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Subject[PATCH v2 4/4] x86: introduce restart_block->arch_data to kill TS_COMPAT_RESTART
With this patch x86 just saves current_thread_info()->status in the
new restart_block->arch_data field, TS_COMPAT_RESTART can be removed.

Rather than saving "status" we could shift the code from
get_nr_restart_syscall() to arch_set_restart_data() and save the syscall
number in ->arch_data.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
arch/x86/include/asm/thread_info.h | 12 ++----------
arch/x86/kernel/signal.c | 2 +-
include/linux/restart_block.h | 1 +
3 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index a4de7aa..75c4a0a 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -233,18 +233,10 @@ static inline int arch_within_stack_frames(const void * const stack,
#ifndef __ASSEMBLY__
#ifdef CONFIG_COMPAT
#define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */
-#define TS_COMPAT_RESTART 0x0008

-#define arch_set_restart_data arch_set_restart_data
+#define arch_set_restart_data(restart) \
+ do { restart->arch_data = current_thread_info()->status; } while (0)

-static inline void arch_set_restart_data(struct restart_block *restart)
-{
- struct thread_info *ti = current_thread_info();
- if (ti->status & TS_COMPAT)
- ti->status |= TS_COMPAT_RESTART;
- else
- ti->status &= ~TS_COMPAT_RESTART;
-}
#endif

#ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 2fdbf5e..2e52767 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -771,7 +771,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
{
#ifdef CONFIG_IA32_EMULATION
- if (current_thread_info()->status & TS_COMPAT_RESTART)
+ if (current->restart_block.arch_data & TS_COMPAT)
return __NR_ia32_restart_syscall;
#endif
#ifdef CONFIG_X86_X32_ABI
diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h
index bba2920..980a655 100644
--- a/include/linux/restart_block.h
+++ b/include/linux/restart_block.h
@@ -23,6 +23,7 @@ enum timespec_type {
* System call restart block.
*/
struct restart_block {
+ unsigned long arch_data;
long (*fn)(struct restart_block *);
union {
/* For futex_wait and futex_wait_requeue_pi */
--
2.5.0

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