Messages in this thread Patch in this message | | | From | Gabriel Krisman Bertazi <> | Subject | [PATCH 6/6] arch: x86: Reclaim TIF_X32 flag | Date | Tue, 28 Jul 2020 16:22:29 -0400 |
| |
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_X32 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/events/core.c | 2 +- arch/x86/include/asm/thread_info.h | 4 +--- arch/x86/kernel/process_64.c | 3 --- 3 files changed, 2 insertions(+), 7 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 42dff74c6197..389a840e2211 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2574,7 +2574,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs * IA32 - Where we need to look at GDT/LDT segment descriptor tables * to figure out what the 32bit base address is. * - * X32 - has TIF_X32 set, but is running in x86_64 + * X32 - has PSABI_X32 set, but is running in x86_64 * * X86_64 - CS,DS,SS,ES are all zero based. */ diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index aa7d27054a8a..3059af355cdb 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -108,7 +108,6 @@ struct thread_info { #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 */ -#define TIF_X32 30 /* 32-bit native x86-64 binary */ #define TIF_FSCHECK 31 /* Check FS is USER_DS on return */ #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) @@ -136,7 +135,6 @@ struct thread_info { #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES) #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) #define _TIF_ADDR32 (1 << TIF_ADDR32) -#define _TIF_X32 (1 << TIF_X32) #define _TIF_FSCHECK (1 << TIF_FSCHECK) /* flags to check in __switch_to() */ @@ -244,6 +242,6 @@ extern void arch_setup_new_exec(void); #endif /* !__ASSEMBLY__ */ #define TASK_IA32(tsk) (task_thread_info(tsk)->psabi == PSABI_IA32) -#define TASK_X32(tsk) test_tsk_thread_flag(tsk, TIF_X32) +#define TASK_X32(tsk) (task_thread_info(tsk)->psabi == PSABI_X32) #endif /* _ASM_X86_THREAD_INFO_H */ diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 75059c9de829..d9a72e186db6 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -534,7 +534,6 @@ void set_personality_64bit(void) /* Make sure to be in 64bit mode */ current_thread_info()->psabi = PSABI_IA64; clear_thread_flag(TIF_ADDR32); - clear_thread_flag(TIF_X32); /* Pretend that this comes from a 64bit execve */ task_pt_regs(current)->orig_ax = __NR_execve; current_thread_info()->status &= ~TS_COMPAT; @@ -554,7 +553,6 @@ static void __set_personality_x32(void) { #ifdef CONFIG_X86_X32 current_thread_info()->psabi = PSABI_X32; - set_thread_flag(TIF_X32); if (current->mm) current->mm->context.ia32_compat = PSABI_X32; current->personality &= ~READ_IMPLIES_EXEC; @@ -575,7 +573,6 @@ static void __set_personality_ia32(void) { #ifdef CONFIG_IA32_EMULATION current_thread_info()->psabi = PSABI_IA32; - clear_thread_flag(TIF_X32); if (current->mm) current->mm->context.ia32_compat = PSABI_IA32; current->personality |= force_personality32; -- 2.27.0
| |