wrong TP from kernel stack. Fix it by
directly storing TP into CSR SCRATCH.
Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Marouene Boubakri <marouene.boubakri@nxp.com>
Tested-by: Marouene Boubakri <marouene.boubakri@nxp.com>
|
| /optee_os/core/arch/riscv/kernel/ |
| H A D | asm-defines.c | 09653bca94ae052074ccc7d6a5b3e44408057828 Mon Oct 23 09:28:17 UTC 2023 Alvin Chang <alvinga@andestech.com> core: riscv: Apply exception return to resume thread
In current implementation, the thread is resumed by function return. It
is not suitable for all scenarios, especially when the thread should be
resumed to user mode. The kernel mode can not return to user mode by
pure function return.
This commit applies exception return to resume the thread. The EPC and
IE are added into thread context. The xstatus_for_xret() helper function
is added to prepare the value of CSR STATUS for exception return.
Currently we only consider PIE(previous interrupt-enable) and
PP(previous privilege mode) for exception return.
We clear thread context when the context is reinitialized, enable native
interrupt, and setup kernel GP/TP. The thread_resume() now takes care of
restoring CSR EPC, STATUS, IE, SCRATCH and all general-purpose
registers. Finally it executes exception return to target privilege mode
encoded in CSR STATUS. The registers GP and TP are also restored since
user mode may use them.
This commit also modify the usage of CSR SCRATCH. In current
implementation the SCRATCH is used to save kernel stack pointer when the
thread is in user mode. The value of TP, which stores thread_core_local
structure, is saved into kernel stack before entering user mode. The
trap handler can then get TP(thread_core_local) from kernel stack. This
is not suitable for SMP system, since the thread might be resumed to
another core, and that core gets wrong TP from kernel stack. Fix it by
directly storing TP into CSR SCRATCH.
Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Marouene Boubakri <marouene.boubakri@nxp.com>
Tested-by: Marouene Boubakri <marouene.boubakri@nxp.com>
|
| H A D | thread_arch.c | 09653bca94ae052074ccc7d6a5b3e44408057828 Mon Oct 23 09:28:17 UTC 2023 Alvin Chang <alvinga@andestech.com> core: riscv: Apply exception return to resume thread
In current implementation, the thread is resumed by function return. It
is not suitable for all scenarios, especially when the thread should be
resumed to user mode. The kernel mode can not return to user mode by
pure function return.
This commit applies exception return to resume the thread. The EPC and
IE are added into thread context. The xstatus_for_xret() helper function
is added to prepare the value of CSR STATUS for exception return.
Currently we only consider PIE(previous interrupt-enable) and
PP(previous privilege mode) for exception return.
We clear thread context when the context is reinitialized, enable native
interrupt, and setup kernel GP/TP. The thread_resume() now takes care of
restoring CSR EPC, STATUS, IE, SCRATCH and all general-purpose
registers. Finally it executes exception return to target privilege mode
encoded in CSR STATUS. The registers GP and TP are also restored since
user mode may use them.
This commit also modify the usage of CSR SCRATCH. In current
implementation the SCRATCH is used to save kernel stack pointer when the
thread is in user mode. The value of TP, which stores thread_core_local
structure, is saved into kernel stack before entering user mode. The
trap handler can then get TP(thread_core_local) from kernel stack. This
is not suitable for SMP system, since the thread might be resumed to
another core, and that core gets wrong TP from kernel stack. Fix it by
directly storing TP into CSR SCRATCH.
Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Marouene Boubakri <marouene.boubakri@nxp.com>
Tested-by: Marouene Boubakri <marouene.boubakri@nxp.com>
|
| H A D | thread_rv.S | 09653bca94ae052074ccc7d6a5b3e44408057828 Mon Oct 23 09:28:17 UTC 2023 Alvin Chang <alvinga@andestech.com> core: riscv: Apply exception return to resume thread
In current implementation, the thread is resumed by function return. It
is not suitable for all scenarios, especially when the thread should be
resumed to user mode. The kernel mode can not return to user mode by
pure function return.
This commit applies exception return to resume the thread. The EPC and
IE are added into thread context. The xstatus_for_xret() helper function
is added to prepare the value of CSR STATUS for exception return.
Currently we only consider PIE(previous interrupt-enable) and
PP(previous privilege mode) for exception return.
We clear thread context when the context is reinitialized, enable native
interrupt, and setup kernel GP/TP. The thread_resume() now takes care of
restoring CSR EPC, STATUS, IE, SCRATCH and all general-purpose
registers. Finally it executes exception return to target privilege mode
encoded in CSR STATUS. The registers GP and TP are also restored since
user mode may use them.
This commit also modify the usage of CSR SCRATCH. In current
implementation the SCRATCH is used to save kernel stack pointer when the
thread is in user mode. The value of TP, which stores thread_core_local
structure, is saved into kernel stack before entering user mode. The
trap handler can then get TP(thread_core_local) from kernel stack. This
is not suitable for SMP system, since the thread might be resumed to
another core, and that core gets wrong TP from kernel stack. Fix it by
directly storing TP into CSR SCRATCH.
Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Marouene Boubakri <marouene.boubakri@nxp.com>
Tested-by: Marouene Boubakri <marouene.boubakri@nxp.com>
|
| /optee_os/core/arch/riscv/include/ |
| H A D | riscv.h | 09653bca94ae052074ccc7d6a5b3e44408057828 Mon Oct 23 09:28:17 UTC 2023 Alvin Chang <alvinga@andestech.com> core: riscv: Apply exception return to resume thread
In current implementation, the thread is resumed by function return. It
is not suitable for all scenarios, especially when the thread should be
resumed to user mode. The kernel mode can not return to user mode by
pure function return.
This commit applies exception return to resume the thread. The EPC and
IE are added into thread context. The xstatus_for_xret() helper function
is added to prepare the value of CSR STATUS for exception return.
Currently we only consider PIE(previous interrupt-enable) and
PP(previous privilege mode) for exception return.
We clear thread context when the context is reinitialized, enable native
interrupt, and setup kernel GP/TP. The thread_resume() now takes care of
restoring CSR EPC, STATUS, IE, SCRATCH and all general-purpose
registers. Finally it executes exception return to target privilege mode
encoded in CSR STATUS. The registers GP and TP are also restored since
user mode may use them.
This commit also modify the usage of CSR SCRATCH. In current
implementation the SCRATCH is used to save kernel stack pointer when the
thread is in user mode. The value of TP, which stores thread_core_local
structure, is saved into kernel stack before entering user mode. The
trap handler can then get TP(thread_core_local) from kernel stack. This
is not suitable for SMP system, since the thread might be resumed to
another core, and that core gets wrong TP from kernel stack. Fix it by
directly storing TP into CSR SCRATCH.
Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Marouene Boubakri <marouene.boubakri@nxp.com>
Tested-by: Marouene Boubakri <marouene.boubakri@nxp.com>
|