similar to: ftrace_enabled set to 1 on bootup, slow downs with CONFIG_FUNCTION_TRACER in virt environments?

On Wed 2018-05-23 12:54:15, Thomas Garnier wrote: > When using -fPIE/PIC with function tracing, the compiler generates a > call through the GOT (call *__fentry__ at GOTPCREL). This instruction > takes 6 bytes instead of 5 on the usual 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 5-bytes as before.

On Wed 2018-05-23 12:54:15, Thomas Garnier wrote: > When using -fPIE/PIC with function tracing, the compiler generates a > call through the GOT (call *__fentry__ at GOTPCREL). This instruction > takes 6 bytes instead of 5 on the usual 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 5-bytes as before.

On Thu, May 24, 2018 at 1:16 PM Steven Rostedt <rostedt at goodmis.org> wrote: > On Thu, 24 May 2018 13:40:24 +0200 > Petr Mladek <pmladek at suse.com> wrote: > > On Wed 2018-05-23 12:54:15, Thomas Garnier wrote: > > > When using -fPIE/PIC with function tracing, the compiler generates a > > > call through the GOT (call *__fentry__ at GOTPCREL). This

On Thu, Oct 5, 2017 at 6:06 AM, Steven Rostedt <rostedt at goodmis.org> wrote: > On Wed, 4 Oct 2017 14:19:56 -0700 > Thomas Garnier <thgarnie at google.com> wrote: > >> When using -fPIE/PIC with function tracing, the compiler generates a >> call through the GOT (call *__fentry__ at GOTPCREL). This instruction >> takes 6 bytes instead of 5 on the usual

On Thu, Oct 5, 2017 at 6:06 AM, Steven Rostedt <rostedt at goodmis.org> wrote: > On Wed, 4 Oct 2017 14:19:56 -0700 > Thomas Garnier <thgarnie at google.com> wrote: > >> When using -fPIE/PIC with function tracing, the compiler generates a >> call through the GOT (call *__fentry__ at GOTPCREL). This instruction >> takes 6 bytes instead of 5 on the usual

Hi, I am trying to compile a simple program with Clang 3.3 on Linux and used -pg and -O2 option. The program would crash with segfault. Interestingly if I compile it with -pg option only it works. Do you have any idea why it crashes? And any workaround? $ cat myprog.c int main() { return 0; } $ clang -v -pg -O2 myprog.c clang version 3.3 (tags/RELEASE_33/final) Target:

Hi Qiao, On 24/07/13 08:23, Qiao Yang wrote: > Hi, > > I am trying to compile a simple program with Clang 3.3 on Linux and used -pg and -O2 option. The program would crash with segfault. Interestingly if I compile it with -pg option only it works. Do you have any idea why it crashes? And any workaround? > > $ cat myprog.c > int main() { > return 0; > } > > $

When using -fPIE/PIC with function tracing, the compiler generates a call through the GOT (call *__fentry__ at GOTPCREL). This instruction takes 6 bytes instead of 5 on the usual relative call. With this change, function tracing supports 6 bytes on traceable function and can still replace relative calls on the ftrace assembly functions. Position Independent Executable (PIE) support will allow to

Hmnnn... This is the third version of R I have installed and I am stumped on this one. There is some unresolved external I cannot find... /opt/SUNWspro/bin/cc -v -o R.bin CConverters.o Rdynload.o RNG.o apply.o arithmetic.o array.o attrib.o bind.o builtin.o character.o coerce.o colors.o complex.o connections.o context.o cov.o cum.o dcf.o datetime.o debug.o devPS.o devPicTeX.o deparse.o

[Added Chris Wright, Rusty and Virt list because they were involved with this issue before] On Thu, 3 Jan 2008, Ingo Molnar wrote: > > * Steven Rostedt <rostedt@goodmis.org> wrote: > > > +# function tracing might turn this off: > > +config REGPARM > > + bool > > + depends on !MCOUNT > > + default y > > are you sure -pg really needs this? Nope!

[Added Chris Wright, Rusty and Virt list because they were involved with this issue before] On Thu, 3 Jan 2008, Ingo Molnar wrote: > > * Steven Rostedt <rostedt@goodmis.org> wrote: > > > +# function tracing might turn this off: > > +config REGPARM > > + bool > > + depends on !MCOUNT > > + default y > > are you sure -pg really needs this? Nope!

On Thu, 24 May 2018 13:40:24 +0200 Petr Mladek <pmladek at suse.com> wrote: > On Wed 2018-05-23 12:54:15, Thomas Garnier wrote: > > When using -fPIE/PIC with function tracing, the compiler generates a > > call through the GOT (call *__fentry__ at GOTPCREL). This instruction > > takes 6 bytes instead of 5 on the usual relative call. > > > > If PIE is

Hello, I am trying to replicate the output from opt -O3 foo.bc -o foo.opt.bc by specifying the individual passes instead of the -O3 flag. Looking at the passes from opt -O3 foo.bc -o foo.bc -debug-pass=Executions it seems there are two passes being run. When I run the flags indicated for the two passes specified in the 'Pass Arguments:' as two sequential opt processes or a single opt

Greetings, I am trying to compile a linux kernel module (currently a small part of the gpu driver) into the bitcode ".bc" format so that I can run a pass on it using the "opt" command. This pass will count the number of times copy_to/from_user() is invoked. Compiling the gnu driver kernel modules works with clang as a front end. However, I am unable to get the

When using -fPIE/PIC with function tracing, the compiler generates a call through the GOT (call *__fentry__ at GOTPCREL). This instruction takes 6 bytes instead of 5 on the usual 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 5-bytes as before. Position Independent Executable (PIE) support will allow to extended the KASLR

When using -fPIE/PIC with function tracing, the compiler generates a call through the GOT (call *__fentry__ at GOTPCREL). This instruction takes 6 bytes instead of 5 on the usual 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 5-bytes as before. Position Independent Executable (PIE) support will allow to extended the KASLR

Hi Kevin, On 01/06/13 09:59, Kevin Boos wrote: > Greetings, > > I am trying to compile a linux kernel module (currently a small part of the gpu driver) into the bitcode ".bc" format so that I can run a pass on it using the "opt" command. This pass will count the number of times copy_to/from_user() is invoked. > > Compiling the gnu driver kernel modules works

Splitting the previous serie in two. This part contains assembly code changes required for PIE but without any direct dependencies with the rest of the patchset. Changes: - patch v8 (assembly): - Fix issues in crypto changes (thanks to Eric Biggers). - Remove unnecessary jump table change. - Change author and signoff to chromium email address. - patch v7 (assembly): - Split patchset

Splitting the previous serie in two. This part contains assembly code changes required for PIE but without any direct dependencies with the rest of the patchset. Changes: - patch v8 (assembly): - Fix issues in crypto changes (thanks to Eric Biggers). - Remove unnecessary jump table change. - Change author and signoff to chromium email address. - patch v7 (assembly): - Split patchset

Greatings, I am encountering the same issue with Kevin. Does anyone know how to compile the linux kernel to .bc file? Is there any oneline guide for this? Thanks!~ Bests,Ping > Date: Sat, 1 Jun 2013 20:15:56 +0200 > From: baldrick at free.fr > To: llvmdev at cs.uiuc.edu > Subject: Re: [LLVMdev] Compile Linux Kernel module into LLVM bitcode > > Hi Kevin, >