[Xen-devel] [patch 04/34] Xen-pv_ops: use paravirt_nop to consistently mark no-op operations

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

Add a _paravirt_nop function for use as a stub for no-op operations,
and paravirt_nop #defined void * version to make using it easier
(since all its uses are as a void *).

This is useful to allow the patcher to automatically identify noop
operations so it can simply nop out the callsite.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>

---
 arch/i386/kernel/paravirt.c |   26 +++++++++++++-------------
 include/asm-i386/paravirt.h |    3 +++
 2 files changed, 16 insertions(+), 13 deletions(-)

===================================================================
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -35,7 +35,7 @@
 #include <asm/timer.h>
 
 /* nop stub */
-static void native_nop(void)
+void _paravirt_nop(void)
 {
 }
 
@@ -490,7 +490,7 @@ struct paravirt_ops paravirt_ops = {
 
        .patch = native_patch,
        .banner = default_banner,
-       .arch_setup = native_nop,
+       .arch_setup = paravirt_nop,
        .memory_setup = machine_specific_memory_setup,
        .get_wallclock = native_get_wallclock,
        .set_wallclock = native_set_wallclock,
@@ -546,25 +546,25 @@ struct paravirt_ops paravirt_ops = {
        .setup_boot_clock = setup_boot_APIC_clock,
        .setup_secondary_clock = setup_secondary_APIC_clock,
 #endif
-       .set_lazy_mode = (void *)native_nop,
+       .set_lazy_mode = paravirt_nop,
 
        .flush_tlb_user = native_flush_tlb,
        .flush_tlb_kernel = native_flush_tlb_global,
        .flush_tlb_single = native_flush_tlb_single,
 
-       .map_pt_hook = (void *)native_nop,
-
-       .alloc_pt = (void *)native_nop,
-       .alloc_pd = (void *)native_nop,
-       .alloc_pd_clone = (void *)native_nop,
-       .release_pt = (void *)native_nop,
-       .release_pd = (void *)native_nop,
+       .map_pt_hook = paravirt_nop,
+
+       .alloc_pt = paravirt_nop,
+       .alloc_pd = paravirt_nop,
+       .alloc_pd_clone = paravirt_nop,
+       .release_pt = paravirt_nop,
+       .release_pd = paravirt_nop,
 
        .set_pte = native_set_pte,
        .set_pte_at = native_set_pte_at,
        .set_pmd = native_set_pmd,
-       .pte_update = (void *)native_nop,
-       .pte_update_defer = (void *)native_nop,
+       .pte_update = paravirt_nop,
+       .pte_update_defer = paravirt_nop,
 #ifdef CONFIG_X86_PAE
        .set_pte_atomic = native_set_pte_atomic,
        .set_pte_present = native_set_pte_present,
@@ -576,7 +576,7 @@ struct paravirt_ops paravirt_ops = {
        .irq_enable_sysexit = native_irq_enable_sysexit,
        .iret = native_iret,
 
-       .startup_ipi_hook = (void *)native_nop,
+       .startup_ipi_hook = paravirt_nop,
 };
 
 /*
===================================================================
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -430,6 +430,9 @@ static inline void pmd_clear(pmd_t *pmdp
 #define arch_enter_lazy_mmu_mode() 
paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_MMU)
 #define arch_leave_lazy_mmu_mode() 
paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_NONE)
 
+void _paravirt_nop(void);
+#define paravirt_nop   ((void *)_paravirt_nop)
+
 /* These all sit in the .parainstructions section to tell us what to patch. */
 struct paravirt_patch {
        u8 *instr;              /* original instructions */

-- 


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