mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 04:31:50 +00:00
3847dab774
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> |
||
|---|---|---|
| .. | ||
| asp.c | ||
| ccio-dma.c | ||
| dino.c | ||
| eisa_eeprom.c | ||
| eisa_enumerator.c | ||
| eisa.c | ||
| gsc.c | ||
| gsc.h | ||
| hppb.c | ||
| iommu-helpers.h | ||
| iosapic_private.h | ||
| iosapic.c | ||
| Kconfig | ||
| lasi.c | ||
| lba_pci.c | ||
| led.c | ||
| Makefile | ||
| pdc_stable.c | ||
| power.c | ||
| README.dino | ||
| sba_iommu.c | ||
| superio.c | ||
| wax.c | ||
/* ** HP VISUALIZE Workstation PCI Bus Defect ** ** "HP has discovered a potential system defect that can affect ** the behavior of five models of HP VISUALIZE workstations when ** equipped with third-party or customer-installed PCI I/O expansion ** cards. The defect is limited to the HP C180, C160, C160L, B160L, ** and B132L VISUALIZE workstations, and will only be encountered ** when data is transmitted through PCI I/O expansion cards on the ** PCI bus. HP-supplied graphics cards that utilize the PCI bus are ** not affected." ** ** http://h20000.www2.hp.com/bizsupport/TechSupport/Home.jsp?locale=en_US&prodTypeId=12454&prodSeriesId=44443 ** ** Product First Good Serial Number ** C200/C240 (US) US67350000 **B132L+/B180 (US) US67390000 ** C200 (Europe) 3713G01000 ** B180L (Europe) 3720G01000 ** ** Note that many boards were fixed/replaced under a free replacement ** program. Assume a machine is only "suspect" until proven otherwise. ** ** "The pci_check program will also be available as application ** patch PHSS_12295" */