On Tue, Jul 18, 2017 at 9:35 PM, H. Peter Anvin <h...@zytor.com> wrote: > On 07/18/17 15:33, Thomas Garnier wrote: >> With PIE support and KASLR extended range, the modules may be further >> away from the kernel than before breaking mcmodel=kernel expectations. >> >> Add an option to build modules with mcmodel=large. The modules generated >> code will make no assumptions on placement in memory. >> >> Despite this option, modules still expect kernel functions to be within >> 2G and generate relative calls. To solve this issue, the PLT arm64 code >> was adapted for x86_64. When a relative relocation go outside its range, >> a dynamic PLT entry is used to correctly jump to the destination. > > Why large as opposed to medium or medium-PIC?
Or for that matter, why not small-PIC? We aren't changing the size of the kernel to be larger than 2G text or data. Small-PIC would still allow it to be placed anywhere in the address space, and would generate far better code. -- Brian Gerst _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel