This patch adds the necessary code to patch a running kernel at runtime to improve performance. The current implementation offers a few optimizations variants: - When running a SMP kernel on a single UP processor, unwanted assembler statements like locking functions are overwritten with NOPs. When multiple instructions shall be skipped, one branch instruction is used instead of multiple nop instructions. - In the UP case, some pdtlb and pitlb instructions are patched to become pdtlb,l and pitlb,l which only flushes the CPU-local tlb entries instead of broadcasting the flush to other CPUs in the system and thus may improve performance. - fic and fdc instructions are skipped if no I- or D-caches are installed. This should speed up qemu emulation and cacheless systems. - If no cache coherence is needed for IO operations, the relevant fdc and sync instructions in the sba and ccio drivers are replaced by nops. - On systems which share I- and D-TLBs and thus don't have a seperate instruction TLB, the pitlb instruction is replaced by a nop. Live-patching is done early in the boot process, just after having run the system inventory. No drivers are running and thus no external interrupts should arrive. So the hope is that no TLB exceptions will occur during the patching. If this turns out to be wrong we will probably need to do the patching in real-mode. Signed-off-by: Helge Deller <deller@gmx.de>
While playing with qemu with an emulated RT8139cp NIC, I faced lots of the following warnings: Dino 0x00810000: stuck interrupt 2 This patch ratelimits this warning and reports back that the IRQ was handled. Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
This driver has never been wired up due to the life of the Linux git tree, and has severely bitrotted. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Helge Deller <deller@gmx.de>
Pull dma-mapping updates from Christoph Hellwig:
- replace the force_dma flag with a dma_configure bus method. (Nipun
Gupta, although one patch is Ñ–ncorrectly attributed to me due to a
git rebase bug)
- use GFP_DMA32 more agressively in dma-direct. (Takashi Iwai)
- remove PCI_DMA_BUS_IS_PHYS and rely on the dma-mapping API to do the
right thing for bounce buffering.
- move dma-debug initialization to common code, and apply a few
cleanups to the dma-debug code.
- cleanup the Kconfig mess around swiotlb selection
- swiotlb comment fixup (Yisheng Xie)
- a trivial swiotlb fix. (Dan Carpenter)
- support swiotlb on RISC-V. (based on a patch from Palmer Dabbelt)
- add a new generic dma-noncoherent dma_map_ops implementation and use
it for arc, c6x and nds32.
- improve scatterlist validity checking in dma-debug. (Robin Murphy)
- add a struct device quirk to limit the dma-mask to 32-bit due to
bridge/system issues, and switch x86 to use it instead of a local
hack for VIA bridges.
- handle devices without a dma_mask more gracefully in the dma-direct
code.
* tag 'dma-mapping-4.18' of git://git.infradead.org/users/hch/dma-mapping: (48 commits)
dma-direct: don't crash on device without dma_mask
nds32: use generic dma_noncoherent_ops
nds32: implement the unmap_sg DMA operation
nds32: consolidate DMA cache maintainance routines
x86/pci-dma: switch the VIA 32-bit DMA quirk to use the struct device flag
x86/pci-dma: remove the explicit nodac and allowdac option
x86/pci-dma: remove the experimental forcesac boot option
Documentation/x86: remove a stray reference to pci-nommu.c
core, dma-direct: add a flag 32-bit dma limits
dma-mapping: remove unused gfp_t parameter to arch_dma_alloc_attrs
dma-debug: check scatterlist segments
c6x: use generic dma_noncoherent_ops
arc: use generic dma_noncoherent_ops
arc: fix arc_dma_{map,unmap}_page
arc: fix arc_dma_sync_sg_for_{cpu,device}
arc: simplify arc_dma_sync_single_for_{cpu,device}
dma-mapping: provide a generic dma-noncoherent implementation
dma-mapping: simplify Kconfig dependencies
riscv: add swiotlb support
riscv: only enable ZONE_DMA32 for 64-bit
...
Pull procfs updates from Al Viro:
"Christoph's proc_create_... cleanups series"
* 'hch.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (44 commits)
xfs, proc: hide unused xfs procfs helpers
isdn/gigaset: add back gigaset_procinfo assignment
proc: update SIZEOF_PDE_INLINE_NAME for the new pde fields
tty: replace ->proc_fops with ->proc_show
ide: replace ->proc_fops with ->proc_show
ide: remove ide_driver_proc_write
isdn: replace ->proc_fops with ->proc_show
atm: switch to proc_create_seq_private
atm: simplify procfs code
bluetooth: switch to proc_create_seq_data
netfilter/x_tables: switch to proc_create_seq_private
netfilter/xt_hashlimit: switch to proc_create_{seq,single}_data
neigh: switch to proc_create_seq_data
hostap: switch to proc_create_{seq,single}_data
bonding: switch to proc_create_seq_data
rtc/proc: switch to proc_create_single_data
drbd: switch to proc_create_single
resource: switch to proc_create_seq_data
staging/rtl8192u: simplify procfs code
jfs: simplify procfs code
...
ccio_cujo20_fixup() is called by dino_probe() only, which is in init section already. Signed-off-by: Helge Deller <deller@gmx.de>
Variants of proc_create{,_data} that directly take a seq_file show
callback and drastically reduces the boilerplate code in the callers.
All trivial callers converted over.
Signed-off-by: Christoph Hellwig <hch@lst.de>
This avoids selecting IOMMU_HELPER just for this function. And we only use it once or twice in normal builds so this often even is a size reduction. Signed-off-by: Christoph Hellwig <hch@lst.de>
This was used by the ide, scsi and networking code in the past to determine if they should bounce payloads. Now that the dma mapping always have to support dma to all physical memory (thanks to swiotlb for non-iommu systems) there is no need to this crude hack any more. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Palmer Dabbelt <palmer@sifive.com> (for riscv) Reviewed-by: Jens Axboe <axboe@kernel.dk>