diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-03-27 19:39:08 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-03-27 19:39:08 -0700 |
commit | 7b667acd69e316c2ed1b47e5dcd9d093be4a843f (patch) | |
tree | 970d6a9f3262a0f98152206f0ec94025fbd3f7cc /Documentation | |
parent | a7e135fe59a516b2a981fc5820e7a1e2118b427e (diff) | |
parent | 861efb8a48ee8b73ae4e8817509cd4e82fd52bc4 (diff) |
Merge tag 'powerpc-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Madhavan Srinivasan:
- Remove support for IBM Cell Blades
- SMP support for microwatt platform
- Support for inline static calls on PPC32
- Enable pmu selftests for power11 platform
- Enable hardware trace macro (HTM) hcall support
- Support for limited address mode capability
- Changes to RMA size from 512 MB to 768 MB to handle fadump
- Misc fixes and cleanups
Thanks to Abhishek Dubey, Amit Machhiwal, Andreas Schwab, Arnd Bergmann,
Athira Rajeev, Avnish Chouhan, Christophe Leroy, Disha Goel, Donet Tom,
Gaurav Batra, Gautam Menghani, Hari Bathini, Kajol Jain, Kees Cook,
Mahesh Salgaonkar, Michael Ellerman, Paul Mackerras, Ritesh Harjani
(IBM), Sathvika Vasireddy, Segher Boessenkool, Sourabh Jain, Vaibhav
Jain, and Venkat Rao Bagalkote.
* tag 'powerpc-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (61 commits)
powerpc/kexec: fix physical address calculation in clear_utlb_entry()
crypto: powerpc: Mark ghashp8-ppc.o as an OBJECT_FILES_NON_STANDARD
powerpc: Fix 'intra_function_call not a direct call' warning
powerpc/perf: Fix ref-counting on the PMU 'vpa_pmu'
KVM: PPC: Enable CAP_SPAPR_TCE_VFIO on pSeries KVM guests
powerpc/prom_init: Fixup missing #size-cells on PowerBook6,7
powerpc/microwatt: Add SMP support
powerpc: Define config option for processors with broadcast TLBIE
powerpc/microwatt: Define an idle power-save function
powerpc/microwatt: Device-tree updates
powerpc/microwatt: Select COMMON_CLK in order to get the clock framework
net: toshiba: Remove reference to PPC_IBM_CELL_BLADE
net: spider_net: Remove powerpc Cell driver
cpufreq: ppc_cbe: Remove powerpc Cell driver
genirq: Remove IRQ_EDGE_EOI_HANDLER
docs: Remove reference to removed CBE_CPUFREQ_SPU_GOVERNOR
powerpc: Remove UDBG_RTAS_CONSOLE
powerpc/io: Use standard barrier macros in io.c
powerpc/io: Rename _insw_ns() etc.
powerpc/io: Use generic raw accessors
...
Diffstat (limited to 'Documentation')
6 files changed, 36 insertions, 210 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump index 2f9daa7ca55b..b64b7622e6fc 100644 --- a/Documentation/ABI/testing/sysfs-kernel-fadump +++ b/Documentation/ABI/testing/sysfs-kernel-fadump @@ -55,4 +55,5 @@ Date: May 2024 Contact: linuxppc-dev@lists.ozlabs.org Description: read/write This is a special sysfs file available to setup additional - parameters to be passed to capture kernel. + parameters to be passed to capture kernel. For HASH MMU it + is exported only if RMA size higher than 768MB. diff --git a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst index ea7fa2a8bbf0..ee9a6c94f383 100644 --- a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst +++ b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst @@ -278,12 +278,7 @@ To reduce its OS jitter, do any of the following: due to the rtas_event_scan() function. WARNING: Please check your CPU specifications to make sure that this is safe on your particular system. - e. If running on Cell Processor, build your kernel with - CBE_CPUFREQ_SPU_GOVERNOR=n to avoid OS jitter from - spu_gov_work(). - WARNING: Please check your CPU specifications to - make sure that this is safe on your particular system. - f. If running on PowerMAC, build your kernel with + e. If running on PowerMAC, build your kernel with CONFIG_PMAC_RACKMETER=n to disable the CPU-meter, avoiding OS jitter from rackmeter_do_timer(). diff --git a/Documentation/arch/powerpc/firmware-assisted-dump.rst b/Documentation/arch/powerpc/firmware-assisted-dump.rst index 7e37aadd1f77..7e266e749cd5 100644 --- a/Documentation/arch/powerpc/firmware-assisted-dump.rst +++ b/Documentation/arch/powerpc/firmware-assisted-dump.rst @@ -120,6 +120,28 @@ to ensure that crash data is preserved to process later. e.g. # echo 1 > /sys/firmware/opal/mpipl/release_core +-- Support for Additional Kernel Arguments in Fadump + Fadump has a feature that allows passing additional kernel arguments + to the fadump kernel. This feature was primarily designed to disable + kernel functionalities that are not required for the fadump kernel + and to reduce its memory footprint while collecting the dump. + + Command to Add Additional Kernel Parameters to Fadump: + e.g. + # echo "nr_cpus=16" > /sys/kernel/fadump/bootargs_append + + The above command is sufficient to add additional arguments to fadump. + An explicit service restart is not required. + + Command to Retrieve the Additional Fadump Arguments: + e.g. + # cat /sys/kernel/fadump/bootargs_append + +Note: Additional kernel arguments for fadump with HASH MMU is only + supported if the RMA size is greater than 768 MB. If the RMA + size is less than 768 MB, the kernel does not export the + /sys/kernel/fadump/bootargs_append sysfs node. + Implementation details: ----------------------- diff --git a/Documentation/arch/powerpc/papr_hcalls.rst b/Documentation/arch/powerpc/papr_hcalls.rst index 80d2c0aadab5..805e1cb9bab9 100644 --- a/Documentation/arch/powerpc/papr_hcalls.rst +++ b/Documentation/arch/powerpc/papr_hcalls.rst @@ -289,6 +289,17 @@ to be issued multiple times in order to be completely serviced. The subsequent hcalls to the hypervisor until the hcall is completely serviced at which point H_SUCCESS or other error is returned by the hypervisor. +**H_HTM** + +| Input: flags, target, operation (op), op-param1, op-param2, op-param3 +| Out: *dumphtmbufferdata* +| Return Value: *H_Success,H_Busy,H_LongBusyOrder,H_Partial,H_Parameter, + H_P2,H_P3,H_P4,H_P5,H_P6,H_State,H_Not_Available,H_Authority* + +H_HTM supports setup, configuration, control and dumping of Hardware Trace +Macro (HTM) function and its data. HTM buffer stores tracing data for functions +like core instruction, core LLAT and nest. + References ========== .. [1] "Power Architecture Platform Reference" diff --git a/Documentation/networking/device_drivers/ethernet/index.rst b/Documentation/networking/device_drivers/ethernet/index.rst index 6fc1961492b7..05d822b904b4 100644 --- a/Documentation/networking/device_drivers/ethernet/index.rst +++ b/Documentation/networking/device_drivers/ethernet/index.rst @@ -55,7 +55,6 @@ Contents: ti/cpsw_switchdev ti/am65_nuss_cpsw_switchdev ti/tlan - toshiba/spider_net wangxun/txgbe wangxun/ngbe diff --git a/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst b/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst deleted file mode 100644 index fe5b32be15cd..000000000000 --- a/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst +++ /dev/null @@ -1,202 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -=========================== -The Spidernet Device Driver -=========================== - -Written by Linas Vepstas <linas@austin.ibm.com> - -Version of 7 June 2007 - -Abstract -======== -This document sketches the structure of portions of the spidernet -device driver in the Linux kernel tree. The spidernet is a gigabit -ethernet device built into the Toshiba southbridge commonly used -in the SONY Playstation 3 and the IBM QS20 Cell blade. - -The Structure of the RX Ring. -============================= -The receive (RX) ring is a circular linked list of RX descriptors, -together with three pointers into the ring that are used to manage its -contents. - -The elements of the ring are called "descriptors" or "descrs"; they -describe the received data. This includes a pointer to a buffer -containing the received data, the buffer size, and various status bits. - -There are three primary states that a descriptor can be in: "empty", -"full" and "not-in-use". An "empty" or "ready" descriptor is ready -to receive data from the hardware. A "full" descriptor has data in it, -and is waiting to be emptied and processed by the OS. A "not-in-use" -descriptor is neither empty or full; it is simply not ready. It may -not even have a data buffer in it, or is otherwise unusable. - -During normal operation, on device startup, the OS (specifically, the -spidernet device driver) allocates a set of RX descriptors and RX -buffers. These are all marked "empty", ready to receive data. This -ring is handed off to the hardware, which sequentially fills in the -buffers, and marks them "full". The OS follows up, taking the full -buffers, processing them, and re-marking them empty. - -This filling and emptying is managed by three pointers, the "head" -and "tail" pointers, managed by the OS, and a hardware current -descriptor pointer (GDACTDPA). The GDACTDPA points at the descr -currently being filled. When this descr is filled, the hardware -marks it full, and advances the GDACTDPA by one. Thus, when there is -flowing RX traffic, every descr behind it should be marked "full", -and everything in front of it should be "empty". If the hardware -discovers that the current descr is not empty, it will signal an -interrupt, and halt processing. - -The tail pointer tails or trails the hardware pointer. When the -hardware is ahead, the tail pointer will be pointing at a "full" -descr. The OS will process this descr, and then mark it "not-in-use", -and advance the tail pointer. Thus, when there is flowing RX traffic, -all of the descrs in front of the tail pointer should be "full", and -all of those behind it should be "not-in-use". When RX traffic is not -flowing, then the tail pointer can catch up to the hardware pointer. -The OS will then note that the current tail is "empty", and halt -processing. - -The head pointer (somewhat mis-named) follows after the tail pointer. -When traffic is flowing, then the head pointer will be pointing at -a "not-in-use" descr. The OS will perform various housekeeping duties -on this descr. This includes allocating a new data buffer and -dma-mapping it so as to make it visible to the hardware. The OS will -then mark the descr as "empty", ready to receive data. Thus, when there -is flowing RX traffic, everything in front of the head pointer should -be "not-in-use", and everything behind it should be "empty". If no -RX traffic is flowing, then the head pointer can catch up to the tail -pointer, at which point the OS will notice that the head descr is -"empty", and it will halt processing. - -Thus, in an idle system, the GDACTDPA, tail and head pointers will -all be pointing at the same descr, which should be "empty". All of the -other descrs in the ring should be "empty" as well. - -The show_rx_chain() routine will print out the locations of the -GDACTDPA, tail and head pointers. It will also summarize the contents -of the ring, starting at the tail pointer, and listing the status -of the descrs that follow. - -A typical example of the output, for a nearly idle system, might be:: - - net eth1: Total number of descrs=256 - net eth1: Chain tail located at descr=20 - net eth1: Chain head is at 20 - net eth1: HW curr desc (GDACTDPA) is at 21 - net eth1: Have 1 descrs with stat=x40800101 - net eth1: HW next desc (GDACNEXTDA) is at 22 - net eth1: Last 255 descrs with stat=xa0800000 - -In the above, the hardware has filled in one descr, number 20. Both -head and tail are pointing at 20, because it has not yet been emptied. -Meanwhile, hw is pointing at 21, which is free. - -The "Have nnn decrs" refers to the descr starting at the tail: in this -case, nnn=1 descr, starting at descr 20. The "Last nnn descrs" refers -to all of the rest of the descrs, from the last status change. The "nnn" -is a count of how many descrs have exactly the same status. - -The status x4... corresponds to "full" and status xa... corresponds -to "empty". The actual value printed is RXCOMST_A. - -In the device driver source code, a different set of names are -used for these same concepts, so that:: - - "empty" == SPIDER_NET_DESCR_CARDOWNED == 0xa - "full" == SPIDER_NET_DESCR_FRAME_END == 0x4 - "not in use" == SPIDER_NET_DESCR_NOT_IN_USE == 0xf - - -The RX RAM full bug/feature -=========================== - -As long as the OS can empty out the RX buffers at a rate faster than -the hardware can fill them, there is no problem. If, for some reason, -the OS fails to empty the RX ring fast enough, the hardware GDACTDPA -pointer will catch up to the head, notice the not-empty condition, -ad stop. However, RX packets may still continue arriving on the wire. -The spidernet chip can save some limited number of these in local RAM. -When this local ram fills up, the spider chip will issue an interrupt -indicating this (GHIINT0STS will show ERRINT, and the GRMFLLINT bit -will be set in GHIINT1STS). When the RX ram full condition occurs, -a certain bug/feature is triggered that has to be specially handled. -This section describes the special handling for this condition. - -When the OS finally has a chance to run, it will empty out the RX ring. -In particular, it will clear the descriptor on which the hardware had -stopped. However, once the hardware has decided that a certain -descriptor is invalid, it will not restart at that descriptor; instead -it will restart at the next descr. This potentially will lead to a -deadlock condition, as the tail pointer will be pointing at this descr, -which, from the OS point of view, is empty; the OS will be waiting for -this descr to be filled. However, the hardware has skipped this descr, -and is filling the next descrs. Since the OS doesn't see this, there -is a potential deadlock, with the OS waiting for one descr to fill, -while the hardware is waiting for a different set of descrs to become -empty. - -A call to show_rx_chain() at this point indicates the nature of the -problem. A typical print when the network is hung shows the following:: - - net eth1: Spider RX RAM full, incoming packets might be discarded! - net eth1: Total number of descrs=256 - net eth1: Chain tail located at descr=255 - net eth1: Chain head is at 255 - net eth1: HW curr desc (GDACTDPA) is at 0 - net eth1: Have 1 descrs with stat=xa0800000 - net eth1: HW next desc (GDACNEXTDA) is at 1 - net eth1: Have 127 descrs with stat=x40800101 - net eth1: Have 1 descrs with stat=x40800001 - net eth1: Have 126 descrs with stat=x40800101 - net eth1: Last 1 descrs with stat=xa0800000 - -Both the tail and head pointers are pointing at descr 255, which is -marked xa... which is "empty". Thus, from the OS point of view, there -is nothing to be done. In particular, there is the implicit assumption -that everything in front of the "empty" descr must surely also be empty, -as explained in the last section. The OS is waiting for descr 255 to -become non-empty, which, in this case, will never happen. - -The HW pointer is at descr 0. This descr is marked 0x4.. or "full". -Since its already full, the hardware can do nothing more, and thus has -halted processing. Notice that descrs 0 through 254 are all marked -"full", while descr 254 and 255 are empty. (The "Last 1 descrs" is -descr 254, since tail was at 255.) Thus, the system is deadlocked, -and there can be no forward progress; the OS thinks there's nothing -to do, and the hardware has nowhere to put incoming data. - -This bug/feature is worked around with the spider_net_resync_head_ptr() -routine. When the driver receives RX interrupts, but an examination -of the RX chain seems to show it is empty, then it is probable that -the hardware has skipped a descr or two (sometimes dozens under heavy -network conditions). The spider_net_resync_head_ptr() subroutine will -search the ring for the next full descr, and the driver will resume -operations there. Since this will leave "holes" in the ring, there -is also a spider_net_resync_tail_ptr() that will skip over such holes. - -As of this writing, the spider_net_resync() strategy seems to work very -well, even under heavy network loads. - - -The TX ring -=========== -The TX ring uses a low-watermark interrupt scheme to make sure that -the TX queue is appropriately serviced for large packet sizes. - -For packet sizes greater than about 1KBytes, the kernel can fill -the TX ring quicker than the device can drain it. Once the ring -is full, the netdev is stopped. When there is room in the ring, -the netdev needs to be reawakened, so that more TX packets are placed -in the ring. The hardware can empty the ring about four times per jiffy, -so its not appropriate to wait for the poll routine to refill, since -the poll routine runs only once per jiffy. The low-watermark mechanism -marks a descr about 1/4th of the way from the bottom of the queue, so -that an interrupt is generated when the descr is processed. This -interrupt wakes up the netdev, which can then refill the queue. -For large packets, this mechanism generates a relatively small number -of interrupts, about 1K/sec. For smaller packets, this will drop to zero -interrupts, as the hardware can empty the queue faster than the kernel -can fill it. |