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authorEric W. Biederman <ebiederm@xmission.com>2017-06-26 16:16:17 -0500
committerEric W. Biederman <ebiederm@xmission.com>2017-07-19 19:13:15 -0500
commitea1b75cf9138003eee6389b70e654f5865728525 (patch)
tree8f211dd50b28dcd7ba73f3e665c1fcacfbb94514 /arch
parentcc9f72e474a4da365896d0e528da324f205e8b31 (diff)
downloadop-kernel-dev-ea1b75cf9138003eee6389b70e654f5865728525.zip
op-kernel-dev-ea1b75cf9138003eee6389b70e654f5865728525.tar.gz
signal/mips: Document a conflict with SI_USER with SIGFPE
Setting si_code to __SI_FAULT results in a userspace seeing an si_code of 0. This is the same si_code as SI_USER. Posix and common sense requires that SI_USER not be a signal specific si_code. As such this use of 0 for the si_code is a pretty horribly broken ABI. This use of of __SI_FAULT is only a decade old. Which compared to the other pieces of kernel code that has made this mistake is almost yesterday. This is probably worth fixing but I don't know mips well enough to know what si_code to would be the proper one to use. Cc: Ralf Baechle <ralf@linux-mips.org> Ref: 948a34cf3988 ("[MIPS] Maintain si_code field properly for FP exceptions") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/include/uapi/asm/siginfo.h7
-rw-r--r--arch/mips/kernel/traps.c2
2 files changed, 8 insertions, 1 deletions
diff --git a/arch/mips/include/uapi/asm/siginfo.h b/arch/mips/include/uapi/asm/siginfo.h
index 8069cf7..9becfd1 100644
--- a/arch/mips/include/uapi/asm/siginfo.h
+++ b/arch/mips/include/uapi/asm/siginfo.h
@@ -123,4 +123,11 @@ typedef struct siginfo {
#define SI_TIMER __SI_CODE(__SI_TIMER, -3) /* sent by timer expiration */
#define SI_MESGQ __SI_CODE(__SI_MESGQ, -4) /* sent by real time mesq state change */
+/*
+ * SIGFPE si_codes
+ */
+#ifdef __KERNEL__
+#define FPE_FIXME (__SI_FAULT|0) /* Broken dup of SI_USER */
+#endif /* __KERNEL__ */
+
#endif /* _UAPI_ASM_SIGINFO_H */
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index b68b4d0..6c9cca9 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -735,7 +735,7 @@ void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
else if (fcr31 & FPU_CSR_INE_X)
si.si_code = FPE_FLTRES;
else
- si.si_code = __SI_FAULT;
+ si.si_code = FPE_FIXME;
force_sig_info(SIGFPE, &si, tsk);
}
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