linux-kernel - Re: [PATCH v5 3/3] efi: Add tee-based EFI variable driver

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Message-ID: <CAC_iWjKZNHJxq4VMFnV7oQngwBBCQveh=s34u1LZ59YUqViPbw@mail.gmail.com>
Date:   Wed, 7 Jun 2023 19:09:58 +0300
From:   Ilias Apalodimas <ilias.apalodimas@...aro.org>
To:     Jan Kiszka <jan.kiszka@...mens.com>
Cc:     Sumit Garg <sumit.garg@...aro.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        Masahisa Kojima <masahisa.kojima@...aro.org>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        linux-kernel@...r.kernel.org, op-tee@...ts.trustedfirmware.org,
        Johan Hovold <johan+linaro@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        linux-efi@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org,
        "Su, Bao Cheng (RC-CN DF FA R&D)" <baocheng.su@...mens.com>
Subject: Re: [PATCH v5 3/3] efi: Add tee-based EFI variable driver

Hi Jan,

[...]
> >>> No I don't, this will work reliably without the need to remount the efivarfs.
> >>> As you point out you will still have this dependency if you end up
> >>> building them as modules and you manage to mount the efivarfs before
> >>> those get inserted.  Does anyone see a reasonable workaround?
> >>> Deceiving the kernel and making the bootloader set the RT property bit
> >>> to force the filesystem being mounted as rw is a nasty hack that we
> >>> should avoid.  Maybe adding a kernel command line parameter that says
> >>> "Ignore the RTPROP I know what I am doing"?  I don't particularly love
> >>> this either, but it's not unreasonable.
> >>
> >> In the context of https://github.com/OP-TEE/optee_os/issues/6094,
> >> basically this issue mapped on reboot/shutdown, I would really love to
> >> see the unhandy tee-supplicant daemon to be overcome.
> >
> > I have seen this error before and it has been on my todo list. So I
> > have tried to fix it here [1]. Feel free to test it and let me know if
> > you see any further issues.
> >
> > [1] https://lkml.org/lkml/2023/6/7/927
> >
>
> Ah, nice, will test ASAP!
>
> Meanwhile more food: I managed to build a firmware that was missing
> STMM. But the driver loaded, and I got this:

Thanks for the testing. I'll try to reproduce it locally and get back to you

/Ilias
>
> root@...2050-debian:~# efi-updatevar -f PK.auth PK
> [  243.407097] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> [  243.415959] Mem abort info:
> [  243.418801]   ESR = 0x86000004
> [  243.422099]   EC = 0x21: IABT (current EL), IL = 32 bits
> [  243.427529]   SET = 0, FnV = 0
> [  243.430755]   EA = 0, S1PTW = 0
> [  243.433931] user pgtable: 4k pages, 48-bit VAs, pgdp=000000008b74e000
> [  243.440438] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
> [  243.447274] Internal error: Oops: 86000004 [#1] PREEMPT SMP
> [  243.452835] Modules linked in: ctr ccm mt7601u mac80211 cfg80211 rfkill libarc4 cp210x usbserial pci_endpoint_test ti_k3_r5_remoteproc optee_rng rng_core ti_cal ti_am335x_adc videobuf2_dma_contig kfifo_buf v4l2_fwnode videobuf2_memops videobuf2_v4l2 videobuf2_common irq_pruss_intc at24 fuse ip_tables x_tables ipv6 tpm_ftpm_tee icssg_prueth pru_rproc icss_iep ptp pps_core ti_am335x_tscadc pruss
> [  243.487733] CPU: 0 PID: 875 Comm: efi-updatevar Not tainted 5.10.162-cip24 #1
> [  243.494851] Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2023.07-rc3-00018-g0afdaac6505 07/01/2023
> [  243.505180] pstate: 00000005 (nzcv daif -PAN -UAO -TCO BTYPE=--)
> [  243.511179] pc : 0x0
> [  243.513366] lr : efivar_entry_set_get_size+0xd4/0x1e0
> [  243.518404] sp : ffff8000127a3d00
> [  243.521708] x29: ffff8000127a3d00 x28: 0000000000000f87
> [  243.527012] x27: ffff000005bae400 x26: ffff800011254000
> [  243.532315] x25: ffff000005baf000 x24: ffff800011254aa0
> [  243.537618] x23: ffff8000127a3dab x22: ffff8000111d0268
> [  243.542921] x21: ffff8000127a3db0 x20: 0000000000000000
> [  243.548224] x19: ffff000005bae000 x18: 0000000000000000
> [  243.553527] x17: 0000000000000000 x16: 0000000000000000
> [  243.558829] x15: 0000aaab0876f264 x14: 35cd6a1025d11a20
> [  243.564132] x13: ac6f8dda3945638d x12: fb482642e3487f2d
> [  243.569435] x11: 0000000000000003 x10: ffff00000b792a80
> [  243.574738] x9 : a098e2bf989ff097 x8 : 0000000000000010
> [  243.580041] x7 : ffff800010e35c00 x6 : 4ddcbe2ecfc8fc79
> [  243.585345] x5 : 0000000000000000 x4 : ffff000005baf000
> [  243.590647] x3 : 0000000000000f87 x2 : 0000000000000027
> [  243.595950] x1 : ffff000005bae400 x0 : ffff000005bae000
> [  243.601254] Call trace:
> [  243.603695]  0x0
> [  243.605531]  efivarfs_file_write+0xa4/0x170
> [  243.609709]  vfs_write+0xf0/0x2a4
> [  243.613016]  ksys_write+0x68/0xf4
> [  243.616323]  __arm64_sys_write+0x1c/0x2c
> [  243.620241]  el0_svc_common.constprop.0+0x78/0x1c4
> [  243.625022]  do_el0_svc+0x24/0x8c
> [  243.628331]  el0_svc+0x14/0x20
> [  243.631378]  el0_sync_handler+0xb0/0xb4
> [  243.635206]  el0_sync+0x180/0x1c0
> [  243.638523] Code: bad PC value
> [  243.641573] ---[ end trace 369e4632cb003adc ]---
>
> Jan
>
> --
> Siemens AG, Technology
> Competence Center Embedded Linux
>