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| author | Vadim Sukhomlinov <sukhomlinov@google.com> | 2023-03-28 19:47:32 -0700 |
|---|---|---|
| committer | Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> | 2023-04-07 22:08:29 +0000 |
| commit | 44a748a92f840bc3d4f74ae3b22a8f080d755441 (patch) | |
| tree | 1012c43b2f76d38b1d51f3d9b185bdca8f008486 | |
| parent | c1c637bb53eaa9de9ead652dc9908eef6c15b8a5 (diff) | |
| download | chrome-ec-44a748a92f840bc3d4f74ae3b22a8f080d755441.tar.gz | |
cr50: update TRNG timeout handlingstabilize-15415.B-cr50_stab
1. Due to large share of devices with slow TRNG increase timeout cycles
from 0x7ff to 0xfff.
2. Increase total reset attempts from 16 to 32.
2. Log number of resets.
BUG=b:211648605
TEST=make CRYPTO_TEST=1
Change-Id: Ib0f9472d6f84c39cd7576f374ab482e522a39809
Signed-off-by: Vadim Sukhomlinov <sukhomlinov@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4380143
Reviewed-by: Andrey Pronin <apronin@chromium.org>
Tested-by: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Code-Coverage: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Reviewed-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-by: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Commit-Queue: Vadim Sukhomlinov <sukhomlinov@chromium.org>
| -rw-r--r-- | board/cr50/dcrypto/trng.c | 29 |
1 files changed, 12 insertions, 17 deletions
diff --git a/board/cr50/dcrypto/trng.c b/board/cr50/dcrypto/trng.c index a67d5ef766..e93d0bb051 100644 --- a/board/cr50/dcrypto/trng.c +++ b/board/cr50/dcrypto/trng.c @@ -34,16 +34,15 @@ static volatile struct trng_reg *reg_trng = (void *)(GC_TRNG_BASE_ADDR); /** * Attempts to read TRNG_EMPTY before reporting a stall. Practically data should - * be available in less than 0x7ff cycles under normal conditions. 0x7ff was - * chosen to match the hardware TRNG TIMEOUT_COUNTER. Test on boards with slow - * TRNG before reducing this number. + * be available in less than 0xfff cycles under normal conditions. + * Test on boards with slow TRNG before reducing this number. */ -#define TRNG_EMPTY_COUNT 0x7ff +#define TRNG_EMPTY_COUNT 0xfff /** * Number of attempts to reset TRNG after stall is detected. */ -#define TRNG_RESET_COUNT 16 +#define TRNG_RESET_COUNT 32 void fips_init_trng(void) { @@ -101,7 +100,7 @@ void fips_init_trng(void) */ reg_trng->allowed_values = 0x26; - reg_trng->timeout_counter = 0x7ff; + reg_trng->timeout_counter = TRNG_EMPTY_COUNT; reg_trng->timeout_max_try = 4; reg_trng->power_down_b = 1; reg_trng->go_event = 1; @@ -110,7 +109,7 @@ void fips_init_trng(void) uint64_t read_rand(void) { uint32_t empty_count = 0; - uint32_t reset_count = 0; + uint8_t reset_count = 0; #ifdef CRYPTO_TEST_SETUP /* Do we need to simulate error? */ @@ -130,19 +129,15 @@ uint64_t read_rand(void) empty_count = 0; reset_count++; reg_trng->go_event = 1; -#ifdef CONFIG_FLASH_LOG - /** - * Log stall only first time. Placing it after TRNG - * go_event increase a chance to get random in case - * of slow TRNG. - */ - if (reset_count == 1) - fips_vtable->flash_log_add_event( - FE_LOG_TRNG_STALL, 0, NULL); -#endif } empty_count++; } +#ifdef CONFIG_FLASH_LOG + /* Log stall count if happened .*/ + if (reset_count > 0) + fips_vtable->flash_log_add_event( + FE_LOG_TRNG_STALL, sizeof(reset_count), &reset_count); +#endif /** * High 32-bits set to zero in case of error; * otherwise value >> 32 == 1 |