32e37f2492
git-svn-id: https://svn.disconnected-by-peer.at/svn/linamh/trunk/vmware@1952 6952d904-891a-0410-993b-d76249ca496b
126 lines
4.0 KiB
Diff
126 lines
4.0 KiB
Diff
From d7f01e455acae19ef780e29417ffba50ca90ffde Mon Sep 17 00:00:00 2001
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From: Kirill A. Shutemov <kirill@shutemov.name>
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Date: Wed, 17 Jun 2009 15:14:43 +0200
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Subject: [PATCH 19/33] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets
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From: Kirill A. Shutemov <kirill@shutemov.name>
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qemu's page table can be incomple if /proc/self/maps is unavailable or
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host allocating a memory with mmap(), so we can't use it to find free
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memory area.
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New version mmap_find_vma() uses mmap() without MAP_FIXED to find free
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memory.
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From: Kirill A. Shutemov <kirill@shutemov.name>
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Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
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Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
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---
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linux-user/mmap.c | 79 +++++++++++++++++++++++++++++------------------------
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1 files changed, 43 insertions(+), 36 deletions(-)
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diff --git a/linux-user/mmap.c b/linux-user/mmap.c
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index 9ca8f6f..8d94783 100644
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--- a/linux-user/mmap.c
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+++ b/linux-user/mmap.c
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@@ -277,52 +277,59 @@ static abi_ulong mmap_next_start = 0x40000000;
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unsigned long last_brk;
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-/* find a free memory area of size 'size'. The search starts at
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- 'start'. If 'start' == 0, then a default start address is used.
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- Return -1 if error.
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-*/
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-/* page_init() marks pages used by the host as reserved to be sure not
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- to use them. */
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+/*
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+ * Find and reserve a free memory area of size 'size'. The search
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+ * starts at 'start'.
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+ * It must be called with mmap_lock() held.
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+ * Return -1 if error.
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+ */
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abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
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{
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- abi_ulong addr, addr1, addr_start;
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- int prot;
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- unsigned long new_brk;
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-
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- new_brk = (unsigned long)sbrk(0);
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- if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) {
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- /* This is a hack to catch the host allocating memory with brk().
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- If it uses mmap then we loose.
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- FIXME: We really want to avoid the host allocating memory in
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- the first place, and maybe leave some slack to avoid switching
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- to mmap. */
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- page_set_flags(last_brk & TARGET_PAGE_MASK,
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- TARGET_PAGE_ALIGN(new_brk),
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- PAGE_RESERVED);
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- }
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- last_brk = new_brk;
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+ void *ptr;
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+ abi_ulong addr;
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size = HOST_PAGE_ALIGN(size);
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- start = start & qemu_host_page_mask;
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+ start &= qemu_host_page_mask;
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+
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+ /* If 'start' == 0, then a default start address is used. */
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+ if (start == 0)
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+ start = mmap_next_start;
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+
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addr = start;
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- if (addr == 0)
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- addr = mmap_next_start;
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- addr_start = addr;
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+
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for(;;) {
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- prot = 0;
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- for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) {
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- prot |= page_get_flags(addr1);
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- }
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- if (prot == 0)
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+ /*
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+ * Reserve needed memory area to avoid a race.
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+ * It should be discarded using:
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+ * - mmap() with MAP_FIXED flag
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+ * - mremap() with MREMAP_FIXED flag
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+ * - shmat() with SHM_REMAP flag
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+ */
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+ ptr = mmap((void *)(unsigned long)addr, size, PROT_NONE,
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+ MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
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+
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+ /* ENOMEM, if host address space has no memory */
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+ if (ptr == MAP_FAILED)
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+ return (abi_ulong)-1;
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+
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+ /* If address fits target address space we've found what we need */
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+ if ((unsigned long)ptr + size - 1 <= (abi_ulong)-1)
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break;
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+
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+ /* Unmap and try again with new page */
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+ munmap(ptr, size);
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addr += qemu_host_page_size;
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- /* we found nothing */
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- if (addr == addr_start)
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+
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+ /* ENOMEM if we check whole of target address space */
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+ if (addr == start)
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return (abi_ulong)-1;
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}
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- if (start == 0)
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- mmap_next_start = addr + size;
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- return addr;
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+
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+ /* Update default start address */
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+ if (start == mmap_next_start)
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+ mmap_next_start = (unsigned long)ptr + size;
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+
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+ return h2g(ptr);
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}
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#define SNDRV_PCM_MMAP_OFFSET_STATUS 0x80000000
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--
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1.6.2.1
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