[PATCH 15/21] kgr: make a per-process 'in progress' flag a single bit
From: Jiri Slaby
Date: Mon Jun 23 2014 - 09:34:32 EST
From: Jiri Kosina <jkosina@xxxxxxx>
Having the per-task 'kgr_in_progress' flag stored as long is a waste
of space. And manipulating it is likely slower than just performing
single bit operations. Convert the flag to a thread info flag.
Additionally, making the KGR TI_flag part of _TIF_ALLWORK_MASK and
_TIF_WORK_SYSCALL_ENTRY allows for offloading the flag manipulation to
slow code paths.
js: use *_tsk_thread_flag helpers
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/thread_info.h | 7 ++++---
arch/x86/kernel/asm-offsets.c | 1 -
arch/x86/kernel/entry_64.S | 12 +++++++++---
include/linux/kgraft.h | 5 ++---
include/linux/sched.h | 2 +-
5 files changed, 16 insertions(+), 11 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index e44c8fda9c43..53df17c72359 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -35,7 +35,6 @@ struct thread_info {
void __user *sysenter_return;
unsigned int sig_on_uaccess_error:1;
unsigned int uaccess_err:1; /* uaccess failed */
- unsigned long kgr_in_progress;
};
#define INIT_THREAD_INFO(tsk) \
@@ -88,6 +87,7 @@ struct thread_info {
#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
+#define TIF_KGR_IN_PROGRESS 26 /* kGraft patching running */
#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
#define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
#define TIF_ADDR32 29 /* 32-bit address space on 64 bits */
@@ -112,6 +112,7 @@ struct thread_info {
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
+#define _TIF_KGR_IN_PROGRESS (1 << TIF_KGR_IN_PROGRESS)
#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_ADDR32 (1 << TIF_ADDR32)
@@ -121,7 +122,7 @@ struct thread_info {
#define _TIF_WORK_SYSCALL_ENTRY \
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \
_TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT | \
- _TIF_NOHZ)
+ _TIF_NOHZ | _TIF_KGR_IN_PROGRESS)
/* work to do in syscall_trace_leave() */
#define _TIF_WORK_SYSCALL_EXIT \
@@ -137,7 +138,7 @@ struct thread_info {
/* work to do on any return to user space */
#define _TIF_ALLWORK_MASK \
((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \
- _TIF_NOHZ)
+ _TIF_NOHZ | _TIF_KGR_IN_PROGRESS)
/* Only used for 64 bit */
#define _TIF_DO_NOTIFY_MASK \
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 0db0437967a2..9f6b9341950f 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -32,7 +32,6 @@ void common(void) {
OFFSET(TI_flags, thread_info, flags);
OFFSET(TI_status, thread_info, status);
OFFSET(TI_addr_limit, thread_info, addr_limit);
- OFFSET(TI_kgr_in_progress, thread_info, kgr_in_progress);
BLANK();
OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx);
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index a7c570abc918..edaa5abd58f9 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -409,7 +409,6 @@ GLOBAL(system_call_after_swapgs)
movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
movq %rcx,RIP-ARGOFFSET(%rsp)
CFI_REL_OFFSET rip,RIP-ARGOFFSET
- movq $0, TI_kgr_in_progress+THREAD_INFO(%rsp,RIP-ARGOFFSET)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
jnz tracesys
system_call_fastpath:
@@ -434,7 +433,6 @@ sysret_check:
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
- movq $0, TI_kgr_in_progress+THREAD_INFO(%rsp,RIP-ARGOFFSET)
movl TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET),%edx
andl %edi,%edx
jnz sysret_careful
@@ -454,6 +452,9 @@ sysret_check:
/* Handle reschedules */
/* edx: work, edi: workmask */
sysret_careful:
+#if IS_ENABLED(CONFIG_KGRAFT)
+ andl $~_TIF_KGR_IN_PROGRESS,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+#endif
bt $TIF_NEED_RESCHED,%edx
jnc sysret_signal
TRACE_IRQS_ON
@@ -517,6 +518,9 @@ sysret_audit:
/* Do syscall tracing */
tracesys:
+#if IS_ENABLED(CONFIG_KGRAFT)
+ andl $~_TIF_KGR_IN_PROGRESS,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+#endif
#ifdef CONFIG_AUDITSYSCALL
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
jz auditsys
@@ -557,7 +561,6 @@ GLOBAL(int_ret_from_sys_call)
GLOBAL(int_with_check)
LOCKDEP_SYS_EXIT_IRQ
GET_THREAD_INFO(%rcx)
- movq $0, TI_kgr_in_progress(%rcx)
movl TI_flags(%rcx),%edx
andl %edi,%edx
jnz int_careful
@@ -568,6 +571,9 @@ GLOBAL(int_with_check)
/* First do a reschedule test. */
/* edx: work, edi: workmask */
int_careful:
+#if IS_ENABLED(CONFIG_KGRAFT)
+ andl $~_TIF_KGR_IN_PROGRESS,TI_flags(%rcx)
+#endif
bt $TIF_NEED_RESCHED,%edx
jnc int_very_careful
TRACE_IRQS_ON
diff --git a/include/linux/kgraft.h b/include/linux/kgraft.h
index 93bb1c50e079..92b642408b6f 100644
--- a/include/linux/kgraft.h
+++ b/include/linux/kgraft.h
@@ -73,13 +73,12 @@ extern int kgr_start_patching(struct kgr_patch *);
static inline void kgr_mark_task_in_progress(struct task_struct *p)
{
- /* This is replaced by thread_flag later. */
- set_bit(0, &task_thread_info(p)->kgr_in_progress);
+ set_tsk_thread_flag(p, TIF_KGR_IN_PROGRESS);
}
static inline bool kgr_task_in_progress(struct task_struct *p)
{
- return test_bit(0, &task_thread_info(p)->kgr_in_progress);
+ return test_tsk_thread_flag(p, TIF_KGR_IN_PROGRESS);
}
#endif /* IS_ENABLED(CONFIG_KGRAFT) */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6bc2d63a59c4..0c037f6bba55 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2977,7 +2977,7 @@ static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
#if IS_ENABLED(CONFIG_KGRAFT)
static inline void kgr_task_safe(struct task_struct *p)
{
- clear_bit(0, &task_thread_info(p)->kgr_in_progress);
+ clear_tsk_thread_flag(p, TIF_KGR_IN_PROGRESS);
}
#else
static inline void kgr_task_safe(struct task_struct *p) { }
--
2.0.0
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