[Qemu-devel] [PATCH v3] linux-user/syscall.c: Handle SH4's exceptional alignment for p{read, write}64

[James Clarke <jrtc27@jrtc27.com>]

Fixes: https://bugs.launchpad.net/qemu/+bug/1716767
Signed-off-by: James Clarke <jrtc27@jrtc27.com>
---

Changes since v2:
 * Fixed opening curly brace formatting, both for my new SH4-specific
   regpairs_aligned function, as well as the Arm one I touched, to appease
   checkpatch.pl

Changes since v1:
 * Removed all changes in v1 :)
 * Added syscall num argument to regpairs_aligned
 * Added SH4-specific implementation of regpairs_aligned to return 1 for
   p{read,write}64

 linux-user/syscall.c | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 9b6364a266..0c1bd80bed 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -667,18 +667,32 @@ static inline int next_free_host_timer(void)
 
 /* ARM EABI and MIPS expect 64bit types aligned even on pairs or registers */
 #ifdef TARGET_ARM
-static inline int regpairs_aligned(void *cpu_env) {
+static inline int regpairs_aligned(void *cpu_env, int num)
+{
     return ((((CPUARMState *)cpu_env)->eabi) == 1) ;
 }
 #elif defined(TARGET_MIPS) && (TARGET_ABI_BITS == 32)
-static inline int regpairs_aligned(void *cpu_env) { return 1; }
+static inline int regpairs_aligned(void *cpu_env, int num) { return 1; }
 #elif defined(TARGET_PPC) && !defined(TARGET_PPC64)
 /* SysV AVI for PPC32 expects 64bit parameters to be passed on odd/even pairs
  * of registers which translates to the same as ARM/MIPS, because we start with
  * r3 as arg1 */
-static inline int regpairs_aligned(void *cpu_env) { return 1; }
+static inline int regpairs_aligned(void *cpu_env, int num) { return 1; }
+#elif defined(TARGET_SH4)
+/* SH4 doesn't align register pairs, except for p{read,write}64 */
+static inline int regpairs_aligned(void *cpu_env, int num)
+{
+    switch (num) {
+    case TARGET_NR_pread64:
+    case TARGET_NR_pwrite64:
+        return 1;
+
+    default:
+        return 0;
+    }
+}
 #else
-static inline int regpairs_aligned(void *cpu_env) { return 0; }
+static inline int regpairs_aligned(void *cpu_env, int num) { return 0; }
 #endif
 
 #define ERRNO_TABLE_SIZE 1200
@@ -6857,7 +6871,7 @@ static inline abi_long target_truncate64(void *cpu_env, const char *arg1,
                                          abi_long arg3,
                                          abi_long arg4)
 {
-    if (regpairs_aligned(cpu_env)) {
+    if (regpairs_aligned(cpu_env, TARGET_NR_truncate64)) {
         arg2 = arg3;
         arg3 = arg4;
     }
@@ -6871,7 +6885,7 @@ static inline abi_long target_ftruncate64(void *cpu_env, abi_long arg1,
                                           abi_long arg3,
                                           abi_long arg4)
 {
-    if (regpairs_aligned(cpu_env)) {
+    if (regpairs_aligned(cpu_env, TARGET_NR_ftruncate64)) {
         arg2 = arg3;
         arg3 = arg4;
     }
@@ -10495,7 +10509,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #endif
 #ifdef TARGET_NR_pread64
     case TARGET_NR_pread64:
-        if (regpairs_aligned(cpu_env)) {
+        if (regpairs_aligned(cpu_env, num)) {
             arg4 = arg5;
             arg5 = arg6;
         }
@@ -10505,7 +10519,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         unlock_user(p, arg2, ret);
         break;
     case TARGET_NR_pwrite64:
-        if (regpairs_aligned(cpu_env)) {
+        if (regpairs_aligned(cpu_env, num)) {
             arg4 = arg5;
             arg5 = arg6;
         }
@@ -11275,7 +11289,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         arg6 = ret;
 #else
         /* 6 args: fd, offset (high, low), len (high, low), advice */
-        if (regpairs_aligned(cpu_env)) {
+        if (regpairs_aligned(cpu_env, num)) {
             /* offset is in (3,4), len in (5,6) and advice in 7 */
             arg2 = arg3;
             arg3 = arg4;
@@ -11294,7 +11308,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #ifdef TARGET_NR_fadvise64
     case TARGET_NR_fadvise64:
         /* 5 args: fd, offset (high, low), len, advice */
-        if (regpairs_aligned(cpu_env)) {
+        if (regpairs_aligned(cpu_env, num)) {
             /* offset is in (3,4), len in 5 and advice in 6 */
             arg2 = arg3;
             arg3 = arg4;
@@ -11407,7 +11421,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #ifdef TARGET_NR_readahead
     case TARGET_NR_readahead:
 #if TARGET_ABI_BITS == 32
-        if (regpairs_aligned(cpu_env)) {
+        if (regpairs_aligned(cpu_env, num)) {
             arg2 = arg3;
             arg3 = arg4;
             arg4 = arg5;
-- 
2.13.2