platform_get_irq() has already checked and printed the return value,
the printing here is nothing special, it is not necessary at all.
Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
MODULE_SUPPORTED_DEVICE was added in pre-git era and never was
implemented. We can safely remove it, because the kernel has grown
to have many more reliable mechanisms to determine if device is
supported or not.
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
BCM6368 devices need to reset the IPSEC controller in order to generate true
random numbers.
This is what BCM6368 produces without a reset:
root@OpenWrt:/# cat /dev/hwrng | rngtest -c 1000
rngtest 6.10
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
rngtest: starting FIPS tests...
rngtest: bits received from input: 20000032
rngtest: FIPS 140-2 successes: 0
rngtest: FIPS 140-2 failures: 1000
rngtest: FIPS 140-2(2001-10-10) Monobit: 2
rngtest: FIPS 140-2(2001-10-10) Poker: 1000
rngtest: FIPS 140-2(2001-10-10) Runs: 1000
rngtest: FIPS 140-2(2001-10-10) Long run: 30
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=37.253; avg=320.827; max=635.783)Mibits/s
rngtest: FIPS tests speed: (min=12.141; avg=15.034; max=16.428)Mibits/s
rngtest: Program run time: 1336176 microseconds
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull powerpc fixes from Michael Ellerman:
"One non-fix, the conversion of vio_driver->remove() to return void,
which touches various powerpc specific drivers.
Fix the privilege checks we do in our perf handling, which could cause
soft/hard lockups in some configurations.
Fix a bug with IRQ affinity seen on kdump kernels when CPU 0 is
offline in the second kernel.
Fix missed page faults after mprotect(..., PROT_NONE) on 603 (32-bit).
Fix a bug in our VSX (vector) instruction emulation, which should only
be seen when doing VSX ops to cache inhibited mappings.
Three commits fixing various build issues with obscure configurations.
Thanks to Athira Rajeev, Cédric Le Goater, Christophe Leroy, Christoph
Plattner, Greg Kurz, Jordan Niethe, Laurent Vivier, Ravi Bangoria,
Tyrel Datwyler, and Uwe Kleine-König"
* tag 'powerpc-5.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/sstep: Fix VSX instruction emulation
powerpc/perf: Fix handling of privilege level checks in perf interrupt context
powerpc: Force inlining of mmu_has_feature to fix build failure
vio: make remove callback return void
powerpc/syscall: Force inlining of __prep_irq_for_enabled_exit()
powerpc/603: Fix protection of user pages mapped with PROT_NONE
powerpc/pseries: Don't enforce MSI affinity with kdump
powerpc/4xx: Fix build errors from mfdcr()
This commit fixes the checkpatch warning:
WARNING: Use #include <linux/io.h> instead of <asm/io.h>
drivers/char/hw_random/omap-rng.c:34
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
clk_prepare_enable() and clk_disable_unprepare() will check
NULL clock parameter, so It is not necessary to add additional checks.
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Somewhere along the line, probably during a rebase, an unintentional
dump_stack() got included. Revert this change.
Reported-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Fixes: 90cba8d20f ("tpm/ppi: Constify static struct attribute_group")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct vio_driver::remove() return
void, too. All users already unconditionally return 0, this commit makes
it obvious that returning an error code is a bad idea.
Note there are two nominally different implementations for a vio bus:
one in arch/sparc/kernel/vio.c and the other in
arch/powerpc/platforms/pseries/vio.c. This patch only adapts the powerpc
one.
Before this patch for a device that was bound to a driver without a
remove callback vio_cmo_bus_remove(viodev) wasn't called. As the device
core still considers the device unbound after vio_bus_remove() returns
calling this unconditionally is the consistent behaviour which is
implemented here.
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Acked-by: Lijun Pan <ljp@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[mpe: Drop unneeded hvcs_remove() forward declaration, squash in
change from sfr to drop ibmvnic_remove() forward declaration]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210225221834.160083-1-uwe@kleine-koenig.org
Pull char/misc driver updates from Greg KH:
"Here is the large set of char/misc/whatever driver subsystem updates
for 5.12-rc1. Over time it seems like this tree is collecting more and
more tiny driver subsystems in one place, making it easier for those
maintainers, which is why this is getting larger.
Included in here are:
- coresight driver updates
- habannalabs driver updates
- virtual acrn driver addition (proper acks from the x86 maintainers)
- broadcom misc driver addition
- speakup driver updates
- soundwire driver updates
- fpga driver updates
- amba driver updates
- mei driver updates
- vfio driver updates
- greybus driver updates
- nvmeem driver updates
- phy driver updates
- mhi driver updates
- interconnect driver udpates
- fsl-mc bus driver updates
- random driver fix
- some small misc driver updates (rtsx, pvpanic, etc.)
All of these have been in linux-next for a while, with the only
reported issue being a merge conflict due to the dfl_device_id
addition from the fpga subsystem in here"
* tag 'char-misc-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (311 commits)
spmi: spmi-pmic-arb: Fix hw_irq overflow
Documentation: coresight: Add PID tracing description
coresight: etm-perf: Support PID tracing for kernel at EL2
coresight: etm-perf: Clarify comment on perf options
ACRN: update MAINTAINERS: mailing list is subscribers-only
regmap: sdw-mbq: use MODULE_LICENSE("GPL")
regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ
regmap: sdw: use _no_pm functions in regmap_read/write
soundwire: intel: fix possible crash when no device is detected
MAINTAINERS: replace my with email with replacements
mhi: Fix double dma free
uapi: map_to_7segment: Update example in documentation
uio: uio_pci_generic: don't fail probe if pdev->irq equals to IRQ_NOTCONNECTED
drivers/misc/vmw_vmci: restrict too big queue size in qp_host_alloc_queue
firewire: replace tricky statement by two simple ones
vme: make remove callback return void
firmware: google: make coreboot driver's remove callback return void
firmware: xilinx: Use explicit values for all enum values
sample/acrn: Introduce a sample of HSM ioctl interface usage
virt: acrn: Introduce an interface for Service VM to control vCPU
...
This is shown with Samsung Chromebook Pro (Caroline) with TPM 1.2
(SLB 9670):
[ 4.324298] TPM returned invalid status
[ 4.324806] WARNING: CPU: 2 PID: 1 at drivers/char/tpm/tpm_tis_core.c:275 tpm_tis_status+0x86/0x8f
Background
==========
TCG PC Client Platform TPM Profile (PTP) Specification, paragraph 6.1 FIFO
Interface Locality Usage per Register, Table 39 Register Behavior Based on
Locality Setting for FIFO - a read attempt to TPM_STS_x Registers returns
0xFF in case of lack of locality.
The fix
=======
Decorate tpm_tis_gen_interrupt() with request_locality() and
release_locality().
Cc: Laurent Bigonville <bigon@debian.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org
Fixes: a3fbfae82b ("tpm: take TPM chip power gating out of tpm_transmit()")
Signed-off-by: Lukasz Majczak <lma@semihalf.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
This is shown with Samsung Chromebook Pro (Caroline) with TPM 1.2
(SLB 9670):
[ 4.324298] TPM returned invalid status
[ 4.324806] WARNING: CPU: 2 PID: 1 at drivers/char/tpm/tpm_tis_core.c:275 tpm_tis_status+0x86/0x8f
Background
==========
TCG PC Client Platform TPM Profile (PTP) Specification, paragraph 6.1 FIFO
Interface Locality Usage per Register, Table 39 Register Behavior Based on
Locality Setting for FIFO - a read attempt to TPM_STS_x Registers returns
0xFF in case of lack of locality.
The fix
=======
Decorate tpm_get_timeouts() with request_locality() and release_locality().
Fixes: a3fbfae82b ("tpm: take TPM chip power gating out of tpm_transmit()")
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Laurent Bigonville <bigon@debian.org>
Cc: stable@vger.kernel.org
Reported-by: Lukasz Majczak <lma@semihalf.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Pull IPMI update from Corey Minyard:
"Only one change, but it's required for other things, so it needs to go
in"
* tag 'for-linus-5.12-1' of git://github.com/cminyard/linux-ipmi:
ipmi: remove open coded version of SMBus block write
Pull follow_pfn() updates from Daniel Vetter:
"Fixes around VM_FPNMAP and follow_pfn:
- replace mm/frame_vector.c by get_user_pages in misc/habana and
drm/exynos drivers, then move that into media as it's sole user
- close race in generic_access_phys
- s390 pci ioctl fix of this series landed in 5.11 already
- properly revoke iomem mappings (/dev/mem, pci files)"
* tag 'topic/iomem-mmap-vs-gup-2021-02-22' of git://anongit.freedesktop.org/drm/drm:
PCI: Revoke mappings like devmem
PCI: Also set up legacy files only after sysfs init
sysfs: Support zapping of binary attr mmaps
resource: Move devmem revoke code to resource framework
/dev/mem: Only set filp->f_mapping
PCI: Obey iomem restrictions for procfs mmap
mm: Close race in generic_access_phys
media: videobuf2: Move frame_vector into media subsystem
mm/frame-vector: Use FOLL_LONGTERM
misc/habana: Use FOLL_LONGTERM for userptr
misc/habana: Stop using frame_vector helpers
drm/exynos: Use FOLL_LONGTERM for g2d cmdlists
drm/exynos: Stop using frame_vector helpers
Pull ARM updates from Russell King:
- Generalise byte swapping assembly
- Update debug addresses for STI
- Validate start of physical memory with DTB
- Do not clear SCTLR.nTLSMD in decompressor
- amba/locomo/sa1111 devices remove method return type is void
- address markers for KASAN in page table dump
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 9065/1: OABI compat: fix build when EPOLL is not enabled
ARM: 9055/1: mailbox: arm_mhuv2: make remove callback return void
amba: Make use of bus_type functions
amba: Make the remove callback return void
vfio: platform: simplify device removal
amba: reorder functions
amba: Fix resource leak for drivers without .remove
ARM: 9054/1: arch/arm/mm/mmu.c: Remove duplicate header
ARM: 9053/1: arm/mm/ptdump:Add address markers for KASAN regions
ARM: 9051/1: vdso: remove unneded extra-y addition
ARM: 9050/1: Kconfig: Select ARCH_HAVE_NMI_SAFE_CMPXCHG where possible
ARM: 9049/1: locomo: make locomo bus's remove callback return void
ARM: 9048/1: sa1111: make sa1111 bus's remove callback return void
ARM: 9047/1: smp: remove unused variable
ARM: 9046/1: decompressor: Do not clear SCTLR.nTLSMD for ARMv7+ cores
ARM: 9045/1: uncompress: Validate start of physical memory against passed DTB
ARM: 9042/1: debug: no uncompress debugging while semihosting
ARM: 9041/1: sti LL_UART: add STiH418 SBC UART0 support
ARM: 9040/1: use DEBUG_UART_PHYS and DEBUG_UART_VIRT for sti LL_UART
ARM: 9039/1: assembler: generalize byte swapping macro into rev_l
Pull tpm updates from Jarkko Sakkinen:
"New features:
- Cr50 I2C TPM driver
- sysfs exports of PCR registers in TPM 2.0 chips
Bug fixes:
- bug fixes for tpm_tis driver, which had a racy wait for hardware
state change to be ready to send a command to the TPM chip. The bug
has existed already since 2006, but has only made itself known in
recent past. This is the same as the "last time" :-)
- Otherwise there's bunch of fixes for not as alarming regressions. I
think the list is about the same as last time, except I added fixes
for some disjoint bugs in trusted keys that I found some time ago"
* tag 'tpmdd-next-v5.12-rc1-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
KEYS: trusted: Reserve TPM for seal and unseal operations
KEYS: trusted: Fix migratable=1 failing
KEYS: trusted: Fix incorrect handling of tpm_get_random()
tpm/ppi: Constify static struct attribute_group
ABI: add sysfs description for tpm exports of PCR registers
tpm: add sysfs exports for all banks of PCR registers
keys: Update comment for restrict_link_by_key_or_keyring_chain
tpm: Remove tpm_dev_wq_lock
char: tpm: add i2c driver for cr50
tpm: Fix fall-through warnings for Clang
tpm_tis: Clean up locality release
tpm_tis: Fix check_locality for correct locality acquisition
Pull MIPS updates from Thomas Bogendoerfer:
- added support for Nintendo N64
- added support for Realtek RTL83XX SoCs
- kaslr support for Loongson64
- first steps to get rid of set_fs()
- DMA runtime coherent/non-coherent selection cleanup
- cleanups and fixes
* tag 'mips_5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (98 commits)
Revert "MIPS: Add basic support for ptrace single step"
vmlinux.lds.h: catch more UBSAN symbols into .data
MIPS: kernel: Drop kgdb_call_nmi_hook
MAINTAINERS: Add git tree for KVM/mips
MIPS: Use common way to parse elfcorehdr
MIPS: Simplify EVA cache handling
Revert "MIPS: kernel: {ftrace,kgdb}: Set correct address limit for cache flushes"
MIPS: remove CONFIG_DMA_PERDEV_COHERENT
MIPS: remove CONFIG_DMA_MAYBE_COHERENT
driver core: lift dma_default_coherent into common code
MIPS: refactor the runtime coherent vs noncoherent DMA indicators
MIPS/alchemy: factor out the DMA coherent setup
MIPS/malta: simplify plat_setup_iocoherency
MIPS: Add basic support for ptrace single step
MAINTAINERS: replace non-matching patterns for loongson{2,3}
MIPS: Make check condition for SDBBP consistent with EJTAG spec
mips: Replace lkml.org links with lore
Revert "MIPS: microMIPS: Fix the judgment of mm_jr16_op and mm_jalr_op"
MIPS: crash_dump.c: Simplify copy_oldmem_page()
Revert "mips: Manually call fdt_init_reserved_mem() method"
...
Pull arm64 updates from Will Deacon:
- vDSO build improvements including support for building with BSD.
- Cleanup to the AMU support code and initialisation rework to support
cpufreq drivers built as modules.
- Removal of synthetic frame record from exception stack when entering
the kernel from EL0.
- Add support for the TRNG firmware call introduced by Arm spec
DEN0098.
- Cleanup and refactoring across the board.
- Avoid calling arch_get_random_seed_long() from
add_interrupt_randomness()
- Perf and PMU updates including support for Cortex-A78 and the v8.3
SPE extensions.
- Significant steps along the road to leaving the MMU enabled during
kexec relocation.
- Faultaround changes to initialise prefaulted PTEs as 'old' when
hardware access-flag updates are supported, which drastically
improves vmscan performance.
- CPU errata updates for Cortex-A76 (#1463225) and Cortex-A55
(#1024718)
- Preparatory work for yielding the vector unit at a finer granularity
in the crypto code, which in turn will one day allow us to defer
softirq processing when it is in use.
- Support for overriding CPU ID register fields on the command-line.
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (85 commits)
drivers/perf: Replace spin_lock_irqsave to spin_lock
mm: filemap: Fix microblaze build failure with 'mmu_defconfig'
arm64: Make CPU_BIG_ENDIAN depend on ld.bfd or ld.lld 13.0.0+
arm64: cpufeatures: Allow disabling of Pointer Auth from the command-line
arm64: Defer enabling pointer authentication on boot core
arm64: cpufeatures: Allow disabling of BTI from the command-line
arm64: Move "nokaslr" over to the early cpufeature infrastructure
KVM: arm64: Document HVC_VHE_RESTART stub hypercall
arm64: Make kvm-arm.mode={nvhe, protected} an alias of id_aa64mmfr1.vh=0
arm64: Add an aliasing facility for the idreg override
arm64: Honor VHE being disabled from the command-line
arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line
arm64: cpufeature: Add an early command-line cpufeature override facility
arm64: Extract early FDT mapping from kaslr_early_init()
arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding()
arm64: cpufeature: Add global feature override facility
arm64: Move SCTLR_EL1 initialisation to EL-agnostic code
arm64: Simplify init_el2_state to be non-VHE only
arm64: Move VHE-specific SPE setup to mutate_to_vhe()
arm64: Drop early setting of MDSCR_EL2.TPMS
...
When TPM 2.0 trusted keys code was moved to the trusted keys subsystem,
the operations were unwrapped from tpm_try_get_ops() and tpm_put_ops(),
which are used to take temporarily the ownership of the TPM chip. The
ownership is only taken inside tpm_send(), but this is not sufficient,
as in the key load TPM2_CC_LOAD, TPM2_CC_UNSEAL and TPM2_FLUSH_CONTEXT
need to be done as a one single atom.
Take the TPM chip ownership before sending anything with
tpm_try_get_ops() and tpm_put_ops(), and use tpm_transmit_cmd() to send
TPM commands instead of tpm_send(), reverting back to the old behaviour.
Fixes: 2e19e10131 ("KEYS: trusted: Move TPM2 trusted keys code")
Reported-by: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: stable@vger.kernel.org
Cc: David Howells <dhowells@redhat.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
Acked-by Sumit Garg <sumit.garg@linaro.org>
Tested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The only usage of ppi_attr_grp is to put its address in an array of
pointers to const struct attribute_group. Make it const to allow the
compiler to put it in read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Create sysfs per hash groups with 24 PCR files in them one group,
named pcr-<hash>, for each agile hash of the TPM. The files are
plugged in to a PCR read function which is TPM version agnostic, so
this works also for TPM 1.2 but the hash is only sha1 in that case.
Note: the macros used to create the hashes emit spurious checkpatch
warnings. Do not try to "fix" them as checkpatch recommends, otherwise
they'll break.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Tested-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Add TPM 2.0 compatible I2C interface for chips with cr50 firmware.
The firmware running on the currently supported H1 MCU requires a
special driver to handle its specific protocol, and this makes it
unsuitable to use tpm_tis_core_* and instead it must implement the
underlying TPM protocol similar to the other I2C TPM drivers.
- All 4 bytes of status register must be read/written at once.
- FIFO and burst count is limited to 63 and must be drained by AP.
- Provides an interrupt to indicate when read response data is ready
and when the TPM is finished processing write data.
This driver is based on the existing infineon I2C TPM driver, which
most closely matches the cr50 i2c protocol behavior.
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Tested-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The current release locality code seems to be based on the
misunderstanding that the TPM interrupts when a locality is released:
it doesn't, only when the locality is acquired.
Furthermore, there seems to be no point in waiting for the locality to
be released. All it does is penalize the last TPM user. However, if
there's no next TPM user, this is a pointless wait and if there is a
next TPM user, they'll pay the penalty waiting for the new locality
(or possibly not if it's the same as the old locality).
Fix the code by making release_locality as simple write to release
with no waiting for completion.
Cc: stable@ger.kernel.org
Fixes: 33bafe9082 ("tpm_tis: verify locality released before returning from release_locality")
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The TPM TIS specification says the TPM signals the acquisition of locality
when the TMP_ACCESS_REQUEST_USE bit goes to one *and* the
TPM_ACCESS_REQUEST_USE bit goes to zero. Currently we only check the
former not the latter, so check both. Adding the check on
TPM_ACCESS_REQUEST_USE should fix the case where the locality is
re-requested before the TPM has released it. In this case the locality may
get released briefly before it is reacquired, which causes all sorts of
problems. However, with the added check, TPM_ACCESS_REQUEST_USE should
remain 1 until the second request for the locality is granted.
Cc: stable@ger.kernel.org
Fixes: 27084efee0 ("[PATCH] tpm: driver for next generation TPM chips")
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The block-write function of the core was not used because there was no
client-struct to use. However, in this case it seems apropriate to use a
temporary client struct. Because we are answering a request we recieved
when being a client ourselves. So, convert the code to use a temporary
client and use the block-write function of the I2C core.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Message-Id: <20210128085544.7609-1-wsa+renesas@sang-engineering.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
When reseeding the CRNG periodically, arch_get_random_seed_long() is
called to obtain entropy from an architecture specific source if one
is implemented. In most cases, these are special instructions, but in
some cases, such as on ARM, we may want to back this using firmware
calls, which are considerably more expensive.
Another call to arch_get_random_seed_long() exists in the CRNG driver,
in add_interrupt_randomness(), which collects entropy by capturing
inter-interrupt timing and relying on interrupt jitter to provide
random bits. This is done by keeping a per-CPU state, and mixing in
the IRQ number, the cycle counter and the return address every time an
interrupt is taken, and mixing this per-CPU state into the entropy pool
every 64 invocations, or at least once per second. The entropy that is
gathered this way is credited as 1 bit of entropy. Every time this
happens, arch_get_random_seed_long() is invoked, and the result is
mixed in as well, and also credited with 1 bit of entropy.
This means that arch_get_random_seed_long() is called at least once
per second on every CPU, which seems excessive, and doesn't really
scale, especially in a virtualization scenario where CPUs may be
oversubscribed: in cases where arch_get_random_seed_long() is backed
by an instruction that actually goes back to a shared hardware entropy
source (such as RNDRRS on ARM), we will end up hitting it hundreds of
times per second.
So let's drop the call to arch_get_random_seed_long() from
add_interrupt_randomness(), and instead, rely on crng_reseed() to call
the arch hook to get random seed material from the platform.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20201105152944.16953-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
