Webearly_ioremap_reset at an appropriate time. Without this call, invocations of early_ioremap etc. that are done too late will go: unnoticed and may cause corruption. This is exactly what happened when the first user of this feature: was added in patch f84d02755f5a ("arm64: … WebKernel.org Bugzilla – Bug 121421 Broadwell / Z97 - Early ioremap leak of 1 areas detected Last modified: 2016-08-04 03:20:05 UTC
Bus-Independent Device Accesses — The Linux Kernel …
Web/* * Provide common bits of early_ioremap() support for architectures needing * temporary mappings during boot before ioremap() is available. * * This is mostly a direct copy of the x86 early_ioremap implementation. ... void __init early_ioremap_reset(void) { early_ioremap_shutdown(); after_paging_init = 1; } /* * Generally, ioremap() is ... WebNov 11, 2014 · 1. Memory can be reserved during system boot time by using "mem" in the kernel command line argument. LDD3 Ch-15 Pg 443. For example, if you have 256 MB, the argument mem=255M keeps the kernel from using the top megabyte. Your module could later use the following code to gain access to such memory: sharpe street
The io_mapping functions — The Linux Kernel …
WebFor example, if a PCI device has a BAR, the kernel reads the bus address (A) from the BAR and converts it to a CPU physical address (B). The address B is stored in a struct resource and usually exposed via /proc/iomem. When a driver claims a device, it typically uses ioremap() to map physical address B at a virtual address (C). It can then use ... WebSome architectures support multiple modes for mapping device memory. ioremap_*() variants provide a common abstraction around these architecture-specific modes, with a shared set of semantics. ioremap() is the most common mapping type, and is applicable … WebThe early ioremap interfaces are intended for situations where boot code needs to make temporary virtual mappings before the normal ioremap interfaces are available. Typically, this means before paging_init() has run. These patches are layered on top of generic fixmap patches which were discussed here ... sharpe surfboards