| From foo@baz Thu Jun 16 06:59:24 PM CEST 2022 |
| From: "Jason A. Donenfeld" <Jason@zx2c4.com> |
| Date: Tue, 22 Feb 2022 13:46:10 +0100 |
| Subject: random: round-robin registers as ulong, not u32 |
| |
| From: "Jason A. Donenfeld" <Jason@zx2c4.com> |
| |
| 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: Dominik Brodowski <linux@dominikbrodowski.net> |
| Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/char/random.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/char/random.c |
| +++ b/drivers/char/random.c |
| @@ -1257,15 +1257,15 @@ 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); |
