Re: [PATCH v5 21/27] x86/ftrace: Adapt function tracing for PIE support

2018-06-26 Thread Steven Rostedt
On Mon, 25 Jun 2018 15:39:09 -0700 Thomas Garnier wrote: > When using PIE with function tracing, the compiler generates a > call through the GOT (call *__fentry__@GOTPCREL). This instruction > takes 6-bytes instead of 5-bytes with a relative call. > > If PIE is enabled, replace the 6th byte of

Re: [PATCH v5 21/27] x86/ftrace: Adapt function tracing for PIE support

2018-06-26 Thread Steven Rostedt
On Mon, 25 Jun 2018 15:39:09 -0700 Thomas Garnier wrote: > When using PIE with function tracing, the compiler generates a > call through the GOT (call *__fentry__@GOTPCREL). This instruction > takes 6-bytes instead of 5-bytes with a relative call. > > If PIE is enabled, replace the 6th byte of

[PATCH v5 21/27] x86/ftrace: Adapt function tracing for PIE support

2018-06-25 Thread Thomas Garnier
When using PIE with function tracing, the compiler generates a call through the GOT (call *__fentry__@GOTPCREL). This instruction takes 6-bytes instead of 5-bytes with a relative call. If PIE is enabled, replace the 6th byte of the GOT call by a 1-byte nop so ftrace can handle the previous

[PATCH v5 21/27] x86/ftrace: Adapt function tracing for PIE support

2018-06-25 Thread Thomas Garnier
When using PIE with function tracing, the compiler generates a call through the GOT (call *__fentry__@GOTPCREL). This instruction takes 6-bytes instead of 5-bytes with a relative call. If PIE is enabled, replace the 6th byte of the GOT call by a 1-byte nop so ftrace can handle the previous