arm64: kvm: add prototypes for functions called in asm

A lot of kvm specific functions are called only from assembler
and have no extern prototype, but that causes a W=1 warnings:

arch/arm64/kvm/handle_exit.c:365:24: error: no previous prototype for 'nvhe_hyp_panic_handler' [-Werror=missing-prototypes]
arch/arm64/kvm/va_layout.c:188:6: error: no previous prototype for 'kvm_patch_vector_branch' [-Werror=mi
ssing-prototypes]
arch/arm64/kvm/va_layout.c:287:6: error: no previous prototype for 'kvm_get_kimage_voffset' [-Werror=mis
sing-prototypes]
arch/arm64/kvm/va_layout.c:293:6: error: no previous prototype for 'kvm_compute_final_ctr_el0' [-Werror=
missing-prototypes]
arch/arm64/kvm/hyp/vhe/switch.c:259:17: error: no previous prototype for 'hyp_panic' [-Werror=missing-pr
arch/arm64/kvm/hyp/nvhe/switch.c:389:17: error: no previous prototype for 'kvm_unexpected_el2_exception'
arch/arm64/kvm/hyp/nvhe/switch.c:384:28: error: no previous prototype for 'hyp_panic_bad_stack' [-Werror
arch/arm64/kvm/hyp/nvhe/hyp-main.c:383:6: error: no previous prototype for 'handle_trap' [-Werror=missin
arch/arm64/kvm/hyp/nvhe/psci-relay.c:203:28: error: no previous prototype for 'kvm_host_psci_cpu_entry' [-Werror=missing-prototypes]

Declare those in asm/kvm_asm.h, which already has related declarations.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230516160642.523862-7-arnd@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: arndb

arch/arm64/include/asm/kvm_asm.h

@@ -267,6 +267,24 @@ extern u64 __kvm_get_mdcr_el2(void);
 	__kvm_at_err;							\
 } )
 
+void __noreturn hyp_panic(void);
+asmlinkage void kvm_unexpected_el2_exception(void);
+asmlinkage void __noreturn hyp_panic(void);
+asmlinkage void __noreturn hyp_panic_bad_stack(void);
+asmlinkage void kvm_unexpected_el2_exception(void);
+struct kvm_cpu_context;
+void handle_trap(struct kvm_cpu_context *host_ctxt);
+asmlinkage void __noreturn kvm_host_psci_cpu_entry(bool is_cpu_on);
+void __noreturn __pkvm_init_finalise(void);
+void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
+void kvm_patch_vector_branch(struct alt_instr *alt,
+	__le32 *origptr, __le32 *updptr, int nr_inst);
+void kvm_get_kimage_voffset(struct alt_instr *alt,
+	__le32 *origptr, __le32 *updptr, int nr_inst);
+void kvm_compute_final_ctr_el0(struct alt_instr *alt,
+	__le32 *origptr, __le32 *updptr, int nr_inst);
+void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr, u64 elr_virt,
+	u64 elr_phys, u64 par, uintptr_t vcpu, u64 far, u64 hpfar);
 
 #else /* __ASSEMBLY__ */