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SubjectRe: [PATCH v2 2/2] x86, kexec_file_load: make it work with efi=noruntime or efi=old_map
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On 01/17/19 at 03:41pm, Kairui Song wrote:
> On Wed, Jan 16, 2019 at 5:46 PM Borislav Petkov <bp@alien8.de> 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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