On Thu, 10 Mar 2011 22:10:43 +0800 Amerigo Wang wrote:
> From: Takao Indoh <tindoh@xxxxxxxxxx>
>
> There is a problem with putting the first kernel in EFI virtual mode,
> it is that when the second kernel comes up it tries to initialize the
> EFI again and once we have put EFI in virtual mode we can not really
> do that.
>
> Actually, EFI is not necessary for kdump, we can boot the second kernel
> with "noefi" parameter, but the boot will mostly fail because 2nd kernel
> cannot find RSDP.
>
> In this situation, we introduced "acpi_addr=" kernel parameter,
> so that kexec-tools can pass the "noefi acpi_addr=X" to the second kernel
> to make kdump works.
>
> Signed-off-by: Takao Indoh <tindoh@xxxxxxxxxx>
> [amwang@xxxxxxxxxx: Add documentation.]
> Signed-off-by: WANG Cong <amwang@xxxxxxxxxx>
> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
>
> ---
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index f4a04c0..0fbbdc6 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -163,6 +163,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>
> See also Documentation/power/pm.txt, pci=noacpi
>
> + acpi_addr= [ACPI,EFI]
> + Pass the RSDP address to the kernel, mostly used
> + on machines running EFI runtime service to boot the
> + second kernel for kdump.
> +
I think that "acpi_addr" is a bit too generic. How about
acpi_rsdp or acpi_root instead?
> acpi_apic_instance= [ACPI, IOAPIC]
> Format: <int>
> 2: use 2nd APIC table, if available
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index c90c76a..06dfec0 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -238,8 +238,19 @@ void acpi_os_vprintf(const char *fmt, va_list args)
> #endif
> }
>
> +static unsigned long acpi_addr;
> +static int __init setup_acpi_addr(char *arg)
> +{
> + acpi_addr = simple_strtoul(arg, NULL, 16);
> + return 0;
> +}
> +early_param("acpi_addr", setup_acpi_addr);
> +
> acpi_physical_address __init acpi_os_get_root_pointer(void)
> {
> + if (acpi_addr)
> + return acpi_addr;
> +
> if (efi_enabled) {
> if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
> return efi.acpi20;
---
~Randy
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