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lib/vsprintf: Prepare for more general use of ptr_to_id()
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Move the function and its dependencies up so it can be called from
special pointer type formatting routines.

Link: http://lkml.kernel.org/r/20181011084249.4520-2-geert+renesas@glider.be
To: "Tobin C . Harding" <me@tobin.cc>
To: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[pmladek@suse.com: Split into separate patch]
Signed-off-by: Petr Mladek <pmladek@suse.com>
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Geert Uytterhoeven authored and Petr Mladek committed Oct 12, 2018
1 parent f31b224 commit 9073dac
Showing 1 changed file with 103 additions and 103 deletions.
206 changes: 103 additions & 103 deletions lib/vsprintf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -1651,95 +1740,6 @@ 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, 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);
}

/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
* by an extra set of alphanumeric characters that are extended format
Expand Down

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