6 files changed, 19 insertions, 44 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 0d0c9d4ab6d5..47c410d99f5d 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1059,9 +1059,6 @@ ENTRY(mcount)
 END(mcount)
 
 ENTRY(ftrace_caller)
-	cmpl $0, function_trace_stop
-	jne  ftrace_stub
-
 	pushl %eax
 	pushl %ecx
 	pushl %edx
@@ -1093,8 +1090,6 @@ END(ftrace_caller)
 
 ENTRY(ftrace_regs_caller)
 	pushf	/* push flags before compare (in cs location) */
-	cmpl $0, function_trace_stop
-	jne ftrace_restore_flags
 
 	/*
 	 * i386 does not save SS and ESP when coming from kernel.
@@ -1153,7 +1148,6 @@ GLOBAL(ftrace_regs_call)
 	popf			/* Pop flags at end (no addl to corrupt flags) */
 	jmp ftrace_ret
 
-ftrace_restore_flags:
 	popf
 	jmp  ftrace_stub
 #else /* ! CONFIG_DYNAMIC_FTRACE */
@@ -1162,9 +1156,6 @@ ENTRY(mcount)
 	cmpl $__PAGE_OFFSET, %esp
 	jb ftrace_stub		/* Paging not enabled yet? */
 
-	cmpl $0, function_trace_stop
-	jne  ftrace_stub
-
 	cmpl $ftrace_stub, ftrace_trace_function
 	jnz trace
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b25ca969edd2..c844f0816ab8 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -830,27 +830,24 @@ restore_args:
 	RESTORE_ARGS 1,8,1
 
 irq_return:
+	INTERRUPT_RETURN
+
+ENTRY(native_iret)
 	/*
 	 * Are we returning to a stack segment from the LDT?  Note: in
 	 * 64-bit mode SS:RSP on the exception stack is always valid.
 	 */
 #ifdef CONFIG_X86_ESPFIX64
 	testb $4,(SS-RIP)(%rsp)
-	jnz irq_return_ldt
+	jnz native_irq_return_ldt
 #endif
 
-irq_return_iret:
-	INTERRUPT_RETURN
-	_ASM_EXTABLE(irq_return_iret, bad_iret)
-
-#ifdef CONFIG_PARAVIRT
-ENTRY(native_iret)
+native_irq_return_iret:
 	iretq
-	_ASM_EXTABLE(native_iret, bad_iret)
-#endif
+	_ASM_EXTABLE(native_irq_return_iret, bad_iret)
 
 #ifdef CONFIG_X86_ESPFIX64
-irq_return_ldt:
+native_irq_return_ldt:
 	pushq_cfi %rax
 	pushq_cfi %rdi
 	SWAPGS
@@ -872,7 +869,7 @@ irq_return_ldt:
 	SWAPGS
 	movq %rax,%rsp
 	popq_cfi %rax
-	jmp irq_return_iret
+	jmp native_irq_return_iret
 #endif
 
 	.section .fixup,"ax"
@@ -956,13 +953,8 @@ __do_double_fault:
 	cmpl $__KERNEL_CS,CS(%rdi)
 	jne do_double_fault
 	movq RIP(%rdi),%rax
-	cmpq $irq_return_iret,%rax
-#ifdef CONFIG_PARAVIRT
-	je 1f
-	cmpq $native_iret,%rax
-#endif
+	cmpq $native_irq_return_iret,%rax
 	jne do_double_fault		/* This shouldn't happen... */
-1:
 	movq PER_CPU_VAR(kernel_stack),%rax
 	subq $(6*8-KERNEL_STACK_OFFSET),%rax	/* Reset to original stack */
 	movq %rax,RSP(%rdi)
@@ -1428,7 +1420,7 @@ error_sti:
  */
 error_kernelspace:
 	incl %ebx
-	leaq irq_return_iret(%rip),%rcx
+	leaq native_irq_return_iret(%rip),%rcx
 	cmpq %rcx,RIP+8(%rsp)
 	je error_swapgs
 	movl %ecx,%eax	/* zero extend */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index cbc4a91b131e..3386dc9aa333 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -703,6 +703,9 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
 	unsigned long return_hooker = (unsigned long)
 				&return_to_handler;
 
+	if (unlikely(ftrace_graph_is_dead()))
+		return;
+
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;
 
diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S
index c050a0153168..c73aecf10d34 100644
--- a/arch/x86/kernel/mcount_64.S
+++ b/arch/x86/kernel/mcount_64.S
@@ -46,10 +46,6 @@ END(function_hook)
 .endm
 
 ENTRY(ftrace_caller)
-	/* Check if tracing was disabled (quick check) */
-	cmpl $0, function_trace_stop
-	jne  ftrace_stub
-
 	ftrace_caller_setup
 	/* regs go into 4th parameter (but make it NULL) */
 	movq $0, %rcx
@@ -73,10 +69,6 @@ ENTRY(ftrace_regs_caller)
 	/* Save the current flags before compare (in SS location)*/
 	pushfq
 
-	/* Check if tracing was disabled (quick check) */
-	cmpl $0, function_trace_stop
-	jne  ftrace_restore_flags
-
 	/* skip=8 to skip flags saved in SS */
 	ftrace_caller_setup 8
 
@@ -131,7 +123,7 @@ GLOBAL(ftrace_regs_call)
 	popfq
 
 	jmp ftrace_return
-ftrace_restore_flags:
+
 	popfq
 	jmp  ftrace_stub
 
@@ -141,9 +133,6 @@ END(ftrace_regs_caller)
 #else /* ! CONFIG_DYNAMIC_FTRACE */
 
 ENTRY(function_hook)
-	cmpl $0, function_trace_stop
-	jne  ftrace_stub
-
 	cmpq $ftrace_stub, ftrace_trace_function
 	jnz trace
 
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index 3f08f34f93eb..a1da6737ba5b 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -6,7 +6,6 @@ DEF_NATIVE(pv_irq_ops, irq_disable, "cli");
 DEF_NATIVE(pv_irq_ops, irq_enable, "sti");
 DEF_NATIVE(pv_irq_ops, restore_fl, "pushq %rdi; popfq");
 DEF_NATIVE(pv_irq_ops, save_fl, "pushfq; popq %rax");
-DEF_NATIVE(pv_cpu_ops, iret, "iretq");
 DEF_NATIVE(pv_mmu_ops, read_cr2, "movq %cr2, %rax");
 DEF_NATIVE(pv_mmu_ops, read_cr3, "movq %cr3, %rax");
 DEF_NATIVE(pv_mmu_ops, write_cr3, "movq %rdi, %cr3");
@@ -50,7 +49,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
 		PATCH_SITE(pv_irq_ops, save_fl);
 		PATCH_SITE(pv_irq_ops, irq_enable);
 		PATCH_SITE(pv_irq_ops, irq_disable);
-		PATCH_SITE(pv_cpu_ops, iret);
 		PATCH_SITE(pv_cpu_ops, irq_enable_sysexit);
 		PATCH_SITE(pv_cpu_ops, usergs_sysret32);
 		PATCH_SITE(pv_cpu_ops, usergs_sysret64);
diff --git a/arch/x86/kernel/resource.c b/arch/x86/kernel/resource.c
index 2a26819bb6a8..80eab01c1a68 100644
--- a/arch/x86/kernel/resource.c
+++ b/arch/x86/kernel/resource.c
@@ -37,10 +37,12 @@ static void remove_e820_regions(struct resource *avail)
 
 void arch_remove_reservations(struct resource *avail)
 {
-	/* Trim out BIOS areas (low 1MB and high 2MB) and E820 regions */
+	/*
+	 * Trim out BIOS area (high 2MB) and E820 regions. We do not remove
+	 * the low 1MB unconditionally, as this area is needed for some ISA
+	 * cards requiring a memory range, e.g. the i82365 PCMCIA controller.
+	 */
 	if (avail->flags & IORESOURCE_MEM) {
-		if (avail->start < BIOS_END)
-			avail->start = BIOS_END;
 		resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
 
 		remove_e820_regions(avail);