Merge tag 'x86_paravirt_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 paravirt updates from Borislav Petkov:

 - Convert a couple of paravirt callbacks to asm to prevent
   '-fzero-call-used-regs' builds from zeroing live registers because
   paravirt hides the CALLs from the compiler so latter doesn't know
   there's a CALL in the first place

 - Merge two paravirt callbacks into one, as their functionality is
   identical

* tag 'x86_paravirt_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/paravirt: Convert simple paravirt functions to asm
  x86/paravirt: Merge activate_mm() and dup_mmap() callbacks

Author: torvalds

arch/x86/include/asm/mmu_context.h

@@ -16,13 +16,6 @@
 
 extern atomic64_t last_mm_ctx_id;
 
-#ifndef CONFIG_PARAVIRT_XXL
-static inline void paravirt_activate_mm(struct mm_struct *prev,
-					struct mm_struct *next)
-{
-}
-#endif	/* !CONFIG_PARAVIRT_XXL */
-
 #ifdef CONFIG_PERF_EVENTS
 DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key);
 DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key);
@@ -135,7 +128,7 @@ extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
 
 #define activate_mm(prev, next)			\
 do {						\
-	paravirt_activate_mm((prev), (next));	\
+	paravirt_enter_mmap(next);		\
 	switch_mm((prev), (next), NULL);	\
 } while (0);
 
@@ -168,7 +161,7 @@ static inline void arch_dup_pkeys(struct mm_struct *oldmm,
 static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
 {
 	arch_dup_pkeys(oldmm, mm);
-	paravirt_arch_dup_mmap(oldmm, mm);
+	paravirt_enter_mmap(mm);
 	return ldt_dup_context(oldmm, mm);
 }
 

arch/x86/include/asm/paravirt.h

@@ -334,16 +334,9 @@ static inline void tss_update_io_bitmap(void)
 }
 #endif
 
-static inline void paravirt_activate_mm(struct mm_struct *prev,
-					struct mm_struct *next)
+static inline void paravirt_enter_mmap(struct mm_struct *next)
 {
-	PVOP_VCALL2(mmu.activate_mm, prev, next);
-}
-
-static inline void paravirt_arch_dup_mmap(struct mm_struct *oldmm,
-					  struct mm_struct *mm)
-{
-	PVOP_VCALL2(mmu.dup_mmap, oldmm, mm);
+	PVOP_VCALL1(mmu.enter_mmap, next);
 }
 
 static inline int paravirt_pgd_alloc(struct mm_struct *mm)
@@ -789,8 +782,7 @@ extern void default_banner(void);
 
 #ifndef __ASSEMBLY__
 #ifndef CONFIG_PARAVIRT_XXL
-static inline void paravirt_arch_dup_mmap(struct mm_struct *oldmm,
-					  struct mm_struct *mm)
+static inline void paravirt_enter_mmap(struct mm_struct *mm)
 {
 }
 #endif

arch/x86/include/asm/paravirt_types.h

@@ -164,11 +164,8 @@ struct pv_mmu_ops {
 	unsigned long (*read_cr3)(void);
 	void (*write_cr3)(unsigned long);
 
-	/* Hooks for intercepting the creation/use of an mm_struct. */
-	void (*activate_mm)(struct mm_struct *prev,
-			    struct mm_struct *next);
-	void (*dup_mmap)(struct mm_struct *oldmm,
-			 struct mm_struct *mm);
+	/* Hook for intercepting the creation/use of an mm_struct. */
+	void (*enter_mmap)(struct mm_struct *mm);
 
 	/* Hooks for allocating and freeing a pagetable top-level */
 	int  (*pgd_alloc)(struct mm_struct *mm);
@@ -562,8 +559,14 @@ void paravirt_flush_lazy_mmu(void);
 
 void _paravirt_nop(void);
 void paravirt_BUG(void);
-u64 _paravirt_ident_64(u64);
 unsigned long paravirt_ret0(void);
+#ifdef CONFIG_PARAVIRT_XXL
+u64 _paravirt_ident_64(u64);
+unsigned long pv_native_save_fl(void);
+void pv_native_irq_disable(void);
+void pv_native_irq_enable(void);
+unsigned long pv_native_read_cr2(void);
+#endif
 
 #define paravirt_nop	((void *)_paravirt_nop)
 

arch/x86/kernel/paravirt.c

@@ -64,11 +64,11 @@ static unsigned paravirt_patch_call(void *insn_buff, const void *target,
 }
 
 #ifdef CONFIG_PARAVIRT_XXL
-/* identity function, which can be inlined */
-u64 notrace _paravirt_ident_64(u64 x)
-{
-	return x;
-}
+DEFINE_PARAVIRT_ASM(_paravirt_ident_64, "mov %rdi, %rax", .text);
+DEFINE_PARAVIRT_ASM(pv_native_save_fl, "pushf; pop %rax", .noinstr.text);
+DEFINE_PARAVIRT_ASM(pv_native_irq_disable, "cli", .noinstr.text);
+DEFINE_PARAVIRT_ASM(pv_native_irq_enable, "sti", .noinstr.text);
+DEFINE_PARAVIRT_ASM(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text);
 #endif
 
 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
@@ -197,11 +197,6 @@ void paravirt_end_context_switch(struct task_struct *next)
 		arch_enter_lazy_mmu_mode();
 }
 
-static noinstr unsigned long pv_native_read_cr2(void)
-{
-	return native_read_cr2();
-}
-
 static noinstr void pv_native_write_cr2(unsigned long val)
 {
 	native_write_cr2(val);
@@ -222,16 +217,6 @@ noinstr void pv_native_wbinvd(void)
 	native_wbinvd();
 }
 
-static noinstr void pv_native_irq_enable(void)
-{
-	native_irq_enable();
-}
-
-static noinstr void pv_native_irq_disable(void)
-{
-	native_irq_disable();
-}
-
 static noinstr void pv_native_safe_halt(void)
 {
 	native_safe_halt();
@@ -298,7 +283,7 @@ struct paravirt_patch_template pv_ops = {
 	.cpu.end_context_switch		= paravirt_nop,
 
 	/* Irq ops. */
-	.irq.save_fl		= __PV_IS_CALLEE_SAVE(native_save_fl),
+	.irq.save_fl		= __PV_IS_CALLEE_SAVE(pv_native_save_fl),
 	.irq.irq_disable	= __PV_IS_CALLEE_SAVE(pv_native_irq_disable),
 	.irq.irq_enable		= __PV_IS_CALLEE_SAVE(pv_native_irq_enable),
 	.irq.safe_halt		= pv_native_safe_halt,
@@ -363,8 +348,7 @@ struct paravirt_patch_template pv_ops = {
 	.mmu.make_pte		= PTE_IDENT,
 	.mmu.make_pgd		= PTE_IDENT,
 
-	.mmu.dup_mmap		= paravirt_nop,
-	.mmu.activate_mm	= paravirt_nop,
+	.mmu.enter_mmap		= paravirt_nop,
 
 	.mmu.lazy_mode = {
 		.enter		= paravirt_nop,

arch/x86/mm/init.c

@@ -806,7 +806,7 @@ void __init poking_init(void)
 	BUG_ON(!poking_mm);
 
 	/* Xen PV guests need the PGD to be pinned. */
-	paravirt_arch_dup_mmap(NULL, poking_mm);
+	paravirt_enter_mmap(poking_mm);
 
 	/*
 	 * Randomize the poking address, but make sure that the following page

arch/x86/xen/mmu_pv.c

@@ -885,14 +885,7 @@ void xen_mm_unpin_all(void)
 	spin_unlock(&pgd_lock);
 }
 
-static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
-{
-	spin_lock(&next->page_table_lock);
-	xen_pgd_pin(next);
-	spin_unlock(&next->page_table_lock);
-}
-
-static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+static void xen_enter_mmap(struct mm_struct *mm)
 {
 	spin_lock(&mm->page_table_lock);
 	xen_pgd_pin(mm);
@@ -2153,8 +2146,7 @@ static const typeof(pv_ops) xen_mmu_ops __initconst = {
 		.make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
 #endif
 
-		.activate_mm = xen_activate_mm,
-		.dup_mmap = xen_dup_mmap,
+		.enter_mmap = xen_enter_mmap,
 		.exit_mmap = xen_exit_mmap,
 
 		.lazy_mode = {