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Commit ac0081de authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
Browse files

random: round-robin registers as ulong, not u32 



commit da3951ebdcd1cb1d5c750e08cd05aee7b0c04d9a upstream.

When the interrupt handler does not have a valid cycle counter, it calls
get_reg() to read a register from the irq stack, in round-robin.
Currently it does this assuming that registers are 32-bit. This is
_probably_ the case, and probably all platforms without cycle counters
are in fact 32-bit platforms. But maybe not, and either way, it's not
quite correct. This commit fixes that to deal with `unsigned long`
rather than `u32`.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 62cd795e

drivers/char/random.c

+3 −3
Original line number Diff line number Diff line
@@ -1256,15 +1256,15 @@ int random_online_cpu(unsigned int cpu) 
}

#endif



static u32 get_reg(struct fast_pool *f, struct pt_regs *regs)

static unsigned long get_reg(struct fast_pool *f, struct pt_regs *regs)

{

	u32 *ptr = (u32 *)regs;

	unsigned long *ptr = (unsigned long *)regs;

	unsigned int idx;



	if (regs == NULL)

		return 0;

	idx = READ_ONCE(f->reg_idx);

	if (idx >= sizeof(struct pt_regs) / sizeof(u32))

	if (idx >= sizeof(struct pt_regs) / sizeof(unsigned long))

		idx = 0;

	ptr += idx++;

	WRITE_ONCE(f->reg_idx, idx);