On Thu, Jan 17, 2019 at 9:53 AM Dave Young <dyoung@xxxxxxxxxx> wrote:
>
> Add linux-acpi list
Well, thanks, but please resend the patches with a CC to linux-acpi.
> On 01/17/19 at 03:41pm, Kairui Song wrote:
> > On Wed, Jan 16, 2019 at 5:46 PM Borislav Petkov <bp@xxxxxxxxx> wrote:
> > >
> > > On Wed, Jan 16, 2019 at 03:08:42PM +0800, Kairui Song wrote:
> > > > I didn't see a way to reuse things in that patch series, situation is
> > > > different, in that patch it needs to get RSDP in very early boot stage
> > > > so it did everything from scratch, in this patch kexec_file_load need
> > > > to get RSDP too, but everything is well setup so things are a lot
> > > > easier, just read from current boot_prams, efi and fallback to
> > > > acpi_find_root_pointer should be good.
> > >
> > > No no. Early code should find out that venerable RSDP thing once and
> > > will save it somewhere for further use. No gazillion parsings of it.
> > > Just once and share it with the rest of the code that needs it.
> > >
> >
> > How about we refill the boot_params.acpi_rsdp_addr if it is not valid
> > in early code, so it could be used as a reliable RSDP address source?
> > That should make things easier.
> >
> > But if early code should parse it and store it should be done in
> > Chao's patch, or I can post another patch to do it if Chao's patch is
> > merged.
> >
> > For now I think good to have something like this in this patch series
> > to always keep storing acpi_rsdp in late code,
> > acpi_os_get_root_pointer_late (maybe comeup with a better name later)
> > could be used anytime to get RSDP and no extra parsing:
> >
> > --- a/drivers/acpi/osl.c
> > +++ b/drivers/acpi/osl.c
> > @@ -180,8 +180,8 @@ void acpi_os_vprintf(const char *fmt, va_list args)
> > #endif
> > }
> >
> > -#ifdef CONFIG_KEXEC
> > static unsigned long acpi_rsdp;
> > +#ifdef CONFIG_KEXEC
> > static int __init setup_acpi_rsdp(char *arg)
> > {
> > return kstrtoul(arg, 16, &acpi_rsdp);
> > @@ -189,28 +189,38 @@ static int __init setup_acpi_rsdp(char *arg)
> > early_param("acpi_rsdp", setup_acpi_rsdp);
> > #endif
> >
> > +acpi_physical_address acpi_os_get_root_pointer_late(void) {
> > + return acpi_rsdp;
> > +}
> > +
> > acpi_physical_address __init acpi_os_get_root_pointer(void)
> > {
> > acpi_physical_address pa;
> >
> > -#ifdef CONFIG_KEXEC
> > if (acpi_rsdp)
> > return acpi_rsdp;
> > -#endif
> > +
> > pa = acpi_arch_get_root_pointer();
> > - if (pa)
> > + if (pa) {
> > + acpi_rsdp = pa;
> > return pa;
> > + }
> >
> > if (efi_enabled(EFI_CONFIG_TABLES)) {
> > - if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
> > + if (efi.acpi20 != EFI_INVALID_TABLE_ADDR) {
> > + acpi_rsdp = efi.acpi20;
> > return efi.acpi20;
> > - if (efi.acpi != EFI_INVALID_TABLE_ADDR)
> > + }
> > + if (efi.acpi != EFI_INVALID_TABLE_ADDR) {
> > + acpi_rsdp = efi.acpi;
> > return efi.acpi;
> > + }
> > pr_err(PREFIX "System description tables not found\n");
> > } else if (IS_ENABLED(CONFIG_ACPI_LEGACY_TABLES_LOOKUP)) {
> > acpi_find_root_pointer(&pa);
> > }
> >
> > + acpi_rsdp = pa;
> > return pa;
> > }
> >
> > > --
> > > Regards/Gruss,
> > > Boris.
> > >
> > > Good mailing practices for 400: avoid top-posting and trim the reply.
> > --
> > Best Regards,
> > Kairui Song
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