From 11025e855235144271a0e447e3650b203f8215f4 Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Wed, 6 Feb 2008 01:37:13 -0800 Subject: [PATCH] via-rng: enable secondary noise source on CPUs where it is present In the padlock spec: "SRC Bits[9:8] Noise source select (I): These bits control the two noise sources on the processor that input bits to the accumulation buffers. On Nehemiah processors prior to stepping 8, these bits are reserved and undefined. The default RESET state is both bits = 0." Signed-off-by: Dave Jones Tested-by: Udo van den Heuvel Cc: Michael Buesch Cc: folkert van Heusden Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/hw_random/via-rng.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c index 868e39fd42e4..f7feae4ebb5e 100644 --- a/drivers/char/hw_random/via-rng.c +++ b/drivers/char/hw_random/via-rng.c @@ -42,6 +42,8 @@ enum { VIA_STRFILT_ENABLE = (1 << 14), VIA_RAWBITS_ENABLE = (1 << 13), VIA_RNG_ENABLE = (1 << 6), + VIA_NOISESRC1 = (1 << 8), + VIA_NOISESRC2 = (1 << 9), VIA_XSTORE_CNT_MASK = 0x0F, VIA_RNG_CHUNK_8 = 0x00, /* 64 rand bits, 64 stored bits */ @@ -119,6 +121,7 @@ static int via_rng_data_read(struct hwrng *rng, u32 *data) static int via_rng_init(struct hwrng *rng) { + struct cpuinfo_x86 *c = &cpu_data(0); u32 lo, hi, old_lo; /* Control the RNG via MSR. Tread lightly and pay very close @@ -134,6 +137,17 @@ static int via_rng_init(struct hwrng *rng) lo &= ~VIA_XSTORE_CNT_MASK; lo &= ~(VIA_STRFILT_ENABLE | VIA_STRFILT_FAIL | VIA_RAWBITS_ENABLE); lo |= VIA_RNG_ENABLE; + lo |= VIA_NOISESRC1; + + /* Enable secondary noise source on CPUs where it is present. */ + + /* Nehemiah stepping 8 and higher */ + if ((c->x86_model == 9) && (c->x86_mask > 7)) + lo |= VIA_NOISESRC2; + + /* Esther */ + if (c->x86_model >= 10) + lo |= VIA_NOISESRC2; if (lo != old_lo) wrmsr(MSR_VIA_RNG, lo, hi); -- 2.30.2