x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernels

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

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index ad84239e595eac0cb2ea3510f9480d66735e282b..15255f388a85b8e19830d27ec329ffa924533525 100644 (file)
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -44,17 +44,109 @@ static acpi_physical_address get_acpi_rsdp(void)
        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_rsdp_addr(void)
 
                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();