| Message ID | 1329384365-4028-1-git-send-email-yu.liu@freescale.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On 16.02.2012, at 10:26, Liu Yu <yu.liu@freescale.com> wrote: > from the kvm guest paravirt init code. > > Signed-off-by: Liu Yu <yu.liu@freescale.com> > --- > v4: > 1. code cleanup > 2. move kvm_hypercall_start() to epapr_hypercall_start() > > arch/powerpc/Kconfig | 4 ++ > arch/powerpc/include/asm/epapr_hcalls.h | 2 + > arch/powerpc/kernel/Makefile | 1 + > arch/powerpc/kernel/epapr.S | 25 ++++++++++++++++ > arch/powerpc/kernel/epapr_para.c | 49 +++++++++++++++++++++++++++++++ > arch/powerpc/kernel/kvm.c | 28 ++---------------- > arch/powerpc/kernel/kvm_emul.S | 10 ------ > arch/powerpc/kvm/Kconfig | 1 + > 8 files changed, 85 insertions(+), 35 deletions(-) > create mode 100644 arch/powerpc/kernel/epapr.S > create mode 100644 arch/powerpc/kernel/epapr_para.c > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 1919634..1262b43 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -202,6 +202,10 @@ config EPAPR_BOOT > Used to allow a board to specify it wants an ePAPR compliant wrapper. > default n > > +config EPAPR_PARAVIRT > + bool > + default n > + > config DEFAULT_UIMAGE > bool > help > diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h > index f3b0c2c..0ff3f24 100644 > --- a/arch/powerpc/include/asm/epapr_hcalls.h > +++ b/arch/powerpc/include/asm/epapr_hcalls.h > @@ -148,6 +148,8 @@ > #define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5" > #define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4" > > +extern bool epapr_para_enabled; > +extern u32 epapr_hypercall_start[]; > > /* > * We use "uintptr_t" to define a register because it's guaranteed to be a > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index ee728e4..9e807f3 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -136,6 +136,7 @@ ifneq ($(CONFIG_XMON)$(CONFIG_KEXEC),) > obj-y += ppc_save_regs.o > endif > > +obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_para.o epapr.o > obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o > > # Disable GCOV in odd or sensitive code > diff --git a/arch/powerpc/kernel/epapr.S b/arch/powerpc/kernel/epapr.S > new file mode 100644 > index 0000000..697b390 > --- /dev/null > +++ b/arch/powerpc/kernel/epapr.S > @@ -0,0 +1,25 @@ > +/* > + * Copyright (C) 2012 Freescale Semiconductor, Inc. > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation; either version > + * 2 of the License, or (at your option) any later version. > + */ > + > +#include <linux/threads.h> > +#include <asm/reg.h> > +#include <asm/page.h> > +#include <asm/cputable.h> > +#include <asm/thread_info.h> > +#include <asm/ppc_asm.h> > +#include <asm/asm-offsets.h> > + > +/* Hypercall entry point. Will be patched with device tree instructions. */ > +.global epapr_hypercall_start > +epapr_hypercall_start: > + li r3, -1 > + nop > + nop > + nop > + blr > diff --git a/arch/powerpc/kernel/epapr_para.c b/arch/powerpc/kernel/epapr_para.c > new file mode 100644 > index 0000000..ea13cac > --- /dev/null > +++ b/arch/powerpc/kernel/epapr_para.c > @@ -0,0 +1,49 @@ > +/* > + * ePAPR para-virtualization support. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License, version 2, as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. > + * > + * Copyright (C) 2012 Freescale Semiconductor, Inc. > + */ > + > +#include <linux/of.h> > +#include <asm/epapr_hcalls.h> > +#include <asm/cacheflush.h> > + > +bool epapr_para_enabled = false; > + > +static int __init epapr_para_init(void) > +{ > + struct device_node *hyper_node; > + const u32 *insts; > + int len, i; > + > + hyper_node = of_find_node_by_path("/hypervisor"); > + if (!hyper_node) > + return -ENODEV; > + > + insts = of_get_property(hyper_node, "hcall-instructions", &len); > + if (!(len % 4) && (len >= (4 * 4))) { > + for (i = 0; i < (len / 4); i++) So if the dt passes in less than 4 ops, you bail out, and for more you overwrite the buffer? Not good :) > + epapr_hypercall_start[i] = insts[i]; > + flush_icache_range((ulong)epapr_hypercall_start, > + (ulong)epapr_hypercall_start + len); > + > + epapr_para_enabled = true; > + } > + > + return 0; > +} > + > +early_initcall(epapr_para_init); > diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c > index 62bdf23..9dfc24a 100644 > --- a/arch/powerpc/kernel/kvm.c > +++ b/arch/powerpc/kernel/kvm.c > @@ -31,6 +31,7 @@ > #include <asm/cacheflush.h> > #include <asm/disassemble.h> > #include <asm/ppc-opcode.h> > +#include <asm/epapr_hcalls.h> > > #define KVM_MAGIC_PAGE (-4096L) > #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x) > @@ -726,7 +727,7 @@ unsigned long kvm_hypercall(unsigned long *in, > unsigned long register r11 asm("r11") = nr; > unsigned long register r12 asm("r12"); > > - asm volatile("bl kvm_hypercall_start" > + asm volatile("bl epapr_hypercall_start" > : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6), > "=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11), > "=r"(r12) > @@ -747,29 +748,6 @@ unsigned long kvm_hypercall(unsigned long *in, > } > EXPORT_SYMBOL_GPL(kvm_hypercall); > > -static int kvm_para_setup(void) > -{ > - extern u32 kvm_hypercall_start; > - struct device_node *hyper_node; > - u32 *insts; > - int len, i; > - > - hyper_node = of_find_node_by_path("/hypervisor"); > - if (!hyper_node) > - return -1; > - > - insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len); > - if (len % 4) > - return -1; > - if (len > (4 * 4)) As you can see, the previous code allowed for less than 4 instructions, but not more. Alex > - return -1; > - > - for (i = 0; i < (len / 4); i++) > - kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]); > - > - return 0; > -} > - > static __init void kvm_free_tmp(void) > { > unsigned long start, end; > @@ -791,7 +769,7 @@ static int __init kvm_guest_init(void) > if (!kvm_para_available()) > goto free_tmp; > > - if (kvm_para_setup()) > + if (!epapr_para_enabled) > goto free_tmp; > > if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE)) > diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S > index e291cf3..62ceb2a 100644 > --- a/arch/powerpc/kernel/kvm_emul.S > +++ b/arch/powerpc/kernel/kvm_emul.S > @@ -24,16 +24,6 @@ > #include <asm/page.h> > #include <asm/asm-offsets.h> > > -/* Hypercall entry point. Will be patched with device tree instructions. */ > - > -.global kvm_hypercall_start > -kvm_hypercall_start: > - li r3, -1 > - nop > - nop > - nop > - blr > - > #define KVM_MAGIC_PAGE (-4096) > > #ifdef CONFIG_64BIT > diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig > index 8f64709..9bb9d18 100644 > --- a/arch/powerpc/kvm/Kconfig > +++ b/arch/powerpc/kvm/Kconfig > @@ -20,6 +20,7 @@ config KVM > bool > select PREEMPT_NOTIFIERS > select ANON_INODES > + select EPAPR_PARAVIRT > > config KVM_BOOK3S_HANDLER > bool > -- > 1.7.0.4 > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On 02/16/2012 03:26 AM, Liu Yu wrote: > from the kvm guest paravirt init code. > > Signed-off-by: Liu Yu <yu.liu@freescale.com> > --- > v4: > 1. code cleanup > 2. move kvm_hypercall_start() to epapr_hypercall_start() > > arch/powerpc/Kconfig | 4 ++ > arch/powerpc/include/asm/epapr_hcalls.h | 2 + > arch/powerpc/kernel/Makefile | 1 + > arch/powerpc/kernel/epapr.S | 25 ++++++++++++++++ > arch/powerpc/kernel/epapr_para.c | 49 +++++++++++++++++++++++++++++++ > arch/powerpc/kernel/kvm.c | 28 ++---------------- > arch/powerpc/kernel/kvm_emul.S | 10 ------ > arch/powerpc/kvm/Kconfig | 1 + > 8 files changed, 85 insertions(+), 35 deletions(-) > create mode 100644 arch/powerpc/kernel/epapr.S > create mode 100644 arch/powerpc/kernel/epapr_para.c The comment about spelling out "paravirt" wasnn't meant to be restricted to the kconfig symbol. There are lots of words that begin with "para", and ePAPR isn't just about virtualization. > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 1919634..1262b43 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -202,6 +202,10 @@ config EPAPR_BOOT > Used to allow a board to specify it wants an ePAPR compliant wrapper. > default n > > +config EPAPR_PARAVIRT > + bool > + default n Why isn't this user-selectable? It's useful on its own. > diff --git a/arch/powerpc/kernel/epapr.S b/arch/powerpc/kernel/epapr.S > new file mode 100644 > index 0000000..697b390 > --- /dev/null > +++ b/arch/powerpc/kernel/epapr.S epapr-hcall.S > +bool epapr_para_enabled = false; > + > +static int __init epapr_para_init(void) > +{ > + struct device_node *hyper_node; > + const u32 *insts; > + int len, i; > + > + hyper_node = of_find_node_by_path("/hypervisor"); > + if (!hyper_node) > + return -ENODEV; > + > + insts = of_get_property(hyper_node, "hcall-instructions", &len); > + if (!(len % 4) && (len >= (4 * 4))) { > + for (i = 0; i < (len / 4); i++) > + epapr_hypercall_start[i] = insts[i]; > + flush_icache_range((ulong)epapr_hypercall_start, > + (ulong)epapr_hypercall_start + len); > + > + epapr_para_enabled = true; > + } Use patch_instruction(), fix the if test, and remove unnecessary parentheses. Print an error if the if test fails, but return silently if the property is absent. Please make asm/epapr_hcalls.h and asm/fsl_hcalls.h work with this as well. -Scott
> -----Original Message----- > From: Wood Scott-B07421 > Sent: Friday, February 17, 2012 1:13 AM > To: Liu Yu-B13201 > Cc: agraf@suse.de; kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; > linuxppc-dev@ozlabs.org; Wood Scott-B07421 > Subject: Re: [PATCH v4 1/3] KVM: PPC: epapr: Factor out the epapr init > > On 02/16/2012 03:26 AM, Liu Yu wrote: > > from the kvm guest paravirt init code. > > > > Signed-off-by: Liu Yu <yu.liu@freescale.com> > > --- > > v4: > > 1. code cleanup > > 2. move kvm_hypercall_start() to epapr_hypercall_start() > > > > arch/powerpc/Kconfig | 4 ++ > > arch/powerpc/include/asm/epapr_hcalls.h | 2 + > > arch/powerpc/kernel/Makefile | 1 + > > arch/powerpc/kernel/epapr.S | 25 ++++++++++++++++ > > arch/powerpc/kernel/epapr_para.c | 49 > +++++++++++++++++++++++++++++++ > > arch/powerpc/kernel/kvm.c | 28 ++---------------- > > arch/powerpc/kernel/kvm_emul.S | 10 ------ > > arch/powerpc/kvm/Kconfig | 1 + > > 8 files changed, 85 insertions(+), 35 deletions(-) create mode > > 100644 arch/powerpc/kernel/epapr.S create mode 100644 > > arch/powerpc/kernel/epapr_para.c > > The comment about spelling out "paravirt" wasnn't meant to be restricted > to the kconfig symbol. There are lots of words that begin with "para", > and ePAPR isn't just about virtualization. What do you mean? Do you suggest that we should name it epapr_paravirt.c? Thanks, Yu
On 02/17/2012 04:03 AM, Liu Yu-B13201 wrote: > > >> -----Original Message----- >> From: Wood Scott-B07421 >> Sent: Friday, February 17, 2012 1:13 AM >> To: Liu Yu-B13201 >> Cc: agraf@suse.de; kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; >> linuxppc-dev@ozlabs.org; Wood Scott-B07421 >> Subject: Re: [PATCH v4 1/3] KVM: PPC: epapr: Factor out the epapr init >> >> On 02/16/2012 03:26 AM, Liu Yu wrote: >>> from the kvm guest paravirt init code. >>> >>> Signed-off-by: Liu Yu <yu.liu@freescale.com> >>> --- >>> v4: >>> 1. code cleanup >>> 2. move kvm_hypercall_start() to epapr_hypercall_start() >>> >>> arch/powerpc/Kconfig | 4 ++ >>> arch/powerpc/include/asm/epapr_hcalls.h | 2 + >>> arch/powerpc/kernel/Makefile | 1 + >>> arch/powerpc/kernel/epapr.S | 25 ++++++++++++++++ >>> arch/powerpc/kernel/epapr_para.c | 49 >> +++++++++++++++++++++++++++++++ >>> arch/powerpc/kernel/kvm.c | 28 ++---------------- >>> arch/powerpc/kernel/kvm_emul.S | 10 ------ >>> arch/powerpc/kvm/Kconfig | 1 + >>> 8 files changed, 85 insertions(+), 35 deletions(-) create mode >>> 100644 arch/powerpc/kernel/epapr.S create mode 100644 >>> arch/powerpc/kernel/epapr_para.c >> >> The comment about spelling out "paravirt" wasnn't meant to be restricted >> to the kconfig symbol. There are lots of words that begin with "para", >> and ePAPR isn't just about virtualization. > > What do you mean? Do you suggest that we should name it epapr_paravirt.c? Yes, and likewise with variables and functions and such (at least anything that is exposed outside a single file). -Scott
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 1919634..1262b43 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -202,6 +202,10 @@ config EPAPR_BOOT Used to allow a board to specify it wants an ePAPR compliant wrapper. default n +config EPAPR_PARAVIRT + bool + default n + config DEFAULT_UIMAGE bool help diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h index f3b0c2c..0ff3f24 100644 --- a/arch/powerpc/include/asm/epapr_hcalls.h +++ b/arch/powerpc/include/asm/epapr_hcalls.h @@ -148,6 +148,8 @@ #define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5" #define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4" +extern bool epapr_para_enabled; +extern u32 epapr_hypercall_start[]; /* * We use "uintptr_t" to define a register because it's guaranteed to be a diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index ee728e4..9e807f3 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -136,6 +136,7 @@ ifneq ($(CONFIG_XMON)$(CONFIG_KEXEC),) obj-y += ppc_save_regs.o endif +obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_para.o epapr.o obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o # Disable GCOV in odd or sensitive code diff --git a/arch/powerpc/kernel/epapr.S b/arch/powerpc/kernel/epapr.S new file mode 100644 index 0000000..697b390 --- /dev/null +++ b/arch/powerpc/kernel/epapr.S @@ -0,0 +1,25 @@ +/* + * Copyright (C) 2012 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/threads.h> +#include <asm/reg.h> +#include <asm/page.h> +#include <asm/cputable.h> +#include <asm/thread_info.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> + +/* Hypercall entry point. Will be patched with device tree instructions. */ +.global epapr_hypercall_start +epapr_hypercall_start: + li r3, -1 + nop + nop + nop + blr diff --git a/arch/powerpc/kernel/epapr_para.c b/arch/powerpc/kernel/epapr_para.c new file mode 100644 index 0000000..ea13cac --- /dev/null +++ b/arch/powerpc/kernel/epapr_para.c @@ -0,0 +1,49 @@ +/* + * ePAPR para-virtualization support. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, version 2, as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * Copyright (C) 2012 Freescale Semiconductor, Inc. + */ + +#include <linux/of.h> +#include <asm/epapr_hcalls.h> +#include <asm/cacheflush.h> + +bool epapr_para_enabled = false; + +static int __init epapr_para_init(void) +{ + struct device_node *hyper_node; + const u32 *insts; + int len, i; + + hyper_node = of_find_node_by_path("/hypervisor"); + if (!hyper_node) + return -ENODEV; + + insts = of_get_property(hyper_node, "hcall-instructions", &len); + if (!(len % 4) && (len >= (4 * 4))) { + for (i = 0; i < (len / 4); i++) + epapr_hypercall_start[i] = insts[i]; + flush_icache_range((ulong)epapr_hypercall_start, + (ulong)epapr_hypercall_start + len); + + epapr_para_enabled = true; + } + + return 0; +} + +early_initcall(epapr_para_init); diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c index 62bdf23..9dfc24a 100644 --- a/arch/powerpc/kernel/kvm.c +++ b/arch/powerpc/kernel/kvm.c @@ -31,6 +31,7 @@ #include <asm/cacheflush.h> #include <asm/disassemble.h> #include <asm/ppc-opcode.h> +#include <asm/epapr_hcalls.h> #define KVM_MAGIC_PAGE (-4096L) #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x) @@ -726,7 +727,7 @@ unsigned long kvm_hypercall(unsigned long *in, unsigned long register r11 asm("r11") = nr; unsigned long register r12 asm("r12"); - asm volatile("bl kvm_hypercall_start" + asm volatile("bl epapr_hypercall_start" : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6), "=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11), "=r"(r12) @@ -747,29 +748,6 @@ unsigned long kvm_hypercall(unsigned long *in, } EXPORT_SYMBOL_GPL(kvm_hypercall); -static int kvm_para_setup(void) -{ - extern u32 kvm_hypercall_start; - struct device_node *hyper_node; - u32 *insts; - int len, i; - - hyper_node = of_find_node_by_path("/hypervisor"); - if (!hyper_node) - return -1; - - insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len); - if (len % 4) - return -1; - if (len > (4 * 4)) - return -1; - - for (i = 0; i < (len / 4); i++) - kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]); - - return 0; -} - static __init void kvm_free_tmp(void) { unsigned long start, end; @@ -791,7 +769,7 @@ static int __init kvm_guest_init(void) if (!kvm_para_available()) goto free_tmp; - if (kvm_para_setup()) + if (!epapr_para_enabled) goto free_tmp; if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE)) diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S index e291cf3..62ceb2a 100644 --- a/arch/powerpc/kernel/kvm_emul.S +++ b/arch/powerpc/kernel/kvm_emul.S @@ -24,16 +24,6 @@ #include <asm/page.h> #include <asm/asm-offsets.h> -/* Hypercall entry point. Will be patched with device tree instructions. */ - -.global kvm_hypercall_start -kvm_hypercall_start: - li r3, -1 - nop - nop - nop - blr - #define KVM_MAGIC_PAGE (-4096) #ifdef CONFIG_64BIT diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index 8f64709..9bb9d18 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -20,6 +20,7 @@ config KVM bool select PREEMPT_NOTIFIERS select ANON_INODES + select EPAPR_PARAVIRT config KVM_BOOK3S_HANDLER bool
from the kvm guest paravirt init code. Signed-off-by: Liu Yu <yu.liu@freescale.com> --- v4: 1. code cleanup 2. move kvm_hypercall_start() to epapr_hypercall_start() arch/powerpc/Kconfig | 4 ++ arch/powerpc/include/asm/epapr_hcalls.h | 2 + arch/powerpc/kernel/Makefile | 1 + arch/powerpc/kernel/epapr.S | 25 ++++++++++++++++ arch/powerpc/kernel/epapr_para.c | 49 +++++++++++++++++++++++++++++++ arch/powerpc/kernel/kvm.c | 28 ++---------------- arch/powerpc/kernel/kvm_emul.S | 10 ------ arch/powerpc/kvm/Kconfig | 1 + 8 files changed, 85 insertions(+), 35 deletions(-) create mode 100644 arch/powerpc/kernel/epapr.S create mode 100644 arch/powerpc/kernel/epapr_para.c