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qemu/0006-qemu-cvs-alsa_mmap.patch

46 lines
1.5 KiB
Diff

From 7d78b3ff3cca24f85abe0ae6f7889d802d8a4cd0 Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@suse.de>
Date: Tue, 14 Apr 2009 16:24:15 +0200
Subject: [PATCH] qemu-cvs-alsa_mmap
Hack to prevent ALSA from using mmap() interface to simplify emulation.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Ulrich Hecht <uli@suse.de>
---
linux-user/mmap.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index a249f0c..34a5615 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -366,6 +366,9 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
}
}
+#define SNDRV_PCM_MMAP_OFFSET_STATUS 0x80000000
+#define SNDRV_PCM_MMAP_OFFSET_CONTROL 0x81000000
+
/* NOTE: all the constants are the HOST ones */
abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
int flags, int fd, abi_ulong offset)
@@ -400,6 +403,17 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
}
#endif
+ /* Alsa tries to communcate with the kernel via mmap. This usually
+ * is a good idea when user- and kernelspace are running on the
+ * same architecture but does not work out when not. To make alsa
+ * not to use mmap, we can just have it fail on the mmap calls that
+ * would initiate this.
+ */
+ if(offset == SNDRV_PCM_MMAP_OFFSET_STATUS || offset == SNDRV_PCM_MMAP_OFFSET_CONTROL) {
+ errno = EINVAL;
+ return -1;
+ }
+
if (offset & ~TARGET_PAGE_MASK) {
errno = EINVAL;
goto fail;