On Wed, Dec 12, 2018 at 11:10:50AM +0800, Chao Fan wrote:
> Memory information in SRAT is necessary to fix the conflict between
> KASLR and memory-hotremove. So RSDP and SRAT should be parsed.
>
> When booting form KEXEC/EFI/BIOS, the methods to compute RSDP
> are different. When booting from EFI, EFI table points to RSDP.
> So parse the EFI table and find the RSDP.
>
> Signed-off-by: Chao Fan <[email protected]>
> ---
> arch/x86/boot/compressed/acpi.c | 79 +++++++++++++++++++++++++++++++++
> 1 file changed, 79 insertions(+)
>
> diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
> index cad15686f82c..c96008712ec9 100644
> --- a/arch/x86/boot/compressed/acpi.c
> +++ b/arch/x86/boot/compressed/acpi.c
> @@ -28,3 +28,82 @@ static acpi_physical_address get_acpi_rsdp(void)
> return 0;
> #endif
> }
> +
> +/* Search EFI table for RSDP. */
> +static acpi_physical_address efi_get_rsdp_addr(void)
> +{
> +#ifdef CONFIG_EFI
> + acpi_physical_address rsdp_addr = 0;
> + efi_system_table_t *systab;
> + struct efi_info *e;
> + bool efi_64;
> + char *sig;
> + int size;
> + int i;
> +
> + e = &boot_params->efi_info;
> + sig = (char *)&e->efi_loader_signature;
> +
> + if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4))
> + efi_64 = true;
> + else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4))
> + efi_64 = false;
> + else {
> + debug_putstr("Wrong EFI loader signature.\n");
> + return 0;
> + }
> +
> + /* Get systab from boot params. Based on efi_init(). */
> +#ifdef CONFIG_X86_64
> + systab = (efi_system_table_t *)(e->efi_systab |
> ((__u64)e->efi_systab_hi<<32));
> +#else
> + if (e->efi_systab_hi || e->efi_memmap_hi) {
> + debug_putstr("Error getting RSDP address: EFI system table
> located above 4GB.\n");
> + return 0;
> + }
> + systab = (efi_system_table_t *)e->efi_systab;
> +#endif
> +
> + if (!systab)
> + return 0;
> +
> + /*
> + * Get EFI tables from systab. Based on efi_config_init() and
> + * efi_config_parse_tables().
> + */
> + size = efi_64 ? sizeof(efi_config_table_64_t) :
> + sizeof(efi_config_table_32_t);
> +
> + for (i = 0; i < systab->nr_tables; i++) {
> + void *config_tables;
> + unsigned long table;
u64 table;
Otherwise, the following build warning happen in ARCH=i386.
===
arch/x86/boot/compressed/acpi.c:96:44: warning: right shift count >= width of
type [-Wshift-count-overflow]
if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
===
Thanks,
Masa
