Was: Re: [tip:x86/asm] x86/entry: Rename is_{ia32,x32}_task() to
in_{ia32,x32}_syscall()
On Tue, Apr 19 2016, tip-bot for Dmitry Safonov wrote:> Commit-ID: abfb9498ee1327f534df92a7ecaea81a85913bae > Gitweb: http://git.kernel.org/tip/abfb9498ee1327f534df92a7ecaea81a85913bae > Author: Dmitry Safonov <dsafo...@virtuozzo.com> > AuthorDate: Mon, 18 Apr 2016 16:43:43 +0300 > Committer: Ingo Molnar <mi...@kernel.org> > CommitDate: Tue, 19 Apr 2016 10:44:52 +0200 > > x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall() > ... > @@ -318,7 +318,7 @@ static inline bool is_x32_task(void) > > static inline bool in_compat_syscall(void) > { > - return is_ia32_task() || is_x32_task(); > + return in_ia32_syscall() || in_x32_syscall(); > } Hi, I'm reply to this patch largely to make sure I get the right people ..... This test is always true when CONFIG_X86_32 is set, as that forces in_ia32_syscall() to true. However we might not be in a syscall at all - we might be running a kernel thread which is always in 64 mode. Every other implementation of in_compat_syscall() that I found is dependant on a thread flag or syscall register flag, and so returns "false" in a kernel thread. Might something like this be appropriate? diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 2ff2a30a264f..c265b40a78f2 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -219,7 +219,7 @@ static inline int arch_within_stack_frames(const void * const stack, #ifndef __ASSEMBLY__ #ifdef CONFIG_X86_32 -#define in_ia32_syscall() true +#define in_ia32_syscall() (!(current->flags & PF_KTHREAD)) #else #define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \ current_thread_info()->status & TS_COMPAT) This came up in the (no out-of-tree) lustre filesystem where some code needs to assume 32-bit mode in X86_32 syscalls, and 64-bit mode in kernel threads. Thanks, NeilBrown
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