This is a note to let you know that I've just added the patch titled
x86/entry/64: Allocate and enable the SYSENTER stack
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-entry-64-allocate-and-enable-the-sysenter-stack.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1a79797b58cddfa948420a7553241c79c013e3ca Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@xxxxxxxxxx>
Date: Mon, 4 Dec 2017 15:07:12 +0100
Subject: x86/entry/64: Allocate and enable the SYSENTER stack
From: Andy Lutomirski <luto@xxxxxxxxxx>
commit 1a79797b58cddfa948420a7553241c79c013e3ca upstream.
This will simplify future changes that want scratch variables early in
the SYSENTER handler -- they'll be able to spill registers to the
stack. It also lets us get rid of a SWAPGS_UNSAFE_STACK user.
This does not depend on CONFIG_IA32_EMULATION=y because we'll want the
stack space even without IA32 emulation.
As far as I can tell, the reason that this wasn't done from day 1 is
that we use IST for #DB and #BP, which is IMO rather nasty and causes
a lot more problems than it solves. But, since #DB uses IST, we don't
actually need a real stack for SYSENTER (because SYSENTER with TF set
will invoke #DB on the IST stack rather than the SYSENTER stack).
I want to remove IST usage from these vectors some day, and this patch
is a prerequisite for that as well.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Borislav Petkov <bpetkov@xxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Eduardo Valentin <eduval@xxxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: aliguori@xxxxxxxxxx
Cc: daniel.gruss@xxxxxxxxxxxxxx
Cc: hughd@xxxxxxxxxx
Cc: keescook@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20171204150605.312726423@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/entry/entry_64_compat.S | 2 +-
arch/x86/include/asm/processor.h | 3 ---
arch/x86/kernel/asm-offsets.c | 5 +++++
arch/x86/kernel/asm-offsets_32.c | 5 -----
arch/x86/kernel/cpu/common.c | 4 +++-
arch/x86/kernel/process.c | 2 --
arch/x86/kernel/traps.c | 3 +--
7 files changed, 10 insertions(+), 14 deletions(-)
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -48,7 +48,7 @@
*/
ENTRY(entry_SYSENTER_compat)
/* Interrupts are off on entry. */
- SWAPGS_UNSAFE_STACK
+ SWAPGS
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
/*
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -339,14 +339,11 @@ struct tss_struct {
*/
unsigned long io_bitmap[IO_BITMAP_LONGS + 1];
-#ifdef CONFIG_X86_32
/*
* Space for the temporary SYSENTER stack.
*/
unsigned long SYSENTER_stack_canary;
unsigned long SYSENTER_stack[64];
-#endif
-
} ____cacheline_aligned;
DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -93,4 +93,9 @@ void common(void) {
BLANK();
DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
+
+ /* Offset from cpu_tss to SYSENTER_stack */
+ OFFSET(CPU_TSS_SYSENTER_stack, tss_struct, SYSENTER_stack);
+ /* Size of SYSENTER_stack */
+ DEFINE(SIZEOF_SYSENTER_stack, sizeof(((struct tss_struct *)0)->SYSENTER_stack));
}
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -50,11 +50,6 @@ void foo(void)
DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) -
offsetofend(struct tss_struct, SYSENTER_stack));
- /* Offset from cpu_tss to SYSENTER_stack */
- OFFSET(CPU_TSS_SYSENTER_stack, tss_struct, SYSENTER_stack);
- /* Size of SYSENTER_stack */
- DEFINE(SIZEOF_SYSENTER_stack, sizeof(((struct tss_struct *)0)->SYSENTER_stack));
-
#ifdef CONFIG_CC_STACKPROTECTOR
BLANK();
OFFSET(stack_canary_offset, stack_canary, canary);
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1361,7 +1361,9 @@ void syscall_init(void)
* AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
*/
wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
- wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
+ wrmsrl_safe(MSR_IA32_SYSENTER_ESP,
+ (unsigned long)this_cpu_ptr(&cpu_tss) +
+ offsetofend(struct tss_struct, SYSENTER_stack));
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
#else
wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret);
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -71,9 +71,7 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(
*/
.io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 },
#endif
-#ifdef CONFIG_X86_32
.SYSENTER_stack_canary = STACK_END_MAGIC,
-#endif
};
EXPORT_PER_CPU_SYMBOL(cpu_tss);
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -794,14 +794,13 @@ dotraplinkage void do_debug(struct pt_re
debug_stack_usage_dec();
exit:
-#if defined(CONFIG_X86_32)
/*
* This is the most likely code path that involves non-trivial use
* of the SYSENTER stack. Check that we haven't overrun it.
*/
WARN(this_cpu_read(cpu_tss.SYSENTER_stack_canary) != STACK_END_MAGIC,
"Overran or corrupted SYSENTER stack\n");
-#endif
+
ist_exit(regs);
}
NOKPROBE_SYMBOL(do_debug);
Patches currently in stable-queue which might be from luto@xxxxxxxxxx are
queue-4.14/x86-entry-64-simplify-reg-restore-code-in-the-standard-iret-paths.patch
queue-4.14/x86-cpufeatures-fix-various-details-in-the-feature-definitions.patch
queue-4.14/x86-entry-64-move-the-ist-stacks-into-struct-cpu_entry_area.patch
queue-4.14/x86-dumpstack-add-get_stack_info-support-for-the-sysenter-stack.patch
queue-4.14/x86-asm-don-t-use-the-confusing-.ifeq-directive.patch
queue-4.14/selftests-x86-ldt_gdt-add-infrastructure-to-test-set_thread_area.patch
queue-4.14/x86-entry-remap-the-tss-into-the-cpu-entry-area.patch
queue-4.14/x86-entry-64-paravirt-use-paravirt-safe-macro-to-access-eflags.patch
queue-4.14/x86-mm-fixmap-generalize-the-gdt-fixmap-mechanism-introduce-struct-cpu_entry_area.patch
queue-4.14/x86-paravirt-dont-patch-flush_tlb_single.patch
queue-4.14/x86-dumpstack-handle-stack-overflow-on-all-stacks.patch
queue-4.14/x86-entry-64-use-pop-instead-of-movq-in-syscall_return_via_sysret.patch
queue-4.14/x86-entry-64-return-to-userspace-from-the-trampoline-stack.patch
queue-4.14/x86-paravirt-provide-a-way-to-check-for-hypervisors.patch
queue-4.14/xen-x86-entry-64-add-xen-nmi-trap-entry.patch
queue-4.14/x86-entry-64-remove-the-restore_c_regs_and_iret-label.patch
queue-4.14/x86-entry-64-create-a-per-cpu-syscall-entry-trampoline.patch
queue-4.14/x86-entry-64-remove-the-restore_..._regs-infrastructure.patch
queue-4.14/x86-xen-64-x86-entry-64-clean-up-sp-code-in-cpu_initialize_context.patch
queue-4.14/x86-entry-add-task_top_of_stack-to-find-the-top-of-a-task-s-stack.patch
queue-4.14/x86-entry-64-remove-all-remaining-direct-thread_struct-sp0-reads.patch
queue-4.14/x86-boot-relocate-definition-of-the-initial-state-of-cr0.patch
queue-4.14/x86-entry-64-stop-initializing-tss.sp0-at-boot.patch
queue-4.14/x86-entry-64-de-xen-ify-our-nmi-code.patch
queue-4.14/objtool-don-t-report-end-of-section-error-after-an-empty-unwind-hint.patch
queue-4.14/x86-entry-64-pass-sp0-directly-to-load_sp0.patch
queue-4.14/x86-entry-64-use-a-per-cpu-trampoline-stack-for-idt-entries.patch
queue-4.14/x86-entry-64-move-swapgs-into-the-common-iret-to-usermode-path.patch
queue-4.14/x86-entry-64-shorten-test-instructions.patch
queue-4.14/x86-cpufeature-add-user-mode-instruction-prevention-definitions.patch
queue-4.14/x86-cpufeatures-make-cpu-bugs-sticky.patch
queue-4.14/x86-espfix-64-stop-assuming-that-pt_regs-is-on-the-entry-stack.patch
queue-4.14/x86-traps-use-a-new-on_thread_stack-helper-to-clean-up-an-assertion.patch
queue-4.14/x86-xen-fix-xen-head-elf-annotations.patch
queue-4.14/x86-entry-64-remove-thread_struct-sp0.patch
queue-4.14/x86-entry-move-sysenter_stack-to-the-beginning-of-struct-tss_struct.patch
queue-4.14/x86-entry-64-allocate-and-enable-the-sysenter-stack.patch
queue-4.14/x86-unwinder-orc-dont-bail-on-stack-overflow.patch
queue-4.14/x86-head-fix-head-elf-function-annotations.patch
queue-4.14/selftests-x86-ldt_gdt-run-most-existing-ldt-test-cases-against-the-gdt-as-well.patch
queue-4.14/x86-entry-32-pull-the-msr_ia32_sysenter_cs-update-code-out-of-native_load_sp0.patch
queue-4.14/x86-entry-64-split-the-iret-to-user-and-iret-to-kernel-paths.patch
queue-4.14/x86-entry-64-shrink-paranoid_exit_restore-and-make-labels-local.patch
queue-4.14/x86-head-add-unwind-hint-annotations.patch
queue-4.14/x86-head-remove-unused-bad_address-code.patch
queue-4.14/x86-xen-add-unwind-hint-annotations.patch
queue-4.14/x86-kasan-64-teach-kasan-about-the-cpu_entry_area.patch
queue-4.14/x86-head-remove-confusing-comment.patch
queue-4.14/x86-entry-64-remove-the-sysenter-stack-canary.patch
queue-4.14/x86-mm-kasan-don-t-use-vmemmap_populate-to-initialize-shadow.patch
queue-4.14/x86-entry-gdt-put-per-cpu-gdt-remaps-in-ascending-order.patch
queue-4.14/x86-entry-fix-assumptions-that-the-hw-tss-is-at-the-beginning-of-cpu_tss.patch
queue-4.14/x86-cpufeatures-re-tabulate-the-x86_feature-definitions.patch
queue-4.14/x86-entry-32-fix-cpu_current_top_of_stack-initialization-at-boot.patch
queue-4.14/ptrace-x86-make-user_64bit_mode-available-to-32-bit-builds.patch
queue-4.14/x86-entry-64-make-cpu_entry_area.tss-read-only.patch
queue-4.14/x86-mm-relocate-page-fault-error-codes-to-traps.h.patch
queue-4.14/x86-unwinder-handle-stack-overflows-more-gracefully.patch
queue-4.14/x86-entry-64-use-pop-instead-of-mov-to-restore-regs-on-nmi-return.patch
queue-4.14/x86-irq-64-print-the-offending-ip-in-the-stack-overflow-warning.patch
queue-4.14/x86-entry-clean-up-the-sysenter_stack-code.patch
queue-4.14/x86-entry-64-merge-the-fast-and-slow-sysret-paths.patch
queue-4.14/x86-entry-64-separate-cpu_current_top_of_stack-from-tss.sp0.patch
queue-4.14/x86-boot-annotate-verify_cpu-as-a-callable-function.patch
queue-4.14/x86-irq-remove-an-old-outdated-comment-about-context-tracking-races.patch