| Message ID | 20180125100454.23203-3-jgross@suse.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
On Thu, Jan 25, 2018 at 11:04:54AM +0100, Juergen Gross wrote: > Add acpi_arch_get_root_pointer() for Xen PVH guests to communicate > the address of the RSDP table given to the kernel via Xen start info. > > This makes the kernel boot again in PVH mode after on recent Xen the > RSDP was moved to higher addresses. So up to that change it was pure > luck that the legacy method to locate the RSDP was working when > running as PVH mode. > > Cc: <stable@vger.kernel.org> # 4.11 > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > arch/x86/xen/enlighten_pvh.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c > index 436c4f003e17..9a5c3a7fe673 100644 > --- a/arch/x86/xen/enlighten_pvh.c > +++ b/arch/x86/xen/enlighten_pvh.c > @@ -16,15 +16,24 @@ > /* > * PVH variables. > * > - * xen_pvh and pvh_bootparams need to live in data segment since they > - * are used after startup_{32|64}, which clear .bss, are invoked. > + * xen_pvh, pvh_bootparams and pvh_start_info need to live in data segment > + * since they are used after startup_{32|64}, which clear .bss, are invoked. > */ > bool xen_pvh __attribute__((section(".data"))) = 0; > struct boot_params pvh_bootparams __attribute__((section(".data"))); > +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); > > -struct hvm_start_info pvh_start_info; > unsigned int pvh_start_info_sz = sizeof(pvh_start_info); > > +acpi_physical_address acpi_arch_get_root_pointer(void) > +{ > + if (xen_pvh) > + return pvh_start_info.rsdp_paddr; > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(acpi_arch_get_root_pointer); Why does this have to be an exported symbol? Does this code get built as a module and will the linker somehow go and rewrite the previous call places with this one if it gets loaded? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 25/01/18 11:37, Greg KH wrote: > On Thu, Jan 25, 2018 at 11:04:54AM +0100, Juergen Gross wrote: >> Add acpi_arch_get_root_pointer() for Xen PVH guests to communicate >> the address of the RSDP table given to the kernel via Xen start info. >> >> This makes the kernel boot again in PVH mode after on recent Xen the >> RSDP was moved to higher addresses. So up to that change it was pure >> luck that the legacy method to locate the RSDP was working when >> running as PVH mode. >> >> Cc: <stable@vger.kernel.org> # 4.11 >> Signed-off-by: Juergen Gross <jgross@suse.com> >> --- >> arch/x86/xen/enlighten_pvh.c | 15 ++++++++++++--- >> 1 file changed, 12 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c >> index 436c4f003e17..9a5c3a7fe673 100644 >> --- a/arch/x86/xen/enlighten_pvh.c >> +++ b/arch/x86/xen/enlighten_pvh.c >> @@ -16,15 +16,24 @@ >> /* >> * PVH variables. >> * >> - * xen_pvh and pvh_bootparams need to live in data segment since they >> - * are used after startup_{32|64}, which clear .bss, are invoked. >> + * xen_pvh, pvh_bootparams and pvh_start_info need to live in data segment >> + * since they are used after startup_{32|64}, which clear .bss, are invoked. >> */ >> bool xen_pvh __attribute__((section(".data"))) = 0; >> struct boot_params pvh_bootparams __attribute__((section(".data"))); >> +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); >> >> -struct hvm_start_info pvh_start_info; >> unsigned int pvh_start_info_sz = sizeof(pvh_start_info); >> >> +acpi_physical_address acpi_arch_get_root_pointer(void) >> +{ >> + if (xen_pvh) >> + return pvh_start_info.rsdp_paddr; >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(acpi_arch_get_root_pointer); > > Why does this have to be an exported symbol? Does this code get built > as a module and will the linker somehow go and rewrite the previous call > places with this one if it gets loaded? With being called by drivers/acpi/... I just wanted to make sure it is working properly even in case the acpi code is built as a module. Juergen -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 25, 2018 at 11:49:35AM +0100, Juergen Gross wrote: > On 25/01/18 11:37, Greg KH wrote: > > On Thu, Jan 25, 2018 at 11:04:54AM +0100, Juergen Gross wrote: > >> Add acpi_arch_get_root_pointer() for Xen PVH guests to communicate > >> the address of the RSDP table given to the kernel via Xen start info. > >> > >> This makes the kernel boot again in PVH mode after on recent Xen the > >> RSDP was moved to higher addresses. So up to that change it was pure > >> luck that the legacy method to locate the RSDP was working when > >> running as PVH mode. > >> > >> Cc: <stable@vger.kernel.org> # 4.11 > >> Signed-off-by: Juergen Gross <jgross@suse.com> > >> --- > >> arch/x86/xen/enlighten_pvh.c | 15 ++++++++++++--- > >> 1 file changed, 12 insertions(+), 3 deletions(-) > >> > >> diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c > >> index 436c4f003e17..9a5c3a7fe673 100644 > >> --- a/arch/x86/xen/enlighten_pvh.c > >> +++ b/arch/x86/xen/enlighten_pvh.c > >> @@ -16,15 +16,24 @@ > >> /* > >> * PVH variables. > >> * > >> - * xen_pvh and pvh_bootparams need to live in data segment since they > >> - * are used after startup_{32|64}, which clear .bss, are invoked. > >> + * xen_pvh, pvh_bootparams and pvh_start_info need to live in data segment > >> + * since they are used after startup_{32|64}, which clear .bss, are invoked. > >> */ > >> bool xen_pvh __attribute__((section(".data"))) = 0; > >> struct boot_params pvh_bootparams __attribute__((section(".data"))); > >> +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); > >> > >> -struct hvm_start_info pvh_start_info; > >> unsigned int pvh_start_info_sz = sizeof(pvh_start_info); > >> > >> +acpi_physical_address acpi_arch_get_root_pointer(void) > >> +{ > >> + if (xen_pvh) > >> + return pvh_start_info.rsdp_paddr; > >> + > >> + return 0; > >> +} > >> +EXPORT_SYMBOL_GPL(acpi_arch_get_root_pointer); > > > > Why does this have to be an exported symbol? Does this code get built > > as a module and will the linker somehow go and rewrite the previous call > > places with this one if it gets loaded? > > With being called by drivers/acpi/... I just wanted to make sure it is > working properly even in case the acpi code is built as a module. I didn't think the core ACPI code can be built as a module, have you tried that? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 25/01/18 12:00, Greg KH wrote: > On Thu, Jan 25, 2018 at 11:49:35AM +0100, Juergen Gross wrote: >> On 25/01/18 11:37, Greg KH wrote: >>> On Thu, Jan 25, 2018 at 11:04:54AM +0100, Juergen Gross wrote: >>>> Add acpi_arch_get_root_pointer() for Xen PVH guests to communicate >>>> the address of the RSDP table given to the kernel via Xen start info. >>>> >>>> This makes the kernel boot again in PVH mode after on recent Xen the >>>> RSDP was moved to higher addresses. So up to that change it was pure >>>> luck that the legacy method to locate the RSDP was working when >>>> running as PVH mode. >>>> >>>> Cc: <stable@vger.kernel.org> # 4.11 >>>> Signed-off-by: Juergen Gross <jgross@suse.com> >>>> --- >>>> arch/x86/xen/enlighten_pvh.c | 15 ++++++++++++--- >>>> 1 file changed, 12 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c >>>> index 436c4f003e17..9a5c3a7fe673 100644 >>>> --- a/arch/x86/xen/enlighten_pvh.c >>>> +++ b/arch/x86/xen/enlighten_pvh.c >>>> @@ -16,15 +16,24 @@ >>>> /* >>>> * PVH variables. >>>> * >>>> - * xen_pvh and pvh_bootparams need to live in data segment since they >>>> - * are used after startup_{32|64}, which clear .bss, are invoked. >>>> + * xen_pvh, pvh_bootparams and pvh_start_info need to live in data segment >>>> + * since they are used after startup_{32|64}, which clear .bss, are invoked. >>>> */ >>>> bool xen_pvh __attribute__((section(".data"))) = 0; >>>> struct boot_params pvh_bootparams __attribute__((section(".data"))); >>>> +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); >>>> >>>> -struct hvm_start_info pvh_start_info; >>>> unsigned int pvh_start_info_sz = sizeof(pvh_start_info); >>>> >>>> +acpi_physical_address acpi_arch_get_root_pointer(void) >>>> +{ >>>> + if (xen_pvh) >>>> + return pvh_start_info.rsdp_paddr; >>>> + >>>> + return 0; >>>> +} >>>> +EXPORT_SYMBOL_GPL(acpi_arch_get_root_pointer); >>> >>> Why does this have to be an exported symbol? Does this code get built >>> as a module and will the linker somehow go and rewrite the previous call >>> places with this one if it gets loaded? >> >> With being called by drivers/acpi/... I just wanted to make sure it is >> working properly even in case the acpi code is built as a module. > > I didn't think the core ACPI code can be built as a module, have you > tried that? No, but as the build wouldn't break whenever this is changed I wanted to make sure the symbol is found. If you feel strong about that I can remove the EXPORT_SYMBOL_GPL(). Juergen -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 25, 2018 at 01:06:26PM +0100, Juergen Gross wrote: > On 25/01/18 12:00, Greg KH wrote: > > On Thu, Jan 25, 2018 at 11:49:35AM +0100, Juergen Gross wrote: > >> On 25/01/18 11:37, Greg KH wrote: > >>> On Thu, Jan 25, 2018 at 11:04:54AM +0100, Juergen Gross wrote: > >>>> Add acpi_arch_get_root_pointer() for Xen PVH guests to communicate > >>>> the address of the RSDP table given to the kernel via Xen start info. > >>>> > >>>> This makes the kernel boot again in PVH mode after on recent Xen the > >>>> RSDP was moved to higher addresses. So up to that change it was pure > >>>> luck that the legacy method to locate the RSDP was working when > >>>> running as PVH mode. > >>>> > >>>> Cc: <stable@vger.kernel.org> # 4.11 > >>>> Signed-off-by: Juergen Gross <jgross@suse.com> > >>>> --- > >>>> arch/x86/xen/enlighten_pvh.c | 15 ++++++++++++--- > >>>> 1 file changed, 12 insertions(+), 3 deletions(-) > >>>> > >>>> diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c > >>>> index 436c4f003e17..9a5c3a7fe673 100644 > >>>> --- a/arch/x86/xen/enlighten_pvh.c > >>>> +++ b/arch/x86/xen/enlighten_pvh.c > >>>> @@ -16,15 +16,24 @@ > >>>> /* > >>>> * PVH variables. > >>>> * > >>>> - * xen_pvh and pvh_bootparams need to live in data segment since they > >>>> - * are used after startup_{32|64}, which clear .bss, are invoked. > >>>> + * xen_pvh, pvh_bootparams and pvh_start_info need to live in data segment > >>>> + * since they are used after startup_{32|64}, which clear .bss, are invoked. > >>>> */ > >>>> bool xen_pvh __attribute__((section(".data"))) = 0; > >>>> struct boot_params pvh_bootparams __attribute__((section(".data"))); > >>>> +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); > >>>> > >>>> -struct hvm_start_info pvh_start_info; > >>>> unsigned int pvh_start_info_sz = sizeof(pvh_start_info); > >>>> > >>>> +acpi_physical_address acpi_arch_get_root_pointer(void) > >>>> +{ > >>>> + if (xen_pvh) > >>>> + return pvh_start_info.rsdp_paddr; > >>>> + > >>>> + return 0; > >>>> +} > >>>> +EXPORT_SYMBOL_GPL(acpi_arch_get_root_pointer); > >>> > >>> Why does this have to be an exported symbol? Does this code get built > >>> as a module and will the linker somehow go and rewrite the previous call > >>> places with this one if it gets loaded? > >> > >> With being called by drivers/acpi/... I just wanted to make sure it is > >> working properly even in case the acpi code is built as a module. > > > > I didn't think the core ACPI code can be built as a module, have you > > tried that? > > No, but as the build wouldn't break whenever this is changed I wanted > to make sure the symbol is found. > > If you feel strong about that I can remove the EXPORT_SYMBOL_GPL(). Please don't export symbols that do not need to be exported, that's just a waste. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c index 436c4f003e17..9a5c3a7fe673 100644 --- a/arch/x86/xen/enlighten_pvh.c +++ b/arch/x86/xen/enlighten_pvh.c @@ -16,15 +16,24 @@ /* * PVH variables. * - * xen_pvh and pvh_bootparams need to live in data segment since they - * are used after startup_{32|64}, which clear .bss, are invoked. + * xen_pvh, pvh_bootparams and pvh_start_info need to live in data segment + * since they are used after startup_{32|64}, which clear .bss, are invoked. */ bool xen_pvh __attribute__((section(".data"))) = 0; struct boot_params pvh_bootparams __attribute__((section(".data"))); +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); -struct hvm_start_info pvh_start_info; unsigned int pvh_start_info_sz = sizeof(pvh_start_info); +acpi_physical_address acpi_arch_get_root_pointer(void) +{ + if (xen_pvh) + return pvh_start_info.rsdp_paddr; + + return 0; +} +EXPORT_SYMBOL_GPL(acpi_arch_get_root_pointer); + static void __init init_pvh_bootparams(void) { struct xen_memory_map memmap;
Add acpi_arch_get_root_pointer() for Xen PVH guests to communicate the address of the RSDP table given to the kernel via Xen start info. This makes the kernel boot again in PVH mode after on recent Xen the RSDP was moved to higher addresses. So up to that change it was pure luck that the legacy method to locate the RSDP was working when running as PVH mode. Cc: <stable@vger.kernel.org> # 4.11 Signed-off-by: Juergen Gross <jgross@suse.com> --- arch/x86/xen/enlighten_pvh.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)