powerpc fixes for 6.0 #2

- Ensure we never emit lwarx with EH=1 on 32-bit, because some 32-bit CPUs trap on it
    rather than ignoring it as they should.
 
  - Fix ftrace when building with clang, which was broken by some refactoring.
 
  - A couple of other minor fixes.
 
 Thanks to: Christophe Leroy, Naveen N. Rao, Nick Desaulniers, Ondrej Mosnacek, Pali Rohár,
 Russell Currey Segher Boessenkool.
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Merge tag 'powerpc-6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:

 - Ensure we never emit lwarx with EH=1 on 32-bit, because some 32-bit
   CPUs trap on it rather than ignoring it as they should.

 - Fix ftrace when building with clang, which was broken by some
   refactoring.

 - A couple of other minor fixes.

Thanks to Christophe Leroy, Naveen N.  Rao, Nick Desaulniers, Ondrej
Mosnacek, Pali Rohár, Russell Currey, and Segher Boessenkool.

* tag 'powerpc-6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/kexec: Fix build failure from uninitialised variable
  powerpc/ppc-opcode: Fix PPC_RAW_TW()
  powerpc64/ftrace: Fix ftrace for clang builds
  powerpc: Make eh value more explicit when using lwarx
  powerpc: Don't hide eh field of lwarx behind a macro
  powerpc: Fix eh field when calling lwarx on PPC32

arch/powerpc/include/asm/atomic.h

@@ -140,9 +140,10 @@ static __always_inline bool
 arch_atomic_try_cmpxchg_lock(atomic_t *v, int *old, int new)
 {
 	int r, o = *old;
+	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
 
 	__asm__ __volatile__ (
-"1:	lwarx	%0,0,%2,%5	# atomic_try_cmpxchg_acquire		\n"
+"1:	lwarx	%0,0,%2,%[eh]	# atomic_try_cmpxchg_acquire		\n"
 "	cmpw	0,%0,%3							\n"
 "	bne-	2f							\n"
 "	stwcx.	%4,0,%2							\n"
@@ -150,7 +151,7 @@ arch_atomic_try_cmpxchg_lock(atomic_t *v, int *old, int new)
 "\t"	PPC_ACQUIRE_BARRIER "						\n"
 "2:									\n"
 	: "=&r" (r), "+m" (v->counter)
-	: "r" (&v->counter), "r" (o), "r" (new), "i" (IS_ENABLED(CONFIG_PPC64) ? 1 : 0)
+	: "r" (&v->counter), "r" (o), "r" (new), [eh] "n" (eh)
 	: "cr0", "memory");
 
 	if (unlikely(r != o))

arch/powerpc/include/asm/bitops.h

@@ -163,7 +163,7 @@ static inline unsigned long fn(			\
 	"bne- 1b\n"					\
 	postfix						\
 	: "=&r" (old), "=&r" (t)			\
-	: "rK" (mask), "r" (p), "i" (IS_ENABLED(CONFIG_PPC64) ? eh : 0)	\
+	: "rK" (mask), "r" (p), "n" (eh)		\
 	: "cc", "memory");				\
 	return (old & mask);				\
 }
@@ -171,7 +171,7 @@ static inline unsigned long fn(			\
 DEFINE_TESTOP(test_and_set_bits, or, PPC_ATOMIC_ENTRY_BARRIER,
 	      PPC_ATOMIC_EXIT_BARRIER, 0)
 DEFINE_TESTOP(test_and_set_bits_lock, or, "",
-	      PPC_ACQUIRE_BARRIER, 1)
+	      PPC_ACQUIRE_BARRIER, IS_ENABLED(CONFIG_PPC64))
 DEFINE_TESTOP(test_and_change_bits, xor, PPC_ATOMIC_ENTRY_BARRIER,
 	      PPC_ATOMIC_EXIT_BARRIER, 0)
 

arch/powerpc/include/asm/ppc-opcode.h

@@ -343,6 +343,7 @@
 #define __PPC_SPR(r)	((((r) & 0x1f) << 16) | ((((r) >> 5) & 0x1f) << 11))
 #define __PPC_RC21	(0x1 << 10)
 #define __PPC_PRFX_R(r)	(((r) & 0x1) << 20)
+#define __PPC_EH(eh)	(((eh) & 0x1) << 0)
 
 /*
  * Both low and high 16 bits are added as SIGNED additions, so if low 16 bits
@@ -359,16 +360,6 @@
 #define PPC_LI_MASK	0x03fffffc
 #define PPC_LI(v)	((v) & PPC_LI_MASK)
 
-/*
- * Only use the larx hint bit on 64bit CPUs. e500v1/v2 based CPUs will treat a
- * larx with EH set as an illegal instruction.
- */
-#ifdef CONFIG_PPC64
-#define __PPC_EH(eh)	(((eh) & 0x1) << 0)
-#else
-#define __PPC_EH(eh)	0
-#endif
-
 /* Base instruction encoding */
 #define PPC_RAW_CP_ABORT		(0x7c00068c)
 #define PPC_RAW_COPY(a, b)		(PPC_INST_COPY | ___PPC_RA(a) | ___PPC_RB(b))
@@ -580,7 +571,7 @@
 
 #define PPC_RAW_BRANCH(offset)		(0x48000000 | PPC_LI(offset))
 #define PPC_RAW_BL(offset)		(0x48000001 | PPC_LI(offset))
-#define PPC_RAW_TW(t0, a, b)		(0x7f000008 | ___PPC_RS(t0) | ___PPC_RA(a) | ___PPC_RB(b))
+#define PPC_RAW_TW(t0, a, b)		(0x7c000008 | ___PPC_RS(t0) | ___PPC_RA(a) | ___PPC_RB(b))
 #define PPC_RAW_TRAP()			PPC_RAW_TW(31, 0, 0)
 #define PPC_RAW_SETB(t, bfa)		(0x7c000100 | ___PPC_RT(t) | ___PPC_RA((bfa) << 2))
 

arch/powerpc/include/asm/simple_spinlock.h

@@ -48,10 +48,11 @@ static inline int arch_spin_is_locked(arch_spinlock_t *lock)
 static inline unsigned long __arch_spin_trylock(arch_spinlock_t *lock)
 {
 	unsigned long tmp, token;
+	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
 
 	token = LOCK_TOKEN;
 	__asm__ __volatile__(
-"1:	lwarx		%0,0,%2,1\n\
+"1:	lwarx		%0,0,%2,%[eh]\n\
 	cmpwi		0,%0,0\n\
 	bne-		2f\n\
 	stwcx.		%1,0,%2\n\
@@ -59,7 +60,7 @@ static inline unsigned long __arch_spin_trylock(arch_spinlock_t *lock)
 	PPC_ACQUIRE_BARRIER
 "2:"
 	: "=&r" (tmp)
-	: "r" (token), "r" (&lock->slock)
+	: "r" (token), "r" (&lock->slock), [eh] "n" (eh)
 	: "cr0", "memory");
 
 	return tmp;
@@ -156,9 +157,10 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
 static inline long __arch_read_trylock(arch_rwlock_t *rw)
 {
 	long tmp;
+	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
 
 	__asm__ __volatile__(
-"1:	lwarx		%0,0,%1,1\n"
+"1:	lwarx		%0,0,%1,%[eh]\n"
 	__DO_SIGN_EXTEND
 "	addic.		%0,%0,1\n\
 	ble-		2f\n"
@@ -166,7 +168,7 @@ static inline long __arch_read_trylock(arch_rwlock_t *rw)
 	bne-		1b\n"
 	PPC_ACQUIRE_BARRIER
 "2:"	: "=&r" (tmp)
-	: "r" (&rw->lock)
+	: "r" (&rw->lock), [eh] "n" (eh)
 	: "cr0", "xer", "memory");
 
 	return tmp;
@@ -179,17 +181,18 @@ static inline long __arch_read_trylock(arch_rwlock_t *rw)
 static inline long __arch_write_trylock(arch_rwlock_t *rw)
 {
 	long tmp, token;
+	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
 
 	token = WRLOCK_TOKEN;
 	__asm__ __volatile__(
-"1:	lwarx		%0,0,%2,1\n\
+"1:	lwarx		%0,0,%2,%[eh]\n\
 	cmpwi		0,%0,0\n\
 	bne-		2f\n"
 "	stwcx.		%1,0,%2\n\
 	bne-		1b\n"
 	PPC_ACQUIRE_BARRIER
 "2:"	: "=&r" (tmp)
-	: "r" (token), "r" (&rw->lock)
+	: "r" (token), "r" (&rw->lock), [eh] "n" (eh)
 	: "cr0", "memory");
 
 	return tmp;

arch/powerpc/kernel/trace/ftrace.c

@@ -393,11 +393,11 @@ int ftrace_make_nop(struct module *mod,
  */
 static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
 {
-	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1))
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+		return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP()));
+	else
 		return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) &&
 		       ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC));
-	else
-		return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP()));
 }
 
 static int
@@ -412,7 +412,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 	if (copy_inst_from_kernel_nofault(op, ip))
 		return -EFAULT;
 
-	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1) &&
+	if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) &&
 	    copy_inst_from_kernel_nofault(op + 1, ip + 4))
 		return -EFAULT;
 

arch/powerpc/kexec/file_load_64.c

@@ -1043,17 +1043,17 @@ static int copy_property(void *fdt, int node_offset, const struct device_node *d
 			 const char *propname)
 {
 	const void *prop, *fdtprop;
-	int len = 0, fdtlen = 0, ret;
+	int len = 0, fdtlen = 0;
 
 	prop = of_get_property(dn, propname, &len);
 	fdtprop = fdt_getprop(fdt, node_offset, propname, &fdtlen);
 
 	if (fdtprop && !prop)
-		ret = fdt_delprop(fdt, node_offset, propname);
+		return fdt_delprop(fdt, node_offset, propname);
 	else if (prop)
-		ret = fdt_setprop(fdt, node_offset, propname, prop, len);
-
-	return ret;
+		return fdt_setprop(fdt, node_offset, propname, prop, len);
+	else
+		return -FDT_ERR_NOTFOUND;
 }
 
 static int update_pci_dma_nodes(void *fdt, const char *dmapropname)