[REVIEW][PATCH 16/17] signal/alpha: Replace TRAP_FIXME with TRAP_UNK

From: Eric W. Biederman
Date: Thu Apr 19 2018 - 21:12:11 EST


Using an si_code of 0 that aliases with SI_USER is clearly the wrong
thing to do, and causes problems in interesting ways.

For it really is not clear to me if using TRAP_UNK bugcheck or
the default case of gentrap is really the best way to handle
things. There is certainly enough information that that a more
specific si_code could potentially be used. That said TRAP_UNK
is definitely an improvement over 0 as it removes the ambiguiuty
of what si_code of 0 with SIGTRAP means on alpha.

Recent history suggests no actually cares about crazy corner cases of
the kernel behavior like this so I don't expect any regressions from
changing this. However if something does happen this change is easy
to revert.

Cc: Helge Deller <deller@xxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: linux-alpha@xxxxxxxxxxxxxxx
Fixes: 0a635c7a84cf ("Fill in siginfo_t.")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
arch/alpha/include/uapi/asm/siginfo.h | 7 -------
arch/alpha/kernel/traps.c | 4 ++--
2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/arch/alpha/include/uapi/asm/siginfo.h b/arch/alpha/include/uapi/asm/siginfo.h
index 3ebbb1e17902..db3f0138536f 100644
--- a/arch/alpha/include/uapi/asm/siginfo.h
+++ b/arch/alpha/include/uapi/asm/siginfo.h
@@ -7,11 +7,4 @@

#include <asm-generic/siginfo.h>

-/*
- * SIGTRAP si_codes
- */
-#ifdef __KERNEL__
-#define TRAP_FIXME 0 /* Broken dup of SI_USER */
-#endif /* __KERNEL__ */
-
#endif
diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 422b676b28f2..242c83d86ace 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -288,7 +288,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
case 1: /* bugcheck */
info.si_signo = SIGTRAP;
info.si_errno = 0;
- info.si_code = TRAP_FIXME;
+ info.si_code = TRAP_UNK;
info.si_addr = (void __user *) regs->pc;
info.si_trapno = 0;
send_sig_info(SIGTRAP, &info, current);
@@ -350,7 +350,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
case GEN_SUBRNG7:
default:
signo = SIGTRAP;
- code = TRAP_FIXME;
+ code = TRAP_UNK;
break;
}

--
2.14.1

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