[PATCH v2 3/3] xen/x86: add missing noreturn attributes

[<victorm.lira@xxxxxxx>]

From: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>

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.

No functional change.

Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
Signed-off-by: Victor Lira <victorm.lira@xxxxxxx>
---
Changes in v2:
- improved commit message
---
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>
Cc: Michal Orzel <michal.orzel@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Julien Grall <julien@xxxxxxx>
Cc: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
Cc: Federico Serafini <federico.serafini@xxxxxxxxxxx>
Cc: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 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;
--
2.25.1