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    Subject[PATCH 5.2 51/85] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernels
    Date
    From: Junichi Nomura <j-nomura@ce.jp.nec.com>

    commit 0a23ebc66a46786769dd68bfdaa3102345819b9c upstream.

    Commit

    3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in boot_params")

    broke kexec boot on EFI systems. efi_get_rsdp_addr() in the early
    parsing code tries to search RSDP from the EFI tables but that will
    crash because the table address is virtual when the kernel was booted by
    kexec (set_virtual_address_map() has run in the first kernel and cannot
    be run again in the second kernel).

    In the case of kexec, the physical address of EFI tables is provided via
    efi_setup_data in boot_params, which is set up by kexec(1).

    Factor out the table parsing code and use different pointers depending
    on whether the kernel is booted by kexec or not.

    [ bp: Massage. ]

    Fixes: 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in boot_params")
    Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
    Signed-off-by: Borislav Petkov <bp@suse.de>
    Tested-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
    Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
    Cc: Dave Young <dyoung@redhat.com>
    Link: https://lkml.kernel.org/r/20190408231011.GA5402@jeru.linux.bs1.fc.nec.co.jp
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/x86/boot/compressed/acpi.c | 143 +++++++++++++++++++++++++++++-----------
    1 file changed, 107 insertions(+), 36 deletions(-)

    --- a/arch/x86/boot/compressed/acpi.c
    +++ b/arch/x86/boot/compressed/acpi.c
    @@ -44,17 +44,109 @@ static acpi_physical_address get_acpi_rs
    return addr;
    }

    -/* Search EFI system tables for RSDP. */
    -static acpi_physical_address efi_get_rsdp_addr(void)
    +/*
    + * Search EFI system tables for RSDP. If both ACPI_20_TABLE_GUID and
    + * ACPI_TABLE_GUID are found, take the former, which has more features.
    + */
    +static acpi_physical_address
    +__efi_get_rsdp_addr(unsigned long config_tables, unsigned int nr_tables,
    + bool efi_64)
    {
    acpi_physical_address rsdp_addr = 0;

    #ifdef CONFIG_EFI
    - unsigned long systab, systab_tables, config_tables;
    + int i;
    +
    + /* Get EFI tables from systab. */
    + for (i = 0; i < nr_tables; i++) {
    + acpi_physical_address table;
    + efi_guid_t guid;
    +
    + if (efi_64) {
    + efi_config_table_64_t *tbl = (efi_config_table_64_t *)config_tables + i;
    +
    + guid = tbl->guid;
    + table = tbl->table;
    +
    + if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
    + debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
    + return 0;
    + }
    + } else {
    + efi_config_table_32_t *tbl = (efi_config_table_32_t *)config_tables + i;
    +
    + guid = tbl->guid;
    + table = tbl->table;
    + }
    +
    + if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
    + rsdp_addr = table;
    + else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
    + return table;
    + }
    +#endif
    + return rsdp_addr;
    +}
    +
    +/* EFI/kexec support is 64-bit only. */
    +#ifdef CONFIG_X86_64
    +static struct efi_setup_data *get_kexec_setup_data_addr(void)
    +{
    + struct setup_data *data;
    + u64 pa_data;
    +
    + pa_data = boot_params->hdr.setup_data;
    + while (pa_data) {
    + data = (struct setup_data *)pa_data;
    + if (data->type == SETUP_EFI)
    + return (struct efi_setup_data *)(pa_data + sizeof(struct setup_data));
    +
    + pa_data = data->next;
    + }
    + return NULL;
    +}
    +
    +static acpi_physical_address kexec_get_rsdp_addr(void)
    +{
    + efi_system_table_64_t *systab;
    + struct efi_setup_data *esd;
    + struct efi_info *ei;
    + char *sig;
    +
    + esd = (struct efi_setup_data *)get_kexec_setup_data_addr();
    + if (!esd)
    + return 0;
    +
    + if (!esd->tables) {
    + debug_putstr("Wrong kexec SETUP_EFI data.\n");
    + return 0;
    + }
    +
    + ei = &boot_params->efi_info;
    + sig = (char *)&ei->efi_loader_signature;
    + if (strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
    + debug_putstr("Wrong kexec EFI loader signature.\n");
    + return 0;
    + }
    +
    + /* Get systab from boot params. */
    + systab = (efi_system_table_64_t *) (ei->efi_systab | ((__u64)ei->efi_systab_hi << 32));
    + if (!systab)
    + error("EFI system table not found in kexec boot_params.");
    +
    + return __efi_get_rsdp_addr((unsigned long)esd->tables, systab->nr_tables, true);
    +}
    +#else
    +static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
    +#endif /* CONFIG_X86_64 */
    +
    +static acpi_physical_address efi_get_rsdp_addr(void)
    +{
    +#ifdef CONFIG_EFI
    + unsigned long systab, config_tables;
    unsigned int nr_tables;
    struct efi_info *ei;
    bool efi_64;
    - int size, i;
    char *sig;

    ei = &boot_params->efi_info;
    @@ -88,49 +180,20 @@ static acpi_physical_address efi_get_rsd

    config_tables = stbl->tables;
    nr_tables = stbl->nr_tables;
    - size = sizeof(efi_config_table_64_t);
    } else {
    efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab;

    config_tables = stbl->tables;
    nr_tables = stbl->nr_tables;
    - size = sizeof(efi_config_table_32_t);
    }

    if (!config_tables)
    error("EFI config tables not found.");

    - /* Get EFI tables from systab. */
    - for (i = 0; i < nr_tables; i++) {
    - acpi_physical_address table;
    - efi_guid_t guid;
    -
    - config_tables += size;
    -
    - if (efi_64) {
    - efi_config_table_64_t *tbl = (efi_config_table_64_t *)config_tables;
    -
    - guid = tbl->guid;
    - table = tbl->table;
    -
    - if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
    - debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
    - return 0;
    - }
    - } else {
    - efi_config_table_32_t *tbl = (efi_config_table_32_t *)config_tables;
    -
    - guid = tbl->guid;
    - table = tbl->table;
    - }
    -
    - if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
    - rsdp_addr = table;
    - else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
    - return table;
    - }
    + return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);
    +#else
    + return 0;
    #endif
    - return rsdp_addr;
    }

    static u8 compute_checksum(u8 *buffer, u32 length)
    @@ -220,6 +283,14 @@ acpi_physical_address get_rsdp_addr(void
    if (!pa)
    pa = boot_params->acpi_rsdp_addr;

    + /*
    + * Try to get EFI data from setup_data. This can happen when we're a
    + * kexec'ed kernel and kexec(1) has passed all the required EFI info to
    + * us.
    + */
    + if (!pa)
    + pa = kexec_get_rsdp_addr();
    +
    if (!pa)
    pa = efi_get_rsdp_addr();


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