Commit 9073dac1 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Petr Mladek
Browse files

lib/vsprintf: Prepare for more general use of ptr_to_id() 

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: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
[pmladek@suse.com: Split into separate patch]
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent f31b224c

lib/vsprintf.c

+103 −103
Original line number Diff line number Diff line
@@ -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
@@ -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

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