diff --git a/sw/device/lib/crypto/drivers/BUILD b/sw/device/lib/crypto/drivers/BUILD index 0fe8705302d425..96ac47c3eca6c4 100644 --- a/sw/device/lib/crypto/drivers/BUILD +++ b/sw/device/lib/crypto/drivers/BUILD @@ -183,6 +183,7 @@ cc_library( "//sw/device/lib/base:macros", "//sw/device/lib/base:memory", "//sw/device/lib/crypto/impl:status", + "//sw/device/lib/runtime:log", ], ) diff --git a/sw/device/lib/crypto/drivers/hmac.c b/sw/device/lib/crypto/drivers/hmac.c index 3d10c2d962f6e2..b9363351496d49 100644 --- a/sw/device/lib/crypto/drivers/hmac.c +++ b/sw/device/lib/crypto/drivers/hmac.c @@ -9,6 +9,7 @@ #include "sw/device/lib/base/hardened.h" #include "sw/device/lib/base/memory.h" #include "sw/device/lib/crypto/impl/status.h" +#include "sw/device/lib/runtime/log.h" #include "hmac_regs.h" // Generated. #include "hw/top_earlgrey/sw/autogen/top_earlgrey.h" @@ -69,38 +70,6 @@ enum { kHmacBaseAddr = TOP_EARLGREY_HMAC_BASE_ADDR, }; -/** - * Wait until HMAC becomes idle. - * - * It returns error if HMAC HWIP becomes idle without firing `hmac_done` - * interrupt. - * - * TODO(#23191): It might be beneficial to have a timeout value for the polling. - * - * @return Result of the operation. - */ -OT_WARN_UNUSED_RESULT -static status_t hmac_idle_wait(void) { - // Verify that HMAC HWIP is idle. - // Initialize `status_reg = 0` so that the loop starts with the assumption - // that HMAC HWIP is not idle. - uint32_t status_reg = 0; - while (bitfield_bit32_read(status_reg, HMAC_STATUS_HMAC_IDLE_BIT) == 0) { - status_reg = abs_mmio_read32(kHmacBaseAddr + HMAC_STATUS_REG_OFFSET); - } - - // Verify that HMAC HWIP raises `hmac_done` bit. - uint32_t intr_reg = - abs_mmio_read32(kHmacBaseAddr + HMAC_INTR_STATE_REG_OFFSET); - if (bitfield_bit32_read(intr_reg, HMAC_INTR_STATE_HMAC_DONE_BIT) == 0) { - return OTCRYPTO_FATAL_ERR; - } - - // Clear the interrupt by writing 1, because `INTR_STATE` is rw1c type. - abs_mmio_write32(kHmacBaseAddr + HMAC_INTR_STATE_REG_OFFSET, intr_reg); - return OTCRYPTO_OK; -} - /** * Clear the state of HMAC HWIP so that further driver calls can use it. * @@ -256,6 +225,120 @@ static void msg_fifo_write(const uint8_t *message, size_t message_len) { } } +/** + * Recover HW after a stop has been triggered too long after the block boundary + * + * Temporary workaround linked to issue #24767 + * This function make the HW going into different states to move back on a + * working state. This is required when the stop has been issued later than the + * HW requires to compute the HASH. This duration is equivalent to 64 clock + * cycles in SHA2-256 and 80 clock cycles in SHA2-384/512. + * + * @param[out] ctx Context to which values are written. + */ +static void recover_hw_after_stop(hmac_ctx_t *ctx) { + // Save current context as it it updated after each block even if stop is not + // triggered + context_save(ctx); + + // Store if HMAC is enabled of not + uint32_t cfg_reg = abs_mmio_read32(kHmacBaseAddr + HMAC_CFG_REG_OFFSET); + uint32_t hmac_en = bitfield_bit32_read(cfg_reg, HMAC_CFG_HMAC_EN_BIT); + + // Disable the HMAC to trigger sha_hash_continue_o based on the register + // reg_hash_continue from hmac_core.sv + cfg_reg = bitfield_bit32_write(cfg_reg, HMAC_CFG_HMAC_EN_BIT, false); + abs_mmio_write32(kHmacBaseAddr + HMAC_CFG_REG_OFFSET, cfg_reg); + + // Trigger HASH continue to move from StIdle state to StFifoReceive from + // prim_sha2_pad.sv this will enable us to trigger shaf_rvalid_o later, this + // will unlock us from the state fifo_st_q==FifoLoadFromFifo in the block + // prim_sha2.sv. + uint32_t cmd_reg = abs_mmio_read32(kHmacBaseAddr + HMAC_CMD_REG_OFFSET); + cmd_reg = bitfield_bit32_write(cmd_reg, HMAC_CMD_HASH_CONTINUE_BIT, true); + abs_mmio_write32(kHmacBaseAddr + HMAC_CMD_REG_OFFSET, cmd_reg); + + // Get the current message length to know how much words we need to write to + // fall on the block boundary and trigger digest_on_blk to be able to move + // into done_state_d==DoneAwaitCmd in hmac.sv this will then lead to trigger + // hash_done_event and be back in a stable state on all the FSMs. + uint64_t msg_len = ((uint64_t)ctx->upper << 32) | ctx->lower; + uint32_t digest_size = + bitfield_field32_read(cfg_reg, HMAC_CFG_DIGEST_SIZE_FIELD); + + // Compute next block boundary + uint32_t msg_length_to_wr; + // SHA2-256 mode + if (digest_size == 1) { + msg_length_to_wr = kHmacSha256BlockBits - msg_len % kHmacSha256BlockBits; + } else { + msg_length_to_wr = kHmacSha512BlockBits - msg_len % kHmacSha512BlockBits; + } + + // Write a dummy message into the message FIFO to trigger shaf_rvalid_o + // from prim_sha2_pad.sv + for (int i=0; idigest_wordlen); @@ -512,7 +599,8 @@ status_t hmac(const hmac_mode_t hmac_mode, const uint32_t *key, abs_mmio_write32(kHmacBaseAddr + HMAC_CMD_REG_OFFSET, cmd_reg); // Wait for HMAC HWIP operation to be completed. - HARDENED_TRY(hmac_idle_wait()); + hmac_ctx_t *ctx = NULL; + HARDENED_TRY(hmac_idle_wait(ctx)); digest_read(digest, digest_wordlen);