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Subject[PATCH v2 1/3] lib/vsprintf: Prepare for more general use of ptr_to_id()
Date
  - Make the ptr argument const, to avoid adding casts in future
callers,
- Move the function and its dependencies up, so it can be called from
special pointer type formatting routines.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
- Get rid of the forward declaration for ptr_to_id().
---
lib/vsprintf.c | 205 +++++++++++++++++++++++++------------------------
1 file changed, 103 insertions(+), 102 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 095a677f89c02442..b4e4ab274bde2397 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -612,6 +612,109 @@ char *string(char *buf, char *end, const char *s, struct printf_spec spec)
return widen_string(buf, len, end, spec);
}

+static noinline_for_stack
+char *pointer_string(char *buf, char *end, const void *ptr,
+ struct printf_spec spec)
+{
+ spec.base = 16;
+ spec.flags |= SMALL;
+ if (spec.field_width == -1) {
+ spec.field_width = 2 * sizeof(ptr);
+ spec.flags |= ZEROPAD;
+ }
+
+ return number(buf, end, (unsigned long int)ptr, spec);
+}
+
+/* Make pointers available for printing early in the boot sequence. */
+static int debug_boot_weak_hash __ro_after_init;
+
+static int __init debug_boot_weak_hash_enable(char *str)
+{
+ debug_boot_weak_hash = 1;
+ pr_info("debug_boot_weak_hash enabled\n");
+ return 0;
+}
+early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
+
+static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
+static siphash_key_t ptr_key __read_mostly;
+
+static void enable_ptr_key_workfn(struct work_struct *work)
+{
+ get_random_bytes(&ptr_key, sizeof(ptr_key));
+ /* Needs to run from preemptible context */
+ static_branch_disable(&not_filled_random_ptr_key);
+}
+
+static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
+
+static void fill_random_ptr_key(struct random_ready_callback *unused)
+{
+ /* This may be in an interrupt handler. */
+ queue_work(system_unbound_wq, &enable_ptr_key_work);
+}
+
+static struct random_ready_callback random_ready = {
+ .func = fill_random_ptr_key
+};
+
+static int __init initialize_ptr_random(void)
+{
+ int key_size = sizeof(ptr_key);
+ int ret;
+
+ /* Use hw RNG if available. */
+ if (get_random_bytes_arch(&ptr_key, key_size) == key_size) {
+ static_branch_disable(&not_filled_random_ptr_key);
+ return 0;
+ }
+
+ ret = add_random_ready_callback(&random_ready);
+ if (!ret) {
+ return 0;
+ } else if (ret == -EALREADY) {
+ /* This is in preemptible context */
+ enable_ptr_key_workfn(&enable_ptr_key_work);
+ return 0;
+ }
+
+ return ret;
+}
+early_initcall(initialize_ptr_random);
+
+/* Maps a pointer to a 32 bit unique identifier. */
+static char *ptr_to_id(char *buf, char *end, const void *ptr,
+ struct printf_spec spec)
+{
+ const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
+ unsigned long hashval;
+
+ /* When debugging early boot use non-cryptographically secure hash. */
+ if (unlikely(debug_boot_weak_hash)) {
+ hashval = hash_long((unsigned long)ptr, 32);
+ return pointer_string(buf, end, (const void *)hashval, spec);
+ }
+
+ if (static_branch_unlikely(&not_filled_random_ptr_key)) {
+ spec.field_width = 2 * sizeof(ptr);
+ /* string length must be less than default_width */
+ return string(buf, end, str, spec);
+ }
+
+#ifdef CONFIG_64BIT
+ hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);
+ /*
+ * Mask off the first 32 bits, this makes explicit that we have
+ * modified the address (and 32 bits is plenty for a unique ID).
+ */
+ hashval = hashval & 0xffffffff;
+#else
+ hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key);
+#endif
+ return pointer_string(buf, end, (const void *)hashval, spec);
+}
+
static noinline_for_stack
char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
const char *fmt)
@@ -1357,20 +1460,6 @@ char *uuid_string(char *buf, char *end, const u8 *addr,
return string(buf, end, uuid, spec);
}

-static noinline_for_stack
-char *pointer_string(char *buf, char *end, const void *ptr,
- struct printf_spec spec)
-{
- spec.base = 16;
- spec.flags |= SMALL;
- if (spec.field_width == -1) {
- spec.field_width = 2 * sizeof(ptr);
- spec.flags |= ZEROPAD;
- }
-
- return number(buf, end, (unsigned long int)ptr, spec);
-}
-
int kptr_restrict __read_mostly;

static noinline_for_stack
@@ -1656,94 +1745,6 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
return widen_string(buf, buf - buf_start, end, spec);
}

-/* Make pointers available for printing early in the boot sequence. */
-static int debug_boot_weak_hash __ro_after_init;
-
-static int __init debug_boot_weak_hash_enable(char *str)
-{
- debug_boot_weak_hash = 1;
- pr_info("debug_boot_weak_hash enabled\n");
- return 0;
-}
-early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
-
-static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
-static siphash_key_t ptr_key __read_mostly;
-
-static void enable_ptr_key_workfn(struct work_struct *work)
-{
- get_random_bytes(&ptr_key, sizeof(ptr_key));
- /* Needs to run from preemptible context */
- static_branch_disable(&not_filled_random_ptr_key);
-}
-
-static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
-
-static void fill_random_ptr_key(struct random_ready_callback *unused)
-{
- /* This may be in an interrupt handler. */
- queue_work(system_unbound_wq, &enable_ptr_key_work);
-}
-
-static struct random_ready_callback random_ready = {
- .func = fill_random_ptr_key
-};
-
-static int __init initialize_ptr_random(void)
-{
- int key_size = sizeof(ptr_key);
- int ret;
-
- /* Use hw RNG if available. */
- if (get_random_bytes_arch(&ptr_key, key_size) == key_size) {
- static_branch_disable(&not_filled_random_ptr_key);
- return 0;
- }
-
- ret = add_random_ready_callback(&random_ready);
- if (!ret) {
- return 0;
- } else if (ret == -EALREADY) {
- /* This is in preemptible context */
- enable_ptr_key_workfn(&enable_ptr_key_work);
- return 0;
- }
-
- return ret;
-}
-early_initcall(initialize_ptr_random);
-
-/* Maps a pointer to a 32 bit unique identifier. */
-static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
-{
- const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
- unsigned long hashval;
-
- /* When debugging early boot use non-cryptographically secure hash. */
- if (unlikely(debug_boot_weak_hash)) {
- hashval = hash_long((unsigned long)ptr, 32);
- return pointer_string(buf, end, (const void *)hashval, spec);
- }
-
- if (static_branch_unlikely(&not_filled_random_ptr_key)) {
- spec.field_width = 2 * sizeof(ptr);
- /* string length must be less than default_width */
- return string(buf, end, str, spec);
- }
-
-#ifdef CONFIG_64BIT
- hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);
- /*
- * Mask off the first 32 bits, this makes explicit that we have
- * modified the address (and 32 bits is plenty for a unique ID).
- */
- hashval = hashval & 0xffffffff;
-#else
- hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key);
-#endif
- return pointer_string(buf, end, (const void *)hashval, spec);
-}
-
/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
* by an extra set of alphanumeric characters that are extended format
--
2.17.1
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