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riscv: pmp: switch over to the new implementation

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Add the appropriate hooks effectively replacing the old implementation
with the new one.

Also the stackguard wasn't properly enforced especially with the
usermode combination. This is now fixed.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2022-04-06 22:03:54 -04:00 • committed by Carles Cufí
commit 2fece49a14
9 changed files with 118 additions and 50 deletions
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20
arch/riscv/core/switch.S
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@ -75,19 +75,25 @@ skip_store_fp_callee_saved:
/* Get the new thread's stack pointer */
lr sp, _thread_offset_to_sp(a0)
#ifdef CONFIG_PMP_STACK_GUARD
/* Preserve a0 across following call. s0 is not yet restored. */
#if defined(CONFIG_PMP_STACK_GUARD)
/*
* Stack guard has priority over user space for PMP usage.
* Preserve a0 across following call. s0 is not yet restored.
*/
mv s0, a0
call z_riscv_configure_stack_guard
call z_riscv_pmp_stackguard_enable
mv a0, s0
#endif
#ifdef CONFIG_USERSPACE
#elif defined(CONFIG_USERSPACE)
/*
* When stackguard is not enabled, we need to configure the PMP only
* at context switch time as the PMP is not in effect while inm-mode.
* (it is done on every exception return otherwise).
*/
lb t0, _thread_offset_to_user_options(a0)
andi t0, t0, K_USER
beqz t0, not_user_task
mv s0, a0
call z_riscv_configure_user_allowed_stack
call z_riscv_pmp_usermode_enable
mv a0, s0
not_user_task:
#endif