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81895a65ec
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
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- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
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- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
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- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
130 lines
4.0 KiB
C
130 lines
4.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (c) International Business Machines Corp., 2006
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*
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* Author: Artem Bityutskiy (Битюцкий Артём)
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*/
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#ifndef __UBI_DEBUG_H__
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#define __UBI_DEBUG_H__
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void ubi_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len);
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void ubi_dump_ec_hdr(const struct ubi_ec_hdr *ec_hdr);
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void ubi_dump_vid_hdr(const struct ubi_vid_hdr *vid_hdr);
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#include <linux/random.h>
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#define ubi_assert(expr) do { \
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if (unlikely(!(expr))) { \
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pr_crit("UBI assert failed in %s at %u (pid %d)\n", \
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__func__, __LINE__, current->pid); \
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dump_stack(); \
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} \
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} while (0)
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#define ubi_dbg_print_hex_dump(l, ps, pt, r, g, b, len, a) \
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print_hex_dump(l, ps, pt, r, g, b, len, a)
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#define ubi_dbg_msg(type, fmt, ...) \
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pr_debug("UBI DBG " type " (pid %d): " fmt "\n", current->pid, \
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##__VA_ARGS__)
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/* General debugging messages */
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#define dbg_gen(fmt, ...) ubi_dbg_msg("gen", fmt, ##__VA_ARGS__)
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/* Messages from the eraseblock association sub-system */
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#define dbg_eba(fmt, ...) ubi_dbg_msg("eba", fmt, ##__VA_ARGS__)
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/* Messages from the wear-leveling sub-system */
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#define dbg_wl(fmt, ...) ubi_dbg_msg("wl", fmt, ##__VA_ARGS__)
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/* Messages from the input/output sub-system */
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#define dbg_io(fmt, ...) ubi_dbg_msg("io", fmt, ##__VA_ARGS__)
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/* Initialization and build messages */
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#define dbg_bld(fmt, ...) ubi_dbg_msg("bld", fmt, ##__VA_ARGS__)
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void ubi_dump_vol_info(const struct ubi_volume *vol);
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void ubi_dump_vtbl_record(const struct ubi_vtbl_record *r, int idx);
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void ubi_dump_av(const struct ubi_ainf_volume *av);
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void ubi_dump_aeb(const struct ubi_ainf_peb *aeb, int type);
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void ubi_dump_mkvol_req(const struct ubi_mkvol_req *req);
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int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
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int len);
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int ubi_debugfs_init(void);
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void ubi_debugfs_exit(void);
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int ubi_debugfs_init_dev(struct ubi_device *ubi);
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void ubi_debugfs_exit_dev(struct ubi_device *ubi);
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/**
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* ubi_dbg_is_bgt_disabled - if the background thread is disabled.
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* @ubi: UBI device description object
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*
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* Returns non-zero if the UBI background thread is disabled for testing
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* purposes.
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*/
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static inline int ubi_dbg_is_bgt_disabled(const struct ubi_device *ubi)
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{
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return ubi->dbg.disable_bgt;
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}
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/**
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* ubi_dbg_is_bitflip - if it is time to emulate a bit-flip.
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* @ubi: UBI device description object
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*
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* Returns non-zero if a bit-flip should be emulated, otherwise returns zero.
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*/
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static inline int ubi_dbg_is_bitflip(const struct ubi_device *ubi)
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{
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if (ubi->dbg.emulate_bitflips)
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return !prandom_u32_max(200);
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return 0;
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}
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/**
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* ubi_dbg_is_write_failure - if it is time to emulate a write failure.
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* @ubi: UBI device description object
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*
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* Returns non-zero if a write failure should be emulated, otherwise returns
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* zero.
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*/
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static inline int ubi_dbg_is_write_failure(const struct ubi_device *ubi)
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{
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if (ubi->dbg.emulate_io_failures)
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return !prandom_u32_max(500);
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return 0;
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}
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/**
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* ubi_dbg_is_erase_failure - if its time to emulate an erase failure.
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* @ubi: UBI device description object
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*
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* Returns non-zero if an erase failure should be emulated, otherwise returns
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* zero.
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*/
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static inline int ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
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{
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if (ubi->dbg.emulate_io_failures)
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return !prandom_u32_max(400);
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return 0;
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}
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static inline int ubi_dbg_chk_io(const struct ubi_device *ubi)
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{
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return ubi->dbg.chk_io;
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}
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static inline int ubi_dbg_chk_gen(const struct ubi_device *ubi)
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{
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return ubi->dbg.chk_gen;
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}
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static inline int ubi_dbg_chk_fastmap(const struct ubi_device *ubi)
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{
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return ubi->dbg.chk_fastmap;
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}
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static inline void ubi_enable_dbg_chk_fastmap(struct ubi_device *ubi)
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{
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ubi->dbg.chk_fastmap = 1;
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}
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int ubi_dbg_power_cut(struct ubi_device *ubi, int caller);
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#endif /* !__UBI_DEBUG_H__ */
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