src: Never overwrite `fadt->flags`

Instead, just flip the desired bits using bitwise operations. As this is
initially zero, the resulting value is the same. This allows flags to be
set from anywhere regardless of execution order.

Tested on Asus P8Z77-V LX2 with Linux 5.7.6 and Windows 10 at the end of
the patch train, both operating systems are able to boot successfully.

Change-Id: Icfd580a20524936cd0adac574331b09fb2aea925
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43387
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

11 files changed, 18 insertions, 18 deletions

diff --git a/src/southbridge/amd/agesa/hudson/fadt.c b/src/southbridge/amd/agesa/hudson/fadt.c
index 47835c46851d..3e880fec3573 100644
--- a/src/southbridge/amd/agesa/hudson/fadt.c
+++ b/src/southbridge/amd/agesa/hudson/fadt.c
@@ -55,7 +55,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0;	/* 0x7f to make rtc alarm work */
 	fadt->iapc_boot_arch = FADT_BOOT_ARCH;	/* See table 5-10 */
 	fadt->res2 = 0;		/* reserved, MUST be 0 ACPI 3.0 */
-	fadt->flags = ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
+	fadt->flags |= ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
 				ACPI_FADT_C1_SUPPORTED |
 				ACPI_FADT_SLEEP_BUTTON |
 				ACPI_FADT_S4_RTC_WAKE |
diff --git a/src/southbridge/amd/cimx/sb800/fadt.c b/src/southbridge/amd/cimx/sb800/fadt.c
index c96d713f7d8c..5f31cd5c4e50 100644
--- a/src/southbridge/amd/cimx/sb800/fadt.c
+++ b/src/southbridge/amd/cimx/sb800/fadt.c
@@ -81,7 +81,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0;	/* 0x7f to make rtc alarm work */
 	fadt->iapc_boot_arch = FADT_BOOT_ARCH;	/* See table 5-10 */
 	fadt->res2 = 0;		/* reserved, MUST be 0 ACPI 3.0 */
-	fadt->flags = ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
+	fadt->flags |= ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
 				ACPI_FADT_C1_SUPPORTED |
 				ACPI_FADT_SLEEP_BUTTON |
 				ACPI_FADT_S4_RTC_WAKE |
diff --git a/src/southbridge/amd/pi/hudson/fadt.c b/src/southbridge/amd/pi/hudson/fadt.c
index 544677983ff9..e085df1f3d65 100644
--- a/src/southbridge/amd/pi/hudson/fadt.c
+++ b/src/southbridge/amd/pi/hudson/fadt.c
@@ -55,7 +55,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0;	/* 0x7f to make rtc alarm work */
 	fadt->iapc_boot_arch = FADT_BOOT_ARCH;	/* See table 5-10 */
 	fadt->res2 = 0;		/* reserved, MUST be 0 ACPI 3.0 */
-	fadt->flags = ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
+	fadt->flags |= ACPI_FADT_WBINVD | /* See table 5-10 ACPI 3.0a spec */
 				ACPI_FADT_C1_SUPPORTED |
 				ACPI_FADT_SLEEP_BUTTON |
 				ACPI_FADT_S4_RTC_WAKE |
diff --git a/src/southbridge/intel/bd82x6x/fadt.c b/src/southbridge/intel/bd82x6x/fadt.c
index 40cddb953e1b..7b3658349508 100644
--- a/src/southbridge/intel/bd82x6x/fadt.c
+++ b/src/southbridge/intel/bd82x6x/fadt.c
@@ -50,7 +50,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x00;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_DEVICES | ACPI_FADT_8042;
 
-	fadt->flags = ACPI_FADT_WBINVD |
+	fadt->flags |= ACPI_FADT_WBINVD |
 			ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_SLEEP_BUTTON |
 			ACPI_FADT_RESET_REGISTER |
diff --git a/src/southbridge/intel/i82371eb/fadt.c b/src/southbridge/intel/i82371eb/fadt.c
index 5a3326bc8f75..c775af0c92ce 100644
--- a/src/southbridge/intel/i82371eb/fadt.c
+++ b/src/southbridge/intel/i82371eb/fadt.c
@@ -103,7 +103,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	 * 18   FORCE_APIC_CLUSTER_MODEL
 	 * 19   FORCE_APIC_PHYSICAL_DESTINATION_MODE
 	 */
-	fadt->flags = 0xa5 | ACPI_FADT_RESET_REGISTER;
+	fadt->flags |= 0xa5 | ACPI_FADT_RESET_REGISTER;
 
 	fadt->reset_reg.space_id = ACPI_ADDRESS_SPACE_IO;
 	fadt->reset_reg.bit_width = 8;
diff --git a/src/southbridge/intel/i82801dx/fadt.c b/src/southbridge/intel/i82801dx/fadt.c
index 319e6a6f88b0..8be39bfdb6b4 100644
--- a/src/southbridge/intel/i82801dx/fadt.c
+++ b/src/southbridge/intel/i82801dx/fadt.c
@@ -50,7 +50,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x00;
 	fadt->iapc_boot_arch = 0x03;
 
-	fadt->flags = ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
+	fadt->flags |= ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_C2_MP_SUPPORTED | ACPI_FADT_SLEEP_BUTTON |
 			ACPI_FADT_S4_RTC_WAKE | ACPI_FADT_RESET_REGISTER |
 			ACPI_FADT_PLATFORM_CLOCK;
diff --git a/src/southbridge/intel/i82801gx/fadt.c b/src/southbridge/intel/i82801gx/fadt.c
index 200e7e51b904..35a1facb55ca 100644
--- a/src/southbridge/intel/i82801gx/fadt.c
+++ b/src/southbridge/intel/i82801gx/fadt.c
@@ -49,7 +49,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->mon_alrm = 0x00;
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_8042 | ACPI_FADT_LEGACY_DEVICES;
-	fadt->flags = (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
+	fadt->flags |= (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
 		       | ACPI_FADT_SLEEP_BUTTON | ACPI_FADT_S4_RTC_WAKE
 		       | ACPI_FADT_PLATFORM_CLOCK | ACPI_FADT_RESET_REGISTER
 		       | ACPI_FADT_C2_MP_SUPPORTED);
diff --git a/src/southbridge/intel/i82801ix/fadt.c b/src/southbridge/intel/i82801ix/fadt.c
index 1fd8f73e3bbb..710f585f8c5d 100644
--- a/src/southbridge/intel/i82801ix/fadt.c
+++ b/src/southbridge/intel/i82801ix/fadt.c
@@ -42,7 +42,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->mon_alrm = 0x00;
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_FREE;
-	fadt->flags = ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
+	fadt->flags |= ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_SLEEP_BUTTON | ACPI_FADT_S4_RTC_WAKE |
 			ACPI_FADT_DOCKING_SUPPORTED | ACPI_FADT_RESET_REGISTER |
 			ACPI_FADT_PLATFORM_CLOCK;
diff --git a/src/southbridge/intel/i82801jx/fadt.c b/src/southbridge/intel/i82801jx/fadt.c
index 45003f069840..6f80aa6d669e 100644
--- a/src/southbridge/intel/i82801jx/fadt.c
+++ b/src/southbridge/intel/i82801jx/fadt.c
@@ -45,7 +45,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->mon_alrm = 0x00;
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_8042 | ACPI_FADT_LEGACY_DEVICES;
-	fadt->flags = (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
+	fadt->flags |= (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
 		       | ACPI_FADT_SLEEP_BUTTON | ACPI_FADT_S4_RTC_WAKE
 		       | ACPI_FADT_PLATFORM_CLOCK | ACPI_FADT_RESET_REGISTER
 		       | ACPI_FADT_C2_MP_SUPPORTED);
diff --git a/src/southbridge/intel/ibexpeak/fadt.c b/src/southbridge/intel/ibexpeak/fadt.c
index a4fed96880ba..103fda6ca992 100644
--- a/src/southbridge/intel/ibexpeak/fadt.c
+++ b/src/southbridge/intel/ibexpeak/fadt.c
@@ -50,7 +50,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_DEVICES | ACPI_FADT_8042;
 
-	fadt->flags = ACPI_FADT_WBINVD |
+	fadt->flags |= ACPI_FADT_WBINVD |
 			ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_SLEEP_BUTTON |
 			ACPI_FADT_RESET_REGISTER |
diff --git a/src/southbridge/intel/lynxpoint/fadt.c b/src/southbridge/intel/lynxpoint/fadt.c
index 05189de60cc7..7c1bef99418b 100644
--- a/src/southbridge/intel/lynxpoint/fadt.c
+++ b/src/southbridge/intel/lynxpoint/fadt.c
@@ -55,14 +55,14 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x00;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_DEVICES | ACPI_FADT_8042;
 
-	fadt->flags = ACPI_FADT_WBINVD |
-		      ACPI_FADT_C1_SUPPORTED |
-		      ACPI_FADT_C2_MP_SUPPORTED |
-		      ACPI_FADT_SLEEP_BUTTON |
-		      ACPI_FADT_RESET_REGISTER |
-		      ACPI_FADT_SEALED_CASE |
-		      ACPI_FADT_S4_RTC_WAKE |
-		      ACPI_FADT_PLATFORM_CLOCK;
+	fadt->flags |= ACPI_FADT_WBINVD |
+		       ACPI_FADT_C1_SUPPORTED |
+		       ACPI_FADT_C2_MP_SUPPORTED |
+		       ACPI_FADT_SLEEP_BUTTON |
+		       ACPI_FADT_RESET_REGISTER |
+		       ACPI_FADT_SEALED_CASE |
+		       ACPI_FADT_S4_RTC_WAKE |
+		       ACPI_FADT_PLATFORM_CLOCK;
 
 	if (cfg->docking_supported)
 		fadt->flags |= ACPI_FADT_DOCKING_SUPPORTED;