[Mesa-dev] [PATCH] winsys/svga/drm: Fix 32-bit RPCI send message

[Thomas Hellstrom]

From: Deepak Rawat <drawat at vmware.com>

Depending on whether compiled with frame-pointer or not, the temporary
memory location used for the bp parameter in these macros are referenced
relative to the stack pointer or the frame pointer.
Hence we can never reference that parameter when we've modified either
the stack pointer or the frame pointer, because then the compiler would
generate an incorrect stack reference.

Fix this by pushing the temporary memory parameter on a known location on
the stack before modifying the stack- and frame pointers.

Also in case of failuire RPCI channel is not closed which lead to vmx
running out of channels.

Cc: mesa-stable at lists.freedesktop.org
Signed-off-by: Deepak Rawat <drawat at vmware.com>
Reviewed-by: Sinclair Yeh <syeh at vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom at vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
---
 src/gallium/winsys/svga/drm/vmw_msg.c | 35 ++++++++++++++++++---------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/gallium/winsys/svga/drm/vmw_msg.c b/src/gallium/winsys/svga/drm/vmw_msg.c
index 8cce2241f36..3e8ed2a0fb5 100644
--- a/src/gallium/winsys/svga/drm/vmw_msg.c
+++ b/src/gallium/winsys/svga/drm/vmw_msg.c
@@ -177,17 +177,23 @@ typedef uint64_t VMW_REG;
 
 typedef uint32_t VMW_REG;
 
-/* In the 32-bit version of this macro, we use "m" because there is no
- * more register left for bp
+/* In the 32-bit version of this macro, we store bp in a memory location
+ * because we've ran out of registers.
+ * Now we can't reference that memory location while we've modified
+ * %esp or %ebp, so we first push it on the stack, just before we push
+ * %ebp, and then when we need it we read it from the stack where we
+ * just pushed it.
  */
 #define VMW_PORT_HB_OUT(cmd, in_cx, in_si, in_di, \
          port_num, magic, bp,                     \
          ax, bx, cx, dx, si, di)                  \
 ({                                                \
-   __asm__ volatile ("push %%ebp;"                    \
-      "mov %12, %%ebp;"                           \
+   __asm__ volatile ("push %12;"                  \
+      "push %%ebp;"                               \
+      "mov 0x04(%%esp), %%ebp;"                   \
       "rep outsb;"                                \
-      "pop %%ebp;" :                              \
+      "pop %%ebp;"                                \
+      "add $0x04, %%esp;" :                       \
       "=a"(ax),                                   \
       "=b"(bx),                                   \
       "=c"(cx),                                   \
@@ -209,10 +215,12 @@ typedef uint32_t VMW_REG;
          port_num, magic, bp,                     \
          ax, bx, cx, dx, si, di)                  \
 ({                                                \
-   __asm__ volatile ("push %%ebp;"                    \
-      "mov %12, %%ebp;"                           \
+   __asm__ volatile ("push %12;"                  \
+      "push %%ebp;"                               \
+      "mov 0x04(%%esp), %%ebp;"                   \
       "rep insb;"                                 \
-      "pop %%ebp" :                               \
+      "pop %%ebp;"                                \
+      "add $0x04, %%esp;" :                       \
       "=a"(ax),                                   \
       "=b"(bx),                                   \
       "=c"(cx),                                   \
@@ -418,6 +426,7 @@ vmw_svga_winsys_host_log(struct svga_winsys_screen *sws, const char *log)
    struct rpc_channel channel;
    char *msg;
    int msg_len;
+   int ret;
 
 #ifdef MSG_NOT_IMPLEMENTED
    return;
@@ -435,12 +444,14 @@ vmw_svga_winsys_host_log(struct svga_winsys_screen *sws, const char *log)
 
    util_sprintf(msg, "log %s", log);
 
-   if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM) ||
-       vmw_send_msg(&channel, msg) ||
-       vmw_close_channel(&channel)) {
-      debug_printf("Failed to send log\n");
+   if (!(ret = vmw_open_channel(&channel, RPCI_PROTOCOL_NUM))) {
+      ret = vmw_send_msg(&channel, msg);
+      vmw_close_channel(&channel);
    }
 
+   if (ret)
+      debug_printf("Failed to send log\n");
+
    FREE(msg);
 
    return;
-- 
2.21.0