[RFC PATCH 2/7] efi/runtime: Return success/failure from arch_efi_call_virt_setup()

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

Permit the arch glue to signal failure from arch_efi_call_virt_setup().
This permits the use of sleeping locks in the call wrappers, and this
will allow EFI runtime services to be invoked without the need for
disabling preemption.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/include/asm/efi.h           | 2 +-
 arch/arm64/include/asm/efi.h         | 2 +-
 arch/arm64/kernel/efi.c              | 3 ++-
 arch/loongarch/include/asm/efi.h     | 2 +-
 arch/riscv/include/asm/efi.h         | 2 +-
 arch/x86/include/asm/efi.h           | 2 +-
 arch/x86/platform/efi/efi_32.c       | 3 ++-
 arch/x86/platform/efi/efi_64.c       | 3 ++-
 drivers/firmware/efi/riscv-runtime.c | 3 ++-
 9 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h
index e408399d5f0e..0809a69bb579 100644
--- a/arch/arm/include/asm/efi.h
+++ b/arch/arm/include/asm/efi.h
@@ -23,7 +23,7 @@ void arm_efi_init(void);
 int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
 int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md, bool);
 
-#define arch_efi_call_virt_setup()	efi_virtmap_load()
+#define arch_efi_call_virt_setup()	(efi_virtmap_load(), true)
 #define arch_efi_call_virt_teardown()	efi_virtmap_unload()
 
 #ifdef CONFIG_CPU_TTBR0_PAN
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index bcd5622aa096..decf87777f57 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -37,7 +37,7 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md,
 extern u64 *efi_rt_stack_top;
 efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
 
-void arch_efi_call_virt_setup(void);
+bool arch_efi_call_virt_setup(void);
 void arch_efi_call_virt_teardown(void);
 
 /*
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 250e9d7c08a7..44ad5e759af4 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -166,11 +166,12 @@ asmlinkage efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f)
 
 static DEFINE_RAW_SPINLOCK(efi_rt_lock);
 
-void arch_efi_call_virt_setup(void)
+bool arch_efi_call_virt_setup(void)
 {
 	efi_virtmap_load();
 	raw_spin_lock(&efi_rt_lock);
 	__efi_fpsimd_begin();
+	return true;
 }
 
 void arch_efi_call_virt_teardown(void)
diff --git a/arch/loongarch/include/asm/efi.h b/arch/loongarch/include/asm/efi.h
index eddc8e79b3fa..84cf2151123f 100644
--- a/arch/loongarch/include/asm/efi.h
+++ b/arch/loongarch/include/asm/efi.h
@@ -14,7 +14,7 @@ void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
 
 #define ARCH_EFI_IRQ_FLAGS_MASK  0x00000004  /* Bit 2: CSR.CRMD.IE */
 
-#define arch_efi_call_virt_setup()
+#define arch_efi_call_virt_setup()	true
 #define arch_efi_call_virt_teardown()
 
 #define EFI_ALLOC_ALIGN		SZ_64K
diff --git a/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h
index 46a355913b27..a7b4d719e7be 100644
--- a/arch/riscv/include/asm/efi.h
+++ b/arch/riscv/include/asm/efi.h
@@ -40,7 +40,7 @@ static inline unsigned long efi_get_kimg_min_align(void)
 
 #define EFI_KIMG_PREFERRED_ADDRESS	efi_get_kimg_min_align()
 
-void arch_efi_call_virt_setup(void);
+bool arch_efi_call_virt_setup(void);
 void arch_efi_call_virt_teardown(void);
 
 unsigned long stext_offset(void);
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index f227a70ac91f..879c8402e024 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -140,7 +140,7 @@ extern void efi_delete_dummy_variable(void);
 extern void efi_crash_gracefully_on_page_fault(unsigned long phys_addr);
 extern void efi_free_boot_services(void);
 
-void arch_efi_call_virt_setup(void);
+bool arch_efi_call_virt_setup(void);
 void arch_efi_call_virt_teardown(void);
 
 extern u64 efi_setup;
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
index b2cc7b4552a1..215f16ce84ab 100644
--- a/arch/x86/platform/efi/efi_32.c
+++ b/arch/x86/platform/efi/efi_32.c
@@ -141,10 +141,11 @@ void __init efi_runtime_update_mappings(void)
 	}
 }
 
-void arch_efi_call_virt_setup(void)
+bool arch_efi_call_virt_setup(void)
 {
 	efi_fpu_begin();
 	firmware_restrict_branch_speculation_start();
+	return true;
 }
 
 void arch_efi_call_virt_teardown(void)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index ac57259a432b..023368e9698a 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -445,12 +445,13 @@ static void efi_leave_mm(void)
 	switch_mm(&efi_mm, efi_prev_mm, NULL);
 }
 
-void arch_efi_call_virt_setup(void)
+bool arch_efi_call_virt_setup(void)
 {
 	efi_sync_low_kernel_mappings();
 	efi_fpu_begin();
 	firmware_restrict_branch_speculation_start();
 	efi_enter_mm();
+	return true;
 }
 
 void arch_efi_call_virt_teardown(void)
diff --git a/drivers/firmware/efi/riscv-runtime.c b/drivers/firmware/efi/riscv-runtime.c
index fa71cd898120..07e04b8f982a 100644
--- a/drivers/firmware/efi/riscv-runtime.c
+++ b/drivers/firmware/efi/riscv-runtime.c
@@ -142,10 +142,11 @@ static void efi_virtmap_unload(void)
 	preempt_enable();
 }
 
-void arch_efi_call_virt_setup(void)
+bool arch_efi_call_virt_setup(void)
 {
 	sync_kernel_mappings(efi_mm.pgd);
 	efi_virtmap_load();
+	return true;
 }
 
 void arch_efi_call_virt_teardown(void)
-- 
2.49.0.1101.gccaa498523-goog