[PATCH] powernv: Avoid calling trace tlbie in kexec path.
From: Mahesh J Salgaonkar <hidden>
Date: 2017-11-22 17:32:43
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: Mahesh Salgaonkar <redacted> Rebooting into a new kernel with kexec fails in trace_tlbie() which is called from native_hpte_clear(). This happens if the running kernel has CONFIG_LOCKDEP enabled. With lockdep enabled, the tracepoints always execute few RCU checks regardless of whether tracing is on or off. We are already in the last phase of kexec sequence in real mode with HILE_BE set. At this point the RCU check ends up in RCU_LOCKDEP_WARN and causes kexec to fail. Fix this by not calling trace_tlbie() from native_hpte_clear(). Signed-off-by: Mahesh Salgaonkar <redacted> Reported-by: Aneesh Kumar K.V <redacted> Suggested-by: Michael Ellerman <mpe@ellerman.id.au> --- arch/powerpc/mm/hash_native_64.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index 3848af1..640cf56 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c@@ -47,7 +47,8 @@ DEFINE_RAW_SPINLOCK(native_tlbie_lock); -static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize) +static inline unsigned long ___tlbie(unsigned long vpn, int psize, + int apsize, int ssize) { unsigned long va; unsigned int penc;
@@ -100,7 +101,15 @@ static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize) : "memory"); break; } - trace_tlbie(0, 0, va, 0, 0, 0, 0); + return va; +} + +static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize) +{ + unsigned long rb; + + rb = ___tlbie(vpn, psize, apsize, ssize); + trace_tlbie(0, 0, rb, 0, 0, 0, 0); } static inline void __tlbiel(unsigned long vpn, int psize, int apsize, int ssize)
@@ -652,7 +661,7 @@ static void native_hpte_clear(void) if (hpte_v & HPTE_V_VALID) { hpte_decode(hptep, slot, &psize, &apsize, &ssize, &vpn); hptep->v = 0; - __tlbie(vpn, psize, apsize, ssize); + ___tlbie(vpn, psize, apsize, ssize); } }