Merge tag 'x86_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 core updates from Borislav Petkov:

 - Get rid of all the .fixup sections because this generates
   misleading/wrong stacktraces and confuse RELIABLE_STACKTRACE and
   LIVEPATCH as the backtrace misses the function which is being fixed
   up.

 - Add Straight Line Speculation mitigation support which uses a new
   compiler switch -mharden-sls= which sticks an INT3 after a RET or an
   indirect branch in order to block speculation after them. Reportedly,
   CPUs do speculate behind such insns.

 - The usual set of cleanups and improvements

* tag 'x86_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
  x86/entry_32: Fix segment exceptions
  objtool: Remove .fixup handling
  x86: Remove .fixup section
  x86/word-at-a-time: Remove .fixup usage
  x86/usercopy: Remove .fixup usage
  x86/usercopy_32: Simplify __copy_user_intel_nocache()
  x86/sgx: Remove .fixup usage
  x86/checksum_32: Remove .fixup usage
  x86/vmx: Remove .fixup usage
  x86/kvm: Remove .fixup usage
  x86/segment: Remove .fixup usage
  x86/fpu: Remove .fixup usage
  x86/xen: Remove .fixup usage
  x86/uaccess: Remove .fixup usage
  x86/futex: Remove .fixup usage
  x86/msr: Remove .fixup usage
  x86/extable: Extend extable functionality
  x86/entry_32: Remove .fixup usage
  x86/entry_64: Remove .fixup usage
  x86/copy_mc_64: Remove .fixup usage
  ...

8 files changed, 33 insertions, 42 deletions

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index ccb9d32768f3..a7ec22b1d06c 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -268,19 +268,16 @@
 1:	popl	%ds
 2:	popl	%es
 3:	popl	%fs
-	addl	$(4 + \pop), %esp	/* pop the unused "gs" slot */
+4:	addl	$(4 + \pop), %esp	/* pop the unused "gs" slot */
 	IRET_FRAME
-.pushsection .fixup, "ax"
-4:	movl	$0, (%esp)
-	jmp	1b
-5:	movl	$0, (%esp)
-	jmp	2b
-6:	movl	$0, (%esp)
-	jmp	3b
-.popsection
-	_ASM_EXTABLE(1b, 4b)
-	_ASM_EXTABLE(2b, 5b)
-	_ASM_EXTABLE(3b, 6b)
+
+	/*
+	 * There is no _ASM_EXTABLE_TYPE_REG() for ASM, however since this is
+	 * ASM the registers are known and we can trivially hard-code them.
+	 */
+	_ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_POP_ZERO|EX_REG_DS)
+	_ASM_EXTABLE_TYPE(2b, 3b, EX_TYPE_POP_ZERO|EX_REG_ES)
+	_ASM_EXTABLE_TYPE(3b, 4b, EX_TYPE_POP_ZERO|EX_REG_FS)
 .endm
 
 .macro RESTORE_ALL_NMI cr3_reg:req pop=0
@@ -740,7 +737,7 @@ SYM_FUNC_START(schedule_tail_wrapper)
 	popl	%eax
 
 	FRAME_END
-	ret
+	RET
 SYM_FUNC_END(schedule_tail_wrapper)
 .popsection
 
@@ -925,10 +922,8 @@ SYM_FUNC_START(entry_SYSENTER_32)
 	sti
 	sysexit
 
-.pushsection .fixup, "ax"
-2:	movl	$0, PT_FS(%esp)
-	jmp	1b
-.popsection
+2:	movl    $0, PT_FS(%esp)
+	jmp     1b
 	_ASM_EXTABLE(1b, 2b)
 
 .Lsysenter_fix_flags:
@@ -996,8 +991,7 @@ restore_all_switch_stack:
 	 */
 	iret
 
-.section .fixup, "ax"
-SYM_CODE_START(asm_iret_error)
+.Lasm_iret_error:
 	pushl	$0				# no error code
 	pushl	$iret_error
 
@@ -1014,9 +1008,8 @@ SYM_CODE_START(asm_iret_error)
 #endif
 
 	jmp	handle_exception
-SYM_CODE_END(asm_iret_error)
-.previous
-	_ASM_EXTABLE(.Lirq_return, asm_iret_error)
+
+	_ASM_EXTABLE(.Lirq_return, .Lasm_iret_error)
 SYM_FUNC_END(entry_INT80_32)
 
 .macro FIXUP_ESPFIX_STACK
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 97b1f84bb53f..1ffdbfaad2e2 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -738,14 +738,10 @@ SYM_FUNC_START(asm_load_gs_index)
 2:	ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE
 	swapgs
 	FRAME_END
-	ret
-SYM_FUNC_END(asm_load_gs_index)
-EXPORT_SYMBOL(asm_load_gs_index)
+	RET
 
-	_ASM_EXTABLE(.Lgs_change, .Lbad_gs)
-	.section .fixup, "ax"
 	/* running with kernelgs */
-SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs)
+.Lbad_gs:
 	swapgs					/* switch back to user gs */
 .macro ZAP_GS
 	/* This can't be a string because the preprocessor needs to see it. */
@@ -756,8 +752,11 @@ SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs)
 	xorl	%eax, %eax
 	movl	%eax, %gs
 	jmp	2b
-SYM_CODE_END(.Lbad_gs)
-	.previous
+
+	_ASM_EXTABLE(.Lgs_change, .Lbad_gs)
+
+SYM_FUNC_END(asm_load_gs_index)
+EXPORT_SYMBOL(asm_load_gs_index)
 
 #ifdef CONFIG_XEN_PV
 /*
@@ -889,7 +888,7 @@ SYM_CODE_START_LOCAL(paranoid_entry)
 	 * is needed here.
 	 */
 	SAVE_AND_SET_GSBASE scratch_reg=%rax save_reg=%rbx
-	ret
+	RET
 
 .Lparanoid_entry_checkgs:
 	/* EBX = 1 -> kernel GSBASE active, no restore required */
@@ -910,7 +909,7 @@ SYM_CODE_START_LOCAL(paranoid_entry)
 .Lparanoid_kernel_gsbase:
 
 	FENCE_SWAPGS_KERNEL_ENTRY
-	ret
+	RET
 SYM_CODE_END(paranoid_entry)
 
 /*
@@ -989,7 +988,7 @@ SYM_CODE_START_LOCAL(error_entry)
 	movq	%rax, %rsp			/* switch stack */
 	ENCODE_FRAME_POINTER
 	pushq	%r12
-	ret
+	RET
 
 	/*
 	 * There are two places in the kernel that can potentially fault with
@@ -1020,7 +1019,7 @@ SYM_CODE_START_LOCAL(error_entry)
 	 */
 .Lerror_entry_done_lfence:
 	FENCE_SWAPGS_KERNEL_ENTRY
-	ret
+	RET
 
 .Lbstep_iret:
 	/* Fix truncated RIP */
diff --git a/arch/x86/entry/thunk_32.S b/arch/x86/entry/thunk_32.S
index f1f96d4d8cd6..7591bab060f7 100644
--- a/arch/x86/entry/thunk_32.S
+++ b/arch/x86/entry/thunk_32.S
@@ -24,7 +24,7 @@ SYM_CODE_START_NOALIGN(\name)
 	popl %edx
 	popl %ecx
 	popl %eax
-	ret
+	RET
 	_ASM_NOKPROBE(\name)
 SYM_CODE_END(\name)
 	.endm
diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S
index 496b11ec469d..505b488fcc65 100644
--- a/arch/x86/entry/thunk_64.S
+++ b/arch/x86/entry/thunk_64.S
@@ -50,7 +50,7 @@ SYM_CODE_START_LOCAL_NOALIGN(__thunk_restore)
 	popq %rsi
 	popq %rdi
 	popq %rbp
-	ret
+	RET
 	_ASM_NOKPROBE(__thunk_restore)
 SYM_CODE_END(__thunk_restore)
 #endif
diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index dc8da7695859..bafa73f09e92 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -77,7 +77,6 @@ SECTIONS
 
 	.text		: {
 		*(.text*)
-		*(.fixup)
 	}						:text	=0x90909090,
 
 
diff --git a/arch/x86/entry/vdso/vdso32/system_call.S b/arch/x86/entry/vdso/vdso32/system_call.S
index 6ddd7a937b3e..d33c6513fd2c 100644
--- a/arch/x86/entry/vdso/vdso32/system_call.S
+++ b/arch/x86/entry/vdso/vdso32/system_call.S
@@ -78,7 +78,7 @@ SYM_INNER_LABEL(int80_landing_pad, SYM_L_GLOBAL)
 	popl	%ecx
 	CFI_RESTORE		ecx
 	CFI_ADJUST_CFA_OFFSET	-4
-	ret
+	RET
 	CFI_ENDPROC
 
 	.size __kernel_vsyscall,.-__kernel_vsyscall
diff --git a/arch/x86/entry/vdso/vsgx.S b/arch/x86/entry/vdso/vsgx.S
index 99dafac992e2..d77d278ee9dd 100644
--- a/arch/x86/entry/vdso/vsgx.S
+++ b/arch/x86/entry/vdso/vsgx.S
@@ -81,7 +81,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave)
 	pop	%rbx
 	leave
 	.cfi_def_cfa		%rsp, 8
-	ret
+	RET
 
 	/* The out-of-line code runs with the pre-leave stack frame. */
 	.cfi_def_cfa		%rbp, 16
diff --git a/arch/x86/entry/vsyscall/vsyscall_emu_64.S b/arch/x86/entry/vsyscall/vsyscall_emu_64.S
index 2e203f3a25a7..15e35159ebb6 100644
--- a/arch/x86/entry/vsyscall/vsyscall_emu_64.S
+++ b/arch/x86/entry/vsyscall/vsyscall_emu_64.S
@@ -19,17 +19,17 @@ __vsyscall_page:
 
 	mov $__NR_gettimeofday, %rax
 	syscall
-	ret
+	RET
 
 	.balign 1024, 0xcc
 	mov $__NR_time, %rax
 	syscall
-	ret
+	RET
 
 	.balign 1024, 0xcc
 	mov $__NR_getcpu, %rax
 	syscall
-	ret
+	RET
 
 	.balign 4096, 0xcc