3f5159a922
Recently Andy changed the 64-bit syscall logic so that pt_regs->ax is initially set to -ENOSYS, and on syscall exit, it is updated with the actual return value. This simplified the logic there. This patch does the same for 32-bit syscall entry points. The check for %rax being too big is moved to be just before the call instruction which dispatches execution through the syscall table. There is no way to accidentally skip this check now by jumping to a label after it. This allows us to remove redundant checks after ptrace et al. If %rax is too big, we just skip over the (call, write %rax to pt_regs->ax) instruction pair. pt_regs->ax remains set to -ENOSYS, and it gets returned to userspace. Similar to 64-bit code, this eliminates the "ia32_badsys" code path. Run-tested. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1429632194-13445-2-git-send-email-dvlasenk@redhat.com [ Changelog massage. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| audit.c | ||
| ia32_aout.c | ||
| ia32_signal.c | ||
| ia32entry.S | ||
| Makefile | ||
| sys_ia32.c | ||