diff options
| -rw-r--r-- | arch/x86/include/asm/sigcontext.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/sigcontext.h | 19 | ||||
| -rw-r--r-- | arch/x86/kernel/signal.c | 4 |
3 files changed, 21 insertions, 6 deletions
diff --git a/arch/x86/include/asm/sigcontext.h b/arch/x86/include/asm/sigcontext.h index f910cdcb71fde..6fe6b182c9981 100644 --- a/arch/x86/include/asm/sigcontext.h +++ b/arch/x86/include/asm/sigcontext.h @@ -57,8 +57,8 @@ struct sigcontext { unsigned long ip; unsigned long flags; unsigned short cs; - unsigned short gs; - unsigned short fs; + unsigned short __pad2; /* Was called gs, but was always zero. */ + unsigned short __pad1; /* Was called fs, but was always zero. */ unsigned short ss; unsigned long err; unsigned long trapno; diff --git a/arch/x86/include/uapi/asm/sigcontext.h b/arch/x86/include/uapi/asm/sigcontext.h index 076b11fd6fa1e..16dc4e8a2cd34 100644 --- a/arch/x86/include/uapi/asm/sigcontext.h +++ b/arch/x86/include/uapi/asm/sigcontext.h @@ -177,8 +177,23 @@ struct sigcontext { __u64 rip; __u64 eflags; /* RFLAGS */ __u16 cs; - __u16 gs; - __u16 fs; + + /* + * Prior to 2.5.64 ("[PATCH] x86-64 updates for 2.5.64-bk3"), + * Linux saved and restored fs and gs in these slots. This + * was counterproductive, as fsbase and gsbase were never + * saved, so arch_prctl was presumably unreliable. + * + * If these slots are ever needed for any other purpose, there + * is some risk that very old 64-bit binaries could get + * confused. I doubt that many such binaries still work, + * though, since the same patch in 2.5.64 also removed the + * 64-bit set_thread_area syscall, so it appears that there is + * no TLS API that works in both pre- and post-2.5.64 kernels. + */ + __u16 __pad2; /* Was gs. */ + __u16 __pad1; /* Was fs. */ + __u16 ss; __u64 err; __u64 trapno; diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index e2f6061a9003a..edcb862cdcae5 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -155,8 +155,8 @@ int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, #else /* !CONFIG_X86_32 */ put_user_ex(regs->flags, &sc->flags); put_user_ex(regs->cs, &sc->cs); - put_user_ex(0, &sc->gs); - put_user_ex(0, &sc->fs); + put_user_ex(0, &sc->__pad2); + put_user_ex(0, &sc->__pad1); put_user_ex(regs->ss, &sc->ss); #endif /* CONFIG_X86_32 */ |