On Thu, May 28, 2015 at 07:08:42AM +0100, Li Bin wrote: > On 2015/4/24 17:27, Jiri Kosina wrote: > > On Fri, 24 Apr 2015, AKASHI Takahiro wrote: > > > >> This patchset enables livepatch support on arm64. > >> > >> Livepatch was merged in v4.0, and allows replacying a function dynamically > >> based on ftrace framework, but it also requires -mfentry option of gcc. > >> Currently arm64 gcc doesn't support it, but by adding a helper function to > >> ftrace, we will be able to support livepatch on arch's which don't support > >> this option. > >> > >> I submit this patchset as RFC since I'm not quite sure that I'm doing > >> in the right way, or we should definitely support -fentry instead. > > > > I don't have arm64 cross-compiler handy, could you please copy/paste how > > does function prologue, generated by gcc -pg on arm64 look like? > > > > The function prologue on arm64 with gcc -pg look like as following: > func: > stp x29, x30, [sp, -48]! > add x29, sp, 0 > mov x1, x30 > str w0, [x29,28] > mov x0, x1 > bl _mcount Just for the avoidance of confusion, this looks like a function with a live parameter in x0, which explains the str to the stack and the juggling of x30 into x0. I don't think there's necessarily a golden template for the prologue code. Will -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
