diff mbox series

[v3,2/3] xen/ppc: Implement early serial printk on pseries

Message ID 85172d385a730e196999b366207e2b2e8a261906.1688670018.git.sanastasio@raptorengineering.com (mailing list archive)
State Superseded
Headers show
Series Early serial on Power | expand

Commit Message

Shawn Anastasio July 6, 2023, 7:04 p.m. UTC
On typical Power VMs (e.g. QEMU's -M pseries), a variety of services
including an early serial console are provided by Open Firmware.
Implement the required interfaces to call into Open Firmware and write
to the serial console.

Since Open Firmware runs in 32-bit Big Endian mode and Xen runs in
64-bit Little Endian mode, a thunk is required to save/restore
any potentially-clobbered registers as well as to perform the
required endianness switch. Thankfully, linux already has such
a routine, which was imported into ppc64/of-call.S.

Support for bare metal (PowerNV) will be implemented in a future
patch.

Signed-off-by: Shawn Anastasio <sanastasio@raptorengineering.com>
---
 xen/arch/ppc/Kconfig.debug              |   5 +
 xen/arch/ppc/Makefile                   |   2 +
 xen/arch/ppc/boot-of.c                  | 100 +++++++++++++++++
 xen/arch/ppc/configs/ppc64_defconfig    |   1 +
 xen/arch/ppc/early_printk.c             |  28 +++++
 xen/arch/ppc/include/asm/asm-defns.h    |  17 +++
 xen/arch/ppc/include/asm/boot.h         |  23 ++++
 xen/arch/ppc/include/asm/byteorder.h    |  12 ++
 xen/arch/ppc/include/asm/config.h       |   3 +
 xen/arch/ppc/include/asm/early_printk.h |  15 +++
 xen/arch/ppc/include/asm/msr.h          |  51 +++++++++
 xen/arch/ppc/include/asm/processor.h    | 139 ++++++++++++++++++++++++
 xen/arch/ppc/include/asm/types.h        |  21 ++++
 xen/arch/ppc/ppc64/Makefile             |   1 +
 xen/arch/ppc/ppc64/asm-offsets.c        |  59 ++++++++++
 xen/arch/ppc/ppc64/head.S               |   9 ++
 xen/arch/ppc/ppc64/of-call.S            |  83 ++++++++++++++
 xen/arch/ppc/setup.c                    |  19 +++-
 18 files changed, 585 insertions(+), 3 deletions(-)
 create mode 100644 xen/arch/ppc/boot-of.c
 create mode 100644 xen/arch/ppc/early_printk.c
 create mode 100644 xen/arch/ppc/include/asm/boot.h
 create mode 100644 xen/arch/ppc/include/asm/byteorder.h
 create mode 100644 xen/arch/ppc/include/asm/early_printk.h
 create mode 100644 xen/arch/ppc/include/asm/msr.h
 create mode 100644 xen/arch/ppc/include/asm/processor.h
 create mode 100644 xen/arch/ppc/include/asm/types.h
 create mode 100644 xen/arch/ppc/ppc64/of-call.S

Comments

Jan Beulich July 17, 2023, 4:17 p.m. UTC | #1
On 06.07.2023 21:04, Shawn Anastasio wrote:
> --- a/xen/arch/ppc/Makefile
> +++ b/xen/arch/ppc/Makefile
> @@ -1,5 +1,7 @@
>  obj-$(CONFIG_PPC64) += ppc64/
>  
> +obj-y += boot-of.init.o
> +obj-$(CONFIG_EARLY_PRINTK) += early_printk.o

While in this case I could accept the name as is to be the same as Arm's,
as said before it would be nice if new files could avoid underscores (and
use dashes instead) unless strictly required by something.

Also, with boot-of.c using early_printk.c, shouldn't the latter also
build into early_printk.init.o?

> --- /dev/null
> +++ b/xen/arch/ppc/boot-of.c
> @@ -0,0 +1,100 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright IBM Corp. 2005, 2006, 2007

Judging from the years the file was taken from somewhere. Is the license
there permitting "2.0 or later"? (For files [partly] taken from somewhere,
a clarification as to the originals' licenses would be helpful to have in
the description, or maybe in the post-commit-message area.)

> + * Copyright Raptor Engineering, LLC
> + *
> + * Authors: Jimi Xenidis <jimix@watson.ibm.com>
> + *          Hollis Blanchard <hollisb@us.ibm.com>
> + *          Shawn Anastasio <sanastasio@raptorengineering.com>
> + */
> +
> +#include <xen/init.h>
> +#include <xen/stdarg.h>
> +#include <xen/types.h>
> +#include <asm/boot.h>
> +#include <asm/byteorder.h>
> +#include <asm/early_printk.h>
> +
> +#define ADDR(x) (uint32_t)(unsigned long)(x)

Besides needing to be wrapped in parentheses, this likely needs a comment:
It is hard to see how in 64-bit code uint32_t can suffice as an address.
Unless (see the question on patch 1) you intend to link/run Xen at an
address firmly below 4Gb, now and going forward.

> +/* OF entrypoint*/
> +static unsigned long __initdata of_vec;
> +
> +/* OF device handles*/
> +static int __initdata bof_chosen;
> +static int __initdata of_out;
> +
> +static int __init of_call(const char *service, uint32_t nargs, uint32_t nrets,
> +                   int32_t rets[], ...)

Nit: Indentation.

> +{
> +    int rc;
> +    va_list args;
> +    int i;

unsigned int?

> +    struct of_service s = { 0 };
> +
> +    s.ofs_service = cpu_to_be32(ADDR(service));
> +    s.ofs_nargs = cpu_to_be32(nargs);
> +    s.ofs_nrets = cpu_to_be32(nrets);
> +
> +    /* copy all the params into the args array */

Nit: Style (comments want to start with a capital letter). Again below.

> +    va_start(args, rets);
> +
> +    for ( i = 0; i < nargs; i++ )
> +        s.ofs_args[i] = cpu_to_be32(va_arg(args, uint32_t));
> +
> +    va_end(args);
> +
> +    rc = enter_of(&s, of_vec);
> +
> +    /* copy all return values to the output rets array */
> +    for ( i = 0; i < nrets; i++ )
> +        rets[i] = be32_to_cpu(s.ofs_args[i + nargs]);
> +
> +    return rc;
> +}
> +
> +static int __init of_finddevice(const char *devspec)
> +{
> +    int rets[1] = { OF_FAILURE };

Hmm, of_call() uses int32_t. Again below several times.

> +    of_call("finddevice", 1, 1, rets, devspec);

This could do with using ARRAY_SIZE(rets). Same again below.

Also don't you need to wrap devspec in ADDR()? Similar issues
then again below.

> +    return rets[0];
> +}
> +
> +static int __init of_getprop(int ph, const char *name, void *buf, uint32_t buflen)
> +{
> +    int rets[1] = { OF_FAILURE };
> +
> +    of_call("getprop", 4, 1, rets, ph, ADDR(name), buf, buflen);
> +    return rets[0];
> +}
> +
> +int __init of_write(int ih, const char *addr, uint32_t len)
> +{
> +    int rets[1] = { OF_FAILURE };
> +
> +    of_call("write", 3, 1, rets, ih, addr, len);
> +    return rets[0];
> +}
> +
> +static void __init of_putchar(char c)
> +{
> +    if ( c == '\n' )
> +    {
> +        char buf = '\r';
> +        of_write(of_out, &buf, 1);
> +    }
> +    of_write(of_out, &c, 1);
> +}
> +
> +void __init boot_of_init(unsigned long vec)
> +{
> +    of_vec = vec;
> +
> +    /* Get a handle to the default console */
> +    bof_chosen = of_finddevice("/chosen");
> +    of_getprop(bof_chosen, "stdout", &of_out, sizeof(of_out));
> +    of_out = be32_to_cpu(of_out);
> +
> +    early_printk_init(of_putchar);
> +}

Considering that bof_chosen is used just here, why does it need to be
a file-scope variable?

> --- /dev/null
> +++ b/xen/arch/ppc/early_printk.c
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#include <xen/init.h>
> +#include <asm/boot.h>
> +
> +static void (*putchar_func)(char);

__initdata? (Connected to the question of building into .init.o.)

> --- /dev/null
> +++ b/xen/arch/ppc/include/asm/processor.h
> @@ -0,0 +1,139 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright IBM Corp. 2005, 2006, 2007
> + * Copyright Raptor Engineering, LLC
> + *
> + * Authors: Hollis Blanchard <hollisb@us.ibm.com>
> + *          Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
> + *          Timothy Pearson <tpearson@raptorengineering.com>
> + *          Shawn Anastasio <sanastasio@raptorengineering.com>
> + */
> +
> +#ifndef _ASM_PPC_PROCESSOR_H
> +#define _ASM_PPC_PROCESSOR_H
> +
> +#include <xen/config.h>

No need to - this is force-included by the Makefile machinery.

> +#include <xen/types.h>

Note this. Why ...

> +#define IOBMP_BYTES          8192
> +#define IOBMP_INVALID_OFFSET 0x8000
> +
> +/* Processor Version Register (PVR) field extraction */
> +
> +#define PVR_VER(pvr) (((pvr) >> 16) & 0xFFFF) /* Version field */
> +#define PVR_REV(pvr) (((pvr) >> 0) & 0xFFFF)  /* Revison field */
> +
> +#define __is_processor(pv) (PVR_VER(mfspr(SPRN_PVR)) == (pv))
> +
> +/*
> + * IBM has further subdivided the standard PowerPC 16-bit version and
> + * revision subfields of the PVR for the PowerPC 403s into the following:
> + */
> +
> +#define PVR_FAM(pvr)  (((pvr) >> 20) & 0xFFF) /* Family field */
> +#define PVR_MEM(pvr)  (((pvr) >> 16) & 0xF)   /* Member field */
> +#define PVR_CORE(pvr) (((pvr) >> 12) & 0xF)   /* Core field */
> +#define PVR_CFG(pvr)  (((pvr) >> 8) & 0xF)    /* Configuration field */
> +#define PVR_MAJ(pvr)  (((pvr) >> 4) & 0xF)    /* Major revision field */
> +#define PVR_MIN(pvr)  (((pvr) >> 0) & 0xF)    /* Minor revision field */
> +
> +/* Processor Version Numbers */
> +
> +#define PVR_403GA    0x00200000
> +#define PVR_403GB    0x00200100
> +#define PVR_403GC    0x00200200
> +#define PVR_403GCX   0x00201400
> +#define PVR_405GP    0x40110000
> +#define PVR_STB03XXX 0x40310000
> +#define PVR_NP405H   0x41410000
> +#define PVR_NP405L   0x41610000
> +#define PVR_601      0x00010000
> +#define PVR_602      0x00050000
> +#define PVR_603      0x00030000
> +#define PVR_603e     0x00060000
> +#define PVR_603ev    0x00070000
> +#define PVR_603r     0x00071000
> +#define PVR_604      0x00040000
> +#define PVR_604e     0x00090000
> +#define PVR_604r     0x000A0000
> +#define PVR_620      0x00140000
> +#define PVR_740      0x00080000
> +#define PVR_750      PVR_740
> +#define PVR_740P     0x10080000
> +#define PVR_750P     PVR_740P
> +#define PVR_7400     0x000C0000
> +#define PVR_7410     0x800C0000
> +#define PVR_7450     0x80000000
> +#define PVR_8540     0x80200000
> +#define PVR_8560     0x80200000
> +/*
> + * For the 8xx processors, all of them report the same PVR family for
> + * the PowerPC core. The various versions of these processors must be
> + * differentiated by the version number in the Communication Processor
> + * Module (CPM).
> + */
> +#define PVR_821  0x00500000
> +#define PVR_823  PVR_821
> +#define PVR_850  PVR_821
> +#define PVR_860  PVR_821
> +#define PVR_8240 0x00810100
> +#define PVR_8245 0x80811014
> +#define PVR_8260 PVR_8240
> +
> +/* 64-bit processors */
> +#define PVR_NORTHSTAR 0x0033
> +#define PVR_PULSAR    0x0034
> +#define PVR_POWER4    0x0035
> +#define PVR_ICESTAR   0x0036
> +#define PVR_SSTAR     0x0037
> +#define PVR_POWER4p   0x0038
> +#define PVR_970       0x0039
> +#define PVR_POWER5    0x003A
> +#define PVR_POWER5p   0x003B
> +#define PVR_970FX     0x003C
> +#define PVR_POWER6    0x003E
> +#define PVR_POWER7    0x003F
> +#define PVR_630       0x0040
> +#define PVR_630p      0x0041
> +#define PVR_970MP     0x0044
> +#define PVR_970GX     0x0045
> +#define PVR_POWER7p   0x004A
> +#define PVR_POWER8E   0x004B
> +#define PVR_POWER8NVL 0x004C
> +#define PVR_POWER8    0x004D
> +#define PVR_POWER9    0x004E
> +#define PVR_POWER10   0x0080
> +#define PVR_BE        0x0070
> +#define PVR_PA6T      0x0090
> +
> +/* Macro to adjust thread priority for hardware multithreading */
> +#define HMT_very_low()  asm volatile (" or %r31, %r31, %r31 ")
> +
> +#ifndef __ASSEMBLY__
> +
> +#include <xen/types.h>

... another time here? Or is the first one perhaps too early?

> +/* User-accessible registers: nost of these need to be saved/restored
> + * for every nested Xen invocation. */

Nit: Comment style. Multi-line comments want to be

/*
 * User-accessible registers: most of these need to be saved/restored
 * for every nested Xen invocation.
 */

(also note the s/nost/most/ I did)

> --- a/xen/arch/ppc/ppc64/head.S
> +++ b/xen/arch/ppc/ppc64/head.S
> @@ -18,6 +18,15 @@ ENTRY(start)
>      li %r11, 0
>      stdu %r11, -STACK_FRAME_OVERHEAD(%r1)
>  
> +    /* clear .bss */
> +    LOAD_IMM32(%r14, __bss_start)
> +    LOAD_IMM32(%r15, __bss_end)

Question regarding addressing again.

> --- /dev/null
> +++ b/xen/arch/ppc/ppc64/of-call.S
> @@ -0,0 +1,83 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Adapted from Linux's arch/powerpc/kernel/entry_64.S, with the
> + * following copyright notice:
> + *
> + *  PowerPC version
> + *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
> + *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
> + *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
> + *  Adapted for Power Macintosh by Paul Mackerras.
> + *  Low-level exception handlers and MMU support
> + *  rewritten by Paul Mackerras.
> + *    Copyright (C) 1996 Paul Mackerras.
> + *  MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
> + */
> +
> +#include <asm/asm-offsets.h>
> +#include <asm/asm-defns.h>
> +#include <asm/msr.h>
> +
> +/* size of minimum stack frame that can hold an entire cpu_user_regs struct */
> +#define STACK_SWITCH_FRAME_SIZE UREGS_sizeof
> +
> +    .section .init.text, "ax", @progbits
> +
> +ENTRY(enter_of)
> +    mflr %r0
> +    std %r0, 16(%r1)
> +    stdu %r1,-STACK_SWITCH_FRAME_SIZE(%r1) /* Save SP and create stack space */
> +
> +    /*
> +     * Because PROM is running in 32b mode, it clobbers the high order half
> +     * of all registers that it saves.  We therefore save those registers
> +     * PROM might touch to the stack.  (%r0, %r3-%r13 are caller saved)
> +     */
> +    SAVE_GPR(2, %r1)
> +    SAVE_GPR(13, %r1)
> +    SAVE_NVGPRS(%r1)
> +    mfcr %r10
> +    mfmsr %r11
> +    std %r10, UREGS_cr(%r1)
> +    std %r11, UREGS_msr(%r1)
> +
> +    /* Put PROM address in SRR0 */
> +    mtsrr0 %r4
> +
> +    /* Setup our trampoline return addr in LR */
> +    bcl 20, 31,.+4
> +0:  mflr %r4
> +    addi %r4, %r4,(1f - 0b)

Nit: Missing blank after last comma. I also wonder whether the parentheses
are doing any good here.

Jan
Shawn Anastasio July 17, 2023, 6:32 p.m. UTC | #2
On 7/17/23 11:17 AM, Jan Beulich wrote:
> On 06.07.2023 21:04, Shawn Anastasio wrote:
>> --- a/xen/arch/ppc/Makefile
>> +++ b/xen/arch/ppc/Makefile
>> @@ -1,5 +1,7 @@
>>  obj-$(CONFIG_PPC64) += ppc64/
>>  
>> +obj-y += boot-of.init.o
>> +obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
> 
> While in this case I could accept the name as is to be the same as Arm's,
> as said before it would be nice if new files could avoid underscores (and
> use dashes instead) unless strictly required by something.
> 
> Also, with boot-of.c using early_printk.c, shouldn't the latter also
> build into early_printk.init.o?

Yes, good point. I'll change it to early_printk.init.o.

>> --- /dev/null
>> +++ b/xen/arch/ppc/boot-of.c
>> @@ -0,0 +1,100 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Copyright IBM Corp. 2005, 2006, 2007
> 
> Judging from the years the file was taken from somewhere. Is the license
> there permitting "2.0 or later"? (For files [partly] taken from somewhere,
> a clarification as to the originals' licenses would be helpful to have in
> the description, or maybe in the post-commit-message area.)

The original license of the file that this was derived from
(xen/arch/powerpc/boot_of.c from Xen 3.2) is GPL v2.0 or later.

In any case where I'm deriving code from existing files, I'm always
using the original license of the derived code. Should I still clarify
this in the header comment?

>> + * Copyright Raptor Engineering, LLC
>> + *
>> + * Authors: Jimi Xenidis <jimix@watson.ibm.com>
>> + *          Hollis Blanchard <hollisb@us.ibm.com>
>> + *          Shawn Anastasio <sanastasio@raptorengineering.com>
>> + */
>> +
>> +#include <xen/init.h>
>> +#include <xen/stdarg.h>
>> +#include <xen/types.h>
>> +#include <asm/boot.h>
>> +#include <asm/byteorder.h>
>> +#include <asm/early_printk.h>
>> +
>> +#define ADDR(x) (uint32_t)(unsigned long)(x)
> 
> Besides needing to be wrapped in parentheses, this likely needs a comment:
> It is hard to see how in 64-bit code uint32_t can suffice as an address.
> Unless (see the question on patch 1) you intend to link/run Xen at an
> address firmly below 4Gb, now and going forward.

Calls to the Open Firmware client interface necessitate that the CPU be
running with both the MMU off and in 32-bit mode (MSR_SF unset).
Obviously these two criteria will not always be true for Xen itself, but
we can guarantee that Xen's physical address lies below 4GB. In fact,
the mere act of being booted by Open Firmware should guarantee that this
is the case.

This also came up earlier, but the Open Firmware interface will only
need to be used during early boot. Once the MMU is up it shouldn't be
necessary to use it, but if it does end up being required this could be
changed to use __pa() or equivalent (plus the uint32_t cast).

I'll definitely add a comment explaining the situation, as well as the
extra parenthesis.

>> +/* OF entrypoint*/
>> +static unsigned long __initdata of_vec;
>> +
>> +/* OF device handles*/
>> +static int __initdata bof_chosen;
>> +static int __initdata of_out;
>> +
>> +static int __init of_call(const char *service, uint32_t nargs, uint32_t nrets,
>> +                   int32_t rets[], ...)
> 
> Nit: Indentation.

Will fix.

>> +{
>> +    int rc;
>> +    va_list args;
>> +    int i;
> 
> unsigned int?

I might as well change it to uint32_t to be in line with nargs.

> 
>> +    struct of_service s = { 0 };
>> +
>> +    s.ofs_service = cpu_to_be32(ADDR(service));
>> +    s.ofs_nargs = cpu_to_be32(nargs);
>> +    s.ofs_nrets = cpu_to_be32(nrets);
>> +
>> +    /* copy all the params into the args array */
> 
> Nit: Style (comments want to start with a capital letter). Again below.

Will fix.

>> +    va_start(args, rets);
>> +
>> +    for ( i = 0; i < nargs; i++ )
>> +        s.ofs_args[i] = cpu_to_be32(va_arg(args, uint32_t));
>> +
>> +    va_end(args);
>> +
>> +    rc = enter_of(&s, of_vec);
>> +
>> +    /* copy all return values to the output rets array */
>> +    for ( i = 0; i < nrets; i++ )
>> +        rets[i] = be32_to_cpu(s.ofs_args[i + nargs]);
>> +
>> +    return rc;
>> +}
>> +
>> +static int __init of_finddevice(const char *devspec)
>> +{
>> +    int rets[1] = { OF_FAILURE };
> 
> Hmm, of_call() uses int32_t. Again below several times.

Good catch. I'll switch all of these to int32_t for consistency.

> 
>> +    of_call("finddevice", 1, 1, rets, devspec);
> 
> This could do with using ARRAY_SIZE(rets). Same again below.

Sure, will do this.

> Also don't you need to wrap devspec in ADDR()? Similar issues
> then again below.

Yes, good catch. I'll fix this and the other bare pointers.

>> +    return rets[0];
>> +}
>> +
>> +static int __init of_getprop(int ph, const char *name, void *buf, uint32_t buflen)
>> +{
>> +    int rets[1] = { OF_FAILURE };
>> +
>> +    of_call("getprop", 4, 1, rets, ph, ADDR(name), buf, buflen);
>> +    return rets[0];
>> +}
>> +
>> +int __init of_write(int ih, const char *addr, uint32_t len)
>> +{
>> +    int rets[1] = { OF_FAILURE };
>> +
>> +    of_call("write", 3, 1, rets, ih, addr, len);
>> +    return rets[0];
>> +}
>> +
>> +static void __init of_putchar(char c)
>> +{
>> +    if ( c == '\n' )
>> +    {
>> +        char buf = '\r';
>> +        of_write(of_out, &buf, 1);
>> +    }
>> +    of_write(of_out, &c, 1);
>> +}
>> +
>> +void __init boot_of_init(unsigned long vec)
>> +{
>> +    of_vec = vec;
>> +
>> +    /* Get a handle to the default console */
>> +    bof_chosen = of_finddevice("/chosen");
>> +    of_getprop(bof_chosen, "stdout", &of_out, sizeof(of_out));
>> +    of_out = be32_to_cpu(of_out);
>> +
>> +    early_printk_init(of_putchar);
>> +}
> 
> Considering that bof_chosen is used just here, why does it need to be
> a file-scope variable?

Good point. The original code had it as a file-scope variable to be used
by other routines, but I've pruned them from this version which only
does the bare-minimum required for console printing. I'll change this to
a function-scoped variable.

>> --- /dev/null
>> +++ b/xen/arch/ppc/early_printk.c
>> @@ -0,0 +1,28 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +#include <xen/init.h>
>> +#include <asm/boot.h>
>> +
>> +static void (*putchar_func)(char);
> 
> __initdata? (Connected to the question of building into .init.o.)

Since I'm going to change this to build to .init.o, would this
automatically be put into the correct .init section? Would it still be
preferable style-wise to mark it as __initdata?

>> --- /dev/null
>> +++ b/xen/arch/ppc/include/asm/processor.h
>> @@ -0,0 +1,139 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Copyright IBM Corp. 2005, 2006, 2007
>> + * Copyright Raptor Engineering, LLC
>> + *
>> + * Authors: Hollis Blanchard <hollisb@us.ibm.com>
>> + *          Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
>> + *          Timothy Pearson <tpearson@raptorengineering.com>
>> + *          Shawn Anastasio <sanastasio@raptorengineering.com>
>> + */
>> +
>> +#ifndef _ASM_PPC_PROCESSOR_H
>> +#define _ASM_PPC_PROCESSOR_H
>> +
>> +#include <xen/config.h>
> 
> No need to - this is force-included by the Makefile machinery.

Ah, thanks. I'll remove this.

>> +#include <xen/types.h>
> 
> Note this. Why ...

See below

> 
>> +#define IOBMP_BYTES          8192
>> +#define IOBMP_INVALID_OFFSET 0x8000
>> +
>> +/* Processor Version Register (PVR) field extraction */
>> +
>> +#define PVR_VER(pvr) (((pvr) >> 16) & 0xFFFF) /* Version field */
>> +#define PVR_REV(pvr) (((pvr) >> 0) & 0xFFFF)  /* Revison field */
>> +
>> +#define __is_processor(pv) (PVR_VER(mfspr(SPRN_PVR)) == (pv))
>> +
>> +/*
>> + * IBM has further subdivided the standard PowerPC 16-bit version and
>> + * revision subfields of the PVR for the PowerPC 403s into the following:
>> + */
>> +
>> +#define PVR_FAM(pvr)  (((pvr) >> 20) & 0xFFF) /* Family field */
>> +#define PVR_MEM(pvr)  (((pvr) >> 16) & 0xF)   /* Member field */
>> +#define PVR_CORE(pvr) (((pvr) >> 12) & 0xF)   /* Core field */
>> +#define PVR_CFG(pvr)  (((pvr) >> 8) & 0xF)    /* Configuration field */
>> +#define PVR_MAJ(pvr)  (((pvr) >> 4) & 0xF)    /* Major revision field */
>> +#define PVR_MIN(pvr)  (((pvr) >> 0) & 0xF)    /* Minor revision field */
>> +
>> +/* Processor Version Numbers */
>> +
>> +#define PVR_403GA    0x00200000
>> +#define PVR_403GB    0x00200100
>> +#define PVR_403GC    0x00200200
>> +#define PVR_403GCX   0x00201400
>> +#define PVR_405GP    0x40110000
>> +#define PVR_STB03XXX 0x40310000
>> +#define PVR_NP405H   0x41410000
>> +#define PVR_NP405L   0x41610000
>> +#define PVR_601      0x00010000
>> +#define PVR_602      0x00050000
>> +#define PVR_603      0x00030000
>> +#define PVR_603e     0x00060000
>> +#define PVR_603ev    0x00070000
>> +#define PVR_603r     0x00071000
>> +#define PVR_604      0x00040000
>> +#define PVR_604e     0x00090000
>> +#define PVR_604r     0x000A0000
>> +#define PVR_620      0x00140000
>> +#define PVR_740      0x00080000
>> +#define PVR_750      PVR_740
>> +#define PVR_740P     0x10080000
>> +#define PVR_750P     PVR_740P
>> +#define PVR_7400     0x000C0000
>> +#define PVR_7410     0x800C0000
>> +#define PVR_7450     0x80000000
>> +#define PVR_8540     0x80200000
>> +#define PVR_8560     0x80200000
>> +/*
>> + * For the 8xx processors, all of them report the same PVR family for
>> + * the PowerPC core. The various versions of these processors must be
>> + * differentiated by the version number in the Communication Processor
>> + * Module (CPM).
>> + */
>> +#define PVR_821  0x00500000
>> +#define PVR_823  PVR_821
>> +#define PVR_850  PVR_821
>> +#define PVR_860  PVR_821
>> +#define PVR_8240 0x00810100
>> +#define PVR_8245 0x80811014
>> +#define PVR_8260 PVR_8240
>> +
>> +/* 64-bit processors */
>> +#define PVR_NORTHSTAR 0x0033
>> +#define PVR_PULSAR    0x0034
>> +#define PVR_POWER4    0x0035
>> +#define PVR_ICESTAR   0x0036
>> +#define PVR_SSTAR     0x0037
>> +#define PVR_POWER4p   0x0038
>> +#define PVR_970       0x0039
>> +#define PVR_POWER5    0x003A
>> +#define PVR_POWER5p   0x003B
>> +#define PVR_970FX     0x003C
>> +#define PVR_POWER6    0x003E
>> +#define PVR_POWER7    0x003F
>> +#define PVR_630       0x0040
>> +#define PVR_630p      0x0041
>> +#define PVR_970MP     0x0044
>> +#define PVR_970GX     0x0045
>> +#define PVR_POWER7p   0x004A
>> +#define PVR_POWER8E   0x004B
>> +#define PVR_POWER8NVL 0x004C
>> +#define PVR_POWER8    0x004D
>> +#define PVR_POWER9    0x004E
>> +#define PVR_POWER10   0x0080
>> +#define PVR_BE        0x0070
>> +#define PVR_PA6T      0x0090
>> +
>> +/* Macro to adjust thread priority for hardware multithreading */
>> +#define HMT_very_low()  asm volatile (" or %r31, %r31, %r31 ")
>> +
>> +#ifndef __ASSEMBLY__
>> +
>> +#include <xen/types.h>
> 
> ... another time here? Or is the first one perhaps too early?

Yes, the first include was a mistake -- this is the intended location.
Will fix.

> 
>> +/* User-accessible registers: nost of these need to be saved/restored
>> + * for every nested Xen invocation. */
> 
> Nit: Comment style. Multi-line comments want to be
> 
> /*
>  * User-accessible registers: most of these need to be saved/restored
>  * for every nested Xen invocation.
>  */
> 
> (also note the s/nost/most/ I did)

Will fix.

> 
>> --- a/xen/arch/ppc/ppc64/head.S
>> +++ b/xen/arch/ppc/ppc64/head.S
>> @@ -18,6 +18,15 @@ ENTRY(start)
>>      li %r11, 0
>>      stdu %r11, -STACK_FRAME_OVERHEAD(%r1)
>>  
>> +    /* clear .bss */
>> +    LOAD_IMM32(%r14, __bss_start)
>> +    LOAD_IMM32(%r15, __bss_end)
> 
> Question regarding addressing again.

Hopefully the above explanation answered your questions, but just to
summarize: Xen will always reside within the first 4G of physical
address space.

Also, as mentioned in your review of patch 1/3, this will soon be
changed to use TOC-relative addressing instead of immediate addressing.

> 
>> --- /dev/null
>> +++ b/xen/arch/ppc/ppc64/of-call.S
>> @@ -0,0 +1,83 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Adapted from Linux's arch/powerpc/kernel/entry_64.S, with the
>> + * following copyright notice:
>> + *
>> + *  PowerPC version
>> + *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
>> + *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
>> + *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
>> + *  Adapted for Power Macintosh by Paul Mackerras.
>> + *  Low-level exception handlers and MMU support
>> + *  rewritten by Paul Mackerras.
>> + *    Copyright (C) 1996 Paul Mackerras.
>> + *  MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
>> + */
>> +
>> +#include <asm/asm-offsets.h>
>> +#include <asm/asm-defns.h>
>> +#include <asm/msr.h>
>> +
>> +/* size of minimum stack frame that can hold an entire cpu_user_regs struct */
>> +#define STACK_SWITCH_FRAME_SIZE UREGS_sizeof
>> +
>> +    .section .init.text, "ax", @progbits
>> +
>> +ENTRY(enter_of)
>> +    mflr %r0
>> +    std %r0, 16(%r1)
>> +    stdu %r1,-STACK_SWITCH_FRAME_SIZE(%r1) /* Save SP and create stack space */
>> +
>> +    /*
>> +     * Because PROM is running in 32b mode, it clobbers the high order half
>> +     * of all registers that it saves.  We therefore save those registers
>> +     * PROM might touch to the stack.  (%r0, %r3-%r13 are caller saved)
>> +     */
>> +    SAVE_GPR(2, %r1)
>> +    SAVE_GPR(13, %r1)
>> +    SAVE_NVGPRS(%r1)
>> +    mfcr %r10
>> +    mfmsr %r11
>> +    std %r10, UREGS_cr(%r1)
>> +    std %r11, UREGS_msr(%r1)
>> +
>> +    /* Put PROM address in SRR0 */
>> +    mtsrr0 %r4
>> +
>> +    /* Setup our trampoline return addr in LR */
>> +    bcl 20, 31,.+4
>> +0:  mflr %r4
>> +    addi %r4, %r4,(1f - 0b)
> 
> Nit: Missing blank after last comma. I also wonder whether the parentheses
> are doing any good here.

Will fix the blank. The parentheses here are also unnecessary, so I can
remove them.

> Jan

Thanks,
Shawn
Shawn Anastasio July 17, 2023, 6:40 p.m. UTC | #3
Quick followup,

On 7/17/23 1:32 PM, Shawn Anastasio wrote:
> On 7/17/23 11:17 AM, Jan Beulich wrote:
>> This could do with using ARRAY_SIZE(rets). Same again below.
> 
> Sure, will do this.

ARRAY_SIZE is defined in <xen/lib.h> which can't yet be included due to
missing headers. I could copy its definition into this file along with a
TODO comment to fix it once the include works.

If I were to go down that route, I'd also probably not include the
__must_be_array assertion and related machinery that the <xen/lib.h>
version has, since it'd require a large portion of <xen/lib.h> to be
copy/pasted.
Jan Beulich July 18, 2023, 6:36 a.m. UTC | #4
On 17.07.2023 20:32, Shawn Anastasio wrote:
> On 7/17/23 11:17 AM, Jan Beulich wrote:
>> On 06.07.2023 21:04, Shawn Anastasio wrote:
>>> --- /dev/null
>>> +++ b/xen/arch/ppc/boot-of.c
>>> @@ -0,0 +1,100 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>>> +/*
>>> + * Copyright IBM Corp. 2005, 2006, 2007
>>
>> Judging from the years the file was taken from somewhere. Is the license
>> there permitting "2.0 or later"? (For files [partly] taken from somewhere,
>> a clarification as to the originals' licenses would be helpful to have in
>> the description, or maybe in the post-commit-message area.)
> 
> The original license of the file that this was derived from
> (xen/arch/powerpc/boot_of.c from Xen 3.2) is GPL v2.0 or later.
> 
> In any case where I'm deriving code from existing files, I'm always
> using the original license of the derived code. Should I still clarify
> this in the header comment?

I think it would be good to mention explicitly, as 2.0-only is the
common expectation.

>>> +/* OF entrypoint*/
>>> +static unsigned long __initdata of_vec;
>>> +
>>> +/* OF device handles*/
>>> +static int __initdata bof_chosen;
>>> +static int __initdata of_out;
>>> +
>>> +static int __init of_call(const char *service, uint32_t nargs, uint32_t nrets,
>>> +                   int32_t rets[], ...)
>>
>> Nit: Indentation.
> 
> Will fix.
> 
>>> +{
>>> +    int rc;
>>> +    va_list args;
>>> +    int i;
>>
>> unsigned int?
> 
> I might as well change it to uint32_t to be in line with nargs.

Please don't. See ./CODING_STYLE for when it is okay to use fixed-
width types.

>>> +    va_start(args, rets);
>>> +
>>> +    for ( i = 0; i < nargs; i++ )
>>> +        s.ofs_args[i] = cpu_to_be32(va_arg(args, uint32_t));
>>> +
>>> +    va_end(args);
>>> +
>>> +    rc = enter_of(&s, of_vec);
>>> +
>>> +    /* copy all return values to the output rets array */
>>> +    for ( i = 0; i < nrets; i++ )
>>> +        rets[i] = be32_to_cpu(s.ofs_args[i + nargs]);
>>> +
>>> +    return rc;
>>> +}
>>> +
>>> +static int __init of_finddevice(const char *devspec)
>>> +{
>>> +    int rets[1] = { OF_FAILURE };
>>
>> Hmm, of_call() uses int32_t. Again below several times.
> 
> Good catch. I'll switch all of these to int32_t for consistency.

Here, for example, it is (because of being used to interface with
firmware).

>>> --- /dev/null
>>> +++ b/xen/arch/ppc/early_printk.c
>>> @@ -0,0 +1,28 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>> +#include <xen/init.h>
>>> +#include <asm/boot.h>
>>> +
>>> +static void (*putchar_func)(char);
>>
>> __initdata? (Connected to the question of building into .init.o.)
> 
> Since I'm going to change this to build to .init.o, would this
> automatically be put into the correct .init section? Would it still be
> preferable style-wise to mark it as __initdata?

No, it would complain that .data or .bss is non-empty. Automatic
conversion occurs only for things you can't control at the source
level, e.g. string literals.

Jan
Jan Beulich July 18, 2023, 6:41 a.m. UTC | #5
On 17.07.2023 20:40, Shawn Anastasio wrote:
> Quick followup,
> 
> On 7/17/23 1:32 PM, Shawn Anastasio wrote:
>> On 7/17/23 11:17 AM, Jan Beulich wrote:
>>> This could do with using ARRAY_SIZE(rets). Same again below.
>>
>> Sure, will do this.
> 
> ARRAY_SIZE is defined in <xen/lib.h> which can't yet be included due to
> missing headers. I could copy its definition into this file along with a
> TODO comment to fix it once the include works.
> 
> If I were to go down that route, I'd also probably not include the
> __must_be_array assertion and related machinery that the <xen/lib.h>
> version has, since it'd require a large portion of <xen/lib.h> to be
> copy/pasted.

You (like anyone else) could review (and then offer R-b) my "common:
move a few macros out of xen/lib.h" [1]. That's of course only a tiny
first step (covering little more that what I need in that series). You
(or I or anyone else) could then put a patch on top moving ARRAY_SIZE()
(and its prereqs) to the new header as well. Since the new header has
no other prereqs, it should be usable as is, without the need for any
arch headers, both here and similarly in the RISC-V work.

Jan

[1] https://lists.xen.org/archives/html/xen-devel/2023-07/msg00582.html
diff mbox series

Patch

diff --git a/xen/arch/ppc/Kconfig.debug b/xen/arch/ppc/Kconfig.debug
index e69de29bb2..608c9ff832 100644
--- a/xen/arch/ppc/Kconfig.debug
+++ b/xen/arch/ppc/Kconfig.debug
@@ -0,0 +1,5 @@ 
+config EARLY_PRINTK
+    bool "Enable early printk"
+    default DEBUG
+    help
+      Enables early printk debug messages
diff --git a/xen/arch/ppc/Makefile b/xen/arch/ppc/Makefile
index 530fba2121..e1d4590d67 100644
--- a/xen/arch/ppc/Makefile
+++ b/xen/arch/ppc/Makefile
@@ -1,5 +1,7 @@ 
 obj-$(CONFIG_PPC64) += ppc64/
 
+obj-y += boot-of.init.o
+obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-y += setup.o
 
 $(TARGET): $(TARGET)-syms
diff --git a/xen/arch/ppc/boot-of.c b/xen/arch/ppc/boot-of.c
new file mode 100644
index 0000000000..6c69ca94ba
--- /dev/null
+++ b/xen/arch/ppc/boot-of.c
@@ -0,0 +1,100 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright IBM Corp. 2005, 2006, 2007
+ * Copyright Raptor Engineering, LLC
+ *
+ * Authors: Jimi Xenidis <jimix@watson.ibm.com>
+ *          Hollis Blanchard <hollisb@us.ibm.com>
+ *          Shawn Anastasio <sanastasio@raptorengineering.com>
+ */
+
+#include <xen/init.h>
+#include <xen/stdarg.h>
+#include <xen/types.h>
+#include <asm/boot.h>
+#include <asm/byteorder.h>
+#include <asm/early_printk.h>
+
+#define ADDR(x) (uint32_t)(unsigned long)(x)
+
+/* OF entrypoint*/
+static unsigned long __initdata of_vec;
+
+/* OF device handles*/
+static int __initdata bof_chosen;
+static int __initdata of_out;
+
+static int __init of_call(const char *service, uint32_t nargs, uint32_t nrets,
+                   int32_t rets[], ...)
+{
+    int rc;
+    va_list args;
+    int i;
+    struct of_service s = { 0 };
+
+    s.ofs_service = cpu_to_be32(ADDR(service));
+    s.ofs_nargs = cpu_to_be32(nargs);
+    s.ofs_nrets = cpu_to_be32(nrets);
+
+    /* copy all the params into the args array */
+    va_start(args, rets);
+
+    for ( i = 0; i < nargs; i++ )
+        s.ofs_args[i] = cpu_to_be32(va_arg(args, uint32_t));
+
+    va_end(args);
+
+    rc = enter_of(&s, of_vec);
+
+    /* copy all return values to the output rets array */
+    for ( i = 0; i < nrets; i++ )
+        rets[i] = be32_to_cpu(s.ofs_args[i + nargs]);
+
+    return rc;
+}
+
+static int __init of_finddevice(const char *devspec)
+{
+    int rets[1] = { OF_FAILURE };
+
+    of_call("finddevice", 1, 1, rets, devspec);
+    return rets[0];
+}
+
+static int __init of_getprop(int ph, const char *name, void *buf, uint32_t buflen)
+{
+    int rets[1] = { OF_FAILURE };
+
+    of_call("getprop", 4, 1, rets, ph, ADDR(name), buf, buflen);
+    return rets[0];
+}
+
+int __init of_write(int ih, const char *addr, uint32_t len)
+{
+    int rets[1] = { OF_FAILURE };
+
+    of_call("write", 3, 1, rets, ih, addr, len);
+    return rets[0];
+}
+
+static void __init of_putchar(char c)
+{
+    if ( c == '\n' )
+    {
+        char buf = '\r';
+        of_write(of_out, &buf, 1);
+    }
+    of_write(of_out, &c, 1);
+}
+
+void __init boot_of_init(unsigned long vec)
+{
+    of_vec = vec;
+
+    /* Get a handle to the default console */
+    bof_chosen = of_finddevice("/chosen");
+    of_getprop(bof_chosen, "stdout", &of_out, sizeof(of_out));
+    of_out = be32_to_cpu(of_out);
+
+    early_printk_init(of_putchar);
+}
diff --git a/xen/arch/ppc/configs/ppc64_defconfig b/xen/arch/ppc/configs/ppc64_defconfig
index 8783eb3488..f7cc075e45 100644
--- a/xen/arch/ppc/configs/ppc64_defconfig
+++ b/xen/arch/ppc/configs/ppc64_defconfig
@@ -10,4 +10,5 @@ 
 CONFIG_PPC64=y
 CONFIG_DEBUG=y
 CONFIG_DEBUG_INFO=y
+CONFIG_EARLY_PRINTK=y
 CONFIG_EXPERT=y
diff --git a/xen/arch/ppc/early_printk.c b/xen/arch/ppc/early_printk.c
new file mode 100644
index 0000000000..c5014945ef
--- /dev/null
+++ b/xen/arch/ppc/early_printk.c
@@ -0,0 +1,28 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+#include <xen/init.h>
+#include <asm/boot.h>
+
+static void (*putchar_func)(char);
+
+void __init early_printk_init(void (*putchar)(char))
+{
+    putchar_func = putchar;
+}
+
+void __init early_puts(const char *s, size_t nr)
+{
+    if ( !putchar_func )
+        return;
+
+    while ( nr-- > 0 )
+        putchar_func(*s++);
+}
+
+void __init early_printk(const char *s)
+{
+    if ( !putchar_func )
+        return;
+
+    while ( *s )
+        putchar_func(*s++);
+}
diff --git a/xen/arch/ppc/include/asm/asm-defns.h b/xen/arch/ppc/include/asm/asm-defns.h
index 6ea35f6edb..9d7328f4a2 100644
--- a/xen/arch/ppc/include/asm/asm-defns.h
+++ b/xen/arch/ppc/include/asm/asm-defns.h
@@ -37,4 +37,21 @@ 
     .long 0xa6037b7d; /* mtsrr1 r11                         */                 \
     .long 0x2400004c  /* rfid                               */
 
+
+/* Taken from Linux kernel source (arch/powerpc/boot/crt0.S) */
+.macro OP_REGS op, width, start, end, base, offset
+	.Lreg=\start
+	.rept (\end - \start + 1)
+	\op	.Lreg,\offset+\width*.Lreg(\base)
+	.Lreg=.Lreg+1
+	.endr
+.endm
+
+#define SAVE_GPRS(start, end, base) OP_REGS std, 8, start, end, base, 0
+#define REST_GPRS(start, end, base) OP_REGS ld, 8, start, end, base, 0
+#define SAVE_GPR(n, base)           SAVE_GPRS(n, n, base)
+#define REST_GPR(n, base)           REST_GPRS(n, n, base)
+#define SAVE_NVGPRS(base)           SAVE_GPRS(14, 31, base)
+#define REST_NVGPRS(base)           REST_GPRS(14, 31, base)
+
 #endif /* _ASM_PPC_ASM_DEFNS_H */
diff --git a/xen/arch/ppc/include/asm/boot.h b/xen/arch/ppc/include/asm/boot.h
new file mode 100644
index 0000000000..9b8a7c43c2
--- /dev/null
+++ b/xen/arch/ppc/include/asm/boot.h
@@ -0,0 +1,23 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_PPC_BOOT_H
+#define _ASM_PPC_BOOT_H
+
+#include <xen/types.h>
+
+/* a collection of interfaces used during boot. */
+enum {
+    OF_FAILURE = -1,
+    OF_SUCCESS = 0,
+};
+
+struct of_service {
+    __be32 ofs_service;
+    __be32 ofs_nargs;
+    __be32 ofs_nrets;
+    __be32 ofs_args[10];
+};
+
+int enter_of(struct of_service *args, unsigned long entry);
+void boot_of_init(unsigned long vec);
+
+#endif /* _ASM_PPC_BOOT_H */
diff --git a/xen/arch/ppc/include/asm/byteorder.h b/xen/arch/ppc/include/asm/byteorder.h
new file mode 100644
index 0000000000..2b5f6b9f63
--- /dev/null
+++ b/xen/arch/ppc/include/asm/byteorder.h
@@ -0,0 +1,12 @@ 
+#ifndef _ASM_PPC_BYTEORDER_H
+#define _ASM_PPC_BYTEORDER_H
+
+#define __arch__swab16 __builtin_bswap16
+#define __arch__swab32 __builtin_bswap32
+#define __arch__swab64 __builtin_bswap64
+
+#define __BYTEORDER_HAS_U64__
+
+#include <xen/byteorder/little_endian.h>
+
+#endif /* _ASM_PPC_BYTEORDER_H */
diff --git a/xen/arch/ppc/include/asm/config.h b/xen/arch/ppc/include/asm/config.h
index 01ca5d0803..cb27d2781e 100644
--- a/xen/arch/ppc/include/asm/config.h
+++ b/xen/arch/ppc/include/asm/config.h
@@ -52,6 +52,9 @@ 
 /* size of minimum stack frame; C code can write into the caller's stack */
 #define STACK_FRAME_OVERHEAD 32
 
+/* ELFv2 ABI mandates 16 byte alignment */
+#define STACK_ALIGN 16
+
 #endif /* __PPC_CONFIG_H__ */
 /*
  * Local variables:
diff --git a/xen/arch/ppc/include/asm/early_printk.h b/xen/arch/ppc/include/asm/early_printk.h
new file mode 100644
index 0000000000..d1d8b416f4
--- /dev/null
+++ b/xen/arch/ppc/include/asm/early_printk.h
@@ -0,0 +1,15 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_PPC_EARLY_PRINTK_H
+#define _ASM_PPC_EARLY_PRINTK_H
+
+#include <xen/early_printk.h>
+
+#ifdef CONFIG_EARLY_PRINTK
+void early_printk_init(void (*putchar)(char));
+void early_printk(const char *s);
+#else
+static inline void early_printk_init(void (*putchar)(char)) {}
+static inline void early_printk(const char *s) {}
+#endif
+
+#endif /* _ASM_PPC_EARLY_PRINTK_H */
diff --git a/xen/arch/ppc/include/asm/msr.h b/xen/arch/ppc/include/asm/msr.h
new file mode 100644
index 0000000000..144511e5c3
--- /dev/null
+++ b/xen/arch/ppc/include/asm/msr.h
@@ -0,0 +1,51 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) IBM Corp. 2005
+ * Copyright Raptor Engineering, LLC
+ *
+ * Authors: Jimi Xenidis <jimix@watson.ibm.com>
+ *          Shawn Anastasio <sanastasio@raptorengineering.com>
+ */
+
+#ifndef _ASM_PPC_MSR_H
+#define _ASM_PPC_MSR_H
+
+#include <xen/const.h>
+
+/* Flags in MSR: */
+#define MSR_SF      _AC(0x8000000000000000, ULL)
+#define MSR_TA      _AC(0x4000000000000000, ULL)
+#define MSR_ISF     _AC(0x2000000000000000, ULL)
+#define MSR_HV      _AC(0x1000000000000000, ULL)
+#define MSR_VMX     _AC(0x0000000002000000, ULL)
+#define MSR_MER     _AC(0x0000000000200000, ULL)
+#define MSR_POW     _AC(0x0000000000040000, ULL)
+#define MSR_ILE     _AC(0x0000000000010000, ULL)
+#define MSR_EE      _AC(0x0000000000008000, ULL)
+#define MSR_PR      _AC(0x0000000000004000, ULL)
+#define MSR_FP      _AC(0x0000000000002000, ULL)
+#define MSR_ME      _AC(0x0000000000001000, ULL)
+#define MSR_FE0     _AC(0x0000000000000800, ULL)
+#define MSR_SE      _AC(0x0000000000000400, ULL)
+#define MSR_BE      _AC(0x0000000000000200, ULL)
+#define MSR_FE1     _AC(0x0000000000000100, ULL)
+#define MSR_IP      _AC(0x0000000000000040, ULL)
+#define MSR_IR      _AC(0x0000000000000020, ULL)
+#define MSR_DR      _AC(0x0000000000000010, ULL)
+#define MSR_PMM     _AC(0x0000000000000004, ULL)
+#define MSR_RI      _AC(0x0000000000000002, ULL)
+#define MSR_LE      _AC(0x0000000000000001, ULL)
+
+/* MSR bits set on the systemsim simulator */
+#define MSR_SIM       _AC(0x0000000020000000, ULL)
+#define MSR_SYSTEMSIM _AC(0x0000000010000000, ULL)
+
+/* On a trap, srr1's copy of msr defines some bits as follows: */
+#define MSR_TRAP_FE     _AC(0x0000000000100000, ULL) /* Floating Point Exception */
+#define MSR_TRAP_IOP    _AC(0x0000000000080000, ULL) /* Illegal Instruction */
+#define MSR_TRAP_PRIV   _AC(0x0000000000040000, ULL) /* Privileged Instruction */
+#define MSR_TRAP        _AC(0x0000000000020000, ULL) /* Trap Instruction */
+#define MSR_TRAP_NEXT   _AC(0x0000000000010000, ULL) /* PC is next instruction */
+#define MSR_TRAP_BITS  (MSR_TRAP_FE|MSR_TRAP_IOP|MSR_TRAP_PRIV|MSR_TRAP)
+
+#endif /* _ASM_PPC_MSR_H */
diff --git a/xen/arch/ppc/include/asm/processor.h b/xen/arch/ppc/include/asm/processor.h
new file mode 100644
index 0000000000..2d2e582f08
--- /dev/null
+++ b/xen/arch/ppc/include/asm/processor.h
@@ -0,0 +1,139 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright IBM Corp. 2005, 2006, 2007
+ * Copyright Raptor Engineering, LLC
+ *
+ * Authors: Hollis Blanchard <hollisb@us.ibm.com>
+ *          Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
+ *          Timothy Pearson <tpearson@raptorengineering.com>
+ *          Shawn Anastasio <sanastasio@raptorengineering.com>
+ */
+
+#ifndef _ASM_PPC_PROCESSOR_H
+#define _ASM_PPC_PROCESSOR_H
+
+#include <xen/config.h>
+#include <xen/types.h>
+
+#define IOBMP_BYTES          8192
+#define IOBMP_INVALID_OFFSET 0x8000
+
+/* Processor Version Register (PVR) field extraction */
+
+#define PVR_VER(pvr) (((pvr) >> 16) & 0xFFFF) /* Version field */
+#define PVR_REV(pvr) (((pvr) >> 0) & 0xFFFF)  /* Revison field */
+
+#define __is_processor(pv) (PVR_VER(mfspr(SPRN_PVR)) == (pv))
+
+/*
+ * IBM has further subdivided the standard PowerPC 16-bit version and
+ * revision subfields of the PVR for the PowerPC 403s into the following:
+ */
+
+#define PVR_FAM(pvr)  (((pvr) >> 20) & 0xFFF) /* Family field */
+#define PVR_MEM(pvr)  (((pvr) >> 16) & 0xF)   /* Member field */
+#define PVR_CORE(pvr) (((pvr) >> 12) & 0xF)   /* Core field */
+#define PVR_CFG(pvr)  (((pvr) >> 8) & 0xF)    /* Configuration field */
+#define PVR_MAJ(pvr)  (((pvr) >> 4) & 0xF)    /* Major revision field */
+#define PVR_MIN(pvr)  (((pvr) >> 0) & 0xF)    /* Minor revision field */
+
+/* Processor Version Numbers */
+
+#define PVR_403GA    0x00200000
+#define PVR_403GB    0x00200100
+#define PVR_403GC    0x00200200
+#define PVR_403GCX   0x00201400
+#define PVR_405GP    0x40110000
+#define PVR_STB03XXX 0x40310000
+#define PVR_NP405H   0x41410000
+#define PVR_NP405L   0x41610000
+#define PVR_601      0x00010000
+#define PVR_602      0x00050000
+#define PVR_603      0x00030000
+#define PVR_603e     0x00060000
+#define PVR_603ev    0x00070000
+#define PVR_603r     0x00071000
+#define PVR_604      0x00040000
+#define PVR_604e     0x00090000
+#define PVR_604r     0x000A0000
+#define PVR_620      0x00140000
+#define PVR_740      0x00080000
+#define PVR_750      PVR_740
+#define PVR_740P     0x10080000
+#define PVR_750P     PVR_740P
+#define PVR_7400     0x000C0000
+#define PVR_7410     0x800C0000
+#define PVR_7450     0x80000000
+#define PVR_8540     0x80200000
+#define PVR_8560     0x80200000
+/*
+ * For the 8xx processors, all of them report the same PVR family for
+ * the PowerPC core. The various versions of these processors must be
+ * differentiated by the version number in the Communication Processor
+ * Module (CPM).
+ */
+#define PVR_821  0x00500000
+#define PVR_823  PVR_821
+#define PVR_850  PVR_821
+#define PVR_860  PVR_821
+#define PVR_8240 0x00810100
+#define PVR_8245 0x80811014
+#define PVR_8260 PVR_8240
+
+/* 64-bit processors */
+#define PVR_NORTHSTAR 0x0033
+#define PVR_PULSAR    0x0034
+#define PVR_POWER4    0x0035
+#define PVR_ICESTAR   0x0036
+#define PVR_SSTAR     0x0037
+#define PVR_POWER4p   0x0038
+#define PVR_970       0x0039
+#define PVR_POWER5    0x003A
+#define PVR_POWER5p   0x003B
+#define PVR_970FX     0x003C
+#define PVR_POWER6    0x003E
+#define PVR_POWER7    0x003F
+#define PVR_630       0x0040
+#define PVR_630p      0x0041
+#define PVR_970MP     0x0044
+#define PVR_970GX     0x0045
+#define PVR_POWER7p   0x004A
+#define PVR_POWER8E   0x004B
+#define PVR_POWER8NVL 0x004C
+#define PVR_POWER8    0x004D
+#define PVR_POWER9    0x004E
+#define PVR_POWER10   0x0080
+#define PVR_BE        0x0070
+#define PVR_PA6T      0x0090
+
+/* Macro to adjust thread priority for hardware multithreading */
+#define HMT_very_low()  asm volatile (" or %r31, %r31, %r31 ")
+
+#ifndef __ASSEMBLY__
+
+#include <xen/types.h>
+
+/* User-accessible registers: nost of these need to be saved/restored
+ * for every nested Xen invocation. */
+struct cpu_user_regs
+{
+    uint64_t gprs[32];
+    uint64_t lr;
+    uint64_t ctr;
+    uint64_t srr0;
+    uint64_t srr1;
+    uint64_t pc;
+    uint64_t msr;
+    uint64_t fpscr;
+    uint64_t xer;
+    uint64_t hid4;  /* debug only */
+    uint64_t dar;   /* debug only */
+    uint32_t dsisr; /* debug only */
+    uint32_t cr;
+    uint32_t __pad; /* good spot for another 32bit reg */
+    uint32_t entry_vector;
+};
+
+#endif
+
+#endif /* _ASM_PPC_PROCESSOR_H */
diff --git a/xen/arch/ppc/include/asm/types.h b/xen/arch/ppc/include/asm/types.h
new file mode 100644
index 0000000000..cee08e111a
--- /dev/null
+++ b/xen/arch/ppc/include/asm/types.h
@@ -0,0 +1,21 @@ 
+/* from xen/arch/x86/include/asm/types.h */
+
+#ifndef _ASM_PPC_TYPES_H
+#define _ASM_PPC_TYPES_H
+
+typedef signed char s8;
+typedef unsigned char u8;
+
+typedef signed short s16;
+typedef unsigned short u16;
+
+typedef signed int s32;
+typedef unsigned int u32;
+
+typedef signed long s64;
+typedef unsigned long u64;
+typedef unsigned long paddr_t;
+#define INVALID_PADDR (~0UL)
+#define PRIpaddr "016lx"
+
+#endif /* _ASM_PPC_TYPES_H */
diff --git a/xen/arch/ppc/ppc64/Makefile b/xen/arch/ppc/ppc64/Makefile
index 3340058c08..f4956daaa9 100644
--- a/xen/arch/ppc/ppc64/Makefile
+++ b/xen/arch/ppc/ppc64/Makefile
@@ -1 +1,2 @@ 
 obj-y += head.o
+obj-y += of-call.o
diff --git a/xen/arch/ppc/ppc64/asm-offsets.c b/xen/arch/ppc/ppc64/asm-offsets.c
index e69de29bb2..7fc29d5db1 100644
--- a/xen/arch/ppc/ppc64/asm-offsets.c
+++ b/xen/arch/ppc/ppc64/asm-offsets.c
@@ -0,0 +1,59 @@ 
+/*
+ * Generate definitions needed by assembly language modules.
+ * This code generates raw asm output which is post-processed
+ * to extract and format the required data.
+ */
+
+#include <asm/processor.h>
+
+#define DEFINE(_sym, _val)                                                 \
+    asm volatile ("\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\"" \
+                  : : "i" (_val) )
+#define BLANK()                                                            \
+    asm volatile ( "\n.ascii\"==><==\"" : : )
+#define OFFSET(_sym, _str, _mem)                                           \
+    DEFINE(_sym, offsetof(_str, _mem));
+
+/* base-2 logarithm */
+#define __L2(_x)  (((_x) & 0x00000002) ?   1 : 0)
+#define __L4(_x)  (((_x) & 0x0000000c) ? ( 2 + __L2( (_x)>> 2)) : __L2( _x))
+#define __L8(_x)  (((_x) & 0x000000f0) ? ( 4 + __L4( (_x)>> 4)) : __L4( _x))
+#define __L16(_x) (((_x) & 0x0000ff00) ? ( 8 + __L8( (_x)>> 8)) : __L8( _x))
+#define LOG_2(_x) (((_x) & 0xffff0000) ? (16 + __L16((_x)>>16)) : __L16(_x))
+
+void __dummy__(void)
+{
+    DEFINE(GPR_WIDTH, sizeof(unsigned long));
+    DEFINE(FPR_WIDTH, sizeof(double));
+
+    OFFSET(UREGS_gprs, struct cpu_user_regs, gprs);
+    OFFSET(UREGS_r0, struct cpu_user_regs, gprs[0]);
+    OFFSET(UREGS_r1, struct cpu_user_regs, gprs[1]);
+    OFFSET(UREGS_r13, struct cpu_user_regs, gprs[13]);
+    OFFSET(UREGS_srr0, struct cpu_user_regs, srr0);
+    OFFSET(UREGS_srr1, struct cpu_user_regs, srr1);
+    OFFSET(UREGS_pc, struct cpu_user_regs, pc);
+    OFFSET(UREGS_msr, struct cpu_user_regs, msr);
+    OFFSET(UREGS_lr, struct cpu_user_regs, lr);
+    OFFSET(UREGS_ctr, struct cpu_user_regs, ctr);
+    OFFSET(UREGS_xer, struct cpu_user_regs, xer);
+    OFFSET(UREGS_hid4, struct cpu_user_regs, hid4);
+    OFFSET(UREGS_dar, struct cpu_user_regs, dar);
+    OFFSET(UREGS_dsisr, struct cpu_user_regs, dsisr);
+    OFFSET(UREGS_cr, struct cpu_user_regs, cr);
+    OFFSET(UREGS_fpscr, struct cpu_user_regs, fpscr);
+    DEFINE(UREGS_sizeof, sizeof(struct cpu_user_regs));
+}
+
+/* TODO: Replace with BUILD_BUG_ON + IS_ALIGNED once we can use <xen/lib.h> */
+_Static_assert(sizeof(struct cpu_user_regs) % STACK_ALIGN == 0,
+               "struct cpu_user_regs not stack aligned!");
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/ppc/ppc64/head.S b/xen/arch/ppc/ppc64/head.S
index 7d848611cc..8497d8f37e 100644
--- a/xen/arch/ppc/ppc64/head.S
+++ b/xen/arch/ppc/ppc64/head.S
@@ -18,6 +18,15 @@  ENTRY(start)
     li %r11, 0
     stdu %r11, -STACK_FRAME_OVERHEAD(%r1)
 
+    /* clear .bss */
+    LOAD_IMM32(%r14, __bss_start)
+    LOAD_IMM32(%r15, __bss_end)
+1:
+    std %r11, 0(%r14)
+    addi %r14, %r14, 8
+    cmpld %r14, %r15
+    blt 1b
+
     /* call the C entrypoint */
     bl start_xen
 
diff --git a/xen/arch/ppc/ppc64/of-call.S b/xen/arch/ppc/ppc64/of-call.S
new file mode 100644
index 0000000000..5f13e3b327
--- /dev/null
+++ b/xen/arch/ppc/ppc64/of-call.S
@@ -0,0 +1,83 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Adapted from Linux's arch/powerpc/kernel/entry_64.S, with the
+ * following copyright notice:
+ *
+ *  PowerPC version
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
+ *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
+ *  Adapted for Power Macintosh by Paul Mackerras.
+ *  Low-level exception handlers and MMU support
+ *  rewritten by Paul Mackerras.
+ *    Copyright (C) 1996 Paul Mackerras.
+ *  MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
+ */
+
+#include <asm/asm-offsets.h>
+#include <asm/asm-defns.h>
+#include <asm/msr.h>
+
+/* size of minimum stack frame that can hold an entire cpu_user_regs struct */
+#define STACK_SWITCH_FRAME_SIZE UREGS_sizeof
+
+    .section .init.text, "ax", @progbits
+
+ENTRY(enter_of)
+    mflr %r0
+    std %r0, 16(%r1)
+    stdu %r1,-STACK_SWITCH_FRAME_SIZE(%r1) /* Save SP and create stack space */
+
+    /*
+     * Because PROM is running in 32b mode, it clobbers the high order half
+     * of all registers that it saves.  We therefore save those registers
+     * PROM might touch to the stack.  (%r0, %r3-%r13 are caller saved)
+     */
+    SAVE_GPR(2, %r1)
+    SAVE_GPR(13, %r1)
+    SAVE_NVGPRS(%r1)
+    mfcr %r10
+    mfmsr %r11
+    std %r10, UREGS_cr(%r1)
+    std %r11, UREGS_msr(%r1)
+
+    /* Put PROM address in SRR0 */
+    mtsrr0 %r4
+
+    /* Setup our trampoline return addr in LR */
+    bcl 20, 31,.+4
+0:  mflr %r4
+    addi %r4, %r4,(1f - 0b)
+    mtlr %r4
+
+    /* Prepare a 32-bit mode big endian MSR */
+    LOAD_IMM64(%r12, MSR_SF | MSR_LE)
+    andc %r11, %r11, %r12
+    mtsrr1 %r11
+    rfid
+
+1:  /* Return from OF */
+    FIXUP_ENDIAN
+
+    /* Just make sure that %r1 top 32 bits didn't get corrupt by OF */
+    rldicl %r1, %r1, 0, 32
+
+    /* Restore the MSR (back to 64 bits) */
+    ld %r0, UREGS_msr(%r1)
+    mtmsrd %r0
+    isync
+
+    /* Restore other registers */
+    REST_GPR(2, %r1)
+    REST_GPR(13, %r1)
+    REST_NVGPRS(%r1)
+    ld %r4, UREGS_cr(%r1)
+    mtcr %r4
+
+    addi %r1, %r1, STACK_SWITCH_FRAME_SIZE
+    ld %r0, 16(%r1)
+    mtlr %r0
+    blr
+
+    .size enter_of, . - enter_of
+    .type enter_of, %function
diff --git a/xen/arch/ppc/setup.c b/xen/arch/ppc/setup.c
index 73106474b2..7c623a49f5 100644
--- a/xen/arch/ppc/setup.c
+++ b/xen/arch/ppc/setup.c
@@ -1,16 +1,29 @@ 
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 #include <xen/init.h>
+#include <asm/boot.h>
+#include <asm/early_printk.h>
+#include <asm/processor.h>
 
 /* Xen stack for bringing up the first CPU. */
 unsigned char __initdata cpu0_boot_stack[STACK_SIZE] __aligned(STACK_SIZE);
 
-/* Macro to adjust thread priority for hardware multithreading */
-#define HMT_very_low()  asm volatile (" or %r31, %r31, %r31 ")
-
 void __init noreturn start_xen(unsigned long r3, unsigned long r4,
                                unsigned long r5, unsigned long r6,
                                unsigned long r7)
 {
+    if ( r5 )
+    {
+        /* OpenFirmware boot protocol */
+        boot_of_init(r5);
+    }
+    else
+    {
+        /* kexec boot: Unimplemented */
+        __builtin_trap();
+    }
+
+    early_printk("Hello, ppc64le!\n");
+
     for ( ; ; )
         /* Set current hardware thread to very low priority */
         HMT_very_low();