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Message-ID: <151785233522390@kroah.com>
Date: Mon, 05 Feb 2018 09:38:55 -0800
From: <gregkh@...uxfoundation.org>
To: torvalds@...ux-foundation.org,bp@...en8.de,gregkh@...uxfoundation.org,kernel-hardening@...ts.openwall.com,luto@...nel.org,mingo@...nel.org,tglx@...utronix.de
Cc: <stable@...r.kernel.org>, <stable-commits@...r.kernel.org>
Subject: Patch "x86/asm: Move 'status' from thread_struct to thread_info" has been added to the 4.15-stable tree
This is a note to let you know that I've just added the patch titled
x86/asm: Move 'status' from thread_struct to thread_info
to the 4.15-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:
x86asm_Move_status_from_thread_struct_to_thread_info.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@...r.kernel.org> know about it.
Subject: x86/asm: Move 'status' from thread_struct to thread_info
From: Andy Lutomirski luto@...nel.org
Date: Sun Jan 28 10:38:50 2018 -0800
From: Andy Lutomirski luto@...nel.org
commit 37a8f7c38339b22b69876d6f5a0ab851565284e3
The TS_COMPAT bit is very hot and is accessed from code paths that mostly
also touch thread_info::flags. Move it into struct thread_info to improve
cache locality.
The only reason it was in thread_struct is that there was a brief period
during which arch-specific fields were not allowed in struct thread_info.
Linus suggested further changing:
ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
to:
if (unlikely(ti->status & (TS_COMPAT|TS_I386_REGS_POKED)))
ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
on the theory that frequently dirtying the cacheline even in pure 64-bit
code that never needs to modify status hurts performance. That could be a
reasonable followup patch, but I suspect it matters less on top of this
patch.
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Andy Lutomirski <luto@...nel.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Ingo Molnar <mingo@...nel.org>
Acked-by: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Kernel Hardening <kernel-hardening@...ts.openwall.com>
Link: https://lkml.kernel.org/r/03148bcc1b217100e6e8ecf6a5468c45cf4304b6.1517164461.git.luto@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/entry/common.c | 4 ++--
arch/x86/include/asm/processor.h | 2 --
arch/x86/include/asm/syscall.h | 6 +++---
arch/x86/include/asm/thread_info.h | 3 ++-
arch/x86/kernel/process_64.c | 4 ++--
arch/x86/kernel/ptrace.c | 2 +-
arch/x86/kernel/signal.c | 2 +-
7 files changed, 11 insertions(+), 12 deletions(-)
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -206,7 +206,7 @@ __visible inline void prepare_exit_to_us
* special case only applies after poking regs and before the
* very next return to user mode.
*/
- current->thread.status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
+ ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
#endif
user_enter_irqoff();
@@ -304,7 +304,7 @@ static __always_inline void do_syscall_3
unsigned int nr = (unsigned int)regs->orig_ax;
#ifdef CONFIG_IA32_EMULATION
- current->thread.status |= TS_COMPAT;
+ ti->status |= TS_COMPAT;
#endif
if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -460,8 +460,6 @@ struct thread_struct {
unsigned short gsindex;
#endif
- u32 status; /* thread synchronous flags */
-
#ifdef CONFIG_X86_64
unsigned long fsbase;
unsigned long gsbase;
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -60,7 +60,7 @@ static inline long syscall_get_error(str
* TS_COMPAT is set for 32-bit syscall entries and then
* remains set until we return to user mode.
*/
- if (task->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))
+ if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
/*
* Sign-extend the value so (int)-EFOO becomes (long)-EFOO
* and will match correctly in comparisons.
@@ -116,7 +116,7 @@ static inline void syscall_get_arguments
unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
- if (task->thread.status & TS_COMPAT)
+ if (task->thread_info.status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
@@ -177,7 +177,7 @@ static inline void syscall_set_arguments
const unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
- if (task->thread.status & TS_COMPAT)
+ if (task->thread_info.status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -55,6 +55,7 @@ struct task_struct;
struct thread_info {
unsigned long flags; /* low level flags */
+ u32 status; /* thread synchronous flags */
};
#define INIT_THREAD_INFO(tsk) \
@@ -221,7 +222,7 @@ static inline int arch_within_stack_fram
#define in_ia32_syscall() true
#else
#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
- current->thread.status & TS_COMPAT)
+ current_thread_info()->status & TS_COMPAT)
#endif
/*
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -557,7 +557,7 @@ static void __set_personality_x32(void)
* Pretend to come from a x32 execve.
*/
task_pt_regs(current)->orig_ax = __NR_x32_execve | __X32_SYSCALL_BIT;
- current->thread.status &= ~TS_COMPAT;
+ current_thread_info()->status &= ~TS_COMPAT;
#endif
}
@@ -571,7 +571,7 @@ static void __set_personality_ia32(void)
current->personality |= force_personality32;
/* Prepare the first "return" to user space */
task_pt_regs(current)->orig_ax = __NR_ia32_execve;
- current->thread.status |= TS_COMPAT;
+ current_thread_info()->status |= TS_COMPAT;
#endif
}
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -935,7 +935,7 @@ static int putreg32(struct task_struct *
*/
regs->orig_ax = value;
if (syscall_get_nr(child, regs) >= 0)
- child->thread.status |= TS_I386_REGS_POKED;
+ child->thread_info.status |= TS_I386_REGS_POKED;
break;
case offsetof(struct user32, regs.eflags):
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -787,7 +787,7 @@ static inline unsigned long get_nr_resta
* than the tracee.
*/
#ifdef CONFIG_IA32_EMULATION
- if (current->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))
+ if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED))
return __NR_ia32_restart_syscall;
#endif
#ifdef CONFIG_X86_X32_ABI
Patches currently in stable-queue which might be from torvalds@...ux-foundation.org are
queue-4.15/objtool_Add_support_for_alternatives_at_the_end_of_a_section.patch
queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch
queue-4.15/x86_Introduce_barrier_nospec.patch
queue-4.15/x86speculation_Use_Indirect_Branch_Prediction_Barrier_in_context_switch.patch
queue-4.15/x86get_user_Use_pointer_masking_to_limit_speculation.patch
queue-4.15/x86_Introduce___uaccess_begin_nospec()_and_uaccess_try_nospec.patch
queue-4.15/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch
queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch
queue-4.15/x86paravirt_Remove_noreplace-paravirt_cmdline_option.patch
queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch
queue-4.15/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch
queue-4.15/x86alternative_Print_unadorned_pointers.patch
queue-4.15/KVMVMX_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch
queue-4.15/array_index_nospec_Sanitize_speculative_array_de-references.patch
queue-4.15/Documentation_Document_array_index_nospec.patch
queue-4.15/x86entry64_Remove_the_SYSCALL64_fast_path.patch
queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch
queue-4.15/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch
queue-4.15/KVMSVM_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/x86asm_Move_status_from_thread_struct_to_thread_info.patch
queue-4.15/KVMx86_Add_IBPB_support.patch
queue-4.15/x86_Implement_array_index_mask_nospec.patch
queue-4.15/KVMVMX_Emulate_MSR_IA32_ARCH_CAPABILITIES.patch
queue-4.15/nl80211_Sanitize_array_index_in_parse_txq_params.patch
queue-4.15/moduleretpoline_Warn_about_missing_retpoline_in_module.patch
queue-4.15/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch
queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch
queue-4.15/x86nospec_Fix_header_guards_names.patch
queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch
queue-4.15/x86uaccess_Use___uaccess_begin_nospec()_and_uaccess_try_nospec.patch
queue-4.15/x86entry64_Push_extra_regs_right_away.patch
queue-4.15/x86usercopy_Replace_open_coded_stacclac_with___uaccess_begin_end.patch
queue-4.15/vfs_fdtable_Prevent_bounds-check_bypass_via_speculative_execution.patch
queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch
queue-4.15/objtool_Warn_on_stripped_section_symbol.patch
queue-4.15/x86spectre_Report_get_user_mitigation_for_spectre_v1.patch
queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch
queue-4.15/x86syscall_Sanitize_syscall_table_de-references_under_speculation.patch
queue-4.15/objtool_Improve_retpoline_alternative_handling.patch
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