From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Thu, 11 Apr 2024 10:27:49 +0200
Subject: Adding upstream version 6.6.15.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 arch/arm/kernel/suspend.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 arch/arm/kernel/suspend.c

(limited to 'arch/arm/kernel/suspend.c')

diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
new file mode 100644
index 0000000000..c3ec3861dd
--- /dev/null
+++ b/arch/arm/kernel/suspend.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/mm_types.h>
+#include <linux/pgtable.h>
+
+#include <asm/bugs.h>
+#include <asm/cacheflush.h>
+#include <asm/idmap.h>
+#include <asm/page.h>
+#include <asm/smp_plat.h>
+#include <asm/suspend.h>
+#include <asm/tlbflush.h>
+
+extern int __cpu_suspend(unsigned long, int (*)(unsigned long), u32 cpuid);
+extern void cpu_resume_mmu(void);
+
+#ifdef CONFIG_MMU
+int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
+{
+	struct mm_struct *mm = current->active_mm;
+	u32 __mpidr = cpu_logical_map(smp_processor_id());
+	int ret;
+
+	if (!idmap_pgd)
+		return -EINVAL;
+
+	/*
+	 * Function graph tracer state gets incosistent when the kernel
+	 * calls functions that never return (aka suspend finishers) hence
+	 * disable graph tracing during their execution.
+	 */
+	pause_graph_tracing();
+
+	/*
+	 * Provide a temporary page table with an identity mapping for
+	 * the MMU-enable code, required for resuming.  On successful
+	 * resume (indicated by a zero return code), we need to switch
+	 * back to the correct page tables.
+	 */
+	ret = __cpu_suspend(arg, fn, __mpidr);
+
+	unpause_graph_tracing();
+
+	if (ret == 0) {
+		cpu_switch_mm(mm->pgd, mm);
+		local_flush_bp_all();
+		local_flush_tlb_all();
+		check_other_bugs();
+	}
+
+	return ret;
+}
+#else
+int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
+{
+	u32 __mpidr = cpu_logical_map(smp_processor_id());
+	int ret;
+
+	pause_graph_tracing();
+	ret = __cpu_suspend(arg, fn, __mpidr);
+	unpause_graph_tracing();
+
+	return ret;
+}
+#define	idmap_pgd	NULL
+#endif
+
+/*
+ * This is called by __cpu_suspend() to save the state, and do whatever
+ * flushing is required to ensure that when the CPU goes to sleep we have
+ * the necessary data available when the caches are not searched.
+ */
+void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
+{
+	u32 *ctx = ptr;
+
+	*save_ptr = virt_to_phys(ptr);
+
+	/* This must correspond to the LDM in cpu_resume() assembly */
+	*ptr++ = virt_to_phys(idmap_pgd);
+	*ptr++ = sp;
+	*ptr++ = virt_to_phys(cpu_do_resume);
+
+	cpu_do_suspend(ptr);
+
+	flush_cache_louis();
+
+	/*
+	 * flush_cache_louis does not guarantee that
+	 * save_ptr and ptr are cleaned to main memory,
+	 * just up to the Level of Unification Inner Shareable.
+	 * Since the context pointer and context itself
+	 * are to be retrieved with the MMU off that
+	 * data must be cleaned from all cache levels
+	 * to main memory using "area" cache primitives.
+	*/
+	__cpuc_flush_dcache_area(ctx, ptrsz);
+	__cpuc_flush_dcache_area(save_ptr, sizeof(*save_ptr));
+
+	outer_clean_range(*save_ptr, *save_ptr + ptrsz);
+	outer_clean_range(virt_to_phys(save_ptr),
+			  virt_to_phys(save_ptr) + sizeof(*save_ptr));
+}
+
+extern struct sleep_save_sp sleep_save_sp;
+
+static int cpu_suspend_alloc_sp(void)
+{
+	void *ctx_ptr;
+	/* ctx_ptr is an array of physical addresses */
+	ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(u32), GFP_KERNEL);
+
+	if (WARN_ON(!ctx_ptr))
+		return -ENOMEM;
+	sleep_save_sp.save_ptr_stash = ctx_ptr;
+	sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr);
+	sync_cache_w(&sleep_save_sp);
+	return 0;
+}
+early_initcall(cpu_suspend_alloc_sp);
-- 
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