powerpc fixes for 4.18 #3

Two regression fixes, and a new syscall wire-up.
 
 A fix for the recent conversion to time64_t in the powermac RTC routines, which
 caused time to go backward.
 
 Another fix for fallout from the split PMD PTL conversion.
 
 Wire up the new io_pgetevents() syscall.
 
 Thanks to:
   Aneesh Kumar K.V, Arnd Bergmann, Breno Leitao, Mathieu Malaterre.
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Merge tag 'powerpc-4.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "Two regression fixes, and a new syscall wire-up:

   - A fix for the recent conversion to time64_t in the powermac RTC
     routines, which caused time to go backward.

   - Another fix for fallout from the split PMD PTL conversion.

   - Wire up the new io_pgetevents() syscall.

  Thanks to: Aneesh Kumar K.V, Arnd Bergmann, Breno Leitao, Mathieu
  Malaterre"

* tag 'powerpc-4.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powermac: Fix rtc read/write functions
  powerpc/mm/32: Fix pgtable_page_dtor call
  powerpc: Wire up io_pgetevents

arch/powerpc/include/asm/book3s/32/pgalloc.h

@@ -138,7 +138,6 @@ static inline void pgtable_free_tlb(struct mmu_gather *tlb,
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 				  unsigned long address)
 {
-	pgtable_page_dtor(table);
 	pgtable_free_tlb(tlb, page_address(table), 0);
 }
 #endif /* _ASM_POWERPC_BOOK3S_32_PGALLOC_H */

arch/powerpc/include/asm/nohash/32/pgalloc.h

@@ -140,7 +140,6 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 				  unsigned long address)
 {
 	tlb_flush_pgtable(tlb, address);
-	pgtable_page_dtor(table);
 	pgtable_free_tlb(tlb, page_address(table), 0);
 }
 #endif /* _ASM_POWERPC_PGALLOC_32_H */

arch/powerpc/include/asm/systbl.h

@@ -393,3 +393,4 @@ SYSCALL(pkey_alloc)
 SYSCALL(pkey_free)
 SYSCALL(pkey_mprotect)
 SYSCALL(rseq)
+COMPAT_SYS(io_pgetevents)

arch/powerpc/include/asm/unistd.h

@@ -12,7 +12,7 @@
 #include <uapi/asm/unistd.h>
 
 
-#define NR_syscalls		388
+#define NR_syscalls		389
 
 #define __NR__exit __NR_exit
 

arch/powerpc/include/uapi/asm/unistd.h

@@ -399,5 +399,6 @@
 #define __NR_pkey_free		385
 #define __NR_pkey_mprotect	386
 #define __NR_rseq		387
+#define __NR_io_pgetevents	388
 
 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */

arch/powerpc/platforms/powermac/time.c

@@ -42,7 +42,11 @@
 #define DBG(x...)
 #endif
 
-/* Apparently the RTC stores seconds since 1 Jan 1904 */
+/*
+ * Offset between Unix time (1970-based) and Mac time (1904-based). Cuda and PMU
+ * times wrap in 2040. If we need to handle later times, the read_time functions
+ * need to be changed to interpret wrapped times as post-2040.
+ */
 #define RTC_OFFSET	2082844800
 
 /*
@@ -97,8 +101,11 @@ static time64_t cuda_get_time(void)
 	if (req.reply_len != 7)
 		printk(KERN_ERR "cuda_get_time: got %d byte reply\n",
 		       req.reply_len);
-	now = (req.reply[3] << 24) + (req.reply[4] << 16)
-		+ (req.reply[5] << 8) + req.reply[6];
+	now = (u32)((req.reply[3] << 24) + (req.reply[4] << 16) +
+		    (req.reply[5] << 8) + req.reply[6]);
+	/* it's either after year 2040, or the RTC has gone backwards */
+	WARN_ON(now < RTC_OFFSET);
+
 	return now - RTC_OFFSET;
 }
 
@@ -106,10 +113,10 @@ static time64_t cuda_get_time(void)
 
 static int cuda_set_rtc_time(struct rtc_time *tm)
 {
-	time64_t nowtime;
+	u32 nowtime;
 	struct adb_request req;
 
-	nowtime = rtc_tm_to_time64(tm) + RTC_OFFSET;
+	nowtime = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
 	if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
 			 nowtime >> 24, nowtime >> 16, nowtime >> 8,
 			 nowtime) < 0)
@@ -140,8 +147,12 @@ static time64_t pmu_get_time(void)
 	if (req.reply_len != 4)
 		printk(KERN_ERR "pmu_get_time: got %d byte reply from PMU\n",
 		       req.reply_len);
-	now = (req.reply[0] << 24) + (req.reply[1] << 16)
-		+ (req.reply[2] << 8) + req.reply[3];
+	now = (u32)((req.reply[0] << 24) + (req.reply[1] << 16)	+
+		    (req.reply[2] << 8) + req.reply[3]);
+
+	/* it's either after year 2040, or the RTC has gone backwards */
+	WARN_ON(now < RTC_OFFSET);
+
 	return now - RTC_OFFSET;
 }
 
@@ -149,10 +160,10 @@ static time64_t pmu_get_time(void)
 
 static int pmu_set_rtc_time(struct rtc_time *tm)
 {
-	time64_t nowtime;
+	u32 nowtime;
 	struct adb_request req;
 
-	nowtime = rtc_tm_to_time64(tm) + RTC_OFFSET;
+	nowtime = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
 	if (pmu_request(&req, NULL, 5, PMU_SET_RTC, nowtime >> 24,
 			nowtime >> 16, nowtime >> 8, nowtime) < 0)
 		return -ENXIO;