2018-01-06 17:13:39 +03:00
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From f9bbe642761e841720222bcb912d920875f6ead2 Mon Sep 17 00:00:00 2001
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From: Andy Lutomirski <luto@kernel.org>
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Date: Mon, 4 Dec 2017 15:07:28 +0100
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2018-01-08 13:50:09 +03:00
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Subject: [PATCH 158/242] x86/entry: Clean up the SYSENTER_stack code
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2018-01-06 17:13:39 +03:00
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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The existing code was a mess, mainly because C arrays are nasty. Turn
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SYSENTER_stack into a struct, add a helper to find it, and do all the
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obvious cleanups this enables.
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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Reviewed-by: Borislav Petkov <bpetkov@suse.de>
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Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Dave Hansen <dave.hansen@intel.com>
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Cc: Dave Hansen <dave.hansen@linux.intel.com>
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Cc: David Laight <David.Laight@aculab.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: Eduardo Valentin <eduval@amazon.com>
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Cc: Greg KH <gregkh@linuxfoundation.org>
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Cc: H. Peter Anvin <hpa@zytor.com>
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Cc: Josh Poimboeuf <jpoimboe@redhat.com>
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Cc: Juergen Gross <jgross@suse.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Rik van Riel <riel@redhat.com>
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Cc: Will Deacon <will.deacon@arm.com>
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Cc: aliguori@amazon.com
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Cc: daniel.gruss@iaik.tugraz.at
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Cc: hughd@google.com
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Cc: keescook@google.com
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Link: https://lkml.kernel.org/r/20171204150606.653244723@linutronix.de
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 0f9a48100fba3f189724ae88a450c2261bf91c80)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit a308af33c794110c52427ad11d3a6d35ffc14b76)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/include/asm/fixmap.h | 5 +++++
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arch/x86/include/asm/processor.h | 6 +++++-
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arch/x86/kernel/asm-offsets.c | 6 ++----
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arch/x86/kernel/cpu/common.c | 14 +++-----------
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arch/x86/kernel/dumpstack.c | 7 +++----
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arch/x86/entry/entry_32.S | 4 ++--
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arch/x86/entry/entry_64.S | 2 +-
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7 files changed, 21 insertions(+), 23 deletions(-)
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diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
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index 953aed54cb5e..56aaffbbffd6 100644
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--- a/arch/x86/include/asm/fixmap.h
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+++ b/arch/x86/include/asm/fixmap.h
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@@ -225,5 +225,10 @@ static inline struct cpu_entry_area *get_cpu_entry_area(int cpu)
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return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0));
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}
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+static inline struct SYSENTER_stack *cpu_SYSENTER_stack(int cpu)
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+{
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+ return &get_cpu_entry_area(cpu)->tss.SYSENTER_stack;
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+}
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+
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_X86_FIXMAP_H */
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diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
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index 4737d378d7b5..2d489a414a86 100644
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--- a/arch/x86/include/asm/processor.h
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+++ b/arch/x86/include/asm/processor.h
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@@ -330,12 +330,16 @@ struct x86_hw_tss {
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#define IO_BITMAP_OFFSET (offsetof(struct tss_struct, io_bitmap) - offsetof(struct tss_struct, x86_tss))
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#define INVALID_IO_BITMAP_OFFSET 0x8000
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+struct SYSENTER_stack {
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+ unsigned long words[64];
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+};
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+
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struct tss_struct {
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/*
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* Space for the temporary SYSENTER stack, used for SYSENTER
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* and the entry trampoline as well.
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*/
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- unsigned long SYSENTER_stack[64];
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+ struct SYSENTER_stack SYSENTER_stack;
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/*
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* The fixed hardware portion. This must not cross a page boundary
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diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
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index 822be00c85ff..00ea20bfa857 100644
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--- a/arch/x86/kernel/asm-offsets.c
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+++ b/arch/x86/kernel/asm-offsets.c
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@@ -93,10 +93,8 @@ void common(void) {
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BLANK();
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DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
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- /* Offset from cpu_tss to SYSENTER_stack */
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- OFFSET(CPU_TSS_SYSENTER_stack, tss_struct, SYSENTER_stack);
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- /* Size of SYSENTER_stack */
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- DEFINE(SIZEOF_SYSENTER_stack, sizeof(((struct tss_struct *)0)->SYSENTER_stack));
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+ OFFSET(TSS_STRUCT_SYSENTER_stack, tss_struct, SYSENTER_stack);
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+ DEFINE(SIZEOF_SYSENTER_stack, sizeof(struct SYSENTER_stack));
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/* Layout info for cpu_entry_area */
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OFFSET(CPU_ENTRY_AREA_tss, cpu_entry_area, tss);
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diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
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index f487766855d3..f9541c48c290 100644
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--- a/arch/x86/kernel/cpu/common.c
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+++ b/arch/x86/kernel/cpu/common.c
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@@ -1306,12 +1306,7 @@ void enable_sep_cpu(void)
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tss->x86_tss.ss1 = __KERNEL_CS;
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wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0);
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-
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- wrmsr(MSR_IA32_SYSENTER_ESP,
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- (unsigned long)&get_cpu_entry_area(cpu)->tss +
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- offsetofend(struct tss_struct, SYSENTER_stack),
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- 0);
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-
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+ wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1), 0);
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wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);
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put_cpu();
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@@ -1437,9 +1432,7 @@ void syscall_init(void)
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* AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
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*/
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wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
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- wrmsrl_safe(MSR_IA32_SYSENTER_ESP,
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- (unsigned long)&get_cpu_entry_area(cpu)->tss +
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- offsetofend(struct tss_struct, SYSENTER_stack));
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+ wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1));
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wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
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#else
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wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret);
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@@ -1653,8 +1646,7 @@ void cpu_init(void)
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*/
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set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
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load_TR_desc();
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- load_sp0((unsigned long)&get_cpu_entry_area(cpu)->tss +
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- offsetofend(struct tss_struct, SYSENTER_stack));
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+ load_sp0((unsigned long)(cpu_SYSENTER_stack(cpu) + 1));
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load_mm_ldt(&init_mm);
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diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
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index c32c6cce9dcc..b005e5ef6738 100644
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--- a/arch/x86/kernel/dumpstack.c
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+++ b/arch/x86/kernel/dumpstack.c
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@@ -45,11 +45,10 @@ bool in_task_stack(unsigned long *stack, struct task_struct *task,
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bool in_sysenter_stack(unsigned long *stack, struct stack_info *info)
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{
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- int cpu = smp_processor_id();
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- struct tss_struct *tss = &get_cpu_entry_area(cpu)->tss;
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+ struct SYSENTER_stack *ss = cpu_SYSENTER_stack(smp_processor_id());
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- void *begin = &tss->SYSENTER_stack;
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- void *end = (void *)&tss->SYSENTER_stack + sizeof(tss->SYSENTER_stack);
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+ void *begin = ss;
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+ void *end = ss + 1;
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if ((void *)stack < begin || (void *)stack >= end)
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return false;
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diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
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index 41e0e103f090..04abcd3f8e2d 100644
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--- a/arch/x86/entry/entry_32.S
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+++ b/arch/x86/entry/entry_32.S
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@@ -949,7 +949,7 @@ ENTRY(debug)
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/* Are we currently on the SYSENTER stack? */
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movl PER_CPU_VAR(cpu_entry_area), %ecx
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- addl $CPU_ENTRY_AREA_tss + CPU_TSS_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
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+ addl $CPU_ENTRY_AREA_tss + TSS_STRUCT_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
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subl %eax, %ecx /* ecx = (end of SYSENTER_stack) - esp */
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cmpl $SIZEOF_SYSENTER_stack, %ecx
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jb .Ldebug_from_sysenter_stack
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@@ -993,7 +993,7 @@ ENTRY(nmi)
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/* Are we currently on the SYSENTER stack? */
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movl PER_CPU_VAR(cpu_entry_area), %ecx
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- addl $CPU_ENTRY_AREA_tss + CPU_TSS_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
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+ addl $CPU_ENTRY_AREA_tss + TSS_STRUCT_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
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subl %eax, %ecx /* ecx = (end of SYSENTER_stack) - esp */
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cmpl $SIZEOF_SYSENTER_stack, %ecx
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jb .Lnmi_from_sysenter_stack
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diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
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index dc100a7052ee..7a5e9edcdaf4 100644
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--- a/arch/x86/entry/entry_64.S
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+++ b/arch/x86/entry/entry_64.S
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@@ -153,7 +153,7 @@ END(native_usergs_sysret64)
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_entry_trampoline - CPU_ENTRY_AREA_entry_trampoline(%rip)
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/* The top word of the SYSENTER stack is hot and is usable as scratch space. */
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-#define RSP_SCRATCH CPU_ENTRY_AREA_tss + CPU_TSS_SYSENTER_stack + \
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+#define RSP_SCRATCH CPU_ENTRY_AREA_tss + TSS_STRUCT_SYSENTER_stack + \
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SIZEOF_SYSENTER_stack - 8 + CPU_ENTRY_AREA
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ENTRY(entry_SYSCALL_64_trampoline)
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--
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2.14.2
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