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authorMatt Fleming <matt.fleming@intel.com>2012-11-14 09:42:35 +0000
committerH. Peter Anvin <hpa@linux.intel.com>2013-01-30 11:51:59 -0800
commit83e68189745ad931c2afd45d8ee3303929233e7f (patch)
tree35673a4eebff4c71bda4b1023ccc7cbea36f84b2 /arch
parentf44310b98ddb7f0d06550d73ed67df5865e3eda5 (diff)
downloadlinux-83e68189745ad931c2afd45d8ee3303929233e7f.tar.bz2
efi: Make 'efi_enabled' a function to query EFI facilities
Originally 'efi_enabled' indicated whether a kernel was booted from EFI firmware. Over time its semantics have changed, and it now indicates whether or not we are booted on an EFI machine with bit-native firmware, e.g. 64-bit kernel with 64-bit firmware. The immediate motivation for this patch is the bug report at, https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557 which details how running a platform driver on an EFI machine that is designed to run under BIOS can cause the machine to become bricked. Also, the following report, https://bugzilla.kernel.org/show_bug.cgi?id=47121 details how running said driver can also cause Machine Check Exceptions. Drivers need a new means of detecting whether they're running on an EFI machine, as sadly the expression, if (!efi_enabled) hasn't been a sufficient condition for quite some time. Users actually want to query 'efi_enabled' for different reasons - what they really want access to is the list of available EFI facilities. For instance, the x86 reboot code needs to know whether it can invoke the ResetSystem() function provided by the EFI runtime services, while the ACPI OSL code wants to know whether the EFI config tables were mapped successfully. There are also checks in some of the platform driver code to simply see if they're running on an EFI machine (which would make it a bad idea to do BIOS-y things). This patch is a prereq for the samsung-laptop fix patch. Cc: David Airlie <airlied@linux.ie> Cc: Corentin Chary <corentincj@iksaif.net> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Olof Johansson <olof@lixom.net> Cc: Peter Jones <pjones@redhat.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Steve Langasek <steve.langasek@canonical.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Konrad Rzeszutek Wilk <konrad@kernel.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/efi.h1
-rw-r--r--arch/x86/kernel/reboot.c2
-rw-r--r--arch/x86/kernel/setup.c28
-rw-r--r--arch/x86/platform/efi/efi.c57
4 files changed, 50 insertions, 38 deletions
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 6e8fdf5ad113..28677c55113f 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -94,6 +94,7 @@ extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size,
#endif /* CONFIG_X86_32 */
extern int add_efi_memmap;
+extern unsigned long x86_efi_facility;
extern void efi_set_executable(efi_memory_desc_t *md, bool executable);
extern int efi_memblock_x86_reserve_range(void);
extern void efi_call_phys_prelog(void);
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 4e8ba39eaf0f..76fa1e9a2b39 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -584,7 +584,7 @@ static void native_machine_emergency_restart(void)
break;
case BOOT_EFI:
- if (efi_enabled)
+ if (efi_enabled(EFI_RUNTIME_SERVICES))
efi.reset_system(reboot_mode ?
EFI_RESET_WARM :
EFI_RESET_COLD,
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 00f6c1472b85..8b24289cc10c 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -807,15 +807,15 @@ void __init setup_arch(char **cmdline_p)
#ifdef CONFIG_EFI
if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
"EL32", 4)) {
- efi_enabled = 1;
- efi_64bit = false;
+ set_bit(EFI_BOOT, &x86_efi_facility);
} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
"EL64", 4)) {
- efi_enabled = 1;
- efi_64bit = true;
+ set_bit(EFI_BOOT, &x86_efi_facility);
+ set_bit(EFI_64BIT, &x86_efi_facility);
}
- if (efi_enabled && efi_memblock_x86_reserve_range())
- efi_enabled = 0;
+
+ if (efi_enabled(EFI_BOOT))
+ efi_memblock_x86_reserve_range();
#endif
x86_init.oem.arch_setup();
@@ -888,7 +888,7 @@ void __init setup_arch(char **cmdline_p)
finish_e820_parsing();
- if (efi_enabled)
+ if (efi_enabled(EFI_BOOT))
efi_init();
dmi_scan_machine();
@@ -971,7 +971,7 @@ void __init setup_arch(char **cmdline_p)
* The EFI specification says that boot service code won't be called
* after ExitBootServices(). This is, in fact, a lie.
*/
- if (efi_enabled)
+ if (efi_enabled(EFI_MEMMAP))
efi_reserve_boot_services();
/* preallocate 4k for mptable mpc */
@@ -1114,7 +1114,7 @@ void __init setup_arch(char **cmdline_p)
#ifdef CONFIG_VT
#if defined(CONFIG_VGA_CONSOLE)
- if (!efi_enabled || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
+ if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
conswitchp = &vga_con;
#elif defined(CONFIG_DUMMY_CONSOLE)
conswitchp = &dummy_con;
@@ -1131,14 +1131,14 @@ void __init setup_arch(char **cmdline_p)
register_refined_jiffies(CLOCK_TICK_RATE);
#ifdef CONFIG_EFI
- /* Once setup is done above, disable efi_enabled on mismatched
- * firmware/kernel archtectures since there is no support for
- * runtime services.
+ /* Once setup is done above, unmap the EFI memory map on
+ * mismatched firmware/kernel archtectures since there is no
+ * support for runtime services.
*/
- if (efi_enabled && IS_ENABLED(CONFIG_X86_64) != efi_64bit) {
+ if (efi_enabled(EFI_BOOT) &&
+ IS_ENABLED(CONFIG_X86_64) != efi_enabled(EFI_64BIT)) {
pr_info("efi: Setup done, disabling due to 32/64-bit mismatch\n");
efi_unmap_memmap();
- efi_enabled = 0;
}
#endif
}
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index ad4439145f85..5426e482db6e 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -51,9 +51,6 @@
#define EFI_DEBUG 1
-int efi_enabled;
-EXPORT_SYMBOL(efi_enabled);
-
struct efi __read_mostly efi = {
.mps = EFI_INVALID_TABLE_ADDR,
.acpi = EFI_INVALID_TABLE_ADDR,
@@ -69,19 +66,28 @@ EXPORT_SYMBOL(efi);
struct efi_memory_map memmap;
-bool efi_64bit;
-
static struct efi efi_phys __initdata;
static efi_system_table_t efi_systab __initdata;
static inline bool efi_is_native(void)
{
- return IS_ENABLED(CONFIG_X86_64) == efi_64bit;
+ return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT);
+}
+
+unsigned long x86_efi_facility;
+
+/*
+ * Returns 1 if 'facility' is enabled, 0 otherwise.
+ */
+int efi_enabled(int facility)
+{
+ return test_bit(facility, &x86_efi_facility) != 0;
}
+EXPORT_SYMBOL(efi_enabled);
static int __init setup_noefi(char *arg)
{
- efi_enabled = 0;
+ clear_bit(EFI_BOOT, &x86_efi_facility);
return 0;
}
early_param("noefi", setup_noefi);
@@ -426,6 +432,7 @@ void __init efi_reserve_boot_services(void)
void __init efi_unmap_memmap(void)
{
+ clear_bit(EFI_MEMMAP, &x86_efi_facility);
if (memmap.map) {
early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
memmap.map = NULL;
@@ -460,7 +467,7 @@ void __init efi_free_boot_services(void)
static int __init efi_systab_init(void *phys)
{
- if (efi_64bit) {
+ if (efi_enabled(EFI_64BIT)) {
efi_system_table_64_t *systab64;
u64 tmp = 0;
@@ -552,7 +559,7 @@ static int __init efi_config_init(u64 tables, int nr_tables)
void *config_tables, *tablep;
int i, sz;
- if (efi_64bit)
+ if (efi_enabled(EFI_64BIT))
sz = sizeof(efi_config_table_64_t);
else
sz = sizeof(efi_config_table_32_t);
@@ -572,7 +579,7 @@ static int __init efi_config_init(u64 tables, int nr_tables)
efi_guid_t guid;
unsigned long table;
- if (efi_64bit) {
+ if (efi_enabled(EFI_64BIT)) {
u64 table64;
guid = ((efi_config_table_64_t *)tablep)->guid;
table64 = ((efi_config_table_64_t *)tablep)->table;
@@ -684,7 +691,6 @@ void __init efi_init(void)
if (boot_params.efi_info.efi_systab_hi ||
boot_params.efi_info.efi_memmap_hi) {
pr_info("Table located above 4GB, disabling EFI.\n");
- efi_enabled = 0;
return;
}
efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
@@ -694,10 +700,10 @@ void __init efi_init(void)
((__u64)boot_params.efi_info.efi_systab_hi<<32));
#endif
- if (efi_systab_init(efi_phys.systab)) {
- efi_enabled = 0;
+ if (efi_systab_init(efi_phys.systab))
return;
- }
+
+ set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);
/*
* Show what we know for posterity
@@ -715,10 +721,10 @@ void __init efi_init(void)
efi.systab->hdr.revision >> 16,
efi.systab->hdr.revision & 0xffff, vendor);
- if (efi_config_init(efi.systab->tables, efi.systab->nr_tables)) {
- efi_enabled = 0;
+ if (efi_config_init(efi.systab->tables, efi.systab->nr_tables))
return;
- }
+
+ set_bit(EFI_CONFIG_TABLES, &x86_efi_facility);
/*
* Note: We currently don't support runtime services on an EFI
@@ -727,15 +733,17 @@ void __init efi_init(void)
if (!efi_is_native())
pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
- else if (efi_runtime_init()) {
- efi_enabled = 0;
- return;
+ else {
+ if (efi_runtime_init())
+ return;
+ set_bit(EFI_RUNTIME_SERVICES, &x86_efi_facility);
}
- if (efi_memmap_init()) {
- efi_enabled = 0;
+ if (efi_memmap_init())
return;
- }
+
+ set_bit(EFI_MEMMAP, &x86_efi_facility);
+
#ifdef CONFIG_X86_32
if (efi_is_native()) {
x86_platform.get_wallclock = efi_get_time;
@@ -969,6 +977,9 @@ u32 efi_mem_type(unsigned long phys_addr)
efi_memory_desc_t *md;
void *p;
+ if (!efi_enabled(EFI_MEMMAP))
+ return 0;
+
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
if ((md->phys_addr <= phys_addr) &&