1 files changed, 41 insertions, 14 deletions

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index e4c8fb608873..cea11c8e3049 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -44,6 +44,17 @@ void _paravirt_nop(void)
 {
 }
 
+/* identity function, which can be inlined */
+u32 _paravirt_ident_32(u32 x)
+{
+        return x;
+}
+
+u64 _paravirt_ident_64(u64 x)
+{
+        return x;
+}
+
 static void __init default_banner(void)
 {
         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
@@ -138,9 +149,16 @@ unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
         if (opfunc == NULL)
                 /* If there's no function, patch it with a ud2a (BUG) */
                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
-        else if (opfunc == paravirt_nop)
+        else if (opfunc == _paravirt_nop)
                 /* If the operation is a nop, then nop the callsite */
                 ret = paravirt_patch_nop();
+
+        /* identity functions just return their single argument */
+        else if (opfunc == _paravirt_ident_32)
+                ret = paravirt_patch_ident_32(insnbuf, len);
+        else if (opfunc == _paravirt_ident_64)
+                ret = paravirt_patch_ident_64(insnbuf, len);
+
         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
@@ -292,10 +310,10 @@ struct pv_time_ops pv_time_ops = {
 
 struct pv_irq_ops pv_irq_ops = {
         .init_IRQ = native_init_IRQ,
-        .save_fl = native_save_fl,
-        .restore_fl = native_restore_fl,
-        .irq_disable = native_irq_disable,
-        .irq_enable = native_irq_enable,
+        .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
+        .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
+        .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
+        .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
         .safe_halt = native_safe_halt,
         .halt = native_halt,
 #ifdef CONFIG_X86_64
@@ -373,6 +391,14 @@ struct pv_apic_ops pv_apic_ops = {
 #endif
 };
 
+#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
+/* 32-bit pagetable entries */
+#define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
+#else
+/* 64-bit pagetable entries */
+#define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
+#endif
+
 struct pv_mmu_ops pv_mmu_ops = {
 #ifndef CONFIG_X86_64
         .pagetable_setup_start = native_pagetable_setup_start,
@@ -424,22 +450,23 @@ struct pv_mmu_ops pv_mmu_ops = {
         .pmd_clear = native_pmd_clear,
 #endif
         .set_pud = native_set_pud,
-        .pmd_val = native_pmd_val,
-        .make_pmd = native_make_pmd,
+
+        .pmd_val = PTE_IDENT,
+        .make_pmd = PTE_IDENT,
 
 #if PAGETABLE_LEVELS == 4
-        .pud_val = native_pud_val,
-        .make_pud = native_make_pud,
+        .pud_val = PTE_IDENT,
+        .make_pud = PTE_IDENT,
+
         .set_pgd = native_set_pgd,
 #endif
 #endif /* PAGETABLE_LEVELS >= 3 */
 
-        .pte_val = native_pte_val,
-        .pte_flags = native_pte_flags,
-        .pgd_val = native_pgd_val,
+        .pte_val = PTE_IDENT,
+        .pgd_val = PTE_IDENT,
 
-        .make_pte = native_make_pte,
-        .make_pgd = native_make_pgd,
+        .make_pte = PTE_IDENT,
+        .make_pgd = PTE_IDENT,
 
         .dup_mmap = paravirt_nop,
         .exit_mmap = paravirt_nop,