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Date:   Tue, 20 Sep 2016 15:02:43 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Andy Lutomirski <luto@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Brian Gerst <brgerst@...il.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Nilay Vaish <nilayvaish@...il.com>
Subject: [PATCH 1/9] x86/entry/head/32: use local labels

Add the local label prefix to all non-function named labels in head_32.S
and entry_32.S.  In addition to decluttering the symbol table, it also
will help stack traces to be more sensible.  For example, the last
reported function in the idle task stack trace will be startup_32_smp()
instead of is486().

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 arch/x86/entry/entry_32.S | 55 ++++++++++++++++++++++++-----------------------
 arch/x86/kernel/head_32.S | 32 +++++++++++++--------------
 2 files changed, 44 insertions(+), 43 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index b75a8bc..378e912 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -64,7 +64,7 @@
 # define preempt_stop(clobbers)	DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
 #else
 # define preempt_stop(clobbers)
-# define resume_kernel		restore_all
+# define resume_kernel		.Lrestore_all
 #endif
 
 .macro TRACE_IRQS_IRET
@@ -255,7 +255,7 @@ ENTRY(ret_from_fork)
 	/* When we fork, we trace the syscall return in the child, too. */
 	movl    %esp, %eax
 	call    syscall_return_slowpath
-	jmp     restore_all
+	jmp     .Lrestore_all
 
 	/* kernel thread */
 1:	movl	%edi, %eax
@@ -300,19 +300,19 @@ ENTRY(resume_userspace)
 	TRACE_IRQS_OFF
 	movl	%esp, %eax
 	call	prepare_exit_to_usermode
-	jmp	restore_all
+	jmp	.Lrestore_all
 END(ret_from_exception)
 
 #ifdef CONFIG_PREEMPT
 ENTRY(resume_kernel)
 	DISABLE_INTERRUPTS(CLBR_ANY)
-need_resched:
+.Lneed_resched:
 	cmpl	$0, PER_CPU_VAR(__preempt_count)
-	jnz	restore_all
+	jnz	.Lrestore_all
 	testl	$X86_EFLAGS_IF, PT_EFLAGS(%esp)	# interrupts off (exception path) ?
-	jz	restore_all
+	jz	.Lrestore_all
 	call	preempt_schedule_irq
-	jmp	need_resched
+	jmp	.Lneed_resched
 END(resume_kernel)
 #endif
 
@@ -333,7 +333,7 @@ GLOBAL(__begin_SYSENTER_singlestep_region)
  */
 ENTRY(xen_sysenter_target)
 	addl	$5*4, %esp			/* remove xen-provided frame */
-	jmp	sysenter_past_esp
+	jmp	.Lsysenter_past_esp
 #endif
 
 /*
@@ -370,7 +370,7 @@ ENTRY(xen_sysenter_target)
  */
 ENTRY(entry_SYSENTER_32)
 	movl	TSS_sysenter_sp0(%esp), %esp
-sysenter_past_esp:
+.Lsysenter_past_esp:
 	pushl	$__USER_DS		/* pt_regs->ss */
 	pushl	%ebp			/* pt_regs->sp (stashed in bp) */
 	pushfl				/* pt_regs->flags (except IF = 0) */
@@ -501,11 +501,11 @@ ENTRY(entry_INT80_32)
 	call	do_int80_syscall_32
 .Lsyscall_32_done:
 
-restore_all:
+.Lrestore_all:
 	TRACE_IRQS_IRET
-restore_all_notrace:
+.Lrestore_all_notrace:
 #ifdef CONFIG_X86_ESPFIX32
-	ALTERNATIVE	"jmp restore_nocheck", "", X86_BUG_ESPFIX
+	ALTERNATIVE	"jmp .Lrestore_nocheck", "", X86_BUG_ESPFIX
 
 	movl	PT_EFLAGS(%esp), %eax		# mix EFLAGS, SS and CS
 	/*
@@ -517,22 +517,23 @@ restore_all_notrace:
 	movb	PT_CS(%esp), %al
 	andl	$(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
 	cmpl	$((SEGMENT_LDT << 8) | USER_RPL), %eax
-	je ldt_ss				# returning to user-space with LDT SS
+	je .Lldt_ss				# returning to user-space with LDT SS
 #endif
-restore_nocheck:
+.Lrestore_nocheck:
 	RESTORE_REGS 4				# skip orig_eax/error_code
-irq_return:
+.Lirq_return:
 	INTERRUPT_RETURN
+
 .section .fixup, "ax"
 ENTRY(iret_exc	)
 	pushl	$0				# no error code
 	pushl	$do_iret_error
 	jmp	error_code
 .previous
-	_ASM_EXTABLE(irq_return, iret_exc)
+	_ASM_EXTABLE(.Lirq_return, iret_exc)
 
 #ifdef CONFIG_X86_ESPFIX32
-ldt_ss:
+.Lldt_ss:
 /*
  * Setup and switch to ESPFIX stack
  *
@@ -561,7 +562,7 @@ ldt_ss:
 	 */
 	DISABLE_INTERRUPTS(CLBR_EAX)
 	lss	(%esp), %esp			/* switch to espfix segment */
-	jmp	restore_nocheck
+	jmp	.Lrestore_nocheck
 #endif
 ENDPROC(entry_INT80_32)
 
@@ -881,7 +882,7 @@ ftrace_call:
 	popl	%edx
 	popl	%ecx
 	popl	%eax
-ftrace_ret:
+.Lftrace_ret:
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 .globl ftrace_graph_call
 ftrace_graph_call:
@@ -951,7 +952,7 @@ GLOBAL(ftrace_regs_call)
 	popl	%gs
 	addl	$8, %esp			/* Skip orig_ax and ip */
 	popf					/* Pop flags at end (no addl to corrupt flags) */
-	jmp	ftrace_ret
+	jmp	.Lftrace_ret
 
 	popf
 	jmp	ftrace_stub
@@ -962,7 +963,7 @@ ENTRY(mcount)
 	jb	ftrace_stub			/* Paging not enabled yet? */
 
 	cmpl	$ftrace_stub, ftrace_trace_function
-	jnz	trace
+	jnz	.Ltrace
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	cmpl	$ftrace_stub, ftrace_graph_return
 	jnz	ftrace_graph_caller
@@ -975,7 +976,7 @@ ftrace_stub:
 	ret
 
 	/* taken from glibc */
-trace:
+.Ltrace:
 	pushl	%eax
 	pushl	%ecx
 	pushl	%edx
@@ -1114,7 +1115,7 @@ ENTRY(nmi)
 	movl	%ss, %eax
 	cmpw	$__ESPFIX_SS, %ax
 	popl	%eax
-	je	nmi_espfix_stack
+	je	.Lnmi_espfix_stack
 #endif
 
 	pushl	%eax				# pt_regs->orig_ax
@@ -1130,7 +1131,7 @@ ENTRY(nmi)
 
 	/* Not on SYSENTER stack. */
 	call	do_nmi
-	jmp	restore_all_notrace
+	jmp	.Lrestore_all_notrace
 
 .Lnmi_from_sysenter_stack:
 	/*
@@ -1141,10 +1142,10 @@ ENTRY(nmi)
 	movl	PER_CPU_VAR(cpu_current_top_of_stack), %esp
 	call	do_nmi
 	movl	%ebp, %esp
-	jmp	restore_all_notrace
+	jmp	.Lrestore_all_notrace
 
 #ifdef CONFIG_X86_ESPFIX32
-nmi_espfix_stack:
+.Lnmi_espfix_stack:
 	/*
 	 * create the pointer to lss back
 	 */
@@ -1162,7 +1163,7 @@ nmi_espfix_stack:
 	call	do_nmi
 	RESTORE_REGS
 	lss	12+4(%esp), %esp		# back to espfix stack
-	jmp	irq_return
+	jmp	.Lirq_return
 #endif
 END(nmi)
 
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 5f40126..617fba2 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -247,19 +247,19 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
 #ifdef CONFIG_PARAVIRT
 	/* This is can only trip for a broken bootloader... */
 	cmpw $0x207, pa(boot_params + BP_version)
-	jb default_entry
+	jb .Ldefault_entry
 
 	/* Paravirt-compatible boot parameters.  Look to see what architecture
 		we're booting under. */
 	movl pa(boot_params + BP_hardware_subarch), %eax
 	cmpl $num_subarch_entries, %eax
-	jae bad_subarch
+	jae .Lbad_subarch
 
 	movl pa(subarch_entries)(,%eax,4), %eax
 	subl $__PAGE_OFFSET, %eax
 	jmp *%eax
 
-bad_subarch:
+.Lbad_subarch:
 WEAK(lguest_entry)
 WEAK(xen_entry)
 	/* Unknown implementation; there's really
@@ -269,14 +269,14 @@ WEAK(xen_entry)
 	__INITDATA
 
 subarch_entries:
-	.long default_entry		/* normal x86/PC */
+	.long .Ldefault_entry		/* normal x86/PC */
 	.long lguest_entry		/* lguest hypervisor */
 	.long xen_entry			/* Xen hypervisor */
-	.long default_entry		/* Moorestown MID */
+	.long .Ldefault_entry		/* Moorestown MID */
 num_subarch_entries = (. - subarch_entries) / 4
 .previous
 #else
-	jmp default_entry
+	jmp .Ldefault_entry
 #endif /* CONFIG_PARAVIRT */
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -316,7 +316,7 @@ ENTRY(startup_32_smp)
 	call load_ucode_ap
 #endif
 
-default_entry:
+.Ldefault_entry:
 #define CR0_STATE	(X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
 			 X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \
 			 X86_CR0_PG)
@@ -346,7 +346,7 @@ default_entry:
 	pushfl
 	popl %eax			# get EFLAGS
 	testl $X86_EFLAGS_ID,%eax	# did EFLAGS.ID remained set?
-	jz enable_paging		# hw disallowed setting of ID bit
+	jz .Lenable_paging		# hw disallowed setting of ID bit
 					# which means no CPUID and no CR4
 
 	xorl %eax,%eax
@@ -356,13 +356,13 @@ default_entry:
 	movl $1,%eax
 	cpuid
 	andl $~1,%edx			# Ignore CPUID.FPU
-	jz enable_paging		# No flags or only CPUID.FPU = no CR4
+	jz .Lenable_paging		# No flags or only CPUID.FPU = no CR4
 
 	movl pa(mmu_cr4_features),%eax
 	movl %eax,%cr4
 
 	testb $X86_CR4_PAE, %al		# check if PAE is enabled
-	jz enable_paging
+	jz .Lenable_paging
 
 	/* Check if extended functions are implemented */
 	movl $0x80000000, %eax
@@ -370,7 +370,7 @@ default_entry:
 	/* Value must be in the range 0x80000001 to 0x8000ffff */
 	subl $0x80000001, %eax
 	cmpl $(0x8000ffff-0x80000001), %eax
-	ja enable_paging
+	ja .Lenable_paging
 
 	/* Clear bogus XD_DISABLE bits */
 	call verify_cpu
@@ -379,7 +379,7 @@ default_entry:
 	cpuid
 	/* Execute Disable bit supported? */
 	btl $(X86_FEATURE_NX & 31), %edx
-	jnc enable_paging
+	jnc .Lenable_paging
 
 	/* Setup EFER (Extended Feature Enable Register) */
 	movl $MSR_EFER, %ecx
@@ -389,7 +389,7 @@ default_entry:
 	/* Make changes effective */
 	wrmsr
 
-enable_paging:
+.Lenable_paging:
 
 /*
  * Enable paging
@@ -418,7 +418,7 @@ enable_paging:
  */
 	movb $4,X86			# at least 486
 	cmpl $-1,X86_CPUID
-	je is486
+	je .Lis486
 
 	/* get vendor info */
 	xorl %eax,%eax			# call CPUID with 0 -> return vendor ID
@@ -429,7 +429,7 @@ enable_paging:
 	movl %ecx,X86_VENDOR_ID+8	# last 4 chars
 
 	orl %eax,%eax			# do we have processor info as well?
-	je is486
+	je .Lis486
 
 	movl $1,%eax		# Use the CPUID instruction to get CPU type
 	cpuid
@@ -443,7 +443,7 @@ enable_paging:
 	movb %cl,X86_MASK
 	movl %edx,X86_CAPABILITY
 
-is486:
+.Lis486:
 	movl $0x50022,%ecx	# set AM, WP, NE and MP
 	movl %cr0,%eax
 	andl $0x80000011,%eax	# Save PG,PE,ET
-- 
2.7.4

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