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src/security/tpm: query recovery mode from Cr50

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On the Sarien/Arcada platforms, the EC is not trusted to provide
the state of the ESC+REFRESH+PWR recovery combination. On these
platforms the Cr50 latches the state of REFRESH+PWR for use as the
recovery mode key combination.

BUG=b:122715254
BRANCH=none
TEST=Verify recovery mode screen shown after pressing REFRESH+PWR
Signed-off-by: Keith Short <keithshort@chromium.org>
Change-Id: Ie3ce519956f916023c8c52f1d11fa93331f52f3c
Reviewed-on: https://review.coreboot.org/c/30929
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Keith Short 2019-01-11 07:52:32 -07:00 committed by Patrick Georgi
parent 49bfdb35f4
commit e371d42113
4 changed files with 31 additions and 0 deletions
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5
src/security/tpm/tss/tcg-2.0/tss_marshaling.c
View file

@ -273,6 +273,9 @@ static int marshal_cr50_vendor_command(struct obuf *ob, void *command_body)
rc |= obuf_write_be16(ob, sub_command[0]);
rc |= obuf_write_be16(ob, sub_command[1]);
break;
case TPM2_CR50_SUB_CMD_GET_REC_BTN:
rc |= obuf_write_be16(ob, *sub_command);
break;
default:
/* Unsupported subcommand. */
printk(BIOS_WARNING, "Unsupported cr50 subcommand: 0x%04x\n",
@ -473,6 +476,8 @@ static int unmarshal_vendor_command(struct ibuf *ib,
case TPM2_CR50_SUB_CMD_TURN_UPDATE_ON:
return ibuf_read_be8(ib, &vcr->num_restored_headers);
break;
case TPM2_CR50_SUB_CMD_GET_REC_BTN:
return ibuf_read_be8(ib, &vcr->recovery_button_state);
default:
printk(BIOS_ERR,
"%s:%d - unsupported vendor command %#04x!\n",

1
src/security/tpm/tss/tcg-2.0/tss_structures.h
View file

@ -297,6 +297,7 @@ struct vendor_command_response {
uint16_t vc_subcommand;
union {
uint8_t num_restored_headers;
uint8_t recovery_button_state;
};
};

16
src/security/tpm/tss/vendor/cr50/cr50.c vendored
View file

@ -52,3 +52,19 @@ uint32_t tlcl_cr50_enable_update(uint16_t timeout_ms,
*num_restored_headers = response->vcr.num_restored_headers;
return TPM_SUCCESS;
}
uint32_t tlcl_cr50_get_recovery_button(uint8_t *recovery_button_state)
{
struct tpm2_response *response;
uint16_t sub_command = TPM2_CR50_SUB_CMD_GET_REC_BTN;
printk(BIOS_INFO, "Checking cr50 for recovery request\n");
response = tpm_process_command(TPM2_CR50_VENDOR_COMMAND, &sub_command);
if (!response || response->hdr.tpm_code)
return TPM_E_INTERNAL_INCONSISTENCY;
*recovery_button_state = response->vcr.recovery_button_state;
return TPM_SUCCESS;
}

9
src/security/tpm/tss/vendor/cr50/cr50.h vendored
View file

@ -25,6 +25,7 @@
#define TPM2_CR50_VENDOR_COMMAND ((TPM_CC)(TPM_CC_VENDOR_BIT_MASK | 0))
#define TPM2_CR50_SUB_CMD_NVMEM_ENABLE_COMMITS (21)
#define TPM2_CR50_SUB_CMD_TURN_UPDATE_ON (24)
#define TPM2_CR50_SUB_CMD_GET_REC_BTN (29)
/**
* CR50 specific tpm command to enable nvmem commits before internal timeout
@ -44,4 +45,12 @@ uint32_t tlcl_cr50_enable_nvcommits(void);
uint32_t tlcl_cr50_enable_update(uint16_t timeout_ms,
uint8_t *num_restored_headers);
/**
* CR50 specific tpm command to get the latched state of the recovery button.
*
* Return value indicates success or failure of accessing the TPM; in case of
* success the recovery button state is saved in recovery_button_state.
*/
uint32_t tlcl_cr50_get_recovery_button(uint8_t *recovery_button_state);
#endif /* CR50_TSS_STRUCTURES_H_ */