[xen staging] xen/x86: add missing noreturn attributes

[patchbot@xxxxxxx]

commit 3c36a5a0df7de7d6998d1a5d038b2a0048b372d4
Author:     Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
AuthorDate: Fri Jun 6 14:27:09 2025 -0700
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
CommitDate: Wed Jun 18 17:40:42 2025 -0700

    xen/x86: add missing noreturn attributes
    
    The marked functions never return to their caller, but lack the
    `noreturn' attribute.
    
    Functions that never return should be declared with a `noreturn'
    attribute.
    
    The lack of `noreturn' causes a violation of MISRA C Rule 17.11 (not
    currently accepted in Xen), and also Rule 2.1: "A project shall not
    contain unreachable code". Depending on the compiler used and the
    compiler optimization used, the lack of `noreturn' might lead to the
    presence of unreachable code.
    
    The usage of the noreturn attribute together with asmlinkage is only for
    the benefit of the static analysis tools.
    
    No functional change.
    
    Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
    Signed-off-by: Victor Lira <victorm.lira@xxxxxxx>
    [stefano: improve commit message]
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/cpu/mcheck/mce.c | 3 ++-
 xen/arch/x86/efi/efi-boot.h   | 2 +-
 xen/arch/x86/smp.c            | 2 +-
 xen/arch/x86/traps.c          | 2 +-
 xen/arch/x86/x86_64/traps.c   | 2 +-
 5 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
index 1c348e557d..79214ce56b 100644
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -79,7 +79,8 @@ static int __init cf_check mce_set_verbosity(const char *str)
 custom_param("mce_verbosity", mce_set_verbosity);
 
 /* Handle unconfigured int18 (should never happen) */
-static void cf_check unexpected_machine_check(const struct cpu_user_regs *regs)
+static void noreturn cf_check
+unexpected_machine_check(const struct cpu_user_regs *regs)
 {
     console_force_unlock();
     printk("Unexpected Machine Check Exception\n");
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 0ecf4ca53f..0194720003 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -769,7 +769,7 @@ static void __init efi_arch_blexit(void)
         efi_bs->FreePages(ucode.addr, PFN_UP(ucode.size));
 }
 
-static void __init efi_arch_halt(void)
+static void noreturn __init efi_arch_halt(void)
 {
     local_irq_disable();
     for ( ; ; )
diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c
index 516dab5528..7936294f5f 100644
--- a/xen/arch/x86/smp.c
+++ b/xen/arch/x86/smp.c
@@ -343,7 +343,7 @@ void __stop_this_cpu(void)
     cpumask_clear_cpu(smp_processor_id(), &cpu_online_map);
 }
 
-static void cf_check stop_this_cpu(void *dummy)
+static void noreturn cf_check stop_this_cpu(void *dummy)
 {
     const bool *stop_aps = dummy;
 
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 092c7e4197..34dc077cad 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -805,7 +805,7 @@ void fatal_trap(const struct cpu_user_regs *regs, bool 
show_remote)
           (regs->eflags & X86_EFLAGS_IF) ? "" : " IN INTERRUPT CONTEXT");
 }
 
-void asmlinkage do_unhandled_trap(struct cpu_user_regs *regs)
+void asmlinkage noreturn do_unhandled_trap(struct cpu_user_regs *regs)
 {
     fatal_trap(regs, false);
 }
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index c77f304bb0..8460a4a1ae 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -293,7 +293,7 @@ void show_page_walk(unsigned long addr)
            l1_table_offset(addr), l1e_get_intpte(l1e), pfn);
 }
 
-void asmlinkage do_double_fault(struct cpu_user_regs *regs)
+void asmlinkage noreturn do_double_fault(struct cpu_user_regs *regs)
 {
     unsigned int cpu;
     struct extra_state state;
--
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