commit 44b82b7700d05a52cd983799d3ecde1a976b3bed upstream.
Commit d7a49086f263164a (arm64: cpuinfo: print info for all CPUs)
attempted to clean up /proc/cpuinfo, but due to concerns regarding
further changes was reverted in commit 5e39977edf6500fd (Revert "arm64:
cpuinfo: print info for all CPUs").
There are two major issues with the arm64 /proc/cpuinfo format
currently:
* The "Features" line describes (only) the 64-bit hwcaps, which is
problematic for some 32-bit applications which attempt to parse it. As
the same names are used for analogous ISA features (e.g. aes) despite
these generally being architecturally unrelated, it is not possible to
simply append the 64-bit and 32-bit hwcaps in a manner that might not
be misleading to some applications.
Various potential solutions have appeared in vendor kernels. Typically
the format of the Features line varies depending on whether the task
is 32-bit.
* Information is only printed regarding a single CPU. This does not
match the ARM format, and does not provide sufficient information in
big.LITTLE systems where CPUs are heterogeneous. The CPU information
printed is queried from the current CPU's registers, which is racy
w.r.t. cross-cpu migration.
This patch attempts to solve these issues. The following changes are
made:
* When a task with a LINUX32 personality attempts to read /proc/cpuinfo,
the "Features" line contains the decoded 32-bit hwcaps, as with the
arm port. Otherwise, the decoded 64-bit hwcaps are shown. This aligns
with the behaviour of COMPAT_UTS_MACHINE and COMPAT_ELF_PLATFORM. In
the absense of compat support, the Features line is empty.
The set of hwcaps injected into a task's auxval are unaffected.
* Properties are printed per-cpu, as with the ARM port. The per-cpu
information is queried from pre-recorded cpu information (as used by
the sanity checks).
* As with the previous attempt at fixing up /proc/cpuinfo, the hardware
field is removed. The only users so far are 32-bit applications tied
to particular boards, so no portable applications should be affected,
and this should prevent future tying to particular boards.
The following differences remain:
* No model_name is printed, as this cannot be queried from the hardware
and cannot be provided in a stable fashion. Use of the CPU
{implementor,variant,part,revision} fields is sufficient to identify a
CPU and is portable across arm and arm64.
* The following system-wide properties are not provided, as they are not
possible to provide generally. Programs relying on these are already
tied to particular (32-bit only) boards:
- Hardware
- Revision
- Serial
No software has yet been identified for which these remaining
differences are problematic.
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Ian Campbell <ijc@hellion.org.uk>
Cc: Serban Constantinescu <serban.constantinescu@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: cross-distro@lists.linaro.org
Cc: linux-api@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7d57511d2dba03a8046c8b428dd9192a4bfc1e73 upstream. Commit a469abd0f868 (ARM: elf: add new hwcap for identifying atomic ldrd/strd instructions) introduces HWCAP_ELF for 32-bit ARM applications. As LPAE is always present on arm64, report the corresponding compat HWCAP to user space. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tag 'arm64-suspend' of git://linux-arm.org/linux-2.6-lp:
arm64: add CPU power management menu/entries
arm64: kernel: add PM build infrastructure
arm64: kernel: add CPU idle call
arm64: enable generic clockevent broadcast
arm64: kernel: implement HW breakpoints CPU PM notifier
arm64: kernel: refactor code to install/uninstall breakpoints
arm: kvm: implement CPU PM notifier
arm64: kernel: implement fpsimd CPU PM notifier
arm64: kernel: cpu_{suspend/resume} implementation
arm64: kernel: suspend/resume registers save/restore
arm64: kernel: build MPIDR_EL1 hash function data structure
arm64: kernel: add MPIDR_EL1 accessors macros
Conflicts:
arch/arm64/Kconfig
Advertise the optional cryptographic and CRC32 instructions to user space where present. Several hwcap bits [3-7] are allocated. Signed-off-by: Steve Capper <steve.capper@linaro.org> [bit 2 is taken now so use bits 3-7 instead] Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Code referenced in the comment has moved to arch/arm64/kernel/cputable.c Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch implements optimised percpu variable accesses using the el1 r/w thread register (tpidr_el1) along the same lines as arch/arm/. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On ARM64 SMP systems, cores are identified by their MPIDR_EL1 register.
The MPIDR_EL1 guidelines in the ARM ARM do not provide strict enforcement of
MPIDR_EL1 layout, only recommendations that, if followed, split the MPIDR_EL1
on ARM 64 bit platforms in four affinity levels. In multi-cluster
systems like big.LITTLE, if the affinity guidelines are followed, the
MPIDR_EL1 can not be considered a linear index. This means that the
association between logical CPU in the kernel and the HW CPU identifier
becomes somewhat more complicated requiring methods like hashing to
associate a given MPIDR_EL1 to a CPU logical index, in order for the look-up
to be carried out in an efficient and scalable way.
This patch provides a function in the kernel that starting from the
cpu_logical_map, implement collision-free hashing of MPIDR_EL1 values by
checking all significative bits of MPIDR_EL1 affinity level bitfields.
The hashing can then be carried out through bits shifting and ORing; the
resulting hash algorithm is a collision-free though not minimal hash that can
be executed with few assembly instructions. The mpidr_el1 is filtered through a
mpidr mask that is built by checking all bits that toggle in the set of
MPIDR_EL1s corresponding to possible CPUs. Bits that do not toggle do not
carry information so they do not contribute to the resulting hash.
Pseudo code:
/* check all bits that toggle, so they are required */
for (i = 1, mpidr_el1_mask = 0; i < num_possible_cpus(); i++)
mpidr_el1_mask |= (cpu_logical_map(i) ^ cpu_logical_map(0));
/*
* Build shifts to be applied to aff0, aff1, aff2, aff3 values to hash the
* mpidr_el1
* fls() returns the last bit set in a word, 0 if none
* ffs() returns the first bit set in a word, 0 if none
*/
fs0 = mpidr_el1_mask[7:0] ? ffs(mpidr_el1_mask[7:0]) - 1 : 0;
fs1 = mpidr_el1_mask[15:8] ? ffs(mpidr_el1_mask[15:8]) - 1 : 0;
fs2 = mpidr_el1_mask[23:16] ? ffs(mpidr_el1_mask[23:16]) - 1 : 0;
fs3 = mpidr_el1_mask[39:32] ? ffs(mpidr_el1_mask[39:32]) - 1 : 0;
ls0 = fls(mpidr_el1_mask[7:0]);
ls1 = fls(mpidr_el1_mask[15:8]);
ls2 = fls(mpidr_el1_mask[23:16]);
ls3 = fls(mpidr_el1_mask[39:32]);
bits0 = ls0 - fs0;
bits1 = ls1 - fs1;
bits2 = ls2 - fs2;
bits3 = ls3 - fs3;
aff0_shift = fs0;
aff1_shift = 8 + fs1 - bits0;
aff2_shift = 16 + fs2 - (bits0 + bits1);
aff3_shift = 32 + fs3 - (bits0 + bits1 + bits2);
u32 hash(u64 mpidr_el1) {
u32 l[4];
u64 mpidr_el1_masked = mpidr_el1 & mpidr_el1_mask;
l[0] = mpidr_el1_masked & 0xff;
l[1] = mpidr_el1_masked & 0xff00;
l[2] = mpidr_el1_masked & 0xff0000;
l[3] = mpidr_el1_masked & 0xff00000000;
return (l[0] >> aff0_shift | l[1] >> aff1_shift | l[2] >> aff2_shift |
l[3] >> aff3_shift);
}
The hashing algorithm relies on the inherent properties set in the ARM ARM
recommendations for the MPIDR_EL1. Exotic configurations, where for instance
the MPIDR_EL1 values at a given affinity level have large holes, can end up
requiring big hash tables since the compression of values that can be achieved
through shifting is somewhat crippled when holes are present. Kernel warns if
the number of buckets of the resulting hash table exceeds the number of
possible CPUs by a factor of 4, which is a symptom of a very sparse HW
MPIDR_EL1 configuration.
The hash algorithm is quite simple and can easily be implemented in assembly
code, to be used in code paths where the kernel virtual address space is
not set-up (ie cpu_resume) and instruction and data fetches are strongly
ordered so code must be compact and must carry out few data accesses.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
The asynchronous aborts are generally fatal for the kernel but they can be masked via the pstate A bit. If a system error happens while in kernel mode, it won't be visible until returning to user space. This patch enables this kind of abort early to help identifying the cause. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Pull devicetree updates from Rob Herring:
"DeviceTree updates for 3.13. This is a bit larger pull request than
usual for this cycle with lots of clean-up.
- Cross arch clean-up and consolidation of early DT scanning code.
- Clean-up and removal of arch prom.h headers. Makes arch specific
prom.h optional on all but Sparc.
- Addition of interrupts-extended property for devices connected to
multiple interrupt controllers.
- Refactoring of DT interrupt parsing code in preparation for
deferred probe of interrupts.
- ARM cpu and cpu topology bindings documentation.
- Various DT vendor binding documentation updates"
* tag 'devicetree-for-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (82 commits)
powerpc: add missing explicit OF includes for ppc
dt/irq: add empty of_irq_count for !OF_IRQ
dt: disable self-tests for !OF_IRQ
of: irq: Fix interrupt-map entry matching
MIPS: Netlogic: replace early_init_devtree() call
of: Add Panasonic Corporation vendor prefix
of: Add Chunghwa Picture Tubes Ltd. vendor prefix
of: Add AU Optronics Corporation vendor prefix
of/irq: Fix potential buffer overflow
of/irq: Fix bug in interrupt parsing refactor.
of: set dma_mask to point to coherent_dma_mask
of: add vendor prefix for PHYTEC Messtechnik GmbH
DT: sort vendor-prefixes.txt
of: Add vendor prefix for Cadence
of: Add empty for_each_available_child_of_node() macro definition
arm/versatile: Fix versatile irq specifications.
of/irq: create interrupts-extended property
microblaze/pci: Drop PowerPC-ism from irq parsing
of/irq: Create of_irq_parse_and_map_pci() to consolidate arch code.
of/irq: Use irq_of_parse_and_map()
...
Pull timer changes from Ingo Molnar:
"Main changes in this cycle were:
- Updated full dynticks support.
- Event stream support for architected (ARM) timers.
- ARM clocksource driver updates.
- Move arm64 to using the generic sched_clock framework & resulting
cleanup in the generic sched_clock code.
- Misc fixes and cleanups"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
x86/time: Honor ACPI FADT flag indicating absence of a CMOS RTC
clocksource: sun4i: remove IRQF_DISABLED
clocksource: sun4i: Report the minimum tick that we can program
clocksource: sun4i: Select CLKSRC_MMIO
clocksource: Provide timekeeping for efm32 SoCs
clocksource: em_sti: convert to clk_prepare/unprepare
time: Fix signedness bug in sysfs_get_uname() and its callers
timekeeping: Fix some trivial typos in comments
alarmtimer: return EINVAL instead of ENOTSUPP if rtcdev doesn't exist
clocksource: arch_timer: Do not register arch_sys_counter twice
timer stats: Add a 'Collection: active/inactive' line to timer usage statistics
sched_clock: Remove sched_clock_func() hook
arch_timer: Move to generic sched_clock framework
clocksource: tcb_clksrc: Remove IRQF_DISABLED
clocksource: tcb_clksrc: Improve driver robustness
clocksource: tcb_clksrc: Replace clk_enable/disable with clk_prepare_enable/disable_unprepare
clocksource: arm_arch_timer: Use clocksource for suspend timekeeping
clocksource: dw_apb_timer_of: Mark a few more functions as __init
clocksource: Put nodes passed to CLOCKSOURCE_OF_DECLARE callbacks centrally
arm: zynq: Enable arm_global_timer
...