[More CCs, LKML dropped] On Thursday, July 04, 2013 08:41:00 PM Adam Langley wrote: > All TPM PPI calls appear to result in ACPI errors for me: > > # cat /sys/devices/pnp0/00:09/ppi/version > cat: version: Cannot allocate memory > > (All the nodes in that directory have the same result for read and write.) > > This appears to be coming from acpi_evaluate_object_typed in > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/char/tpm/tpm_ppi.c#n75, > so I added a printk to get the actual value of |status| when it fails > and it's 5 (aka AE_NOT_FOUND I believe). > > My knowledge of ACPI is almost nil, but here's some disassembly from > the DSDT table (I don't know if that's the right one), where it > doesn't seem impossible that it could return the string "1.2". > > Scope (_SB.PCI0.LPCB.TPM) > { > OperationRegion (TSMI, SystemIO, SMIT, 0x02) > Field (TSMI, ByteAcc, NoLock, Preserve) > { > INQ, 8, > DAT, 8 > } > > Method (_DSM, 4, NotSerialized) // _DSM: Device-Specific Method > { > If (LEqual (Arg0, Buffer (0x10) > { > /* 0000 */ 0xA6, 0xFA, 0xDD, 0x3D, 0x1B, 0x36, 0xB4, 0x4E, > /* 0008 */ 0xA4, 0x24, 0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53 > })) > { > Name (_T_0, Zero) // _T_x: Emitted by ASL Compiler > Store (ToInteger (Arg2), _T_0) > If (LEqual (_T_0, Zero)) > { > Return (Buffer (0x02) > { > 0xFF, 0x01 > }) > } > Else > { > If (LEqual (_T_0, One)) > { > Return ("1.2") > } > Else > { > If (LEqual (_T_0, 0x02)) > { > ToInteger (DerefOf (Index (Arg3, Zero)), TMF2) > Store (0x12, TMF1) > Store (TMF1, DAT) > Store (OFST, INQ) > If (LEqual (DAT, 0xFF)) > { > Return (0x02) > } > ... > > # tpm_version > TPM 1.2 Version Info: > Chip Version: 1.2.3.69 > Spec Level: 2 > Errata Revision: 3 > TPM Vendor ID: WEC > TPM Version: 01010000 > Manufacturer Info: 57454300 > > The motherboard is an Intel DQ77KB. > > Any hints would be very helpful because I'm stuck at this point. > > Here's how I got here: > > 1) I want to store 32 bytes of data in a such a way that they can be > safely erased in the future. With log-structured filesystems and SSDs, > that seems quite hard these days. > > 2) Using NVRAM looks like it might be fruitful and the TPM has some > designed to be written to, as opposed to the RTC NVRAM, which seems > dangerous. > > 3) The TPM appears to want a physical presence signal before it'll let > me create a new NVRAM area: > > # tpm_nvdefine -s 32 -i 0x10000002 -p WRITEALL > Tspi_NV_DefineSpace failed: 0x0000002d - layer=tpm, code=002d (45), > Bad physical presence value > > # sudo tpm_setpresence -z > Physical Presence Status: > Command Enable: true > Hardware Enable: false > Lifetime Lock: true > Physical Presence: false > Lock: true > > # sudo tpm_setpresence -z -a > Tspi_TPM_SetStatus failed: 0x00002006 - layer=tcs, code=0006 (6), Not > implemented > > There's nothing that I can find in the BIOS to assert presence but I'm > led to understand the the PPI interface allows one to request that the > BIOS assert physical presence: > > http://www.trustedcomputinggroup.org/resources/tcg_physical_presence_interface_specification > > 4) So I'm trying to get the ppi driver to do something. > > > Cheers > > AGL > > -- > Adam Langley agl@xxxxxxxxxxxxxxxxxx http://www.imperialviolet.org > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
