From: Cyril Bur <cyrilbur@gmail.com>
To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au
Cc: mikey@neuling.org, anton@samba.org, wei.guo.simon@gmail.com
Subject: [PATCH 1/2] powerpc: tm: Add TM Unavailable Exception
Date: Wed, 14 Sep 2016 18:02:15 +1000 [thread overview]
Message-ID: <20160914080216.13833-2-cyrilbur@gmail.com> (raw)
In-Reply-To: <20160914080216.13833-1-cyrilbur@gmail.com>
If the kernel disables transactional memory (TM) and userspace still
tries TM related actions (TM instructions or TM SPR accesses) TM aware
hardware will cause the kernel to take a facility unavailable
exception.
Add checks for the exception being caused by illegal TM access in
userspace.
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
---
arch/powerpc/kernel/traps.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 0eba74b..cd40130 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1372,6 +1372,13 @@ void vsx_unavailable_exception(struct pt_regs *regs)
}
#ifdef CONFIG_PPC64
+static void tm_unavailable(struct pt_regs *regs)
+{
+ pr_emerg("Unrecoverable TM Unavailable Exception "
+ "%lx at %lx\n", regs->trap, regs->nip);
+ die("Unrecoverable TM Unavailable Exception", regs, SIGABRT);
+}
+
void facility_unavailable_exception(struct pt_regs *regs)
{
static char *facility_strings[] = {
@@ -1451,6 +1458,23 @@ void facility_unavailable_exception(struct pt_regs *regs)
return;
}
+ /*
+ * TM Unavailable
+ *
+ * If
+ * - firmware bits say don't do TM or
+ * - CONFIG_PPC_TRANSACTIONAL_MEM was not set and
+ * - hardware is actually TM aware
+ * Then userspace can spam the console (even with the use of
+ * _ratelimited), just send the SIGILL.
+ */
+ if (status == FSCR_TM_LG) {
+ if (!cpu_has_feature(CPU_FTR_TM))
+ goto out;
+ tm_unavailable(regs);
+ return;
+ }
+
if ((status < ARRAY_SIZE(facility_strings)) &&
facility_strings[status])
facility = facility_strings[status];
@@ -1463,6 +1487,7 @@ void facility_unavailable_exception(struct pt_regs *regs)
"%sFacility '%s' unavailable, exception at 0x%lx, MSR=%lx\n",
hv ? "Hypervisor " : "", facility, regs->nip, regs->msr);
+out:
if (user_mode(regs)) {
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return;
--
2.9.3
next prev parent reply other threads:[~2016-09-14 8:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-14 8:02 [PATCH 0/2] Enable MSR_TM lazily Cyril Bur
2016-09-14 8:02 ` Cyril Bur [this message]
2016-10-05 2:36 ` [1/2] powerpc: tm: Add TM Unavailable Exception Michael Ellerman
2016-09-14 8:02 ` [PATCH 2/2] powerpc: tm: Enable transactional memory (TM) lazily for userspace Cyril Bur
2016-09-19 4:47 ` Simon Guo
2016-09-19 5:26 ` Cyril Bur
2016-09-14 11:28 ` [PATCH 0/2] Enable MSR_TM lazily Nicholas Piggin
2016-09-14 11:46 ` Michael Neuling
2016-09-14 12:12 ` Nicholas Piggin
2016-09-14 12:17 ` Michael Neuling
2016-09-14 14:10 ` Carlos Eduardo Seo
2016-09-15 3:59 ` Nicholas Piggin
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