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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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27
arch/riscv/core/thread.c
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@ -9,7 +9,7 @@
#include <ksched.h>
#include <arch/riscv/csr.h>
#include <stdio.h>
#include <core_pmp.h>
#include <pmp.h>
#if defined(CONFIG_USERSPACE) && !defined(CONFIG_SMP)
/*
@ -81,13 +81,9 @@ void arch_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
stack_init->mstatus |= MSTATUS_FS_INIT;
#endif
#if defined(CONFIG_PMP_STACK_GUARD) || defined(CONFIG_USERSPACE)
/* Clear PMP context if RISC-V PMP is used. */
z_riscv_pmp_init_thread(thread);
#endif /* CONFIG_PMP_STACK_GUARD || CONFIG_USERSPACE */
#if defined(CONFIG_USERSPACE)
/* Clear user thread context */
z_riscv_pmp_usermode_init(thread);
thread->arch.priv_stack_start = 0;
/* the unwound stack pointer upon exiting exception */
@ -119,7 +115,7 @@ void arch_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
#if defined(CONFIG_PMP_STACK_GUARD)
/* Setup PMP regions of PMP stack guard of thread. */
z_riscv_init_stack_guard(thread);
z_riscv_pmp_stackguard_prepare(thread);
#endif /* CONFIG_PMP_STACK_GUARD */
#ifdef CONFIG_RISCV_SOC_CONTEXT_SAVE
@ -245,16 +241,17 @@ FUNC_NORETURN void arch_user_mode_enter(k_thread_entry_t user_entry,
csr_write(mstatus, status);
csr_write(mepc, z_thread_entry);
/* exception stack has to be in mscratch */
csr_write(mscratch, top_of_priv_stack);
/* Set up Physical Memory Protection */
#if defined(CONFIG_PMP_STACK_GUARD)
z_riscv_init_stack_guard(_current);
#ifdef CONFIG_PMP_STACK_GUARD
/* reconfigure as the kernel mode stack will be different */
z_riscv_pmp_stackguard_prepare(_current);
#endif
z_riscv_init_user_accesses(_current);
z_riscv_configure_user_allowed_stack(_current);
/* Set up Physical Memory Protection */
z_riscv_pmp_usermode_prepare(_current);
z_riscv_pmp_usermode_enable(_current);
/* exception stack has to be in mscratch */
csr_write(mscratch, top_of_priv_stack);
#if !defined(CONFIG_SMP)
is_user_mode = true;