[PATCH 5/5] ARM64: kernel: acpi: honour acpi=force command line parameter

[Lorenzo Pieralisi]

If acpi=force is passed on the command line, it forces ACPI to be
the only available boot method, hence it must be left enabled even
if the initialization and sanity checks on ACPI tables fails.

This patch refactors ACPI initialization to prevent disabling ACPI
if acpi=force is passed on the command line.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Cc: Hanjun Guo <hanjun.guo at linaro.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
---
 arch/arm64/include/asm/acpi.h | 3 ---
 arch/arm64/kernel/acpi.c      | 6 ++++--
 arch/arm64/kernel/setup.c     | 2 +-
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index e1a8965..59c05d8 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -38,7 +38,6 @@ typedef u64 phys_cpuid_t;
 extern int acpi_disabled;
 extern int acpi_noirq;
 extern int acpi_pci_disabled;
-extern bool param_acpi_force;
 
 /* 1 to indicate PSCI 0.2+ is implemented */
 static inline bool acpi_psci_present(void)
@@ -92,8 +91,6 @@ void __init acpi_init_cpus(void);
 static inline bool acpi_psci_present(void) { return false; }
 static inline bool acpi_psci_use_hvc(void) { return false; }
 static inline void acpi_init_cpus(void) { }
-
-#define param_acpi_force false
 #endif /* CONFIG_ACPI */
 
 #endif /*_ASM_ACPI_H*/
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 542f045..789994a 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -43,7 +43,7 @@ static int enabled_cpus;
 static bool bootcpu_valid  __initdata;
 
 static bool param_acpi_off __initdata;
-bool param_acpi_force __initdata;
+static bool param_acpi_force __initdata;
 
 static int __init parse_acpi(char *arg)
 {
@@ -324,8 +324,10 @@ out:
 	 * If ACPI tables are initialized and FADT sanity checks passed,
 	 * leave ACPI enabled and carry on booting; otherwise disable ACPI
 	 * on initialization error.
+	 * If acpi=force was passed on the command line it forces ACPI
+	 * to be enabled even if its initialization failed.
 	 */
-	if (err)
+	if (err && !param_acpi_force)
 		disable_acpi();
 }
 
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index d60b1ad..b278311 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -390,7 +390,7 @@ void __init setup_arch(char **cmdline_p)
 
 	early_ioremap_reset();
 
-	if (acpi_disabled  && !param_acpi_force) {
+	if (acpi_disabled) {
 		unflatten_device_tree();
 		psci_dt_init();
 		cpu_read_bootcpu_ops();
-- 
2.2.1