Merge tag 'powerpc-6.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:

 - Fix softlockup/crash when using hcall tracing

 - Fix pte_access_permitted() for PAGE_NONE on 8xx

 - Fix inverted pte_young() test in __ptep_test_and_clear_young()
   on 64-bit BookE

 - Fix unhandled math emulation exception on 85xx

 - Fix kernel crash on syscall return on 476

Thanks to Athira Rajeev, Christophe Leroy, Eddie James, and Naveen N
Rao.

* tag 'powerpc-6.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/47x: Fix 47x syscall return crash
  powerpc/85xx: Fix math emulation exception
  powerpc/64e: Fix wrong test in __ptep_test_and_clear_young()
  powerpc/8xx: Fix pte_access_permitted() for PAGE_NONE
  powerpc/pseries: Remove unused r0 in the hcall tracing code
  powerpc/pseries: Fix STK_PARAM access in the hcall tracing code

arch/powerpc/include/asm/nohash/32/pte-8xx.h

@@ -94,6 +94,13 @@ static inline pte_t pte_wrprotect(pte_t pte)
 
 #define pte_wrprotect pte_wrprotect
 
+static inline int pte_read(pte_t pte)
+{
+	return (pte_val(pte) & _PAGE_RO) != _PAGE_NA;
+}
+
+#define pte_read pte_read
+
 static inline int pte_write(pte_t pte)
 {
 	return !(pte_val(pte) & _PAGE_RO);

arch/powerpc/include/asm/nohash/64/pgtable.h

@@ -197,7 +197,7 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
 {
 	unsigned long old;
 
-	if (pte_young(*ptep))
+	if (!pte_young(*ptep))
 		return 0;
 	old = pte_update(mm, addr, ptep, _PAGE_ACCESSED, 0, 0);
 	return (old & _PAGE_ACCESSED) != 0;

arch/powerpc/include/asm/nohash/pgtable.h

@@ -25,7 +25,9 @@ static inline int pte_write(pte_t pte)
 	return pte_val(pte) & _PAGE_RW;
 }
 #endif
+#ifndef pte_read
 static inline int pte_read(pte_t pte)		{ return 1; }
+#endif
 static inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_special(pte_t pte)	{ return pte_val(pte) & _PAGE_SPECIAL; }
 static inline int pte_none(pte_t pte)		{ return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }

arch/powerpc/kernel/entry_32.S

@@ -137,8 +137,9 @@ ret_from_syscall:
 	lis	r4,icache_44x_need_flush@ha
 	lwz	r5,icache_44x_need_flush@l(r4)
 	cmplwi	cr0,r5,0
-	bne-	2f
+	bne-	.L44x_icache_flush
 #endif /* CONFIG_PPC_47x */
+.L44x_icache_flush_return:
 	kuep_unlock
 	lwz	r4,_LINK(r1)
 	lwz	r5,_CCR(r1)
@@ -172,10 +173,11 @@ syscall_exit_finish:
 	b	1b
 
 #ifdef CONFIG_44x
-2:	li	r7,0
+.L44x_icache_flush:
+	li	r7,0
 	iccci	r0,r0
 	stw	r7,icache_44x_need_flush@l(r4)
-	b	1b
+	b	.L44x_icache_flush_return
 #endif  /* CONFIG_44x */
 
 	.globl	ret_from_fork

arch/powerpc/kernel/head_85xx.S

@@ -395,7 +395,7 @@ interrupt_base:
 #ifdef CONFIG_PPC_FPU
 	FP_UNAVAILABLE_EXCEPTION
 #else
-	EXCEPTION(0x0800, FP_UNAVAIL, FloatingPointUnavailable, unknown_exception)
+	EXCEPTION(0x0800, FP_UNAVAIL, FloatingPointUnavailable, emulation_assist_interrupt)
 #endif
 
 	/* System Call Interrupt */

arch/powerpc/platforms/pseries/hvCall.S

@@ -184,9 +184,6 @@ _GLOBAL_TOC(plpar_hcall)
 plpar_hcall_trace:
 	HCALL_INST_PRECALL(R5)
 
-	std	r4,STK_PARAM(R4)(r1)
-	mr	r0,r4
-
 	mr	r4,r5
 	mr	r5,r6
 	mr	r6,r7
@@ -196,7 +193,7 @@ plpar_hcall_trace:
 
 	HVSC
 
-	ld	r12,STK_PARAM(R4)(r1)
+	ld	r12,STACK_FRAME_MIN_SIZE+STK_PARAM(R4)(r1)
 	std	r4,0(r12)
 	std	r5,8(r12)
 	std	r6,16(r12)
@@ -296,9 +293,6 @@ _GLOBAL_TOC(plpar_hcall9)
 plpar_hcall9_trace:
 	HCALL_INST_PRECALL(R5)
 
-	std	r4,STK_PARAM(R4)(r1)
-	mr	r0,r4
-
 	mr	r4,r5
 	mr	r5,r6
 	mr	r6,r7