[U-Boot] [PATCH v1 2/2] x86: zImage: Propagate acpi_rsdp_addr to kernel via boot parameters

[Bin Meng]

On Mon, Jan 15, 2018 at 10:33 AM, Bin Meng <bmeng.cn at gmail.com> wrote:
> On Fri, Jan 12, 2018 at 9:01 PM, Andy Shevchenko
> <andriy.shevchenko at linux.intel.com> wrote:
>> On Fri, 2018-01-12 at 17:00 +0800, Bin Meng wrote:
>>> Hi Andy,
>>>
>>> On Thu, Jan 11, 2018 at 1:40 AM, Andy Shevchenko
>>> <andriy.shevchenko at linux.intel.com> wrote:
>>> > New field acpi_rsdp_addr, which has been introduced in boot protocol
>>> > v2.14 [1], in boot parameters tells kernel the exact address of RDSP
>>> > ACPI table. Knowing it increases robustness of the kernel by
>>> > avoiding
>>> > in some cases traversal through a part of physical memory.
>>> > It will slightly reduce boot time by the same reason.
>>> >
>>> > [1] See Linux kernel commit
>>> >
>>> >   2f74cbf947f4 ("x86/boot: Add the ACPI RSDP address to struct
>>> > setup_header::acpi_rdsp_addr")
>>>
>>> I don't see this commit id in my linux tree. Is this in some
>>> custodian's tree?
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=2
>> f74cbf947f45fa082dda8eac1a1f1299a372f49
>>
>
> thanks!
>
>>> > for the details.
>>> >
>>> > Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
>>> > ---
>>> >  arch/x86/include/asm/bootparam.h |  1 +
>>> >  arch/x86/lib/acpi_table.c        |  7 +++++++
>>> >  arch/x86/lib/acpi_table.h        | 10 ++++++++++
>>> >  arch/x86/lib/zimage.c            |  6 ++++++
>>> >  4 files changed, 24 insertions(+)
>>> >  create mode 100644 arch/x86/lib/acpi_table.h
>>> >
>>> > diff --git a/arch/x86/include/asm/bootparam.h
>>> > b/arch/x86/include/asm/bootparam.h
>>> > index 48b138c6b0..90768a99ce 100644
>>> > --- a/arch/x86/include/asm/bootparam.h
>>> > +++ b/arch/x86/include/asm/bootparam.h
>>> > @@ -66,6 +66,7 @@ struct setup_header {
>>> >         __u64   pref_address;
>>> >         __u32   init_size;
>>> >         __u32   handover_offset;
>>> > +       __u64   acpi_rsdp_addr;
>>> >  } __attribute__((packed));
>>> >
>>> >  struct sys_desc_table {
>>> > diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
>>> > index 7b33cd371e..45bfc111ef 100644
>>> > --- a/arch/x86/lib/acpi_table.c
>>> > +++ b/arch/x86/lib/acpi_table.c
>>> > @@ -20,6 +20,7 @@
>>> >  #include <asm/mpspec.h>
>>> >  #include <asm/tables.h>
>>> >  #include <asm/arch/global_nvs.h>
>>> > +#include "acpi_table.h"
>>> >
>>> >  /*
>>> >   * IASL compiles the dsdt entries and writes the hex values
>>> > @@ -27,6 +28,11 @@
>>> >   */
>>> >  extern const unsigned char AmlCode[];
>>> >
>>> > +/*
>>> > + * ACPI RSDP address to be used in boot parameters.
>>> > + */
>>>
>>> nits: use single line comment format without the ending .
>>
>> OK.
>>
>>>
>>> > +unsigned long acpi_rsdp_addr;
>>> > +
>>> >  static void acpi_write_rsdp(struct acpi_rsdp *rsdp, struct
>>> > acpi_rsdt *rsdt,
>>> >                             struct acpi_xsdt *xsdt)
>>> >  {
>>> > @@ -460,6 +466,7 @@ ulong write_acpi_tables(ulong start)
>>> >
>>> >         debug("current = %x\n", current);
>>> >
>>> > +       acpi_rsdp_addr = (unsigned long)rsdp;
>>> >         debug("ACPI: done\n");
>>> >
>>> >         /* Don't touch ACPI hardware on HW reduced platforms */
>>> > diff --git a/arch/x86/lib/acpi_table.h b/arch/x86/lib/acpi_table.h
>>> > new file mode 100644
>>> > index 0000000000..cece5d1420
>>> > --- /dev/null
>>> > +++ b/arch/x86/lib/acpi_table.h
>>> > @@ -0,0 +1,10 @@
>>> > +/*
>>> > + * SPDX-License-Identifier:    GPL-2.0
>>> > + */
>>> > +
>>> > +#ifndef _X86_LIB_ACPI_TABLES_H
>>> > +#define _X86_LIB_ACPI_TABLES_H
>>> > +
>>> > +extern unsigned long acpi_rsdp_addr;
>>> > +
>>> > +#endif
>>> > diff --git a/arch/x86/lib/zimage.c b/arch/x86/lib/zimage.c
>>> > index d224db4e07..eae26635b1 100644
>>> > --- a/arch/x86/lib/zimage.c
>>> > +++ b/arch/x86/lib/zimage.c
>>> > @@ -24,6 +24,7 @@
>>> >  #include <asm/arch/timestamp.h>
>>> >  #endif
>>> >  #include <linux/compiler.h>
>>> > +#include "acpi_table.h"
>>> >
>>> >  DECLARE_GLOBAL_DATA_PTR;
>>> >
>>> > @@ -255,6 +256,11 @@ int setup_zimage(struct boot_params
>>> > *setup_base, char *cmd_line, int auto_boot,
>>> >                 hdr->hardware_subarch = X86_SUBARCH_INTEL_MID;
>>> >  #endif
>>> >
>>> > +#ifdef CONFIG_GENERATE_ACPI_TABLE
>>> > +       if (bootproto >= 0x020e)
>>> > +               hdr->acpi_rsdp_addr = acpi_rsdp_addr;
>>> > +#endif
>>> > +
>>> >         setup_video(&setup_base->screen_info);
>>> >
>>> >         return 0;
>>> > --
>>>
>>> Other than the above nits,
>>> Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
>>>
>>> I can fix the nits when applying if you like.
>>
>> If you have a chance to do it soon, please, do, otherwise I would send a
>> new version later (next week I suppose).
>
> Fixed the nits and mentioned the git commit URL
>
> applied to u-boot-x86, thanks!

This unfortunately breaks qemu-x86 and qemu-x86_64. I will post
patches to fix this.

Regards,
Bin