arm64: demand_paging: allow page fault processing with IRQs enabled

Convention is to call k_mem_page_fault() with IRQs enabled if they were
enabled when the fault occurred.

(cherry picked from commit 79428bc)

Original-Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
GitOrigin-RevId: 79428bc
Cr-Build-Id: 8736917283475341809
Cr-Build-Url: https://cr-buildbucket.appspot.com/build/8736917283475341809
Copybot-Job-Name: zephyr-main-copybot-downstream
Change-Id: I543efa2a52419279745c9ddc87a7f1a7753c33b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5856311
Commit-Queue: Keith Short <keithshort@chromium.org>
Tested-by: ChromeOS Prod (Robot) <chromeos-ci-prod@chromeos-bot.iam.gserviceaccount.com>
Reviewed-by: Keith Short <keithshort@chromium.org>

arch/arm64/core/fatal.c

@@ -377,7 +377,7 @@ void z_arm64_fatal_error(unsigned int reason, struct arch_esf *esf)
 
 		if (IS_ENABLED(CONFIG_DEMAND_PAGING) &&
 		    reason != K_ERR_STACK_CHK_FAIL &&
-		    z_arm64_do_demand_paging(esr, far)) {
+		    z_arm64_do_demand_paging(esf, esr, far)) {
 			return;
 		}
 

arch/arm64/core/mmu.c

@@ -1563,8 +1563,24 @@ void arch_mem_scratch(uintptr_t phys)
 	}
 }
 
+static bool do_mem_page_fault(struct arch_esf *esf, uintptr_t virt)
+{
+	/*
+	 * The k_mem_page_fault() code expects to be called with IRQs enabled
+	 * if the fault happened in a context where IRQs were enabled.
+	 */
+	if (arch_irq_unlocked(esf->spsr)) {
+		enable_irq();
+	}
+
+	bool ok = k_mem_page_fault((void *)virt);
+
+	disable_irq();
+	return ok;
+}
+
 /* Called from the fault handler. Returns true if the fault is resolved. */
-bool z_arm64_do_demand_paging(uint64_t esr, uint64_t far)
+bool z_arm64_do_demand_paging(struct arch_esf *esf, uint64_t esr, uint64_t far)
 {
 	uintptr_t virt = far;
 	uint64_t *pte, desc;
@@ -1591,12 +1607,12 @@ bool z_arm64_do_demand_paging(uint64_t esr, uint64_t far)
 	pte = get_pte_location(&kernel_ptables, virt);
 	if (!pte) {
 		/* page mapping doesn't exist, let the core code do its thing */
-		return k_mem_page_fault((void *)virt);
+		return do_mem_page_fault(esf, virt);
 	}
 	desc = *pte;
 	if ((desc & PTE_DESC_TYPE_MASK) != PTE_PAGE_DESC) {
 		/* page is not loaded/mapped */
-		return k_mem_page_fault((void *)virt);
+		return do_mem_page_fault(esf, virt);
 	}
 
 	/*

arch/arm64/core/paging.h

@@ -7,6 +7,6 @@
 #ifndef Z_ARM64_PAGING_H
 #define Z_ARM64_PAGING_H
 
-bool z_arm64_do_demand_paging(uint64_t esr, uint64_t far);
+bool z_arm64_do_demand_paging(struct arch_esf *esf, uint64_t esr, uint64_t far);
 
 #endif /* Z_ARM64_PAGING_H */