From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: luto@kernel.org, tglx@linutronix.de
Cc: keescook@chromium.org, x86@kernel.org,
linux-kernel@vger.kernel.org,
Gabriel Krisman Bertazi <krisman@collabora.com>,
kernel@collabora.com
Subject: [PATCH 5/6] arch: x86: Reclaim TIF_IA32 flag
Date: Tue, 28 Jul 2020 16:22:28 -0400 [thread overview]
Message-ID: <20200728202229.1195682-6-krisman@collabora.com> (raw)
In-Reply-To: <20200728202229.1195682-1-krisman@collabora.com>
Dropping this as a TIF flag is interesting given the pressure over x86
remaining x86 flags, plus considering the current common entry code,
reducing arch-specific flags is a good thing.
Notice that no path really relies on TIF_IA32 as part of a critical
path, therefore the cost of checking another field in thread_info
shouldn't be a problem.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
---
arch/x86/include/asm/thread_info.h | 4 +---
arch/x86/kernel/process_64.c | 3 ---
2 files changed, 1 insertion(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 698feefd5f5f..aa7d27054a8a 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -99,7 +99,6 @@ struct thread_info {
#define TIF_NEED_FPU_LOAD 14 /* load FPU on return to userspace */
#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
-#define TIF_IA32 17 /* IA32 compatibility process */
#define TIF_SLD 18 /* Restore split lock detection on context switch */
#define TIF_MEMDIE 20 /* is terminating due to OOM killer */
#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
@@ -129,7 +128,6 @@ struct thread_info {
#define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD)
#define _TIF_NOCPUID (1 << TIF_NOCPUID)
#define _TIF_NOTSC (1 << TIF_NOTSC)
-#define _TIF_IA32 (1 << TIF_IA32)
#define _TIF_SLD (1 << TIF_SLD)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
@@ -245,7 +243,7 @@ extern void arch_setup_new_exec(void);
#define arch_setup_new_exec arch_setup_new_exec
#endif /* !__ASSEMBLY__ */
-#define TASK_IA32(tsk) test_tsk_thread_flag(tsk, TIF_IA32)
+#define TASK_IA32(tsk) (task_thread_info(tsk)->psabi == PSABI_IA32)
#define TASK_X32(tsk) test_tsk_thread_flag(tsk, TIF_X32)
#endif /* _ASM_X86_THREAD_INFO_H */
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index aea2c03e8a5d..75059c9de829 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -533,7 +533,6 @@ void set_personality_64bit(void)
/* Make sure to be in 64bit mode */
current_thread_info()->psabi = PSABI_IA64;
- clear_thread_flag(TIF_IA32);
clear_thread_flag(TIF_ADDR32);
clear_thread_flag(TIF_X32);
/* Pretend that this comes from a 64bit execve */
@@ -555,7 +554,6 @@ static void __set_personality_x32(void)
{
#ifdef CONFIG_X86_X32
current_thread_info()->psabi = PSABI_X32;
- clear_thread_flag(TIF_IA32);
set_thread_flag(TIF_X32);
if (current->mm)
current->mm->context.ia32_compat = PSABI_X32;
@@ -577,7 +575,6 @@ static void __set_personality_ia32(void)
{
#ifdef CONFIG_IA32_EMULATION
current_thread_info()->psabi = PSABI_IA32;
- set_thread_flag(TIF_IA32);
clear_thread_flag(TIF_X32);
if (current->mm)
current->mm->context.ia32_compat = PSABI_IA32;
--
2.27.0
next prev parent reply other threads:[~2020-07-28 20:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-28 20:22 [PATCH 0/6] Reclaim x86 psABI TIF flags Gabriel Krisman Bertazi
2020-07-28 20:22 ` [PATCH 1/6] arch: x86: Don't use TIF flags for mm context Gabriel Krisman Bertazi
2020-07-29 9:03 ` peterz
2020-07-28 20:22 ` [PATCH 2/6] arch: x86: Wrap TIF_IA32 checks Gabriel Krisman Bertazi
2020-07-29 3:43 ` Andy Lutomirski
2020-07-29 4:46 ` Gabriel Krisman Bertazi
2020-07-29 5:09 ` Andy Lutomirski
2020-07-29 18:11 ` Gabriel Krisman Bertazi
2020-07-29 6:59 ` Christoph Hellwig
2020-07-29 9:11 ` peterz
2020-07-28 20:22 ` [PATCH 3/6] arch: x86: Wrap TIF_X32 checks Gabriel Krisman Bertazi
2020-07-29 4:54 ` Andy Lutomirski
2020-07-28 20:22 ` [PATCH 4/6] arch: x86: Expose psABI on thread_info Gabriel Krisman Bertazi
2020-07-29 3:44 ` Andy Lutomirski
2020-07-28 20:22 ` Gabriel Krisman Bertazi [this message]
2020-07-28 20:22 ` [PATCH 6/6] arch: x86: Reclaim TIF_X32 flag Gabriel Krisman Bertazi
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