* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n [not found] ` <20240409175108.1512861-2-seanjc@google.com> @ 2024-04-13 1:53 ` Stephen Rothwell 2024-04-13 9:27 ` Michael Ellerman 0 siblings, 1 reply; 10+ messages in thread From: Stephen Rothwell @ 2024-04-13 1:53 UTC (permalink / raw) To: Sean Christopherson Cc: x86, Jonathan Corbet, Peter Zijlstra, Dave Hansen, linux-doc, linux-kernel, Ingo Molnar, Borislav Petkov, Pawan Gupta, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon [-- Attachment #1: Type: text/plain, Size: 1731 bytes --] Hi Sean, I noticed this commit in linux-next. On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: > > Initialize cpu_mitigations to CPU_MITIGATIONS_OFF if the kernel is built > with CONFIG_SPECULATION_MITIGATIONS=n, as the help text quite clearly > states that disabling SPECULATION_MITIGATIONS is supposed to turn off all > mitigations by default. > > │ If you say N, all mitigations will be disabled. You really > │ should know what you are doing to say so. > > As is, the kernel still defaults to CPU_MITIGATIONS_AUTO, which results in > some mitigations being enabled in spite of SPECULATION_MITIGATIONS=n. > > Fixes: f43b9876e857 ("x86/retbleed: Add fine grained Kconfig knobs") > Cc: stable@vger.kernel.org > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > kernel/cpu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/cpu.c b/kernel/cpu.c > index 8f6affd051f7..07ad53b7f119 100644 > --- a/kernel/cpu.c > +++ b/kernel/cpu.c > @@ -3207,7 +3207,8 @@ enum cpu_mitigations { > }; > > static enum cpu_mitigations cpu_mitigations __ro_after_init = > - CPU_MITIGATIONS_AUTO; > + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : > + CPU_MITIGATIONS_OFF; > > static int __init mitigations_parse_cmdline(char *arg) > { > -- > 2.44.0.478.gd926399ef9-goog > I noticed because it turned off all mitigations for my PowerPC qemu boot tests - probably because CONFIG_SPECULATION_MITIGATIONS only exists in arch/x86/Kconfig ... thus for other architectures that have cpu mitigations, this will always default them to off, right? -- Cheers, Stephen Rothwell [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 488 bytes --] ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-13 1:53 ` [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n Stephen Rothwell @ 2024-04-13 9:27 ` Michael Ellerman 2024-04-13 9:38 ` Michael Ellerman 0 siblings, 1 reply; 10+ messages in thread From: Michael Ellerman @ 2024-04-13 9:27 UTC (permalink / raw) To: Stephen Rothwell, Sean Christopherson Cc: linux-arch, x86, Will Deacon, Jonathan Corbet, Peter Zijlstra, Catalin Marinas, Heiko Carstens, Dave Hansen, linux-doc, linux-kernel, Ingo Molnar, Borislav Petkov, Pawan Gupta, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon Stephen Rothwell <sfr@canb.auug.org.au> writes: > Hi Sean, > > I noticed this commit in linux-next. > > On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: >> >> Initialize cpu_mitigations to CPU_MITIGATIONS_OFF if the kernel is built >> with CONFIG_SPECULATION_MITIGATIONS=n, as the help text quite clearly >> states that disabling SPECULATION_MITIGATIONS is supposed to turn off all >> mitigations by default. >> >> │ If you say N, all mitigations will be disabled. You really >> │ should know what you are doing to say so. >> >> As is, the kernel still defaults to CPU_MITIGATIONS_AUTO, which results in >> some mitigations being enabled in spite of SPECULATION_MITIGATIONS=n. >> >> Fixes: f43b9876e857 ("x86/retbleed: Add fine grained Kconfig knobs") >> Cc: stable@vger.kernel.org >> Signed-off-by: Sean Christopherson <seanjc@google.com> >> --- >> kernel/cpu.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/cpu.c b/kernel/cpu.c >> index 8f6affd051f7..07ad53b7f119 100644 >> --- a/kernel/cpu.c >> +++ b/kernel/cpu.c >> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { >> }; >> >> static enum cpu_mitigations cpu_mitigations __ro_after_init = >> - CPU_MITIGATIONS_AUTO; >> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : >> + CPU_MITIGATIONS_OFF; >> >> static int __init mitigations_parse_cmdline(char *arg) >> { >> -- >> 2.44.0.478.gd926399ef9-goog >> > > I noticed because it turned off all mitigations for my PowerPC qemu > boot tests - probably because CONFIG_SPECULATION_MITIGATIONS only > exists in arch/x86/Kconfig ... thus for other architectures that have > cpu mitigations, this will always default them to off, right? Yep. The patch has the effect of changing the default for non-x86 arches from auto to off. I see at least powerpc, arm64 and s390 use cpu_mitigations_off() and will be affected. cheers ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-13 9:27 ` Michael Ellerman @ 2024-04-13 9:38 ` Michael Ellerman 2024-04-14 22:42 ` Stephen Rothwell 2024-04-15 11:16 ` Geert Uytterhoeven 0 siblings, 2 replies; 10+ messages in thread From: Michael Ellerman @ 2024-04-13 9:38 UTC (permalink / raw) To: Stephen Rothwell, Sean Christopherson Cc: linux-arch, x86, Will Deacon, Jonathan Corbet, Peter Zijlstra, Catalin Marinas, Heiko Carstens, Dave Hansen, linux-doc, linux-kernel, Ingo Molnar, Borislav Petkov, Pawan Gupta, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon Michael Ellerman <mpe@ellerman.id.au> writes: > Stephen Rothwell <sfr@canb.auug.org.au> writes: ... >> On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: ... >>> diff --git a/kernel/cpu.c b/kernel/cpu.c >>> index 8f6affd051f7..07ad53b7f119 100644 >>> --- a/kernel/cpu.c >>> +++ b/kernel/cpu.c >>> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { >>> }; >>> >>> static enum cpu_mitigations cpu_mitigations __ro_after_init = >>> - CPU_MITIGATIONS_AUTO; >>> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : >>> + CPU_MITIGATIONS_OFF; >>> >>> static int __init mitigations_parse_cmdline(char *arg) >>> { I think a minimal workaround/fix would be: diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 2b8fd6bb7da0..290be2f9e909 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -191,6 +191,10 @@ config GENERIC_CPU_AUTOPROBE config GENERIC_CPU_VULNERABILITIES bool +config SPECULATION_MITIGATIONS + def_bool y + depends on !X86 + config SOC_BUS bool select GLOB cheers ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-13 9:38 ` Michael Ellerman @ 2024-04-14 22:42 ` Stephen Rothwell 2024-04-15 11:16 ` Geert Uytterhoeven 1 sibling, 0 replies; 10+ messages in thread From: Stephen Rothwell @ 2024-04-14 22:42 UTC (permalink / raw) To: Sean Christopherson Cc: linux-arch, x86, Will Deacon, Jonathan Corbet, Peter Zijlstra, Heiko Carstens, Dave Hansen, linux-doc, linux-kernel, Ingo Molnar, Borislav Petkov, Catalin Marinas, Pawan Gupta, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon [-- Attachment #1: Type: text/plain, Size: 1380 bytes --] Hi all, On Sat, 13 Apr 2024 19:38:47 +1000 Michael Ellerman <mpe@ellerman.id.au> wrote: > > Michael Ellerman <mpe@ellerman.id.au> writes: > > Stephen Rothwell <sfr@canb.auug.org.au> writes: > ... > >> On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: > ... > >>> diff --git a/kernel/cpu.c b/kernel/cpu.c > >>> index 8f6affd051f7..07ad53b7f119 100644 > >>> --- a/kernel/cpu.c > >>> +++ b/kernel/cpu.c > >>> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { > >>> }; > >>> > >>> static enum cpu_mitigations cpu_mitigations __ro_after_init = > >>> - CPU_MITIGATIONS_AUTO; > >>> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : > >>> + CPU_MITIGATIONS_OFF; > >>> > >>> static int __init mitigations_parse_cmdline(char *arg) > >>> { > > I think a minimal workaround/fix would be: > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 2b8fd6bb7da0..290be2f9e909 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -191,6 +191,10 @@ config GENERIC_CPU_AUTOPROBE > config GENERIC_CPU_VULNERABILITIES > bool > > +config SPECULATION_MITIGATIONS > + def_bool y > + depends on !X86 > + > config SOC_BUS > bool > select GLOB The original commit is now in Linus' tree. -- Cheers, Stephen Rothwell [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 488 bytes --] ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-13 9:38 ` Michael Ellerman 2024-04-14 22:42 ` Stephen Rothwell @ 2024-04-15 11:16 ` Geert Uytterhoeven 2024-04-15 14:31 ` Sean Christopherson 1 sibling, 1 reply; 10+ messages in thread From: Geert Uytterhoeven @ 2024-04-15 11:16 UTC (permalink / raw) To: Michael Ellerman Cc: linux-arch, Stephen Rothwell, x86, Will Deacon, Jonathan Corbet, Peter Zijlstra, Sean Christopherson, Heiko Carstens, Dave Hansen, linux-doc, linux-kernel, Linux-Renesas, Ingo Molnar, Borislav Petkov, Catalin Marinas, Pawan Gupta, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon Hi Michael, On Sat, Apr 13, 2024 at 11:38 AM Michael Ellerman <mpe@ellerman.id.au> wrote: > Michael Ellerman <mpe@ellerman.id.au> writes: > > Stephen Rothwell <sfr@canb.auug.org.au> writes: > ... > >> On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: > ... > >>> diff --git a/kernel/cpu.c b/kernel/cpu.c > >>> index 8f6affd051f7..07ad53b7f119 100644 > >>> --- a/kernel/cpu.c > >>> +++ b/kernel/cpu.c > >>> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { > >>> }; > >>> > >>> static enum cpu_mitigations cpu_mitigations __ro_after_init = > >>> - CPU_MITIGATIONS_AUTO; > >>> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : > >>> + CPU_MITIGATIONS_OFF; > >>> > >>> static int __init mitigations_parse_cmdline(char *arg) > >>> { > > I think a minimal workaround/fix would be: > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 2b8fd6bb7da0..290be2f9e909 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -191,6 +191,10 @@ config GENERIC_CPU_AUTOPROBE > config GENERIC_CPU_VULNERABILITIES > bool > > +config SPECULATION_MITIGATIONS > + def_bool y > + depends on !X86 > + > config SOC_BUS > bool > select GLOB Thanks, that works for me (on arm64), so Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-15 11:16 ` Geert Uytterhoeven @ 2024-04-15 14:31 ` Sean Christopherson 2024-04-16 11:06 ` Michael Ellerman 2024-04-19 14:03 ` Will Deacon 0 siblings, 2 replies; 10+ messages in thread From: Sean Christopherson @ 2024-04-15 14:31 UTC (permalink / raw) To: Geert Uytterhoeven Cc: linux-arch, Stephen Rothwell, x86, Will Deacon, Jonathan Corbet, Peter Zijlstra, Heiko Carstens, Dave Hansen, linux-doc, linux-kernel, Linux-Renesas, Ingo Molnar, Borislav Petkov, Catalin Marinas, Pawan Gupta, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon On Mon, Apr 15, 2024, Geert Uytterhoeven wrote: > Hi Michael, > > On Sat, Apr 13, 2024 at 11:38 AM Michael Ellerman <mpe@ellerman.id.au> wrote: > > Michael Ellerman <mpe@ellerman.id.au> writes: > > > Stephen Rothwell <sfr@canb.auug.org.au> writes: > > ... > > >> On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: > > ... > > >>> diff --git a/kernel/cpu.c b/kernel/cpu.c > > >>> index 8f6affd051f7..07ad53b7f119 100644 > > >>> --- a/kernel/cpu.c > > >>> +++ b/kernel/cpu.c > > >>> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { > > >>> }; > > >>> > > >>> static enum cpu_mitigations cpu_mitigations __ro_after_init = > > >>> - CPU_MITIGATIONS_AUTO; > > >>> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : > > >>> + CPU_MITIGATIONS_OFF; > > >>> > > >>> static int __init mitigations_parse_cmdline(char *arg) > > >>> { > > > > I think a minimal workaround/fix would be: > > > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > > index 2b8fd6bb7da0..290be2f9e909 100644 > > --- a/drivers/base/Kconfig > > +++ b/drivers/base/Kconfig > > @@ -191,6 +191,10 @@ config GENERIC_CPU_AUTOPROBE > > config GENERIC_CPU_VULNERABILITIES > > bool > > > > +config SPECULATION_MITIGATIONS > > + def_bool y > > + depends on !X86 > > + > > config SOC_BUS > > bool > > select GLOB > > Thanks, that works for me (on arm64), so > Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Oof. I completely missed that "cpu_mitigations" wasn't x86-only. I can't think of better solution than an on-by-default generic Kconfig, though can't that it more simply be: diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 2b8fd6bb7da0..5930cb56ee29 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -191,6 +191,9 @@ config GENERIC_CPU_AUTOPROBE config GENERIC_CPU_VULNERABILITIES bool +config SPECULATION_MITIGATIONS + def_bool !X86 + config SOC_BUS bool select GLOB ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-15 14:31 ` Sean Christopherson @ 2024-04-16 11:06 ` Michael Ellerman 2024-04-19 14:03 ` Will Deacon 1 sibling, 0 replies; 10+ messages in thread From: Michael Ellerman @ 2024-04-16 11:06 UTC (permalink / raw) To: Sean Christopherson, Geert Uytterhoeven Cc: linux-arch, Stephen Rothwell, x86, Will Deacon, Jonathan Corbet, Peter Zijlstra, Catalin Marinas, Heiko Carstens, Dave Hansen, linux-doc, linux-kernel, Linux-Renesas, Ingo Molnar, Borislav Petkov, Pawan Gupta, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon Sean Christopherson <seanjc@google.com> writes: > On Mon, Apr 15, 2024, Geert Uytterhoeven wrote: >> On Sat, Apr 13, 2024 at 11:38 AM Michael Ellerman <mpe@ellerman.id.au> wrote: >> > Michael Ellerman <mpe@ellerman.id.au> writes: >> > > Stephen Rothwell <sfr@canb.auug.org.au> writes: >> > ... >> > >> On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: >> > ... >> > >>> diff --git a/kernel/cpu.c b/kernel/cpu.c >> > >>> index 8f6affd051f7..07ad53b7f119 100644 >> > >>> --- a/kernel/cpu.c >> > >>> +++ b/kernel/cpu.c >> > >>> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { >> > >>> }; >> > >>> >> > >>> static enum cpu_mitigations cpu_mitigations __ro_after_init = >> > >>> - CPU_MITIGATIONS_AUTO; >> > >>> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : >> > >>> + CPU_MITIGATIONS_OFF; >> > >>> >> > >>> static int __init mitigations_parse_cmdline(char *arg) >> > >>> { >> > >> > I think a minimal workaround/fix would be: >> > >> > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig >> > index 2b8fd6bb7da0..290be2f9e909 100644 >> > --- a/drivers/base/Kconfig >> > +++ b/drivers/base/Kconfig >> > @@ -191,6 +191,10 @@ config GENERIC_CPU_AUTOPROBE >> > config GENERIC_CPU_VULNERABILITIES >> > bool >> > >> > +config SPECULATION_MITIGATIONS >> > + def_bool y >> > + depends on !X86 >> > + >> > config SOC_BUS >> > bool >> > select GLOB >> >> Thanks, that works for me (on arm64), so >> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> > > Oof. I completely missed that "cpu_mitigations" wasn't x86-only. I can't think > of better solution than an on-by-default generic Kconfig, though can't that it > more simply be: > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 2b8fd6bb7da0..5930cb56ee29 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -191,6 +191,9 @@ config GENERIC_CPU_AUTOPROBE > config GENERIC_CPU_VULNERABILITIES > bool > > +config SPECULATION_MITIGATIONS > + def_bool !X86 > + Yeah that works too. cheers ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-15 14:31 ` Sean Christopherson 2024-04-16 11:06 ` Michael Ellerman @ 2024-04-19 14:03 ` Will Deacon 2024-04-19 14:06 ` Sean Christopherson 1 sibling, 1 reply; 10+ messages in thread From: Will Deacon @ 2024-04-19 14:03 UTC (permalink / raw) To: Sean Christopherson Cc: linux-arch, Stephen Rothwell, x86, Jonathan Corbet, Peter Zijlstra, Pawan Gupta, Dave Hansen, linux-doc, linux-kernel, Linux-Renesas, Heiko Carstens, Ingo Molnar, Geert Uytterhoeven, Catalin Marinas, Borislav Petkov, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon On Mon, Apr 15, 2024 at 07:31:23AM -0700, Sean Christopherson wrote: > On Mon, Apr 15, 2024, Geert Uytterhoeven wrote: > > On Sat, Apr 13, 2024 at 11:38 AM Michael Ellerman <mpe@ellerman.id.au> wrote: > > > Michael Ellerman <mpe@ellerman.id.au> writes: > > > > Stephen Rothwell <sfr@canb.auug.org.au> writes: > > > ... > > > >> On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson <seanjc@google.com> wrote: > > > ... > > > >>> diff --git a/kernel/cpu.c b/kernel/cpu.c > > > >>> index 8f6affd051f7..07ad53b7f119 100644 > > > >>> --- a/kernel/cpu.c > > > >>> +++ b/kernel/cpu.c > > > >>> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { > > > >>> }; > > > >>> > > > >>> static enum cpu_mitigations cpu_mitigations __ro_after_init = > > > >>> - CPU_MITIGATIONS_AUTO; > > > >>> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : > > > >>> + CPU_MITIGATIONS_OFF; > > > >>> > > > >>> static int __init mitigations_parse_cmdline(char *arg) > > > >>> { > > > > > > I think a minimal workaround/fix would be: > > > > > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > > > index 2b8fd6bb7da0..290be2f9e909 100644 > > > --- a/drivers/base/Kconfig > > > +++ b/drivers/base/Kconfig > > > @@ -191,6 +191,10 @@ config GENERIC_CPU_AUTOPROBE > > > config GENERIC_CPU_VULNERABILITIES > > > bool > > > > > > +config SPECULATION_MITIGATIONS > > > + def_bool y > > > + depends on !X86 > > > + > > > config SOC_BUS > > > bool > > > select GLOB > > > > Thanks, that works for me (on arm64), so > > Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> > > Oof. I completely missed that "cpu_mitigations" wasn't x86-only. I can't think > of better solution than an on-by-default generic Kconfig, though can't that it > more simply be: > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 2b8fd6bb7da0..5930cb56ee29 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -191,6 +191,9 @@ config GENERIC_CPU_AUTOPROBE > config GENERIC_CPU_VULNERABILITIES > bool > > +config SPECULATION_MITIGATIONS > + def_bool !X86 > + > config SOC_BUS > bool > select GLOB I can't see this in -next yet. Do you plan to post it as a proper patch to collect acks etc? Cheers, Will ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-19 14:03 ` Will Deacon @ 2024-04-19 14:06 ` Sean Christopherson 2024-04-19 14:38 ` Will Deacon 0 siblings, 1 reply; 10+ messages in thread From: Sean Christopherson @ 2024-04-19 14:06 UTC (permalink / raw) To: Will Deacon Cc: linux-arch, Stephen Rothwell, x86, Jonathan Corbet, Peter Zijlstra, Pawan Gupta, Dave Hansen, linux-doc, linux-kernel, Linux-Renesas, Heiko Carstens, Ingo Molnar, Geert Uytterhoeven, Catalin Marinas, Borislav Petkov, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon On Fri, Apr 19, 2024, Will Deacon wrote: > On Mon, Apr 15, 2024 at 07:31:23AM -0700, Sean Christopherson wrote: > > On Mon, Apr 15, 2024, Geert Uytterhoeven wrote: > > Oof. I completely missed that "cpu_mitigations" wasn't x86-only. I can't think > > of better solution than an on-by-default generic Kconfig, though can't that it > > more simply be: > > > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > > index 2b8fd6bb7da0..5930cb56ee29 100644 > > --- a/drivers/base/Kconfig > > +++ b/drivers/base/Kconfig > > @@ -191,6 +191,9 @@ config GENERIC_CPU_AUTOPROBE > > config GENERIC_CPU_VULNERABILITIES > > bool > > > > +config SPECULATION_MITIGATIONS > > + def_bool !X86 > > + > > config SOC_BUS > > bool > > select GLOB > > I can't see this in -next yet. Do you plan to post it as a proper patch > to collect acks etc? Sorry, I neglected to Cc everyone. https://lore.kernel.org/all/20240417001507.2264512-2-seanjc@google.com ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-19 14:06 ` Sean Christopherson @ 2024-04-19 14:38 ` Will Deacon 0 siblings, 0 replies; 10+ messages in thread From: Will Deacon @ 2024-04-19 14:38 UTC (permalink / raw) To: Sean Christopherson Cc: linux-arch, Stephen Rothwell, x86, Jonathan Corbet, Peter Zijlstra, Pawan Gupta, Dave Hansen, linux-doc, linux-kernel, Linux-Renesas, Heiko Carstens, Ingo Molnar, Geert Uytterhoeven, Catalin Marinas, Borislav Petkov, Thomas Gleixner, linuxppc-dev, Josh Poimboeuf, Daniel Sneddon On Fri, Apr 19, 2024 at 07:06:00AM -0700, Sean Christopherson wrote: > On Fri, Apr 19, 2024, Will Deacon wrote: > > On Mon, Apr 15, 2024 at 07:31:23AM -0700, Sean Christopherson wrote: > > > On Mon, Apr 15, 2024, Geert Uytterhoeven wrote: > > > Oof. I completely missed that "cpu_mitigations" wasn't x86-only. I can't think > > > of better solution than an on-by-default generic Kconfig, though can't that it > > > more simply be: > > > > > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > > > index 2b8fd6bb7da0..5930cb56ee29 100644 > > > --- a/drivers/base/Kconfig > > > +++ b/drivers/base/Kconfig > > > @@ -191,6 +191,9 @@ config GENERIC_CPU_AUTOPROBE > > > config GENERIC_CPU_VULNERABILITIES > > > bool > > > > > > +config SPECULATION_MITIGATIONS > > > + def_bool !X86 > > > + > > > config SOC_BUS > > > bool > > > select GLOB > > > > I can't see this in -next yet. Do you plan to post it as a proper patch > > to collect acks etc? > > Sorry, I neglected to Cc everyone. > > https://lore.kernel.org/all/20240417001507.2264512-2-seanjc@google.com Ah, thanks. I'll go Ack that... Will ^ permalink raw reply [flat|nested] 10+ messages in thread
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2024-04-13 1:53 ` [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n Stephen Rothwell
2024-04-13 9:27 ` Michael Ellerman
2024-04-13 9:38 ` Michael Ellerman
2024-04-14 22:42 ` Stephen Rothwell
2024-04-15 11:16 ` Geert Uytterhoeven
2024-04-15 14:31 ` Sean Christopherson
2024-04-16 11:06 ` Michael Ellerman
2024-04-19 14:03 ` Will Deacon
2024-04-19 14:06 ` Sean Christopherson
2024-04-19 14:38 ` Will Deacon
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