* [PATCH v2 0/2] Forcibly enable some MISC_ENABLE features on Intel @ 2011-08-06 11:42 Andy Lutomirski 2011-08-06 11:42 ` [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already Andy Lutomirski 2011-08-06 11:42 ` [PATCH v2 2/2] x86: Enable monitor/mwait " Andy Lutomirski 0 siblings, 2 replies; 9+ messages in thread From: Andy Lutomirski @ 2011-08-06 11:42 UTC (permalink / raw) To: x86, linux-kernel Cc: Fenghua Yu, Matthew Garrett, Len Brown, linux-acpi, Ingo Molnar, Andy Lutomirski Intel allows BIOS or the OS to enable or disable some CPU fueatures via IA32_MISC_ENABLE. I have machines that don't enable fast strings or monitor/mwait in BIOS, so do it on bootup instead. The Intel SDM volume 3, appendix B.1 says that the OS should not touch the monitor enable bit if SSE3 is not present, which presumably means that the OS may touch that bit if SSE3 is present. In any case, these patches seem to work. Changes from v1: - Display FW_WARN messages. - Don't change the kmemcheck message. - Improve the fast string comment. - Improve the changelogs. Andy Lutomirski (2): x86: Enable fast strings on Intel if BIOS hasn't already x86: Enable monitor/mwait on Intel if BIOS hasn't already arch/x86/kernel/cpu/intel.c | 50 ++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 47 insertions(+), 3 deletions(-) -- 1.7.6 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already 2011-08-06 11:42 [PATCH v2 0/2] Forcibly enable some MISC_ENABLE features on Intel Andy Lutomirski @ 2011-08-06 11:42 ` Andy Lutomirski 2011-08-06 19:33 ` Yu, Fenghua 2011-08-06 11:42 ` [PATCH v2 2/2] x86: Enable monitor/mwait " Andy Lutomirski 1 sibling, 1 reply; 9+ messages in thread From: Andy Lutomirski @ 2011-08-06 11:42 UTC (permalink / raw) To: x86, linux-kernel Cc: Fenghua Yu, Matthew Garrett, Len Brown, linux-acpi, Ingo Molnar, Andy Lutomirski Intel SDM volume 3A, 8.4.2 says: Software can disable fast-string operation by clearing the fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR. However, Intel recomments that system software always enable fast-string operation. The Intel DQ67SW board (with latest BIOS) disables fast string operations if TXT is enabled. A Lenovo X220 disables it regardless of TXT setting. I doubt I'm the only person with a dumb BIOS like this. Signed-off-by: Andy Lutomirski <luto@mit.edu> --- arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++++++++--- 1 files changed, 22 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index ed6086e..c80ab41 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -30,6 +30,7 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) { u64 misc_enable; + bool allow_fast_string = true; /* Unmask CPUID levels if masked: */ if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { @@ -118,8 +119,9 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) * (model 2) with the same problem. */ if (c->x86 == 15) { - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); + allow_fast_string = false; + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) { printk(KERN_INFO "kmemcheck: Disabling fast string operations\n"); @@ -130,11 +132,28 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) #endif /* - * If fast string is not enabled in IA32_MISC_ENABLE for any reason, - * clear the fast string and enhanced fast string CPU capabilities. + * If BIOS didn't enable fast string operation, try to enable + * it ourselves. If that fails, then clear the fast string + * and enhanced fast string CPU capabilities. */ if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); + + if (allow_fast_string && + !(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) { + misc_enable |= MSR_IA32_MISC_ENABLE_FAST_STRING; + wrmsr_safe(MSR_IA32_MISC_ENABLE, (u32)misc_enable, + (u32)(misc_enable >> 32)); + + /* Re-read to make sure it stuck. */ + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); + + if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) + printk(KERN_WARNING FW_WARN "CPU #%d: " + "IA32_MISC_ENABLE.FAST_STRING_ENABLE " + "was not set", c->cpu_index); + } + if (!(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) { printk(KERN_INFO "Disabled fast string operations\n"); setup_clear_cpu_cap(X86_FEATURE_REP_GOOD); -- 1.7.6 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* RE: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already 2011-08-06 11:42 ` [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already Andy Lutomirski @ 2011-08-06 19:33 ` Yu, Fenghua 2011-08-06 23:31 ` Andrew Lutomirski 0 siblings, 1 reply; 9+ messages in thread From: Yu, Fenghua @ 2011-08-06 19:33 UTC (permalink / raw) To: Andy Lutomirski, x86, linux-kernel Cc: Matthew Garrett, Len Brown, linux-acpi, Ingo Molnar > -----Original Message----- > From: Andy Lutomirski [mailto:luto@MIT.EDU] > Sent: Saturday, August 06, 2011 4:43 AM > To: x86@kernel.org; linux-kernel@vger.kernel.org > Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux- > acpi@vger.kernel.org; Ingo Molnar; Andy Lutomirski > Subject: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > hasn't already > > Intel SDM volume 3A, 8.4.2 says: > > Software can disable fast-string operation by clearing the > fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR. > However, Intel recomments that system software always enable > fast-string operation. > > The Intel DQ67SW board (with latest BIOS) disables fast string > operations if TXT is enabled. A Lenovo X220 disables it regardless > of TXT setting. I doubt I'm the only person with a dumb BIOS like > this. > > Signed-off-by: Andy Lutomirski <luto@mit.edu> > --- > arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++++++++--- > 1 files changed, 22 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c > index ed6086e..c80ab41 100644 > --- a/arch/x86/kernel/cpu/intel.c > +++ b/arch/x86/kernel/cpu/intel.c > @@ -30,6 +30,7 @@ > static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) > { > u64 misc_enable; > + bool allow_fast_string = true; > > /* Unmask CPUID levels if masked: */ > if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > @@ -118,8 +119,9 @@ static void __cpuinit early_init_intel(struct > cpuinfo_x86 *c) > * (model 2) with the same problem. > */ > if (c->x86 == 15) { > - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > + allow_fast_string = false; > > + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) { > printk(KERN_INFO "kmemcheck: Disabling fast string > operations\n"); > > @@ -130,11 +132,28 @@ static void __cpuinit early_init_intel(struct > cpuinfo_x86 *c) > #endif > > /* > - * If fast string is not enabled in IA32_MISC_ENABLE for any > reason, > - * clear the fast string and enhanced fast string CPU > capabilities. > + * If BIOS didn't enable fast string operation, try to enable > + * it ourselves. If that fails, then clear the fast string > + * and enhanced fast string CPU capabilities. > */ > if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > + > + if (allow_fast_string && > + !(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) { > + misc_enable |= MSR_IA32_MISC_ENABLE_FAST_STRING; > + wrmsr_safe(MSR_IA32_MISC_ENABLE, (u32)misc_enable, > + (u32)(misc_enable >> 32)); > + > + /* Re-read to make sure it stuck. */ > + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > + > + if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) > + printk(KERN_WARNING FW_WARN "CPU #%d: " > + "IA32_MISC_ENABLE.FAST_STRING_ENABLE " > + "was not set", c->cpu_index); This printk is redundant because the same info is dumped in the below printk. Plus it's not firmware's issue if we can not set fast string bit 0 in MISC_ENABLE register. So I don't think FW_WARN is right. I would suggest to remove this printk (and the if () statement) and change KERN_INFO to KERN_WARNING in the following printk. > + } > + > if (!(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) { > printk(KERN_INFO "Disabled fast string > operations\n"); > setup_clear_cpu_cap(X86_FEATURE_REP_GOOD); > -- > 1.7.6 ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already 2011-08-06 19:33 ` Yu, Fenghua @ 2011-08-06 23:31 ` Andrew Lutomirski 2011-08-07 23:44 ` Yu, Fenghua 2011-08-08 18:42 ` Yu, Fenghua 0 siblings, 2 replies; 9+ messages in thread From: Andrew Lutomirski @ 2011-08-06 23:31 UTC (permalink / raw) To: Yu, Fenghua Cc: x86, linux-kernel, Matthew Garrett, Len Brown, linux-acpi, Ingo Molnar On Sat, Aug 6, 2011 at 3:33 PM, Yu, Fenghua <fenghua.yu@intel.com> wrote: >> -----Original Message----- >> From: Andy Lutomirski [mailto:luto@MIT.EDU] >> Sent: Saturday, August 06, 2011 4:43 AM >> To: x86@kernel.org; linux-kernel@vger.kernel.org >> Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux- >> acpi@vger.kernel.org; Ingo Molnar; Andy Lutomirski >> Subject: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS >> hasn't already >> >> Intel SDM volume 3A, 8.4.2 says: >> >> Software can disable fast-string operation by clearing the >> fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR. >> However, Intel recomments that system software always enable >> fast-string operation. >> >> The Intel DQ67SW board (with latest BIOS) disables fast string >> operations if TXT is enabled. A Lenovo X220 disables it regardless >> of TXT setting. I doubt I'm the only person with a dumb BIOS like >> this. >> >> Signed-off-by: Andy Lutomirski <luto@mit.edu> >> --- >> arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++++++++--- >> 1 files changed, 22 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c >> index ed6086e..c80ab41 100644 >> --- a/arch/x86/kernel/cpu/intel.c >> +++ b/arch/x86/kernel/cpu/intel.c >> @@ -30,6 +30,7 @@ >> static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) >> { >> u64 misc_enable; >> + bool allow_fast_string = true; >> >> /* Unmask CPUID levels if masked: */ >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { >> @@ -118,8 +119,9 @@ static void __cpuinit early_init_intel(struct >> cpuinfo_x86 *c) >> * (model 2) with the same problem. >> */ >> if (c->x86 == 15) { >> - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> + allow_fast_string = false; >> >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) { >> printk(KERN_INFO "kmemcheck: Disabling fast string >> operations\n"); >> >> @@ -130,11 +132,28 @@ static void __cpuinit early_init_intel(struct >> cpuinfo_x86 *c) >> #endif >> >> /* >> - * If fast string is not enabled in IA32_MISC_ENABLE for any >> reason, >> - * clear the fast string and enhanced fast string CPU >> capabilities. >> + * If BIOS didn't enable fast string operation, try to enable >> + * it ourselves. If that fails, then clear the fast string >> + * and enhanced fast string CPU capabilities. >> */ >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { >> rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> + >> + if (allow_fast_string && >> + !(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) { >> + misc_enable |= MSR_IA32_MISC_ENABLE_FAST_STRING; >> + wrmsr_safe(MSR_IA32_MISC_ENABLE, (u32)misc_enable, >> + (u32)(misc_enable >> 32)); >> + >> + /* Re-read to make sure it stuck. */ >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> + >> + if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) >> + printk(KERN_WARNING FW_WARN "CPU #%d: " >> + "IA32_MISC_ENABLE.FAST_STRING_ENABLE " >> + "was not set", c->cpu_index); > This printk is redundant because the same info is dumped in the below printk. Plus it's not firmware's issue if we can not set fast string bit 0 in MISC_ENABLE register. So I don't think FW_WARN is right. Huh? This is the success path -- the patch prints the warning if flipping the bit worked... > > I would suggest to remove this printk (and the if () statement) and change KERN_INFO to KERN_WARNING in the following printk. > >> + } >> + >> if (!(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) { >> printk(KERN_INFO "Disabled fast string >> operations\n"); >> setup_clear_cpu_cap(X86_FEATURE_REP_GOOD); ...and this (which could be more clear) is displayed if flipping the bit did not work, in which case the problem isn't BIOS's fault. --Andy ^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already 2011-08-06 23:31 ` Andrew Lutomirski @ 2011-08-07 23:44 ` Yu, Fenghua 2011-08-09 15:00 ` Ingo Molnar 2011-08-08 18:42 ` Yu, Fenghua 1 sibling, 1 reply; 9+ messages in thread From: Yu, Fenghua @ 2011-08-07 23:44 UTC (permalink / raw) To: Andrew Lutomirski Cc: x86, linux-kernel, Matthew Garrett, Len Brown, linux-acpi, Ingo Molnar > -----Original Message----- > From: amluto@gmail.com [mailto:amluto@gmail.com] On Behalf Of Andrew > Lutomirski > Sent: Saturday, August 06, 2011 4:32 PM > To: Yu, Fenghua > Cc: x86@kernel.org; linux-kernel@vger.kernel.org; Matthew Garrett; Len > Brown; linux-acpi@vger.kernel.org; Ingo Molnar > Subject: Re: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > hasn't already > > On Sat, Aug 6, 2011 at 3:33 PM, Yu, Fenghua <fenghua.yu@intel.com> > wrote: > >> -----Original Message----- > >> From: Andy Lutomirski [mailto:luto@MIT.EDU] > >> Sent: Saturday, August 06, 2011 4:43 AM > >> To: x86@kernel.org; linux-kernel@vger.kernel.org > >> Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux- > >> acpi@vger.kernel.org; Ingo Molnar; Andy Lutomirski > >> Subject: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > >> hasn't already > >> > >> Intel SDM volume 3A, 8.4.2 says: > >> > >> Software can disable fast-string operation by clearing the > >> fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR. > >> However, Intel recomments that system software always enable > >> fast-string operation. > >> > >> The Intel DQ67SW board (with latest BIOS) disables fast string > >> operations if TXT is enabled. A Lenovo X220 disables it regardless > >> of TXT setting. I doubt I'm the only person with a dumb BIOS like > >> this. > >> > >> Signed-off-by: Andy Lutomirski <luto@mit.edu> > >> --- > >> arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++++++++--- > >> 1 files changed, 22 insertions(+), 3 deletions(-) > >> > >> diff --git a/arch/x86/kernel/cpu/intel.c > b/arch/x86/kernel/cpu/intel.c > >> index ed6086e..c80ab41 100644 > >> --- a/arch/x86/kernel/cpu/intel.c > >> +++ b/arch/x86/kernel/cpu/intel.c > >> @@ -30,6 +30,7 @@ > >> static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) > >> { > >> u64 misc_enable; > >> + bool allow_fast_string = true; > >> > >> /* Unmask CPUID levels if masked: */ > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > >> @@ -118,8 +119,9 @@ static void __cpuinit early_init_intel(struct > >> cpuinfo_x86 *c) > >> * (model 2) with the same problem. > >> */ > >> if (c->x86 == 15) { > >> - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > >> + allow_fast_string = false; > >> > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > >> if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) { > >> printk(KERN_INFO "kmemcheck: Disabling fast > string > >> operations\n"); > >> > >> @@ -130,11 +132,28 @@ static void __cpuinit early_init_intel(struct > >> cpuinfo_x86 *c) > >> #endif > >> > >> /* > >> - * If fast string is not enabled in IA32_MISC_ENABLE for any > >> reason, > >> - * clear the fast string and enhanced fast string CPU > >> capabilities. > >> + * If BIOS didn't enable fast string operation, try to enable > >> + * it ourselves. If that fails, then clear the fast string > >> + * and enhanced fast string CPU capabilities. > >> */ > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > >> rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > >> + > >> + if (allow_fast_string && > >> + !(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) > { > >> + misc_enable |= > MSR_IA32_MISC_ENABLE_FAST_STRING; > >> + wrmsr_safe(MSR_IA32_MISC_ENABLE, > (u32)misc_enable, > >> + (u32)(misc_enable >> 32)); > >> + > >> + /* Re-read to make sure it stuck. */ > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > >> + > >> + if (misc_enable & > MSR_IA32_MISC_ENABLE_FAST_STRING) > >> + printk(KERN_WARNING FW_WARN "CPU #%d: > " > >> + > "IA32_MISC_ENABLE.FAST_STRING_ENABLE " > >> + "was not set", c->cpu_index); > > This printk is redundant because the same info is dumped in the below > printk. Plus it's not firmware's issue if we can not set fast string > bit 0 in MISC_ENABLE register. So I don't think FW_WARN is right. > > Huh? This is the success path -- the patch prints the warning if > flipping the bit worked... Ok. I see. Still I would suggest to remove this printk. This info will be printed on every single CPU if BIOS doesn't enable fast string. This could flood the log buffer on big machines or many threads machines. And the info doesn't really provide useful message because we enable fast string in OS anyway. Reporting BIOS issue by this info probably will be viewed as low priority or ignored. The following info is more important because it reports an abnormal behavior. Thanks. -Fenghua ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already 2011-08-07 23:44 ` Yu, Fenghua @ 2011-08-09 15:00 ` Ingo Molnar 2011-08-09 15:12 ` Andrew Lutomirski 0 siblings, 1 reply; 9+ messages in thread From: Ingo Molnar @ 2011-08-09 15:00 UTC (permalink / raw) To: Yu, Fenghua Cc: Andrew Lutomirski, x86, linux-kernel, Matthew Garrett, Len Brown, linux-acpi * Yu, Fenghua <fenghua.yu@intel.com> wrote: > > -----Original Message----- > > From: amluto@gmail.com [mailto:amluto@gmail.com] On Behalf Of Andrew > > Lutomirski > > Sent: Saturday, August 06, 2011 4:32 PM > > To: Yu, Fenghua > > Cc: x86@kernel.org; linux-kernel@vger.kernel.org; Matthew Garrett; Len > > Brown; linux-acpi@vger.kernel.org; Ingo Molnar > > Subject: Re: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > > hasn't already > > > > On Sat, Aug 6, 2011 at 3:33 PM, Yu, Fenghua <fenghua.yu@intel.com> > > wrote: > > >> -----Original Message----- > > >> From: Andy Lutomirski [mailto:luto@MIT.EDU] > > >> Sent: Saturday, August 06, 2011 4:43 AM > > >> To: x86@kernel.org; linux-kernel@vger.kernel.org > > >> Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux- > > >> acpi@vger.kernel.org; Ingo Molnar; Andy Lutomirski > > >> Subject: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > > >> hasn't already > > >> > > >> Intel SDM volume 3A, 8.4.2 says: > > >> > > >> Software can disable fast-string operation by clearing the > > >> fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR. > > >> However, Intel recomments that system software always enable > > >> fast-string operation. > > >> > > >> The Intel DQ67SW board (with latest BIOS) disables fast string > > >> operations if TXT is enabled. A Lenovo X220 disables it regardless > > >> of TXT setting. I doubt I'm the only person with a dumb BIOS like > > >> this. > > >> > > >> Signed-off-by: Andy Lutomirski <luto@mit.edu> > > >> --- > > >> arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++++++++--- > > >> 1 files changed, 22 insertions(+), 3 deletions(-) > > >> > > >> diff --git a/arch/x86/kernel/cpu/intel.c > > b/arch/x86/kernel/cpu/intel.c > > >> index ed6086e..c80ab41 100644 > > >> --- a/arch/x86/kernel/cpu/intel.c > > >> +++ b/arch/x86/kernel/cpu/intel.c > > >> @@ -30,6 +30,7 @@ > > >> static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) > > >> { > > >> u64 misc_enable; > > >> + bool allow_fast_string = true; > > >> > > >> /* Unmask CPUID levels if masked: */ > > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > > >> @@ -118,8 +119,9 @@ static void __cpuinit early_init_intel(struct > > >> cpuinfo_x86 *c) > > >> * (model 2) with the same problem. > > >> */ > > >> if (c->x86 == 15) { > > >> - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> + allow_fast_string = false; > > >> > > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) { > > >> printk(KERN_INFO "kmemcheck: Disabling fast > > string > > >> operations\n"); > > >> > > >> @@ -130,11 +132,28 @@ static void __cpuinit early_init_intel(struct > > >> cpuinfo_x86 *c) > > >> #endif > > >> > > >> /* > > >> - * If fast string is not enabled in IA32_MISC_ENABLE for any > > >> reason, > > >> - * clear the fast string and enhanced fast string CPU > > >> capabilities. > > >> + * If BIOS didn't enable fast string operation, try to enable > > >> + * it ourselves. If that fails, then clear the fast string > > >> + * and enhanced fast string CPU capabilities. > > >> */ > > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > > >> rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> + > > >> + if (allow_fast_string && > > >> + !(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) > > { > > >> + misc_enable |= > > MSR_IA32_MISC_ENABLE_FAST_STRING; > > >> + wrmsr_safe(MSR_IA32_MISC_ENABLE, > > (u32)misc_enable, > > >> + (u32)(misc_enable >> 32)); > > >> + > > >> + /* Re-read to make sure it stuck. */ > > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> + > > >> + if (misc_enable & > > MSR_IA32_MISC_ENABLE_FAST_STRING) > > >> + printk(KERN_WARNING FW_WARN "CPU #%d: > > " > > >> + > > "IA32_MISC_ENABLE.FAST_STRING_ENABLE " > > >> + "was not set", c->cpu_index); > > > This printk is redundant because the same info is dumped in the below > > printk. Plus it's not firmware's issue if we can not set fast string > > bit 0 in MISC_ENABLE register. So I don't think FW_WARN is right. > > > > Huh? This is the success path -- the patch prints the warning if > > flipping the bit worked... > > Ok. I see. > > Still I would suggest to remove this printk. This info will be > printed on every single CPU if BIOS doesn't enable fast string. just do printk_once(). We want to inform the user that something's going on. Thanks, Ingo ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already 2011-08-09 15:00 ` Ingo Molnar @ 2011-08-09 15:12 ` Andrew Lutomirski 0 siblings, 0 replies; 9+ messages in thread From: Andrew Lutomirski @ 2011-08-09 15:12 UTC (permalink / raw) To: Ingo Molnar Cc: Yu, Fenghua, x86, linux-kernel, Matthew Garrett, Len Brown, linux-acpi On Tue, Aug 9, 2011 at 11:00 AM, Ingo Molnar <mingo@elte.hu> wrote: > > * Yu, Fenghua <fenghua.yu@intel.com> wrote: > >> > -----Original Message----- >> > From: amluto@gmail.com [mailto:amluto@gmail.com] On Behalf Of Andrew >> > Lutomirski >> > Sent: Saturday, August 06, 2011 4:32 PM >> > To: Yu, Fenghua >> > Cc: x86@kernel.org; linux-kernel@vger.kernel.org; Matthew Garrett; Len >> > Brown; linux-acpi@vger.kernel.org; Ingo Molnar >> > Subject: Re: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS >> > hasn't already >> > >> > On Sat, Aug 6, 2011 at 3:33 PM, Yu, Fenghua <fenghua.yu@intel.com> >> > wrote: >> > >> -----Original Message----- >> > >> From: Andy Lutomirski [mailto:luto@MIT.EDU] >> > >> Sent: Saturday, August 06, 2011 4:43 AM >> > >> To: x86@kernel.org; linux-kernel@vger.kernel.org >> > >> Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux- >> > >> acpi@vger.kernel.org; Ingo Molnar; Andy Lutomirski >> > >> Subject: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS >> > >> hasn't already >> > >> >> > >> Intel SDM volume 3A, 8.4.2 says: >> > >> >> > >> Software can disable fast-string operation by clearing the >> > >> fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR. >> > >> However, Intel recomments that system software always enable >> > >> fast-string operation. >> > >> >> > >> The Intel DQ67SW board (with latest BIOS) disables fast string >> > >> operations if TXT is enabled. A Lenovo X220 disables it regardless >> > >> of TXT setting. I doubt I'm the only person with a dumb BIOS like >> > >> this. >> > >> >> > >> Signed-off-by: Andy Lutomirski <luto@mit.edu> >> > >> --- >> > >> arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++++++++--- >> > >> 1 files changed, 22 insertions(+), 3 deletions(-) >> > >> >> > >> diff --git a/arch/x86/kernel/cpu/intel.c >> > b/arch/x86/kernel/cpu/intel.c >> > >> index ed6086e..c80ab41 100644 >> > >> --- a/arch/x86/kernel/cpu/intel.c >> > >> +++ b/arch/x86/kernel/cpu/intel.c >> > >> @@ -30,6 +30,7 @@ >> > >> static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) >> > >> { >> > >> u64 misc_enable; >> > >> + bool allow_fast_string = true; >> > >> >> > >> /* Unmask CPUID levels if masked: */ >> > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { >> > >> @@ -118,8 +119,9 @@ static void __cpuinit early_init_intel(struct >> > >> cpuinfo_x86 *c) >> > >> * (model 2) with the same problem. >> > >> */ >> > >> if (c->x86 == 15) { >> > >> - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> > >> + allow_fast_string = false; >> > >> >> > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> > >> if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) { >> > >> printk(KERN_INFO "kmemcheck: Disabling fast >> > string >> > >> operations\n"); >> > >> >> > >> @@ -130,11 +132,28 @@ static void __cpuinit early_init_intel(struct >> > >> cpuinfo_x86 *c) >> > >> #endif >> > >> >> > >> /* >> > >> - * If fast string is not enabled in IA32_MISC_ENABLE for any >> > >> reason, >> > >> - * clear the fast string and enhanced fast string CPU >> > >> capabilities. >> > >> + * If BIOS didn't enable fast string operation, try to enable >> > >> + * it ourselves. If that fails, then clear the fast string >> > >> + * and enhanced fast string CPU capabilities. >> > >> */ >> > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { >> > >> rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> > >> + >> > >> + if (allow_fast_string && >> > >> + !(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) >> > { >> > >> + misc_enable |= >> > MSR_IA32_MISC_ENABLE_FAST_STRING; >> > >> + wrmsr_safe(MSR_IA32_MISC_ENABLE, >> > (u32)misc_enable, >> > >> + (u32)(misc_enable >> 32)); >> > >> + >> > >> + /* Re-read to make sure it stuck. */ >> > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> > >> + >> > >> + if (misc_enable & >> > MSR_IA32_MISC_ENABLE_FAST_STRING) >> > >> + printk(KERN_WARNING FW_WARN "CPU #%d: >> > " >> > >> + >> > "IA32_MISC_ENABLE.FAST_STRING_ENABLE " >> > >> + "was not set", c->cpu_index); >> > > This printk is redundant because the same info is dumped in the below >> > printk. Plus it's not firmware's issue if we can not set fast string >> > bit 0 in MISC_ENABLE register. So I don't think FW_WARN is right. >> > >> > Huh? This is the success path -- the patch prints the warning if >> > flipping the bit worked... >> >> Ok. I see. >> >> Still I would suggest to remove this printk. This info will be >> printed on every single CPU if BIOS doesn't enable fast string. > > just do printk_once(). We want to inform the user that something's > going on. Already there in v3. --Andy > > Thanks, > > Ingo > ^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already 2011-08-06 23:31 ` Andrew Lutomirski 2011-08-07 23:44 ` Yu, Fenghua @ 2011-08-08 18:42 ` Yu, Fenghua 1 sibling, 0 replies; 9+ messages in thread From: Yu, Fenghua @ 2011-08-08 18:42 UTC (permalink / raw) To: Andrew Lutomirski Cc: x86, linux-kernel, Matthew Garrett, Len Brown, linux-acpi, Ingo Molnar > -----Original Message----- > From: Yu, Fenghua > Sent: Sunday, August 07, 2011 4:45 PM > To: 'Andrew Lutomirski' > Cc: x86@kernel.org; linux-kernel@vger.kernel.org; Matthew Garrett; Len > Brown; linux-acpi@vger.kernel.org; Ingo Molnar > Subject: RE: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > hasn't already > > > -----Original Message----- > > From: amluto@gmail.com [mailto:amluto@gmail.com] On Behalf Of Andrew > > Lutomirski > > Sent: Saturday, August 06, 2011 4:32 PM > > To: Yu, Fenghua > > Cc: x86@kernel.org; linux-kernel@vger.kernel.org; Matthew Garrett; > Len > > Brown; linux-acpi@vger.kernel.org; Ingo Molnar > > Subject: Re: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > > hasn't already > > > > On Sat, Aug 6, 2011 at 3:33 PM, Yu, Fenghua <fenghua.yu@intel.com> > > wrote: > > >> -----Original Message----- > > >> From: Andy Lutomirski [mailto:luto@MIT.EDU] > > >> Sent: Saturday, August 06, 2011 4:43 AM > > >> To: x86@kernel.org; linux-kernel@vger.kernel.org > > >> Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux- > > >> acpi@vger.kernel.org; Ingo Molnar; Andy Lutomirski > > >> Subject: [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS > > >> hasn't already > > >> > > >> Intel SDM volume 3A, 8.4.2 says: > > >> > > >> Software can disable fast-string operation by clearing the > > >> fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR. > > >> However, Intel recomments that system software always enable > > >> fast-string operation. > > >> > > >> The Intel DQ67SW board (with latest BIOS) disables fast string > > >> operations if TXT is enabled. A Lenovo X220 disables it > regardless > > >> of TXT setting. I doubt I'm the only person with a dumb BIOS like > > >> this. > > >> > > >> Signed-off-by: Andy Lutomirski <luto@mit.edu> > > >> --- > > >> arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++++++++--- > > >> 1 files changed, 22 insertions(+), 3 deletions(-) > > >> > > >> diff --git a/arch/x86/kernel/cpu/intel.c > > b/arch/x86/kernel/cpu/intel.c > > >> index ed6086e..c80ab41 100644 > > >> --- a/arch/x86/kernel/cpu/intel.c > > >> +++ b/arch/x86/kernel/cpu/intel.c > > >> @@ -30,6 +30,7 @@ > > >> static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) > > >> { > > >> u64 misc_enable; > > >> + bool allow_fast_string = true; > > >> > > >> /* Unmask CPUID levels if masked: */ > > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > > >> @@ -118,8 +119,9 @@ static void __cpuinit early_init_intel(struct > > >> cpuinfo_x86 *c) > > >> * (model 2) with the same problem. > > >> */ > > >> if (c->x86 == 15) { > > >> - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> + allow_fast_string = false; > > >> > > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) > { > > >> printk(KERN_INFO "kmemcheck: Disabling fast > > string > > >> operations\n"); > > >> > > >> @@ -130,11 +132,28 @@ static void __cpuinit > early_init_intel(struct > > >> cpuinfo_x86 *c) > > >> #endif > > >> > > >> /* > > >> - * If fast string is not enabled in IA32_MISC_ENABLE for any > > >> reason, > > >> - * clear the fast string and enhanced fast string CPU > > >> capabilities. > > >> + * If BIOS didn't enable fast string operation, try to > enable > > >> + * it ourselves. If that fails, then clear the fast string > > >> + * and enhanced fast string CPU capabilities. > > >> */ > > >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { > > >> rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> + > > >> + if (allow_fast_string && > > >> + !(misc_enable & > MSR_IA32_MISC_ENABLE_FAST_STRING)) > > { > > >> + misc_enable |= > > MSR_IA32_MISC_ENABLE_FAST_STRING; > > >> + wrmsr_safe(MSR_IA32_MISC_ENABLE, > > (u32)misc_enable, > > >> + (u32)(misc_enable >> 32)); > > >> + > > >> + /* Re-read to make sure it stuck. */ > > >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); > > >> + > > >> + if (misc_enable & > > MSR_IA32_MISC_ENABLE_FAST_STRING) > > >> + printk(KERN_WARNING FW_WARN "CPU > #%d: > > " > > >> + > > "IA32_MISC_ENABLE.FAST_STRING_ENABLE " > > >> + "was not set", c->cpu_index); > > > This printk is redundant because the same info is dumped in the > below > > printk. Plus it's not firmware's issue if we can not set fast string > > bit 0 in MISC_ENABLE register. So I don't think FW_WARN is right. > > > > Huh? This is the success path -- the patch prints the warning if > > flipping the bit worked... > > Ok. I see. > > Still I would suggest to remove this printk. This info will be printed > on every single CPU if BIOS doesn't enable fast string. This could > flood the log buffer on big machines or many threads machines. And the On the bottom line, you need to use printk_once to reduce repeated message on each CPU. Thanks. -Fenghua ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2 2/2] x86: Enable monitor/mwait on Intel if BIOS hasn't already 2011-08-06 11:42 [PATCH v2 0/2] Forcibly enable some MISC_ENABLE features on Intel Andy Lutomirski 2011-08-06 11:42 ` [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already Andy Lutomirski @ 2011-08-06 11:42 ` Andy Lutomirski 1 sibling, 0 replies; 9+ messages in thread From: Andy Lutomirski @ 2011-08-06 11:42 UTC (permalink / raw) To: x86, linux-kernel Cc: Fenghua Yu, Matthew Garrett, Len Brown, linux-acpi, Ingo Molnar, Andy Lutomirski My Intel DQ67SW (latest BIOS) disables monitor/mwait on the boot CPU if TXT is enabled. We're lucky that the system works at all, since the feature is still enabled on other CPUs. The obvious fix is to just re-enable it ourselves. Signed-off-by: Andy Lutomirski <luto@mit.edu> --- arch/x86/kernel/cpu/intel.c | 25 +++++++++++++++++++++++++ 1 files changed, 25 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index c80ab41..5a0150c 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -493,6 +493,31 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c) wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb); } } + + /* Enable monitor/mwait if BIOS didn't do it for us. */ + if (!cpu_has(c, X86_FEATURE_MWAIT) && cpu_has(c, X86_FEATURE_XMM3) + && c->x86 >= 6 && !(c->x86 == 6 && c->x86_model < 0x1c) + && !(c->x86 == 0xf && c->x86_model < 3)) { + u64 misc_enable; + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); + misc_enable |= MSR_IA32_MISC_ENABLE_MWAIT; + + /* + * Some non-SSE3 cpus will #GP. We check for that, + * but it can't hurt to be safe. + */ + wrmsr_safe(MSR_IA32_MISC_ENABLE, (u32)misc_enable, + (u32)(misc_enable >> 32)); + + /* Re-read monitor capability. */ + if (cpuid_ecx(1) & 0x8) { + set_cpu_cap(c, X86_FEATURE_MWAIT); + + printk(KERN_WARNING FW_WARN "CPU #%d: " + "IA32_MISC_ENABLE.ENABLE_MONITOR_FSM " + "was not set\n", c->cpu_index); + } + } } #ifdef CONFIG_X86_32 -- 1.7.6 ^ permalink raw reply related [flat|nested] 9+ messages in thread
end of thread, other threads:[~2011-08-09 15:13 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2011-08-06 11:42 [PATCH v2 0/2] Forcibly enable some MISC_ENABLE features on Intel Andy Lutomirski 2011-08-06 11:42 ` [PATCH v2 1/2] x86: Enable fast strings on Intel if BIOS hasn't already Andy Lutomirski 2011-08-06 19:33 ` Yu, Fenghua 2011-08-06 23:31 ` Andrew Lutomirski 2011-08-07 23:44 ` Yu, Fenghua 2011-08-09 15:00 ` Ingo Molnar 2011-08-09 15:12 ` Andrew Lutomirski 2011-08-08 18:42 ` Yu, Fenghua 2011-08-06 11:42 ` [PATCH v2 2/2] x86: Enable monitor/mwait " Andy Lutomirski
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