Merge branch 'iov_iter' into for-next

4 files changed, 75 insertions, 8 deletions

diff --git a/arch/powerpc/platforms/powernv/opal-lpc.c b/arch/powerpc/platforms/powernv/opal-lpc.c
index dd2c285ad170..e4169d68cb32 100644
--- a/arch/powerpc/platforms/powernv/opal-lpc.c
+++ b/arch/powerpc/platforms/powernv/opal-lpc.c
@@ -191,7 +191,6 @@ static ssize_t lpc_debug_read(struct file *filp, char __user *ubuf,
 {
 	struct lpc_debugfs_entry *lpc = filp->private_data;
 	u32 data, pos, len, todo;
-	__be32 bedata;
 	int rc;
 
 	if (!access_ok(VERIFY_WRITE, ubuf, count))
@@ -214,18 +213,57 @@ static ssize_t lpc_debug_read(struct file *filp, char __user *ubuf,
 				len = 2;
 		}
 		rc = opal_lpc_read(opal_lpc_chip_id, lpc->lpc_type, pos,
-				   &bedata, len);
+				   &data, len);
 		if (rc)
 			return -ENXIO;
-		data = be32_to_cpu(bedata);
+
+		/*
+		 * Now there is some trickery with the data returned by OPAL
+		 * as it's the desired data right justified in a 32-bit BE
+		 * word.
+		 *
+		 * This is a very bad interface and I'm to blame for it :-(
+		 *
+		 * So we can't just apply a 32-bit swap to what comes from OPAL,
+		 * because user space expects the *bytes* to be in their proper
+		 * respective positions (ie, LPC position).
+		 *
+		 * So what we really want to do here is to shift data right
+		 * appropriately on a LE kernel.
+		 *
+		 * IE. If the LPC transaction has bytes B0, B1, B2 and B3 in that
+		 * order, we have in memory written to by OPAL at the "data"
+		 * pointer:
+		 *
+		 *               Bytes:      OPAL "data"   LE "data"
+		 *   32-bit:   B0 B1 B2 B3   B0B1B2B3      B3B2B1B0
+		 *   16-bit:   B0 B1         0000B0B1      B1B00000
+		 *    8-bit:   B0            000000B0      B0000000
+		 *
+		 * So a BE kernel will have the leftmost of the above in the MSB
+		 * and rightmost in the LSB and can just then "cast" the u32 "data"
+		 * down to the appropriate quantity and write it.
+		 *
+		 * However, an LE kernel can't. It doesn't need to swap because a
+		 * load from data followed by a store to user are going to preserve
+		 * the byte ordering which is the wire byte order which is what the
+		 * user wants, but in order to "crop" to the right size, we need to
+		 * shift right first.
+		 */
 		switch(len) {
 		case 4:
 			rc = __put_user((u32)data, (u32 __user *)ubuf);
 			break;
 		case 2:
+#ifdef __LITTLE_ENDIAN__
+			data >>= 16;
+#endif
 			rc = __put_user((u16)data, (u16 __user *)ubuf);
 			break;
 		default:
+#ifdef __LITTLE_ENDIAN__
+			data >>= 24;
+#endif
 			rc = __put_user((u8)data, (u8 __user *)ubuf);
 			break;
 		}
@@ -265,12 +303,31 @@ static ssize_t lpc_debug_write(struct file *filp, const char __user *ubuf,
 			else if (todo > 1 && (pos & 1) == 0)
 				len = 2;
 		}
+
+		/*
+		 * Similarly to the read case, we have some trickery here but
+		 * it's different to handle. We need to pass the value to OPAL in
+		 * a register whose layout depends on the access size. We want
+		 * to reproduce the memory layout of the user, however we aren't
+		 * doing a load from user and a store to another memory location
+		 * which would achieve that. Here we pass the value to OPAL via
+		 * a register which is expected to contain the "BE" interpretation
+		 * of the byte sequence. IE: for a 32-bit access, byte 0 should be
+		 * in the MSB. So here we *do* need to byteswap on LE.
+		 *
+		 *           User bytes:    LE "data"  OPAL "data"
+		 *  32-bit:  B0 B1 B2 B3    B3B2B1B0   B0B1B2B3
+		 *  16-bit:  B0 B1          0000B1B0   0000B0B1
+		 *   8-bit:  B0             000000B0   000000B0
+		 */
 		switch(len) {
 		case 4:
 			rc = __get_user(data, (u32 __user *)ubuf);
+			data = cpu_to_be32(data);
 			break;
 		case 2:
 			rc = __get_user(data, (u16 __user *)ubuf);
+			data = cpu_to_be16(data);
 			break;
 		default:
 			rc = __get_user(data, (u8 __user *)ubuf);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index e9e2450c1fdd..feb549aa3eea 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -58,7 +58,7 @@ END_FTR_SECTION(0, 1);						\
  */
 
 #define OPAL_CALL(name, token)		\
- _GLOBAL(name);				\
+ _GLOBAL_TOC(name);			\
 	mflr	r0;			\
 	std	r0,16(r1);		\
 	li	r0,token;		\
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index 6ad83bd11fe2..c22bb1b4beb8 100644
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -382,7 +382,7 @@ static int dlpar_online_cpu(struct device_node *dn)
 			BUG_ON(get_cpu_current_state(cpu)
 					!= CPU_STATE_OFFLINE);
 			cpu_maps_update_done();
-			rc = cpu_up(cpu);
+			rc = device_online(get_cpu_device(cpu));
 			if (rc)
 				goto out;
 			cpu_maps_update_begin();
@@ -467,7 +467,7 @@ static int dlpar_offline_cpu(struct device_node *dn)
 			if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
 				set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
 				cpu_maps_update_done();
-				rc = cpu_down(cpu);
+				rc = device_offline(get_cpu_device(cpu));
 				if (rc)
 					goto out;
 				cpu_maps_update_begin();
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 8c509d5397c6..f6880d2a40fb 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -43,6 +43,7 @@
 #include <asm/trace.h>
 #include <asm/firmware.h>
 #include <asm/plpar_wrappers.h>
+#include <asm/fadump.h>
 
 #include "pseries.h"
 
@@ -247,8 +248,17 @@ static void pSeries_lpar_hptab_clear(void)
 	}
 
 #ifdef __LITTLE_ENDIAN__
-	/* Reset exceptions to big endian */
-	if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
+	/*
+	 * Reset exceptions to big endian.
+	 *
+	 * FIXME this is a hack for kexec, we need to reset the exception
+	 * endian before starting the new kernel and this is a convenient place
+	 * to do it.
+	 *
+	 * This is also called on boot when a fadump happens. In that case we
+	 * must not change the exception endian mode.
+	 */
+	if (firmware_has_feature(FW_FEATURE_SET_MODE) && !is_fadump_active()) {
 		long rc;
 
 		rc = pseries_big_endian_exceptions();