From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/drivers/base/devres.c | 184 ++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 177 insertions(+), 7 deletions(-)
diff --git a/kernel/drivers/base/devres.c b/kernel/drivers/base/devres.c
index d68b52c..586e9a7 100644
--- a/kernel/drivers/base/devres.c
+++ b/kernel/drivers/base/devres.c
@@ -11,6 +11,8 @@
#include <linux/slab.h>
#include <linux/percpu.h>
+#include <asm/sections.h>
+
#include "base.h"
struct devres_node {
@@ -87,15 +89,23 @@
return NULL;
}
+static bool check_dr_size(size_t size, size_t *tot_size)
+{
+ /* We must catch any near-SIZE_MAX cases that could overflow. */
+ if (unlikely(check_add_overflow(sizeof(struct devres),
+ size, tot_size)))
+ return false;
+
+ return true;
+}
+
static __always_inline struct devres * alloc_dr(dr_release_t release,
size_t size, gfp_t gfp, int nid)
{
size_t tot_size;
struct devres *dr;
- /* We must catch any near-SIZE_MAX cases that could overflow. */
- if (unlikely(check_add_overflow(sizeof(struct devres), size,
- &tot_size)))
+ if (!check_dr_size(size, &tot_size))
return NULL;
dr = kmalloc_node_track_caller(tot_size, gfp, nid);
@@ -114,6 +124,14 @@
devres_log(dev, node, "ADD");
BUG_ON(!list_empty(&node->entry));
list_add_tail(&node->entry, &dev->devres_head);
+}
+
+static void replace_dr(struct device *dev,
+ struct devres_node *old, struct devres_node *new)
+{
+ devres_log(dev, old, "REPLACE");
+ BUG_ON(!list_empty(&new->entry));
+ list_replace(&old->entry, &new->entry);
}
#ifdef CONFIG_DEBUG_DEVRES
@@ -753,9 +771,31 @@
WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
&devres));
-
}
EXPORT_SYMBOL_GPL(devm_remove_action);
+
+/**
+ * devm_release_action() - release previously added custom action
+ * @dev: Device that owns the action
+ * @action: Function implementing the action
+ * @data: Pointer to data passed to @action implementation
+ *
+ * Releases and removes instance of @action previously added by
+ * devm_add_action(). Both action and data should match one of the
+ * existing entries.
+ */
+void devm_release_action(struct device *dev, void (*action)(void *), void *data)
+{
+ struct action_devres devres = {
+ .data = data,
+ .action = action,
+ };
+
+ WARN_ON(devres_release(dev, devm_action_release, devm_action_match,
+ &devres));
+
+}
+EXPORT_SYMBOL_GPL(devm_release_action);
/*
* Managed kmalloc/kfree
@@ -783,9 +823,12 @@
* RETURNS:
* Pointer to allocated memory on success, NULL on failure.
*/
-void * devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
+void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
{
struct devres *dr;
+
+ if (unlikely(!size))
+ return ZERO_SIZE_PTR;
/* use raw alloc_dr for kmalloc caller tracing */
dr = alloc_dr(devm_kmalloc_release, size, gfp, dev_to_node(dev));
@@ -801,6 +844,103 @@
return dr->data;
}
EXPORT_SYMBOL_GPL(devm_kmalloc);
+
+/**
+ * devm_krealloc - Resource-managed krealloc()
+ * @dev: Device to re-allocate memory for
+ * @ptr: Pointer to the memory chunk to re-allocate
+ * @new_size: New allocation size
+ * @gfp: Allocation gfp flags
+ *
+ * Managed krealloc(). Resizes the memory chunk allocated with devm_kmalloc().
+ * Behaves similarly to regular krealloc(): if @ptr is NULL or ZERO_SIZE_PTR,
+ * it's the equivalent of devm_kmalloc(). If new_size is zero, it frees the
+ * previously allocated memory and returns ZERO_SIZE_PTR. This function doesn't
+ * change the order in which the release callback for the re-alloc'ed devres
+ * will be called (except when falling back to devm_kmalloc() or when freeing
+ * resources when new_size is zero). The contents of the memory are preserved
+ * up to the lesser of new and old sizes.
+ */
+void *devm_krealloc(struct device *dev, void *ptr, size_t new_size, gfp_t gfp)
+{
+ size_t total_new_size, total_old_size;
+ struct devres *old_dr, *new_dr;
+ unsigned long flags;
+
+ if (unlikely(!new_size)) {
+ devm_kfree(dev, ptr);
+ return ZERO_SIZE_PTR;
+ }
+
+ if (unlikely(ZERO_OR_NULL_PTR(ptr)))
+ return devm_kmalloc(dev, new_size, gfp);
+
+ if (WARN_ON(is_kernel_rodata((unsigned long)ptr)))
+ /*
+ * We cannot reliably realloc a const string returned by
+ * devm_kstrdup_const().
+ */
+ return NULL;
+
+ if (!check_dr_size(new_size, &total_new_size))
+ return NULL;
+
+ total_old_size = ksize(container_of(ptr, struct devres, data));
+ if (total_old_size == 0) {
+ WARN(1, "Pointer doesn't point to dynamically allocated memory.");
+ return NULL;
+ }
+
+ /*
+ * If new size is smaller or equal to the actual number of bytes
+ * allocated previously - just return the same pointer.
+ */
+ if (total_new_size <= total_old_size)
+ return ptr;
+
+ /*
+ * Otherwise: allocate new, larger chunk. We need to allocate before
+ * taking the lock as most probably the caller uses GFP_KERNEL.
+ */
+ new_dr = alloc_dr(devm_kmalloc_release,
+ total_new_size, gfp, dev_to_node(dev));
+ if (!new_dr)
+ return NULL;
+
+ /*
+ * The spinlock protects the linked list against concurrent
+ * modifications but not the resource itself.
+ */
+ spin_lock_irqsave(&dev->devres_lock, flags);
+
+ old_dr = find_dr(dev, devm_kmalloc_release, devm_kmalloc_match, ptr);
+ if (!old_dr) {
+ spin_unlock_irqrestore(&dev->devres_lock, flags);
+ kfree(new_dr);
+ WARN(1, "Memory chunk not managed or managed by a different device.");
+ return NULL;
+ }
+
+ replace_dr(dev, &old_dr->node, &new_dr->node);
+
+ spin_unlock_irqrestore(&dev->devres_lock, flags);
+
+ /*
+ * We can copy the memory contents after releasing the lock as we're
+ * no longer modyfing the list links.
+ */
+ memcpy(new_dr->data, old_dr->data,
+ total_old_size - offsetof(struct devres, data));
+ /*
+ * Same for releasing the old devres - it's now been removed from the
+ * list. This is also the reason why we must not use devm_kfree() - the
+ * links are no longer valid.
+ */
+ kfree(old_dr);
+
+ return new_dr->data;
+}
+EXPORT_SYMBOL_GPL(devm_krealloc);
/**
* devm_kstrdup - Allocate resource managed space and
@@ -827,6 +967,28 @@
return buf;
}
EXPORT_SYMBOL_GPL(devm_kstrdup);
+
+/**
+ * devm_kstrdup_const - resource managed conditional string duplication
+ * @dev: device for which to duplicate the string
+ * @s: the string to duplicate
+ * @gfp: the GFP mask used in the kmalloc() call when allocating memory
+ *
+ * Strings allocated by devm_kstrdup_const will be automatically freed when
+ * the associated device is detached.
+ *
+ * RETURNS:
+ * Source string if it is in .rodata section otherwise it falls back to
+ * devm_kstrdup.
+ */
+const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
+{
+ if (is_kernel_rodata((unsigned long)s))
+ return s;
+
+ return devm_kstrdup(dev, s, gfp);
+}
+EXPORT_SYMBOL_GPL(devm_kstrdup_const);
/**
* devm_kvasprintf - Allocate resource managed space and format a string
@@ -891,11 +1053,19 @@
*
* Free memory allocated with devm_kmalloc().
*/
-void devm_kfree(struct device *dev, void *p)
+void devm_kfree(struct device *dev, const void *p)
{
int rc;
- rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
+ /*
+ * Special cases: pointer to a string in .rodata returned by
+ * devm_kstrdup_const() or NULL/ZERO ptr.
+ */
+ if (unlikely(is_kernel_rodata((unsigned long)p) || ZERO_OR_NULL_PTR(p)))
+ return;
+
+ rc = devres_destroy(dev, devm_kmalloc_release,
+ devm_kmalloc_match, (void *)p);
WARN_ON(rc);
}
EXPORT_SYMBOL_GPL(devm_kfree);
--
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