[RFC 0/4] arm64: add livepatch support

From
Li Bin <hidden>
Date
2015-05-28 06:06:48
Reply to
Jiri Kosina, 2015-04-24
On 2015/4/24 17:27, Jiri Kosina wrote:
On Fri, 24 Apr 2015, AKASHI Takahiro wrote:
quoted
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
	...
Thanks,
	Li Bin
Thanks,
Thread (18 messages) 18 messages, 6 authors, last reply 2015-05-28
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