The comment-based justifications for MISRA C:2012 Rule 8.4 are replaced
by the asmlinkage pseudo-attribute, for the sake of uniformity.

asmlinkage may in the future have the effect of altering the calling
convention, therefore three special where the calling convention is
altered by another macro retain the textual deviation.

No functional change.

Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Acked-by: Julien Grall <jgrall@amazon.com>
---
This patch does not depend on any other patch.

Changes in v2:
- Edit safe.json.
- Remove mention of SAF-1-safe in deviations.rst.
Changes in v3:
- Sorted #include-s and rebased against
7ad0c774e474 ("x86/boot: tidy #include-s")
Changes in v4:
- Drop functions that shouldn't have the attribute added
- Drop the change in safe.json, as now SAF-1-safe is still used
- Edited the commit message accordingly
---
 xen/arch/arm/cpuerrata.c |  7 +++----
 xen/arch/arm/setup.c     |  5 ++---
 xen/arch/arm/smpboot.c   |  3 +--
 xen/arch/arm/traps.c     | 21 +++++++--------------
 xen/arch/x86/extable.c   |  3 +--
 xen/arch/x86/setup.c     |  3 +--
 xen/arch/x86/traps.c     | 27 +++++++++------------------
 7 files changed, 24 insertions(+), 45 deletions(-)

diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
index 9137958fb682..a28fa6ac78cc 100644
--- a/xen/arch/arm/cpuerrata.c
+++ b/xen/arch/arm/cpuerrata.c
@@ -370,10 +370,9 @@ custom_param("spec-ctrl", parse_spec_ctrl);
 
 /* Arm64 only for now as for Arm32 the workaround is currently handled in C. */
 #ifdef CONFIG_ARM_64
-/* SAF-1-safe */
-void __init arm_enable_wa2_handling(const struct alt_instr *alt,
-                                    const uint32_t *origptr,
-                                    uint32_t *updptr, int nr_inst)
+void asmlinkage __init arm_enable_wa2_handling(const struct alt_instr *alt,
+                                               const uint32_t *origptr,
+                                               uint32_t *updptr, int nr_inst)
 {
     BUG_ON(nr_inst != 1);
 
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 9b9018574919..188ddd490437 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -759,9 +759,8 @@ static bool __init is_dom0less_mode(void)
 size_t __read_mostly dcache_line_bytes;
 
 /* C entry point for boot CPU */
-/* SAF-1-safe */
-void __init start_xen(unsigned long boot_phys_offset,
-                      unsigned long fdt_paddr)
+void asmlinkage __init start_xen(unsigned long boot_phys_offset,
+                                 unsigned long fdt_paddr)
 {
     size_t fdt_size;
     const char *cmdline;
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 36db6b8880d3..7110bc11fc05 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -303,8 +303,7 @@ smp_prepare_cpus(void)
 }
 
 /* Boot the current CPU */
-/* SAF-1-safe */
-void start_secondary(void)
+void asmlinkage start_secondary(void)
 {
     unsigned int cpuid = init_data.cpuid;
 
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 8492e2b7bbb8..3784e8276ef6 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -161,8 +161,7 @@ void init_traps(void)
     isb();
 }
 
-/* SAF-1-safe */
-void __div0(void)
+void asmlinkage __div0(void)
 {
     printk("Division by zero in hypervisor.\n");
     BUG();
@@ -1955,8 +1954,7 @@ static inline bool needs_ssbd_flip(struct vcpu *v)
  * Actions that needs to be done after entering the hypervisor from the
  * guest and before the interrupts are unmasked.
  */
-/* SAF-1-safe */
-void enter_hypervisor_from_guest_preirq(void)
+void asmlinkage enter_hypervisor_from_guest_preirq(void)
 {
     struct vcpu *v = current;
 
@@ -1970,8 +1968,7 @@ void enter_hypervisor_from_guest_preirq(void)
  * guest and before we handle any request. Depending on the exception trap,
  * this may be called with interrupts unmasked.
  */
-/* SAF-1-safe */
-void enter_hypervisor_from_guest(void)
+void asmlinkage enter_hypervisor_from_guest(void)
 {
     struct vcpu *v = current;
 
@@ -1999,8 +1996,7 @@ void enter_hypervisor_from_guest(void)
     vgic_sync_from_lrs(v);
 }
 
-/* SAF-1-safe */
-void do_trap_guest_sync(struct cpu_user_regs *regs)
+void asmlinkage do_trap_guest_sync(struct cpu_user_regs *regs)
 {
     const union hsr hsr = { .bits = regs->hsr };
 
@@ -2195,14 +2191,12 @@ void do_trap_guest_serror(struct cpu_user_regs *regs)
     __do_trap_serror(regs, true);
 }
 
-/* SAF-1-safe */
-void do_trap_irq(struct cpu_user_regs *regs)
+void asmlinkage do_trap_irq(struct cpu_user_regs *regs)
 {
     gic_interrupt(regs, 0);
 }
 
-/* SAF-1-safe */
-void do_trap_fiq(struct cpu_user_regs *regs)
+void asmlinkage do_trap_fiq(struct cpu_user_regs *regs)
 {
     gic_interrupt(regs, 1);
 }
@@ -2275,8 +2269,7 @@ static bool check_for_vcpu_work(void)
  *
  * The function will return with IRQ masked.
  */
-/* SAF-1-safe */
-void leave_hypervisor_to_guest(void)
+void asmlinkage leave_hypervisor_to_guest(void)
 {
     local_irq_disable();
 
diff --git a/xen/arch/x86/extable.c b/xen/arch/x86/extable.c
index 652010f4138c..1555b9408f42 100644
--- a/xen/arch/x86/extable.c
+++ b/xen/arch/x86/extable.c
@@ -194,8 +194,7 @@ static int __init cf_check stub_selftest(void)
 __initcall(stub_selftest);
 #endif
 
-/* SAF-1-safe */
-unsigned long search_pre_exception_table(struct cpu_user_regs *regs)
+unsigned long asmlinkage search_pre_exception_table(struct cpu_user_regs *regs)
 {
     unsigned long addr = regs->rip;
     unsigned long fixup = search_one_extable(
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index f6b8a3efd752..3cba2be0af6c 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -976,8 +976,7 @@ static struct domain *__init create_dom0(const module_t *image,
 /* How much of the directmap is prebuilt at compile time. */
 #define PREBUILT_MAP_LIMIT (1 << L2_PAGETABLE_SHIFT)
 
-/* SAF-1-safe */
-void __init noreturn __start_xen(unsigned long mbi_p)
+void asmlinkage __init noreturn __start_xen(unsigned long mbi_p)
 {
     const char *memmap_type = NULL, *loader, *cmdline = "";
     char *kextra;
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index f2a77003ab81..7724306116e9 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -833,8 +833,7 @@ void fatal_trap(const struct cpu_user_regs *regs, bool show_remote)
           (regs->eflags & X86_EFLAGS_IF) ? "" : " IN INTERRUPT CONTEXT");
 }
 
-/* SAF-1-safe */
-void do_unhandled_trap(struct cpu_user_regs *regs)
+void asmlinkage do_unhandled_trap(struct cpu_user_regs *regs)
 {
     unsigned int trapnr = regs->entry_vector;
 
@@ -921,8 +920,7 @@ static bool extable_fixup(struct cpu_user_regs *regs, bool print)
     return true;
 }
 
-/* SAF-1-safe */
-void do_trap(struct cpu_user_regs *regs)
+void asmlinkage do_trap(struct cpu_user_regs *regs)
 {
     unsigned int trapnr = regs->entry_vector;
 
@@ -1154,8 +1152,7 @@ void cpuid_hypervisor_leaves(const struct vcpu *v, uint32_t leaf,
     }
 }
 
-/* SAF-1-safe */
-void do_invalid_op(struct cpu_user_regs *regs)
+void asmlinkage do_invalid_op(struct cpu_user_regs *regs)
 {
     u8 bug_insn[2];
     const void *eip = (const void *)regs->rip;
@@ -1200,8 +1197,7 @@ void do_invalid_op(struct cpu_user_regs *regs)
     panic("FATAL TRAP: vector = %d (invalid opcode)\n", X86_EXC_UD);
 }
 
-/* SAF-1-safe */
-void do_int3(struct cpu_user_regs *regs)
+void asmlinkage do_int3(struct cpu_user_regs *regs)
 {
     struct vcpu *curr = current;
 
@@ -1568,8 +1564,7 @@ static int fixup_page_fault(unsigned long addr, struct cpu_user_regs *regs)
     return 0;
 }
 
-/* SAF-1-safe */
-void do_page_fault(struct cpu_user_regs *regs)
+void asmlinkage do_page_fault(struct cpu_user_regs *regs)
 {
     unsigned long addr;
     unsigned int error_code;
@@ -1646,8 +1641,7 @@ void do_page_fault(struct cpu_user_regs *regs)
  * during early boot (an issue was seen once, but was most likely a hardware
  * problem).
  */
-/* SAF-1-safe */
-void __init do_early_page_fault(struct cpu_user_regs *regs)
+void asmlinkage __init do_early_page_fault(struct cpu_user_regs *regs)
 {
     static unsigned int __initdata stuck;
     static unsigned long __initdata prev_eip, prev_cr2;
@@ -1847,8 +1841,7 @@ void trigger_nmi_continuation(void)
     apic_wait_icr_idle();
 }
 
-/* SAF-1-safe */
-void do_device_not_available(struct cpu_user_regs *regs)
+void asmlinkage do_device_not_available(struct cpu_user_regs *regs)
 {
 #ifdef CONFIG_PV
     struct vcpu *curr = current;
@@ -1886,8 +1879,7 @@ void do_device_not_available(struct cpu_user_regs *regs)
 
 void nocall sysenter_eflags_saved(void);
 
-/* SAF-1-safe */
-void do_debug(struct cpu_user_regs *regs)
+void asmlinkage do_debug(struct cpu_user_regs *regs)
 {
     unsigned long dr6;
     struct vcpu *v = current;
@@ -2012,8 +2004,7 @@ void do_debug(struct cpu_user_regs *regs)
     pv_inject_hw_exception(X86_EXC_DB, X86_EVENT_NO_EC);
 }
 
-/* SAF-1-safe */
-void do_entry_CP(struct cpu_user_regs *regs)
+void asmlinkage do_entry_CP(struct cpu_user_regs *regs)
 {
     static const char errors[][10] = {
         [1] = "near ret",
-- 
2.34.1

On 24.11.2023 09:11, Nicola Vetrini wrote:
> The comment-based justifications for MISRA C:2012 Rule 8.4 are replaced
> by the asmlinkage pseudo-attribute, for the sake of uniformity.
> 
> asmlinkage may in the future have the effect of altering the calling
> convention, therefore three special where the calling convention is
> altered by another macro retain the textual deviation.
> 
> No functional change.
> 
> Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
> Acked-by: Julien Grall <jgrall@amazon.com>

Acked-by: Jan Beulich <jbeulich@suse.com>

Irrespective guidelines on when to use which will likely want spelling out
somewhere.

Jan