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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 relative call. >> >> With this change, function tr...

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 relative call. >> >> With this change, function tr...

On 21/05/2019 01:19, Thomas Garnier wrote: > From: Thomas Garnier <thgarnie at google.com> > > if PIE is enabled, switch the paravirt assembly constraints to be > compatible. The %c/i constrains generate smaller code so is kept by > default. > > Position Independent Executable (PIE) support will allow to extend the > KASLR randomization range bel...

On Fri, Oct 20, 2017 at 1:26 AM, Ingo Molnar <mingo at kernel.org> wrote: > > * Thomas Garnier <thgarnie at google.com> wrote: > >> Change the assembly code to use only relative references of symbols for the >> kernel to be PIE compatible. >> >> Position Independent Executable (PIE) support will allow to extended the >> KASLR randomization range below the -2G memor...

On Fri, Oct 20, 2017 at 1:26 AM, Ingo Molnar <mingo at kernel.org> wrote: > > * Thomas Garnier <thgarnie at google.com> wrote: > >> Change the assembly code to use only relative references of symbols for the >> kernel to be PIE compatible. >> >> Position Independent Executable (PIE) support will allow to extended the >> KASLR randomization range below the -2G memor...

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 v7 (assembly): - Split patchset and reorder changes. - patch v6: - Rebase on latest changes in jump tables and crypto. - Fix wording on couple commits. - Revisit checkpatch warnings. - Moving to

...upport will allow to extended the will allow us to extend the > KASLR randomization range below the -2G memory limit. Does that say "below th negative 2G memory limit"? I don't get it. > > Signed-off-by: Thomas Garnier <thgarnie at google.com> > --- > arch/x86/Makefile | 4 + > arch/x86/include/asm/module.h | 11 ++ > arch/x86/include/asm/sections.h | 4 + > arch/x86/kernel/module.c | 181 +++++++++++++++++++++++++++++++- > arch/x86/kernel/module.lds | 3 + > 5 f...

...upport will allow to extended the will allow us to extend the > KASLR randomization range below the -2G memory limit. Does that say "below th negative 2G memory limit"? I don't get it. > > Signed-off-by: Thomas Garnier <thgarnie at google.com> > --- > arch/x86/Makefile | 4 + > arch/x86/include/asm/module.h | 11 ++ > arch/x86/include/asm/sections.h | 4 + > arch/x86/kernel/module.c | 181 +++++++++++++++++++++++++++++++- > arch/x86/kernel/module.lds | 3 + > 5 f...

...; Change the assembly code to use only relative references of symbols for the > kernel to be PIE compatible. > > Position Independent Executable (PIE) support will allow to extended the > KASLR randomization range below the -2G memory limit. > > Signed-off-by: Thomas Garnier <thgarnie at google.com> Again, was this tested? > diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S > index ce8da3a0412c..6fdd7bbc3c33 100644 > --- a/arch/x86/power/hibernate_asm_64.S > +++ b/arch/x86/power/hibernate_asm_64.S > @@ -24,7 +24,7 @@ > #i...

...; Change the assembly code to use only relative references of symbols for the > kernel to be PIE compatible. > > Position Independent Executable (PIE) support will allow to extended the > KASLR randomization range below the -2G memory limit. > > Signed-off-by: Thomas Garnier <thgarnie at google.com> Again, was this tested? > diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S > index ce8da3a0412c..6fdd7bbc3c33 100644 > --- a/arch/x86/power/hibernate_asm_64.S > +++ b/arch/x86/power/hibernate_asm_64.S > @@ -24,7 +24,7 @@ > #i...

Change the assembly code to use only relative references of symbols for the kernel to be PIE compatible. Position Independent Executable (PIE) support will allow to extended the KASLR randomization range below the -2G memory limit. Signed-off-by: Thomas Garnier <thgarnie at google.com> --- arch/x86/entry/entry_64.S | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 49167258d587..15bd5530d2ae 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S...

...t assembly constraints to be > compatible. The %c/i constrains generate smaller code so is kept by > default. > > Position Independent Executable (PIE) support will allow to extend the > KASLR randomization range below 0xffffffff80000000. > > Signed-off-by: Thomas Garnier <thgarnie at chromium.org> > Acked-by: Juergen Gross <jgross at suse.com> > --- > arch/x86/include/asm/paravirt_types.h | 25 +++++++++++++++++++++---- > 1 file changed, 21 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/as...

...t assembly constraints to be > compatible. The %c/i constrains generate smaller code so is kept by > default. > > Position Independent Executable (PIE) support will allow to extend the > KASLR randomization range below 0xffffffff80000000. > > Signed-off-by: Thomas Garnier <thgarnie at chromium.org> > Acked-by: Juergen Gross <jgross at suse.com> > --- > arch/x86/include/asm/paravirt_types.h | 25 +++++++++++++++++++++---- > 1 file changed, 21 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/as...

Changes: - patch v3: - Update on message to describe longer term PIE goal. - Minor change on ftrace if condition. - Changed code using xchgq. - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - patch v1: - Simplify ftrace

On Thu, 5 Oct 2017 09:01:14 -0700 Thomas Garnier <thgarnie at google.com> wrote: > 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...

* Thomas Garnier <thgarnie at google.com> wrote: > Change the assembly code to use only relative references of symbols for the > kernel to be PIE compatible. > > Position Independent Executable (PIE) support will allow to extended the > KASLR randomization range below the -2G memory limit. > > Sig...

From: Thomas Garnier <thgarnie at google.com> if PIE is enabled, switch the paravirt assembly constraints to be compatible. The %c/i constrains generate smaller code so is kept by default. Position Independent Executable (PIE) support will allow to extend the KASLR randomization range below 0xffffffff80000000. Signed-off-...

...t assembly constraints to be > compatible. The %c/i constrains generate smaller code so is kept by > default. > > Position Independent Executable (PIE) support will allow to extend the > KASLR randomization range below 0xffffffff80000000. > > Signed-off-by: Thomas Garnier <thgarnie at chromium.org> > Acked-by: Juergen Gross <jgross at suse.com> > --- > arch/x86/include/asm/paravirt_types.h | 32 +++++++++++++++++++++++---- > 1 file changed, 28 insertions(+), 4 deletions(-) More missed feedback: https://lkml.kernel.org/r/CAJcbSZG-JhBC9b1JMv1zq2r5uRQipY...

...> > so ftrace can handle the previous 5-bytes as before. > > > > > > Position Independent Executable (PIE) support will allow to extended the > > > KASLR randomization range below the -2G memory limit. > > > > > > Signed-off-by: Thomas Garnier <thgarnie at google.com> > > > --- > > > arch/x86/include/asm/ftrace.h | 6 +++-- > > > arch/x86/include/asm/sections.h | 4 ++++ > > > arch/x86/kernel/ftrace.c | 42 +++++++++++++++++++++++++++++++-- > > > 3 files changed, 48 insertions(+), 4 dele...

These patches make the changes necessary to build the kernel as Position Independent Executable (PIE) on x86_64. A PIE kernel can be relocated below the top 2G of the virtual address space. It allows to optionally extend the KASLR randomization range from 1G to 3G. Thanks a lot to Ard Biesheuvel & Kees Cook on their feedback on compiler changes, PIE support and KASLR in general. Thanks to