[PATCH v4 11/19] efi: create efi_enabled()

[Daniel Kiper <daniel.kiper@oracle.com>]

First of all we need to differentiate between legacy BIOS
and EFI platforms during runtime, not during build, because
one image will have legacy and EFI code and can be executed
on both platforms. Additionally, we need more fine grained
knowledge about EFI environment and check for EFI platform
and EFI loader separately to properly support multiboot2
protocol. In general Xen loaded by this protocol uses memory
mappings and loaded modules in similar way to Xen loaded by
multiboot (v1) protocol. Hence, create efi_enabled() which
checks available features in efi.flags. This patch only defines
EFI_BOOT feature which is equal to old efi_enabled == 1.
Subsequent patches will define EFI_LOADER and EFI_RS features
accordingly. Latter one is added to ease control on runtime
services usage.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
---
v4 - suggestions/fixes:
   - rename EFI_PLATFORM to EFI_BOOT
     (suggested by Jan Beulich),
   - move EFI_BOOT definition to efi struct definition
     (suggested by Jan Beulich),
   - remove unneeded efi.flags initialization
     (suggested by Jan Beulich),
   - use __set_bit() instead of set_bit() if possible
     (suggested by Jan Beulich),
   - do efi_enabled() cleanup
     (suggested by Jan Beulich),
   - improve comments
     (suggested by Jan Beulich),
   - improve commit message.

v3 - suggestions/fixes:
   - define efi struct in xen/arch/x86/efi/stub.c
     in earlier patch
     (suggested by Jan Beulich),
   - improve comments
     (suggested by Jan Beulich),
   - improve commit message
     (suggested by Jan Beulich).
---
 xen/arch/x86/dmi_scan.c    |    4 ++--
 xen/arch/x86/domain_page.c |    2 +-
 xen/arch/x86/efi/stub.c    |    4 ----
 xen/arch/x86/mpparse.c     |    4 ++--
 xen/arch/x86/setup.c       |   10 +++++-----
 xen/arch/x86/shutdown.c    |    2 +-
 xen/arch/x86/time.c        |    2 +-
 xen/common/efi/boot.c      |    2 ++
 xen/common/efi/runtime.c   |    6 ------
 xen/drivers/acpi/osl.c     |    2 +-
 xen/include/xen/efi.h      |   11 +++++++++--
 11 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/xen/arch/x86/dmi_scan.c b/xen/arch/x86/dmi_scan.c
index b049e31..8dcb640 100644
--- a/xen/arch/x86/dmi_scan.c
+++ b/xen/arch/x86/dmi_scan.c
@@ -238,7 +238,7 @@ const char *__init dmi_get_table(paddr_t *base, u32 *len)
 {
 	static unsigned int __initdata instance;
 
-	if (efi_enabled) {
+	if (efi_enabled(EFI_BOOT)) {
 		if (efi_smbios3_size && !(instance & 1)) {
 			*base = efi_smbios3_address;
 			*len = efi_smbios3_size;
@@ -696,7 +696,7 @@ static void __init dmi_decode(struct dmi_header *dm)
 
 void __init dmi_scan_machine(void)
 {
-	if ((!efi_enabled ? dmi_iterate(dmi_decode) :
+	if ((!efi_enabled(EFI_BOOT) ? dmi_iterate(dmi_decode) :
 	                    dmi_efi_iterate(dmi_decode)) == 0)
  		dmi_check_system(dmi_blacklist);
 	else
diff --git a/xen/arch/x86/domain_page.c b/xen/arch/x86/domain_page.c
index d86f8fe..71ade05 100644
--- a/xen/arch/x86/domain_page.c
+++ b/xen/arch/x86/domain_page.c
@@ -36,7 +36,7 @@ static inline struct vcpu *mapcache_current_vcpu(void)
      * domain's page tables but current may point at another domain's VCPU.
      * Return NULL as though current is not properly set up yet.
      */
-    if ( efi_enabled && efi_rs_using_pgtables() )
+    if ( efi_enabled(EFI_BOOT) && efi_rs_using_pgtables() )
         return NULL;
 
     /*
diff --git a/xen/arch/x86/efi/stub.c b/xen/arch/x86/efi/stub.c
index 07c2bd0..3e1d1ea 100644
--- a/xen/arch/x86/efi/stub.c
+++ b/xen/arch/x86/efi/stub.c
@@ -4,10 +4,6 @@
 #include <xen/lib.h>
 #include <asm/page.h>
 
-#ifndef efi_enabled
-const bool_t efi_enabled = 0;
-#endif
-
 void __init efi_init_memory(void) { }
 
 void efi_update_l4_pgtable(unsigned int l4idx, l4_pgentry_t l4e) { }
diff --git a/xen/arch/x86/mpparse.c b/xen/arch/x86/mpparse.c
index ef6557c..c3d5bdc 100644
--- a/xen/arch/x86/mpparse.c
+++ b/xen/arch/x86/mpparse.c
@@ -564,7 +564,7 @@ static inline void __init construct_default_ISA_mptable(int mpc_default_type)
 
 static __init void efi_unmap_mpf(void)
 {
-	if (efi_enabled)
+	if (efi_enabled(EFI_BOOT))
 		clear_fixmap(FIX_EFI_MPF);
 }
 
@@ -722,7 +722,7 @@ void __init find_smp_config (void)
 {
 	unsigned int address;
 
-	if (efi_enabled) {
+	if (efi_enabled(EFI_BOOT)) {
 		efi_check_config();
 		return;
 	}
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 217c775..1e8dfa5 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -438,8 +438,8 @@ static void __init parse_video_info(void)
 {
     struct boot_video_info *bvi = &bootsym(boot_vid_info);
 
-    /* The EFI loader fills vga_console_info directly. */
-    if ( efi_enabled )
+    /* vga_console_info is filled directly on EFI platform. */
+    if ( efi_enabled(EFI_BOOT) )
         return;
 
     if ( (bvi->orig_video_isVGA == 1) && (bvi->orig_video_mode == 3) )
@@ -725,7 +725,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     if ( !(mbi->flags & MBI_MODULES) || (mbi->mods_count == 0) )
         panic("dom0 kernel not specified. Check bootloader configuration.");
 
-    if ( efi_enabled )
+    if ( efi_enabled(EFI_BOOT) )
     {
         set_pdx_range(xen_phys_start >> PAGE_SHIFT,
                       (xen_phys_start + BOOTSTRAP_MAP_BASE) >> PAGE_SHIFT);
@@ -836,7 +836,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
      * we can relocate the dom0 kernel and other multiboot modules. Also, on
      * x86/64, we relocate Xen to higher memory.
      */
-    for ( i = 0; !efi_enabled && i < mbi->mods_count; i++ )
+    for ( i = 0; !efi_enabled(EFI_BOOT) && i < mbi->mods_count; i++ )
     {
         if ( mod[i].mod_start & (PAGE_SIZE - 1) )
             panic("Bootloader didn't honor module alignment request.");
@@ -1077,7 +1077,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 
     if ( !xen_phys_start )
         panic("Not enough memory to relocate Xen.");
-    reserve_e820_ram(&boot_e820, efi_enabled ? mbi->mem_upper : __pa(&_start),
+    reserve_e820_ram(&boot_e820, efi_enabled(EFI_BOOT) ? mbi->mem_upper : __pa(&_start),
                      __pa(&_end));
 
     /* Late kexec reservation (dynamic start address). */
diff --git a/xen/arch/x86/shutdown.c b/xen/arch/x86/shutdown.c
index 3cdd4e8..7ce3761 100644
--- a/xen/arch/x86/shutdown.c
+++ b/xen/arch/x86/shutdown.c
@@ -119,7 +119,7 @@ void machine_halt(void)
 static void default_reboot_type(void)
 {
     if ( reboot_type == BOOT_INVALID )
-        reboot_type = efi_enabled ? BOOT_EFI
+        reboot_type = efi_enabled(EFI_BOOT) ? BOOT_EFI
                                   : acpi_disabled ? BOOT_KBD
                                                   : BOOT_ACPI;
 }
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 9707e76..b2ecc8e 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -686,7 +686,7 @@ static unsigned long get_cmos_time(void)
     static bool_t __read_mostly cmos_rtc_probe;
     boolean_param("cmos-rtc-probe", cmos_rtc_probe);
 
-    if ( efi_enabled )
+    if ( efi_enabled(EFI_BOOT) )
     {
         res = efi_get_time();
         if ( res )
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 125c9ce..edd0434 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -934,6 +934,8 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     char *option_str;
     bool_t use_cfg_file;
 
+    __set_bit(EFI_BOOT, &efi.flags);
+
     efi_init(ImageHandle, SystemTable);
 
     use_cfg_file = efi_arch_use_config_file(SystemTable);
diff --git a/xen/common/efi/runtime.c b/xen/common/efi/runtime.c
index 82c45bc..900c011 100644
--- a/xen/common/efi/runtime.c
+++ b/xen/common/efi/runtime.c
@@ -10,12 +10,6 @@ DEFINE_XEN_GUEST_HANDLE(CHAR16);
 
 #ifndef COMPAT
 
-/*
- * Currently runtime services are not implemented on ARM. To boot Xen with ACPI,
- * set efi_enabled to 1, so that Xen can get the ACPI root pointer from EFI.
- */
-const bool_t efi_enabled = 1;
-
 #ifndef CONFIG_ARM
 # include <asm/i387.h>
 # include <asm/xstate.h>
diff --git a/xen/drivers/acpi/osl.c b/xen/drivers/acpi/osl.c
index 9a49029..3616dfd 100644
--- a/xen/drivers/acpi/osl.c
+++ b/xen/drivers/acpi/osl.c
@@ -66,7 +66,7 @@ void __init acpi_os_vprintf(const char *fmt, va_list args)
 
 acpi_physical_address __init acpi_os_get_root_pointer(void)
 {
-	if (efi_enabled) {
+	if (efi_enabled(EFI_BOOT)) {
 		if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 			return efi.acpi20;
 		else if (efi.acpi != EFI_INVALID_TABLE_ADDR)
diff --git a/xen/include/xen/efi.h b/xen/include/xen/efi.h
index e74dad1..be18e4d 100644
--- a/xen/include/xen/efi.h
+++ b/xen/include/xen/efi.h
@@ -2,15 +2,16 @@
 #define __XEN_EFI_H__
 
 #ifndef __ASSEMBLY__
+#include <xen/bitops.h>
 #include <xen/types.h>
 #endif
 
-extern const bool_t efi_enabled;
-
 #define EFI_INVALID_TABLE_ADDR (~0UL)
 
 /* Add fields here only if they need to be referenced from non-EFI code. */
 struct efi {
+    unsigned long flags;        /* Bit fields representing available EFI features/properties */
+#define EFI_BOOT	0	/* Were we booted from EFI? */
     unsigned long mps;          /* MPS table */
     unsigned long acpi;         /* ACPI table (IA64 ext 0.71) */
     unsigned long acpi20;       /* ACPI table (ACPI 2.0) */
@@ -40,6 +41,12 @@ int efi_runtime_call(struct xenpf_efi_runtime_call *);
 int efi_compat_get_info(uint32_t idx, union compat_pf_efi_info *);
 int efi_compat_runtime_call(struct compat_pf_efi_runtime_call *);
 
+/* Test whether the above defined EFI_* bits are enabled. */
+static inline unsigned int efi_enabled(int feature)
+{
+    return !!test_bit(feature, &efi.flags);
+}
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __XEN_EFI_H__ */
-- 
1.7.10.4


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