diff options
| author | Jason A. Donenfeld | 2022-04-08 18:14:57 +0200 |
|---|---|---|
| committer | Jason A. Donenfeld | 2022-04-13 13:58:57 +0200 |
| commit | b0c3e796f24b588b862b61ce235d3c9417dc8983 (patch) | |
| tree | 7d583242af33f434736d0f26bf5003489b4a050b | |
| parent | 5209aed5137880fa229746cb521f715e55596460 (diff) | |
random: make random_get_entropy() return an unsigned long
Some implementations were returning type `unsigned long`, while others
that fell back to get_cycles() were implicitly returning a `cycles_t` or
an untyped constant int literal. That makes for weird and confusing
code, and basically all code in the kernel already handled it like it
was an `unsigned long`. I recently tried to handle it as the largest
type it could be, a `cycles_t`, but doing so doesn't really help with
much.
Instead let's just make random_get_entropy() return an unsigned long all
the time. This also matches the commonly used `arch_get_random_long()`
function, so now RDRAND and RDTSC return the same sized integer, which
means one can fallback to the other more gracefully.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
| -rw-r--r-- | drivers/char/random.c | 20 | ||||
| -rw-r--r-- | include/linux/timex.h | 2 |
2 files changed, 8 insertions, 14 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index df43c5060f00..6b01b2be9dd4 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1018,7 +1018,7 @@ int __init rand_initialize(void) */ void add_device_randomness(const void *buf, size_t size) { - cycles_t cycles = random_get_entropy(); + unsigned long cycles = random_get_entropy(); unsigned long flags, now = jiffies; if (crng_init == 0 && size) @@ -1049,8 +1049,7 @@ struct timer_rand_state { */ static void add_timer_randomness(struct timer_rand_state *state, unsigned int num) { - cycles_t cycles = random_get_entropy(); - unsigned long flags, now = jiffies; + unsigned long cycles = random_get_entropy(), now = jiffies, flags; long delta, delta2, delta3; spin_lock_irqsave(&input_pool.lock, flags); @@ -1339,8 +1338,7 @@ static void mix_interrupt_randomness(struct work_struct *work) void add_interrupt_randomness(int irq) { enum { MIX_INFLIGHT = 1U << 31 }; - cycles_t cycles = random_get_entropy(); - unsigned long now = jiffies; + unsigned long cycles = random_get_entropy(), now = jiffies; struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness); struct pt_regs *regs = get_irq_regs(); unsigned int new_count; @@ -1353,16 +1351,12 @@ void add_interrupt_randomness(int irq) if (cycles == 0) cycles = get_reg(fast_pool, regs); - if (sizeof(cycles) == 8) + if (sizeof(unsigned long) == 8) { irq_data.u64[0] = cycles ^ rol64(now, 32) ^ irq; - else { + irq_data.u64[1] = regs ? instruction_pointer(regs) : _RET_IP_; + } else { irq_data.u32[0] = cycles ^ irq; irq_data.u32[1] = now; - } - - if (sizeof(unsigned long) == 8) - irq_data.u64[1] = regs ? instruction_pointer(regs) : _RET_IP_; - else { irq_data.u32[2] = regs ? instruction_pointer(regs) : _RET_IP_; irq_data.u32[3] = get_reg(fast_pool, regs); } @@ -1409,7 +1403,7 @@ static void entropy_timer(struct timer_list *t) static void try_to_generate_entropy(void) { struct { - cycles_t cycles; + unsigned long cycles; struct timer_list timer; } stack; diff --git a/include/linux/timex.h b/include/linux/timex.h index 059b18eb1f1f..5745c90c8800 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -75,7 +75,7 @@ * By default we use get_cycles() for this purpose, but individual * architectures may override this in their asm/timex.h header file. */ -#define random_get_entropy() get_cycles() +#define random_get_entropy() ((unsigned long)get_cycles()) #endif /* |