[PATCH 06/15] kmsg: fix msg body alignment

[Luca Dariz]

* ipc/ipc_kmsg.c: align msg body to 4 bytes as done in mig

Signed-off-by: Luca Dariz <luca@orpolo.org>
---
 ipc/ipc_kmsg.c | 49 ++++++++++++++++++++++---------------------------
 1 file changed, 22 insertions(+), 27 deletions(-)

diff --git a/ipc/ipc_kmsg.c b/ipc/ipc_kmsg.c
index b9d29853..09801924 100644
--- a/ipc/ipc_kmsg.c
+++ b/ipc/ipc_kmsg.c
@@ -68,9 +68,10 @@
 #include <ipc/ipc_print.h>
 #endif
 
-#define is_misaligned(x)       ( ((vm_offset_t)(x)) & (sizeof(vm_offset_t)-1) )
-#define ptr_align(x)   \
-       ( ( ((vm_offset_t)(x)) + (sizeof(vm_offset_t)-1) ) & 
~(sizeof(vm_offset_t)-1) )
+/* msg body is always aligned to 4 bytes */
+#define msg_is_misaligned(x)   ( ((vm_offset_t)(x)) & (sizeof(uint32_t)-1) )
+#define msg_align(x)   \
+       ( ( ((vm_offset_t)(x)) + (sizeof(uint32_t)-1) ) & ~(sizeof(uint32_t)-1) 
)
 
 ipc_kmsg_t ipc_kmsg_cache[NCPUS];
 
@@ -232,8 +233,8 @@ ipc_kmsg_clean_body(
                if (((mach_msg_type_t*)type)->msgt_longform) {
                        /* This must be aligned */
                        if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
-                           (is_misaligned(type))) {
-                               saddr = ptr_align(saddr);
+                           (msg_is_misaligned(type))) {
+                               saddr = msg_align(saddr);
                                continue;
                        }
                        name = type->msgtl_name;
@@ -250,7 +251,7 @@ ipc_kmsg_clean_body(
                /* padding (ptrs and ports) ? */
                if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
                    ((size >> 3) == sizeof(natural_t)))
-                       saddr = ptr_align(saddr);
+                       saddr = msg_align(saddr);
 
                /* calculate length of data in bytes, rounding up */
 
@@ -393,8 +394,8 @@ xxx:                type = (mach_msg_type_long_t *) eaddr;
                if (((mach_msg_type_t*)type)->msgt_longform) {
                        /* This must be aligned */
                        if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
-                           (is_misaligned(type))) {
-                               eaddr = ptr_align(eaddr);
+                           (msg_is_misaligned(type))) {
+                               eaddr = msg_align(eaddr);
                                goto xxx;
                        }
                        name = type->msgtl_name;
@@ -411,7 +412,7 @@ xxx:                type = (mach_msg_type_long_t *) eaddr;
                /* padding (ptrs and ports) ? */
                if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
                    ((size >> 3) == sizeof(natural_t)))
-                       eaddr = ptr_align(eaddr);
+                       eaddr = msg_align(eaddr);
 
                /* calculate length of data in bytes, rounding up */
 
@@ -1324,8 +1325,8 @@ ipc_kmsg_copyin_body(
                if (longform) {
                        /* This must be aligned */
                        if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
-                           (is_misaligned(type))) {
-                               saddr = ptr_align(saddr);
+                           (msg_is_misaligned(type))) {
+                               saddr = msg_align(saddr);
                                continue;
                        }
                        name = type->msgtl_name;
@@ -1354,7 +1355,7 @@ ipc_kmsg_copyin_body(
                /* padding (ptrs and ports) ? */
                if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
                    ((size >> 3) == sizeof(natural_t)))
-                       saddr = ptr_align(saddr);
+                       saddr = msg_align(saddr);
 
                /* calculate length of data in bytes, rounding up */
 
@@ -1376,9 +1377,6 @@ ipc_kmsg_copyin_body(
                } else {
                        vm_offset_t addr;
 
-                       if (sizeof(vm_offset_t) > sizeof(mach_msg_type_t))
-                               saddr = ptr_align(saddr);
-
                        if ((eaddr - saddr) < sizeof(vm_offset_t)) {
                                ipc_kmsg_clean_partial(kmsg, taddr, FALSE, 0);
                                return MACH_SEND_MSG_TOO_SMALL;
@@ -1591,8 +1589,8 @@ ipc_kmsg_copyin_from_kernel(ipc_kmsg_t kmsg)
                if (longform) {
                        /* This must be aligned */
                        if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
-                           (is_misaligned(type))) {
-                               saddr = ptr_align(saddr);
+                           (msg_is_misaligned(type))) {
+                               saddr = msg_align(saddr);
                                continue;
                        }
                        name = type->msgtl_name;
@@ -1609,7 +1607,7 @@ ipc_kmsg_copyin_from_kernel(ipc_kmsg_t kmsg)
                /* padding (ptrs and ports) ? */
                if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
                    ((size >> 3) == sizeof(natural_t)))
-                       saddr = ptr_align(saddr);
+                       saddr = msg_align(saddr);
 
                /* calculate length of data in bytes, rounding up */
 
@@ -2364,8 +2362,8 @@ ipc_kmsg_copyout_body(
                if (longform) {
                        /* This must be aligned */
                        if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
-                           (is_misaligned(type))) {
-                               saddr = ptr_align(saddr);
+                           (msg_is_misaligned(type))) {
+                               saddr = msg_align(saddr);
                                continue;
                        }
                        name = type->msgtl_name;
@@ -2382,7 +2380,7 @@ ipc_kmsg_copyout_body(
                /* padding (ptrs and ports) ? */
                if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
                    ((size >> 3) == sizeof(natural_t)))
-                       saddr = ptr_align(saddr);
+                       saddr = msg_align(saddr);
 
                /* calculate length of data in bytes, rounding up */
 
@@ -2426,9 +2424,6 @@ ipc_kmsg_copyout_body(
                } else {
                        vm_offset_t data;
 
-                       if (sizeof(vm_offset_t) > sizeof(mach_msg_type_t))
-                               saddr = ptr_align(saddr);
-
                        data = * (vm_offset_t *) saddr;
 
                        /* copyout memory carried in the message */
@@ -2795,8 +2790,8 @@ ipc_msg_print(mach_msg_header_t *msgh)
                if (longform) {
                        /* This must be aligned */
                        if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
-                           (is_misaligned(type))) {
-                               saddr = ptr_align(saddr);
+                           (msg_is_misaligned(type))) {
+                               saddr = msg_align(saddr);
                                continue;
                        }
                        name = type->msgtl_name;
@@ -2841,7 +2836,7 @@ ipc_msg_print(mach_msg_header_t *msgh)
                /* padding (ptrs and ports) ? */
                if ((sizeof(natural_t) > sizeof(mach_msg_type_t)) &&
                    ((size >> 3) == sizeof(natural_t)))
-                       saddr = ptr_align(saddr);
+                       saddr = msg_align(saddr);
 
                /* calculate length of data in bytes, rounding up */
 
-- 
2.30.2