Merge tag 'x86_bugs_retbleed' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 retbleed fixes from Borislav Petkov:
 "Just when you thought that all the speculation bugs were addressed and
  solved and the nightmare is complete, here's the next one: speculating
  after RET instructions and leaking privileged information using the
  now pretty much classical covert channels.

  It is called RETBleed and the mitigation effort and controlling
  functionality has been modelled similar to what already existing
  mitigations provide"

* tag 'x86_bugs_retbleed' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
  x86/speculation: Disable RRSBA behavior
  x86/kexec: Disable RET on kexec
  x86/bugs: Do not enable IBPB-on-entry when IBPB is not supported
  x86/entry: Move PUSH_AND_CLEAR_REGS() back into error_entry
  x86/bugs: Add Cannon lake to RETBleed affected CPU list
  x86/retbleed: Add fine grained Kconfig knobs
  x86/cpu/amd: Enumerate BTC_NO
  x86/common: Stamp out the stepping madness
  KVM: VMX: Prevent RSB underflow before vmenter
  x86/speculation: Fill RSB on vmexit for IBRS
  KVM: VMX: Fix IBRS handling after vmexit
  KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS
  KVM: VMX: Convert launched argument to flags
  KVM: VMX: Flatten __vmx_vcpu_run()
  objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}
  x86/speculation: Remove x86_spec_ctrl_mask
  x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit
  x86/speculation: Fix SPEC_CTRL write on SMT state change
  x86/speculation: Fix firmware entry SPEC_CTRL handling
  x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n
  ...

4 files changed, 22 insertions, 21 deletions

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 81aa46f770c5..cfa99e8f054b 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -918,7 +918,7 @@ void xen_enable_sysenter(void)
 	if (!boot_cpu_has(sysenter_feature))
 		return;
 
-	ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
+	ret = register_callback(CALLBACKTYPE_sysenter, xen_entry_SYSENTER_compat);
 	if(ret != 0)
 		setup_clear_cpu_cap(sysenter_feature);
 }
@@ -927,7 +927,7 @@ void xen_enable_syscall(void)
 {
 	int ret;
 
-	ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
+	ret = register_callback(CALLBACKTYPE_syscall, xen_entry_SYSCALL_64);
 	if (ret != 0) {
 		printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
 		/* Pretty fatal; 64-bit userspace has no other
@@ -936,7 +936,7 @@ void xen_enable_syscall(void)
 
 	if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
 		ret = register_callback(CALLBACKTYPE_syscall32,
-					xen_syscall32_target);
+					xen_entry_SYSCALL_compat);
 		if (ret != 0)
 			setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
 	}
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index caa9bc2fa100..6b4fdf6b9542 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -121,7 +121,7 @@ SYM_FUNC_END(xen_read_cr2_direct);
 
 .macro xen_pv_trap name
 SYM_CODE_START(xen_\name)
-	UNWIND_HINT_EMPTY
+	UNWIND_HINT_ENTRY
 	ENDBR
 	pop %rcx
 	pop %r11
@@ -234,8 +234,8 @@ SYM_CODE_END(xenpv_restore_regs_and_return_to_usermode)
  */
 
 /* Normal 64-bit system call target */
-SYM_CODE_START(xen_syscall_target)
-	UNWIND_HINT_EMPTY
+SYM_CODE_START(xen_entry_SYSCALL_64)
+	UNWIND_HINT_ENTRY
 	ENDBR
 	popq %rcx
 	popq %r11
@@ -249,13 +249,13 @@ SYM_CODE_START(xen_syscall_target)
 	movq $__USER_CS, 1*8(%rsp)
 
 	jmp entry_SYSCALL_64_after_hwframe
-SYM_CODE_END(xen_syscall_target)
+SYM_CODE_END(xen_entry_SYSCALL_64)
 
 #ifdef CONFIG_IA32_EMULATION
 
 /* 32-bit compat syscall target */
-SYM_CODE_START(xen_syscall32_target)
-	UNWIND_HINT_EMPTY
+SYM_CODE_START(xen_entry_SYSCALL_compat)
+	UNWIND_HINT_ENTRY
 	ENDBR
 	popq %rcx
 	popq %r11
@@ -269,11 +269,11 @@ SYM_CODE_START(xen_syscall32_target)
 	movq $__USER32_CS, 1*8(%rsp)
 
 	jmp entry_SYSCALL_compat_after_hwframe
-SYM_CODE_END(xen_syscall32_target)
+SYM_CODE_END(xen_entry_SYSCALL_compat)
 
 /* 32-bit compat sysenter target */
-SYM_CODE_START(xen_sysenter_target)
-	UNWIND_HINT_EMPTY
+SYM_CODE_START(xen_entry_SYSENTER_compat)
+	UNWIND_HINT_ENTRY
 	ENDBR
 	/*
 	 * NB: Xen is polite and clears TF from EFLAGS for us.  This means
@@ -291,19 +291,19 @@ SYM_CODE_START(xen_sysenter_target)
 	movq $__USER32_CS, 1*8(%rsp)
 
 	jmp entry_SYSENTER_compat_after_hwframe
-SYM_CODE_END(xen_sysenter_target)
+SYM_CODE_END(xen_entry_SYSENTER_compat)
 
 #else /* !CONFIG_IA32_EMULATION */
 
-SYM_CODE_START(xen_syscall32_target)
-SYM_CODE_START(xen_sysenter_target)
-	UNWIND_HINT_EMPTY
+SYM_CODE_START(xen_entry_SYSCALL_compat)
+SYM_CODE_START(xen_entry_SYSENTER_compat)
+	UNWIND_HINT_ENTRY
 	ENDBR
 	lea 16(%rsp), %rsp	/* strip %rcx, %r11 */
 	mov $-ENOSYS, %rax
 	pushq $0
 	jmp hypercall_iret
-SYM_CODE_END(xen_sysenter_target)
-SYM_CODE_END(xen_syscall32_target)
+SYM_CODE_END(xen_entry_SYSENTER_compat)
+SYM_CODE_END(xen_entry_SYSCALL_compat)
 
 #endif	/* CONFIG_IA32_EMULATION */
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index 13af6fe453e3..ffaa62167f6e 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -26,6 +26,7 @@ SYM_CODE_START(hypercall_page)
 	.rept (PAGE_SIZE / 32)
 		UNWIND_HINT_FUNC
 		ANNOTATE_NOENDBR
+		ANNOTATE_UNRET_SAFE
 		ret
 		/*
 		 * Xen will write the hypercall page, and sort out ENDBR.
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index fd0fec6e92f4..9a8bb972193d 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -10,10 +10,10 @@
 /* These are code, but not functions.  Defined in entry.S */
 extern const char xen_failsafe_callback[];
 
-void xen_sysenter_target(void);
+void xen_entry_SYSENTER_compat(void);
 #ifdef CONFIG_X86_64
-void xen_syscall_target(void);
-void xen_syscall32_target(void);
+void xen_entry_SYSCALL_64(void);
+void xen_entry_SYSCALL_compat(void);
 #endif
 
 extern void *xen_initial_gdt;