x86/paravirt: use callee-saved convention for pte_val/make_pte/etc

Impact: Optimization

In the native case, pte_val, make_pte, etc are all just identity
functions, so there's no need to clobber a lot of registers over them.

(This changes the 32-bit callee-save calling convention to return both
EAX and EDX so functions can return 64-bit values.)

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 12 insertions, 41 deletions

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 8adb6b5aa421..cea11c8e3049 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -391,43 +391,12 @@ struct pv_apic_ops pv_apic_ops = {
 #endif
 };
 
-typedef pte_t make_pte_t(pteval_t);
-typedef pmd_t make_pmd_t(pmdval_t);
-typedef pud_t make_pud_t(pudval_t);
-typedef pgd_t make_pgd_t(pgdval_t);
-
-typedef pteval_t pte_val_t(pte_t);
-typedef pmdval_t pmd_val_t(pmd_t);
-typedef pudval_t pud_val_t(pud_t);
-typedef pgdval_t pgd_val_t(pgd_t);
-
-
 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
 /* 32-bit pagetable entries */
-#define paravirt_native_make_pte        (make_pte_t *)_paravirt_ident_32
-#define paravirt_native_pte_val         (pte_val_t *)_paravirt_ident_32
-
-#define paravirt_native_make_pmd        (make_pmd_t *)_paravirt_ident_32
-#define paravirt_native_pmd_val         (pmd_val_t *)_paravirt_ident_32
-
-#define paravirt_native_make_pud        (make_pud_t *)_paravirt_ident_32
-#define paravirt_native_pud_val         (pud_val_t *)_paravirt_ident_32
-
-#define paravirt_native_make_pgd        (make_pgd_t *)_paravirt_ident_32
-#define paravirt_native_pgd_val         (pgd_val_t *)_paravirt_ident_32
+#define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
 #else
 /* 64-bit pagetable entries */
-#define paravirt_native_make_pte        (make_pte_t *)_paravirt_ident_64
-#define paravirt_native_pte_val         (pte_val_t *)_paravirt_ident_64
-
-#define paravirt_native_make_pmd        (make_pmd_t *)_paravirt_ident_64
-#define paravirt_native_pmd_val         (pmd_val_t *)_paravirt_ident_64
-
-#define paravirt_native_make_pud        (make_pud_t *)_paravirt_ident_64
-#define paravirt_native_pud_val         (pud_val_t *)_paravirt_ident_64
-
-#define paravirt_native_make_pgd        (make_pgd_t *)_paravirt_ident_64
-#define paravirt_native_pgd_val         (pgd_val_t *)_paravirt_ident_64
+#define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
 #endif
 
 struct pv_mmu_ops pv_mmu_ops = {
@@ -481,21 +450,23 @@ struct pv_mmu_ops pv_mmu_ops = {
         .pmd_clear = native_pmd_clear,
 #endif
         .set_pud = native_set_pud,
-        .pmd_val = paravirt_native_pmd_val,
-        .make_pmd = paravirt_native_make_pmd,
+
+        .pmd_val = PTE_IDENT,
+        .make_pmd = PTE_IDENT,
 
 #if PAGETABLE_LEVELS == 4
-        .pud_val = paravirt_native_pud_val,
-        .make_pud = paravirt_native_make_pud,
+        .pud_val = PTE_IDENT,
+        .make_pud = PTE_IDENT,
+
         .set_pgd = native_set_pgd,
 #endif
 #endif /* PAGETABLE_LEVELS >= 3 */
 
-        .pte_val = paravirt_native_pte_val,
-        .pgd_val = paravirt_native_pgd_val,
+        .pte_val = PTE_IDENT,
+        .pgd_val = PTE_IDENT,
 
-        .make_pte = paravirt_native_make_pte,
-        .make_pgd = paravirt_native_make_pgd,
+        .make_pte = PTE_IDENT,
+        .make_pgd = PTE_IDENT,
 
         .dup_mmap = paravirt_nop,
         .exit_mmap = paravirt_nop,