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author | Eric W. Biederman <ebiederm@xmission.com> | 2017-08-19 15:26:01 -0500 |
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committer | Eric W. Biederman <ebiederm@xmission.com> | 2018-01-12 14:21:04 -0600 |
commit | cf4674c46c66e45f238f8f7e81af2a444b970c0a (patch) | |
tree | 8742792c826b15a8fe7d673524d3a99415b682b6 /arch/powerpc/kernel/traps.c | |
parent | b80328be53c215346b153769267b38f531d89b4f (diff) | |
download | linux-cf4674c46c66e45f238f8f7e81af2a444b970c0a.tar.bz2 |
signal/powerpc: Document conflicts with SI_USER and SIGFPE and SIGTRAP
Setting si_code to 0 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.
Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a
value of __SI_KILL and now sees a value of SIL_KILL with the result
that uid and pid fields are copied and which might copying the si_addr
field by accident but certainly not by design. Making this a very
flakey implementation.
Utilizing FPE_FIXME and TRAP_FIXME, siginfo_layout() will now return
SIL_FAULT and the appropriate fields will be reliably copied.
Possible ABI fixes includee:
- Send the signal without siginfo
- Don't generate a signal
- Possibly assign and use an appropriate si_code
- Don't handle cases which can't happen
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kumar Gala <kumar.gala@freescale.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
Ref: 9bad068c24d7 ("[PATCH] ppc32: support for e500 and 85xx")
Ref: 0ed70f6105ef ("PPC32: Provide proper siginfo information on various exceptions.")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'arch/powerpc/kernel/traps.c')
-rw-r--r-- | arch/powerpc/kernel/traps.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index f3eb61be0d30..f2e6e1838952 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -917,7 +917,7 @@ void unknown_exception(struct pt_regs *regs) printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n", regs->nip, regs->msr, regs->trap); - _exception(SIGTRAP, regs, 0, 0); + _exception(SIGTRAP, regs, TRAP_FIXME, 0); exception_exit(prev_state); } @@ -939,7 +939,7 @@ bail: void RunModeException(struct pt_regs *regs) { - _exception(SIGTRAP, regs, 0, 0); + _exception(SIGTRAP, regs, TRAP_FIXME, 0); } void single_step_exception(struct pt_regs *regs) @@ -978,7 +978,7 @@ static void emulate_single_step(struct pt_regs *regs) static inline int __parse_fpscr(unsigned long fpscr) { - int ret = 0; + int ret = FPE_FIXME; /* Invalid operation */ if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX)) @@ -1929,7 +1929,7 @@ void SPEFloatingPointException(struct pt_regs *regs) extern int do_spe_mathemu(struct pt_regs *regs); unsigned long spefscr; int fpexc_mode; - int code = 0; + int code = FPE_FIXME; int err; flush_spe_to_thread(current); @@ -1998,7 +1998,7 @@ void SPEFloatingPointRoundException(struct pt_regs *regs) printk(KERN_ERR "unrecognized spe instruction " "in %s at %lx\n", current->comm, regs->nip); } else { - _exception(SIGFPE, regs, 0, regs->nip); + _exception(SIGFPE, regs, FPE_FIXME, regs->nip); return; } } |