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Re: [Qemu-devel] [PATCH] bsd-user/mmap.c: Don't try to override g_malloc
From: |
Sean Bruno |
Subject: |
Re: [Qemu-devel] [PATCH] bsd-user/mmap.c: Don't try to override g_malloc/g_free |
Date: |
Wed, 04 Jun 2014 07:34:46 -0700 |
On Wed, 2014-06-04 at 00:51 +0100, Peter Maydell wrote:
> Trying to override the implementations of g_malloc and g_free is
> a really bad idea -- it means statically linked builds fail to
> link (because of the multiple definitions provided by this file
> and by glib), and non-statically linked builds segfault as soon
> as they try to do anything more complicated than printing the
> usage message. Remove these overridden versions and just use
> the glib ones.
>
> This is sufficient that bsd-user can run basic x86-64
> binaries on OpenBSD again; FreeBSD and NetBSD seem to have
> further issues.
>
> Signed-off-by: Peter Maydell <address@hidden>
Reviewed by: Sean Bruno address@hidden
> ---
> The FreeBSD QEMU bsd-user tree took this same approach.
>
> Blue, I'm planning to put this together with a few other bsd-user
> patches (and further submissions from the FreeBSD folk as they
> get them into shape) into a 'bsd-user.next' queue. Let me
> know if you'd rather do that yourself (as the listed bsd-user
> maintainer). My current queue is at:
> https://git.linaro.org/people/peter.maydell/qemu-arm.git/shortlog/refs/heads/bsd-user.next
> (though not all of those have been through review yet).
>
> bsd-user/mmap.c | 60
> ---------------------------------------------------------
> 1 file changed, 60 deletions(-)
>
> diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
> index aae8ea1..092bf7f 100644
> --- a/bsd-user/mmap.c
> +++ b/bsd-user/mmap.c
> @@ -74,66 +74,6 @@ void mmap_unlock(void)
> }
> #endif
>
> -static void *bsd_vmalloc(size_t size)
> -{
> - void *p;
> - mmap_lock();
> - /* Use map and mark the pages as used. */
> - p = mmap(NULL, size, PROT_READ | PROT_WRITE,
> - MAP_PRIVATE | MAP_ANON, -1, 0);
> -
> - if (h2g_valid(p)) {
> - /* Allocated region overlaps guest address space.
> - This may recurse. */
> - abi_ulong addr = h2g(p);
> - page_set_flags(addr & TARGET_PAGE_MASK, TARGET_PAGE_ALIGN(addr +
> size),
> - PAGE_RESERVED);
> - }
> -
> - mmap_unlock();
> - return p;
> -}
> -
> -void *g_malloc(size_t size)
> -{
> - char * p;
> - size += 16;
> - p = bsd_vmalloc(size);
> - *(size_t *)p = size;
> - return p + 16;
> -}
> -
> -/* We use map, which is always zero initialized. */
> -void * g_malloc0(size_t size)
> -{
> - return g_malloc(size);
> -}
> -
> -void g_free(void *ptr)
> -{
> - /* FIXME: We should unmark the reserved pages here. However this gets
> - complicated when one target page spans multiple host pages, so we
> - don't bother. */
> - size_t *p;
> - p = (size_t *)((char *)ptr - 16);
> - munmap(p, *p);
> -}
> -
> -void *g_realloc(void *ptr, size_t size)
> -{
> - size_t old_size, copy;
> - void *new_ptr;
> -
> - if (!ptr)
> - return g_malloc(size);
> - old_size = *(size_t *)((char *)ptr - 16);
> - copy = old_size < size ? old_size : size;
> - new_ptr = g_malloc(size);
> - memcpy(new_ptr, ptr, copy);
> - g_free(ptr);
> - return new_ptr;
> -}
> -
> /* NOTE: all the constants are the HOST ones, but addresses are target. */
> int target_mprotect(abi_ulong start, abi_ulong len, int prot)
> {