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authorCyril Bur <cyrilbur@gmail.com>2016-08-10 08:44:46 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2016-08-10 09:34:20 +0300
commitc7a318ba868c61fc9be710a4970172d8c2eeb8b9 (patch)
treeb3967ee9f5b893af024f0376d120bb30d6297dd1
parent1bc8b816cb8058c31f61fe78442f10a43209e582 (diff)
downloadlinux-c7a318ba868c61fc9be710a4970172d8c2eeb8b9.tar.xz
powerpc/ptrace: Fix coredump since ptrace TM changes
Commit 8d460f6156cd ("powerpc/process: Add the function flush_tmregs_to_thread") added flush_tmregs_to_thread() and included the assumption that it would only be called for a task which is not current. Although this is correct for ptrace, when generating a core dump, some of the routines which call flush_tmregs_to_thread() are called. This leads to a WARNing such as: Not expecting ptrace on self: TM regs may be incorrect ------------[ cut here ]------------ WARNING: CPU: 123 PID: 7727 at arch/powerpc/kernel/process.c:1088 flush_tmregs_to_thread+0x78/0x80 CPU: 123 PID: 7727 Comm: libvirtd Not tainted 4.8.0-rc1-gcc6x-g61e8a0d #1 task: c000000fe631b600 task.stack: c000000fe63b0000 NIP: c00000000001a1a8 LR: c00000000001a1a4 CTR: c000000000717780 REGS: c000000fe63b3420 TRAP: 0700 Not tainted (4.8.0-rc1-gcc6x-g61e8a0d) MSR: 900000010282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]> CR: 28004222 XER: 20000000 ... NIP [c00000000001a1a8] flush_tmregs_to_thread+0x78/0x80 LR [c00000000001a1a4] flush_tmregs_to_thread+0x74/0x80 Call Trace: flush_tmregs_to_thread+0x74/0x80 (unreliable) vsr_get+0x64/0x1a0 elf_core_dump+0x604/0x1430 do_coredump+0x5fc/0x1200 get_signal+0x398/0x740 do_signal+0x54/0x2b0 do_notify_resume+0x98/0xb0 ret_from_except_lite+0x70/0x74 So fix flush_tmregs_to_thread() to detect the case where it is called on current, and a transaction is active, and in that case flush the TM regs to the thread_struct. This patch also moves flush_tmregs_to_thread() into ptrace.c as it is only called from that file. Fixes: 8d460f6156cd ("powerpc/process: Add the function flush_tmregs_to_thread") Signed-off-by: Cyril Bur <cyrilbur@gmail.com> [mpe: Flesh out change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/include/asm/switch_to.h8
-rw-r--r--arch/powerpc/kernel/process.c20
-rw-r--r--arch/powerpc/kernel/ptrace.c19
3 files changed, 19 insertions, 28 deletions
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index 0a74ebe934e1..17c8380673a6 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -75,14 +75,6 @@ static inline void disable_kernel_spe(void)
static inline void __giveup_spe(struct task_struct *t) { }
#endif
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-extern void flush_tmregs_to_thread(struct task_struct *);
-#else
-static inline void flush_tmregs_to_thread(struct task_struct *t)
-{
-}
-#endif
-
static inline void clear_task_ebb(struct task_struct *t)
{
#ifdef CONFIG_PPC_BOOK3S_64
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 58ccf86415b4..9ee2623e0f67 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1074,26 +1074,6 @@ static inline void restore_sprs(struct thread_struct *old_thread,
#endif
}
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-void flush_tmregs_to_thread(struct task_struct *tsk)
-{
- /*
- * Process self tracing is not yet supported through
- * ptrace interface. Ptrace generic code should have
- * prevented this from happening in the first place.
- * Warn once here with the message, if some how it
- * is attempted.
- */
- WARN_ONCE(tsk == current,
- "Not expecting ptrace on self: TM regs may be incorrect\n");
-
- /*
- * If task is not current, it should have been flushed
- * already to it's thread_struct during __switch_to().
- */
-}
-#endif
-
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *new)
{
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 4f3c5756cc09..bf91658a8a40 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -38,6 +38,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/switch_to.h>
+#include <asm/tm.h>
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
@@ -118,6 +119,24 @@ static const struct pt_regs_offset regoffset_table[] = {
REG_OFFSET_END,
};
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+static void flush_tmregs_to_thread(struct task_struct *tsk)
+{
+ /*
+ * If task is not current, it will have been flushed already to
+ * it's thread_struct during __switch_to().
+ *
+ * A reclaim flushes ALL the state.
+ */
+
+ if (tsk == current && MSR_TM_SUSPENDED(mfmsr()))
+ tm_reclaim_current(TM_CAUSE_SIGNAL);
+
+}
+#else
+static inline void flush_tmregs_to_thread(struct task_struct *tsk) { }
+#endif
+
/**
* regs_query_register_offset() - query register offset from its name
* @name: the name of a register