Merge tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core x86 updates from Ingo Molnar:

 - The biggest change is the rework of the percpu code, to support the
   'Named Address Spaces' GCC feature, by Uros Bizjak:

      - This allows C code to access GS and FS segment relative memory
        via variables declared with such attributes, which allows the
        compiler to better optimize those accesses than the previous
        inline assembly code.

      - The series also includes a number of micro-optimizations for
        various percpu access methods, plus a number of cleanups of %gs
        accesses in assembly code.

      - These changes have been exposed to linux-next testing for the
        last ~5 months, with no known regressions in this area.

 - Fix/clean up __switch_to()'s broken but accidentally working handling
   of FPU switching - which also generates better code

 - Propagate more RIP-relative addressing in assembly code, to generate
   slightly better code

 - Rework the CPU mitigations Kconfig space to be less idiosyncratic, to
   make it easier for distros to follow & maintain these options

 - Rework the x86 idle code to cure RCU violations and to clean up the
   logic

 - Clean up the vDSO Makefile logic

 - Misc cleanups and fixes

* tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  x86/idle: Select idle routine only once
  x86/idle: Let prefer_mwait_c1_over_halt() return bool
  x86/idle: Cleanup idle_setup()
  x86/idle: Clean up idle selection
  x86/idle: Sanitize X86_BUG_AMD_E400 handling
  sched/idle: Conditionally handle tick broadcast in default_idle_call()
  x86: Increase brk randomness entropy for 64-bit systems
  x86/vdso: Move vDSO to mmap region
  x86/vdso/kbuild: Group non-standard build attributes and primary object file rules together
  x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o
  x86/retpoline: Ensure default return thunk isn't used at runtime
  x86/vdso: Use CONFIG_COMPAT_32 to specify vdso32
  x86/vdso: Use $(addprefix ) instead of $(foreach )
  x86/vdso: Simplify obj-y addition
  x86/vdso: Consolidate targets and clean-files
  x86/bugs: Rename CONFIG_RETHUNK              => CONFIG_MITIGATION_RETHUNK
  x86/bugs: Rename CONFIG_CPU_SRSO             => CONFIG_MITIGATION_SRSO
  x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY       => CONFIG_MITIGATION_IBRS_ENTRY
  x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY      => CONFIG_MITIGATION_UNRET_ENTRY
  x86/bugs: Rename CONFIG_SLS                  => CONFIG_MITIGATION_SLS
  ...

8 files changed, 108 insertions, 160 deletions

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 1c3b561528fd..ea81770629ee 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -147,10 +147,10 @@ For 32-bit we have the following conventions - kernel is built with
 	.endif
 .endm
 
-#ifdef CONFIG_PAGE_TABLE_ISOLATION
+#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
 
 /*
- * PAGE_TABLE_ISOLATION PGDs are 8k.  Flip bit 12 to switch between the two
+ * MITIGATION_PAGE_TABLE_ISOLATION PGDs are 8k.  Flip bit 12 to switch between the two
  * halves:
  */
 #define PTI_USER_PGTABLE_BIT		PAGE_SHIFT
@@ -165,7 +165,7 @@ For 32-bit we have the following conventions - kernel is built with
 
 .macro ADJUST_KERNEL_CR3 reg:req
 	ALTERNATIVE "", "SET_NOFLUSH_BIT \reg", X86_FEATURE_PCID
-	/* Clear PCID and "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */
+	/* Clear PCID and "MITIGATION_PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */
 	andq    $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg
 .endm
 
@@ -178,7 +178,7 @@ For 32-bit we have the following conventions - kernel is built with
 .endm
 
 #define THIS_CPU_user_pcid_flush_mask   \
-	PER_CPU_VAR(cpu_tlbstate) + TLB_STATE_user_pcid_flush_mask
+	PER_CPU_VAR(cpu_tlbstate + TLB_STATE_user_pcid_flush_mask)
 
 .macro SWITCH_TO_USER_CR3 scratch_reg:req scratch_reg2:req
 	mov	%cr3, \scratch_reg
@@ -274,7 +274,7 @@ For 32-bit we have the following conventions - kernel is built with
 .Lend_\@:
 .endm
 
-#else /* CONFIG_PAGE_TABLE_ISOLATION=n: */
+#else /* CONFIG_MITIGATION_PAGE_TABLE_ISOLATION=n: */
 
 .macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
 .endm
@@ -302,7 +302,7 @@ For 32-bit we have the following conventions - kernel is built with
  * Assumes x86_spec_ctrl_{base,current} to have SPEC_CTRL_IBRS set.
  */
 .macro IBRS_ENTER save_reg
-#ifdef CONFIG_CPU_IBRS_ENTRY
+#ifdef CONFIG_MITIGATION_IBRS_ENTRY
 	ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS
 	movl	$MSR_IA32_SPEC_CTRL, %ecx
 
@@ -331,7 +331,7 @@ For 32-bit we have the following conventions - kernel is built with
  * regs. Must be called after the last RET.
  */
 .macro IBRS_EXIT save_reg
-#ifdef CONFIG_CPU_IBRS_ENTRY
+#ifdef CONFIG_MITIGATION_IBRS_ENTRY
 	ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS
 	movl	$MSR_IA32_SPEC_CTRL, %ecx
 
@@ -425,3 +425,63 @@ For 32-bit we have the following conventions - kernel is built with
 .endm
 
 #endif /* CONFIG_SMP */
+
+#ifdef CONFIG_X86_64
+
+/* rdi:	arg1 ... normal C conventions. rax is saved/restored. */
+.macro THUNK name, func
+SYM_FUNC_START(\name)
+	pushq %rbp
+	movq %rsp, %rbp
+
+	pushq %rdi
+	pushq %rsi
+	pushq %rdx
+	pushq %rcx
+	pushq %rax
+	pushq %r8
+	pushq %r9
+	pushq %r10
+	pushq %r11
+
+	call \func
+
+	popq %r11
+	popq %r10
+	popq %r9
+	popq %r8
+	popq %rax
+	popq %rcx
+	popq %rdx
+	popq %rsi
+	popq %rdi
+	popq %rbp
+	RET
+SYM_FUNC_END(\name)
+	_ASM_NOKPROBE(\name)
+.endm
+
+#else /* CONFIG_X86_32 */
+
+/* put return address in eax (arg1) */
+.macro THUNK name, func, put_ret_addr_in_eax=0
+SYM_CODE_START_NOALIGN(\name)
+	pushl %eax
+	pushl %ecx
+	pushl %edx
+
+	.if \put_ret_addr_in_eax
+	/* Place EIP in the arg1 */
+	movl 3*4(%esp), %eax
+	.endif
+
+	call \func
+	popl %edx
+	popl %ecx
+	popl %eax
+	RET
+	_ASM_NOKPROBE(\name)
+SYM_CODE_END(\name)
+	.endm
+
+#endif
diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S
index 003379049924..d9feadffa972 100644
--- a/arch/x86/entry/entry.S
+++ b/arch/x86/entry/entry.S
@@ -10,6 +10,8 @@
 #include <asm/segment.h>
 #include <asm/cache.h>
 
+#include "calling.h"
+
 .pushsection .noinstr.text, "ax"
 
 SYM_FUNC_START(entry_ibpb)
@@ -43,3 +45,4 @@ EXPORT_SYMBOL_GPL(mds_verw_sel);
 
 .popsection
 
+THUNK warn_thunk_thunk, __warn_thunk
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index b8be0164385c..d3a814efbff6 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -305,7 +305,7 @@
 .macro CHECK_AND_APPLY_ESPFIX
 #ifdef CONFIG_X86_ESPFIX32
 #define GDT_ESPFIX_OFFSET (GDT_ENTRY_ESPFIX_SS * 8)
-#define GDT_ESPFIX_SS PER_CPU_VAR(gdt_page) + GDT_ESPFIX_OFFSET
+#define GDT_ESPFIX_SS PER_CPU_VAR(gdt_page + GDT_ESPFIX_OFFSET)
 
 	ALTERNATIVE	"jmp .Lend_\@", "", X86_BUG_ESPFIX
 
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index a19ed151a813..8af2a26b24f6 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -191,7 +191,7 @@ SYM_FUNC_START(__switch_to_asm)
 
 #ifdef CONFIG_STACKPROTECTOR
 	movq	TASK_stack_canary(%rsi), %rbx
-	movq	%rbx, PER_CPU_VAR(fixed_percpu_data) + FIXED_stack_canary
+	movq	%rbx, PER_CPU_VAR(fixed_percpu_data + FIXED_stack_canary)
 #endif
 
 	/*
@@ -561,7 +561,7 @@ SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL)
 #ifdef CONFIG_XEN_PV
 	ALTERNATIVE "", "jmp xenpv_restore_regs_and_return_to_usermode", X86_FEATURE_XENPV
 #endif
-#ifdef CONFIG_PAGE_TABLE_ISOLATION
+#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
 	ALTERNATIVE "", "jmp .Lpti_restore_regs_and_return_to_usermode", X86_FEATURE_PTI
 #endif
 
@@ -578,7 +578,7 @@ SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL)
 	jnz	.Lnative_iret
 	ud2
 
-#ifdef CONFIG_PAGE_TABLE_ISOLATION
+#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
 .Lpti_restore_regs_and_return_to_usermode:
 	POP_REGS pop_rdi=0
 
@@ -1098,7 +1098,7 @@ SYM_CODE_END(error_return)
  *
  * Registers:
  *	%r14: Used to save/restore the CR3 of the interrupted context
- *	      when PAGE_TABLE_ISOLATION is in use.  Do not clobber.
+ *	      when MITIGATION_PAGE_TABLE_ISOLATION is in use.  Do not clobber.
  */
 SYM_CODE_START(asm_exc_nmi)
 	UNWIND_HINT_IRET_ENTRY
diff --git a/arch/x86/entry/thunk_32.S b/arch/x86/entry/thunk_32.S
index 0103e103a657..da37f42f4549 100644
--- a/arch/x86/entry/thunk_32.S
+++ b/arch/x86/entry/thunk_32.S
@@ -4,33 +4,15 @@
  * Copyright 2008 by Steven Rostedt, Red Hat, Inc
  *  (inspired by Andi Kleen's thunk_64.S)
  */
-	#include <linux/export.h>
-	#include <linux/linkage.h>
-	#include <asm/asm.h>
 
-	/* put return address in eax (arg1) */
-	.macro THUNK name, func, put_ret_addr_in_eax=0
-SYM_CODE_START_NOALIGN(\name)
-	pushl %eax
-	pushl %ecx
-	pushl %edx
+#include <linux/export.h>
+#include <linux/linkage.h>
+#include <asm/asm.h>
 
-	.if \put_ret_addr_in_eax
-	/* Place EIP in the arg1 */
-	movl 3*4(%esp), %eax
-	.endif
+#include "calling.h"
 
-	call \func
-	popl %edx
-	popl %ecx
-	popl %eax
-	RET
-	_ASM_NOKPROBE(\name)
-SYM_CODE_END(\name)
-	.endm
-
-	THUNK preempt_schedule_thunk, preempt_schedule
-	THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace
-	EXPORT_SYMBOL(preempt_schedule_thunk)
-	EXPORT_SYMBOL(preempt_schedule_notrace_thunk)
+THUNK preempt_schedule_thunk, preempt_schedule
+THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace
+EXPORT_SYMBOL(preempt_schedule_thunk)
+EXPORT_SYMBOL(preempt_schedule_notrace_thunk)
 
diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S
index 416b400f39db..119ebdc3d362 100644
--- a/arch/x86/entry/thunk_64.S
+++ b/arch/x86/entry/thunk_64.S
@@ -9,39 +9,6 @@
 #include "calling.h"
 #include <asm/asm.h>
 
-	/* rdi:	arg1 ... normal C conventions. rax is saved/restored. */
-	.macro THUNK name, func
-SYM_FUNC_START(\name)
-	pushq %rbp
-	movq %rsp, %rbp
-
-	pushq %rdi
-	pushq %rsi
-	pushq %rdx
-	pushq %rcx
-	pushq %rax
-	pushq %r8
-	pushq %r9
-	pushq %r10
-	pushq %r11
-
-	call \func
-
-	popq %r11
-	popq %r10
-	popq %r9
-	popq %r8
-	popq %rax
-	popq %rcx
-	popq %rdx
-	popq %rsi
-	popq %rdi
-	popq %rbp
-	RET
-SYM_FUNC_END(\name)
-	_ASM_NOKPROBE(\name)
-	.endm
-
 THUNK preempt_schedule_thunk, preempt_schedule
 THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace
 EXPORT_SYMBOL(preempt_schedule_thunk)
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index b1b8dd1608f7..620f6257bbe9 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -3,7 +3,7 @@
 # Building vDSO images for x86.
 #
 
-# Include the generic Makefile to check the built vdso.
+# Include the generic Makefile to check the built vDSO:
 include $(srctree)/lib/vdso/Makefile
 
 # Sanitizer runtimes are unavailable and cannot be linked here.
@@ -18,48 +18,39 @@ OBJECT_FILES_NON_STANDARD	:= y
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT		:= n
 
-VDSO64-$(CONFIG_X86_64)		:= y
-VDSOX32-$(CONFIG_X86_X32_ABI)	:= y
-VDSO32-$(CONFIG_X86_32)		:= y
-VDSO32-$(CONFIG_IA32_EMULATION)	:= y
-
-# files to link into the vdso
+# Files to link into the vDSO:
 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
 vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
 vobjs32-y += vdso32/vclock_gettime.o vdso32/vgetcpu.o
 vobjs-$(CONFIG_X86_SGX)	+= vsgx.o
 
-# files to link into kernel
-obj-y					+= vma.o extable.o
-KASAN_SANITIZE_vma.o			:= y
-UBSAN_SANITIZE_vma.o			:= y
-KCSAN_SANITIZE_vma.o			:= y
-OBJECT_FILES_NON_STANDARD_vma.o		:= n
-OBJECT_FILES_NON_STANDARD_extable.o	:= n
+# Files to link into the kernel:
+obj-y						+= vma.o extable.o
+KASAN_SANITIZE_vma.o				:= y
+UBSAN_SANITIZE_vma.o				:= y
+KCSAN_SANITIZE_vma.o				:= y
+
+OBJECT_FILES_NON_STANDARD_vma.o			:= n
+OBJECT_FILES_NON_STANDARD_extable.o		:= n
 
-# vDSO images to build
-vdso_img-$(VDSO64-y)		+= 64
-vdso_img-$(VDSOX32-y)		+= x32
-vdso_img-$(VDSO32-y)		+= 32
+# vDSO images to build:
+obj-$(CONFIG_X86_64)				+= vdso-image-64.o
+obj-$(CONFIG_X86_X32_ABI)			+= vdso-image-x32.o
+obj-$(CONFIG_COMPAT_32)				+= vdso-image-32.o vdso32-setup.o
 
-obj-$(VDSO32-y)				 += vdso32-setup.o
-OBJECT_FILES_NON_STANDARD_vdso32-setup.o := n
+OBJECT_FILES_NON_STANDARD_vdso-image-32.o	:= n
+OBJECT_FILES_NON_STANDARD_vdso-image-64.o	:= n
+OBJECT_FILES_NON_STANDARD_vdso32-setup.o	:= n
 
-vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
-vobjs32 := $(foreach F,$(vobjs32-y),$(obj)/$F)
+vobjs := $(addprefix $(obj)/, $(vobjs-y))
+vobjs32 := $(addprefix $(obj)/, $(vobjs32-y))
 
 $(obj)/vdso.o: $(obj)/vdso.so
 
 targets += vdso.lds $(vobjs-y)
 targets += vdso32/vdso32.lds $(vobjs32-y)
 
-# Build the vDSO image C files and link them in.
-vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
-vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
-vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
-obj-y += $(vdso_img_objs)
-targets += $(vdso_img_cfiles)
-targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
+targets += $(foreach x, 64 x32 32, vdso-image-$(x).c vdso$(x).so vdso$(x).so.dbg)
 
 CPPFLAGS_vdso.lds += -P -C
 
@@ -87,7 +78,7 @@ CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
        -fno-omit-frame-pointer -foptimize-sibling-calls \
        -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
 
-ifdef CONFIG_RETPOLINE
+ifdef CONFIG_MITIGATION_RETPOLINE
 ifneq ($(RETPOLINE_VDSO_CFLAGS),)
   CFL += $(RETPOLINE_VDSO_CFLAGS)
 endif
@@ -123,7 +114,7 @@ VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
 vobjx32s-y := $(vobjs-y:.o=-x32.o)
 
 # same thing, but in the output directory
-vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
+vobjx32s := $(addprefix $(obj)/, $(vobjx32s-y))
 
 # Convert 64bit object file to x32 for x32 vDSO.
 quiet_cmd_x32 = X32     $@
@@ -164,7 +155,7 @@ KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
 
-ifdef CONFIG_RETPOLINE
+ifdef CONFIG_MITIGATION_RETPOLINE
 ifneq ($(RETPOLINE_VDSO_CFLAGS),)
   KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS)
 endif
@@ -190,5 +181,3 @@ GCOV_PROFILE := n
 
 quiet_cmd_vdso_and_check = VDSO    $@
       cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check)
-
-clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 7645730dc228..6d83ceb7f1ba 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -274,59 +274,6 @@ up_fail:
 	return ret;
 }
 
-#ifdef CONFIG_X86_64
-/*
- * Put the vdso above the (randomized) stack with another randomized
- * offset.  This way there is no hole in the middle of address space.
- * To save memory make sure it is still in the same PTE as the stack
- * top.  This doesn't give that many random bits.
- *
- * Note that this algorithm is imperfect: the distribution of the vdso
- * start address within a PMD is biased toward the end.
- *
- * Only used for the 64-bit and x32 vdsos.
- */
-static unsigned long vdso_addr(unsigned long start, unsigned len)
-{
-	unsigned long addr, end;
-	unsigned offset;
-
-	/*
-	 * Round up the start address.  It can start out unaligned as a result
-	 * of stack start randomization.
-	 */
-	start = PAGE_ALIGN(start);
-
-	/* Round the lowest possible end address up to a PMD boundary. */
-	end = (start + len + PMD_SIZE - 1) & PMD_MASK;
-	if (end >= DEFAULT_MAP_WINDOW)
-		end = DEFAULT_MAP_WINDOW;
-	end -= len;
-
-	if (end > start) {
-		offset = get_random_u32_below(((end - start) >> PAGE_SHIFT) + 1);
-		addr = start + (offset << PAGE_SHIFT);
-	} else {
-		addr = start;
-	}
-
-	/*
-	 * Forcibly align the final address in case we have a hardware
-	 * issue that requires alignment for performance reasons.
-	 */
-	addr = align_vdso_addr(addr);
-
-	return addr;
-}
-
-static int map_vdso_randomized(const struct vdso_image *image)
-{
-	unsigned long addr = vdso_addr(current->mm->start_stack, image->size-image->sym_vvar_start);
-
-	return map_vdso(image, addr);
-}
-#endif
-
 int map_vdso_once(const struct vdso_image *image, unsigned long addr)
 {
 	struct mm_struct *mm = current->mm;
@@ -369,7 +316,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (!vdso64_enabled)
 		return 0;
 
-	return map_vdso_randomized(&vdso_image_64);
+	return map_vdso(&vdso_image_64, 0);
 }
 
 #ifdef CONFIG_COMPAT
@@ -380,7 +327,7 @@ int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
 	if (x32) {
 		if (!vdso64_enabled)
 			return 0;
-		return map_vdso_randomized(&vdso_image_x32);
+		return map_vdso(&vdso_image_x32, 0);
 	}
 #endif
 #ifdef CONFIG_IA32_EMULATION