Propagate the alignment to mmap_find_vma(), effectively
embedding mmap_find_vma_aligned() within mmap_find_vma().
Since we ignore the alignment in do_bsd_shmat(), leave a
FIXME comment.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
bsd-user/bsd-mem.h | 2 +-
bsd-user/qemu.h | 2 +-
bsd-user/mmap.c | 10 ++--------
3 files changed, 4 insertions(+), 10 deletions(-)
diff --git a/bsd-user/bsd-mem.h b/bsd-user/bsd-mem.h
index f5ec0de24ca..87219da2919 100644
--- a/bsd-user/bsd-mem.h
+++ b/bsd-user/bsd-mem.h
@@ -372,7 +372,7 @@ static inline abi_long do_bsd_shmat(int shmid, abi_ulong shmaddr, int shmflg)
} else {
abi_ulong mmap_start;
- mmap_start = mmap_find_vma(0, shm_info.shm_segsz);
+ mmap_start = mmap_find_vma(0, shm_info.shm_segsz, 0 /* FIXME??? */);
if (mmap_start == -1) {
return -TARGET_ENOMEM;
diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
index 4e97c796318..0b3bd65b180 100644
--- a/bsd-user/qemu.h
+++ b/bsd-user/qemu.h
@@ -242,7 +242,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
abi_ulong new_addr);
int target_msync(abi_ulong start, abi_ulong len, int flags);
extern abi_ulong mmap_next_start;
-abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size);
+abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size, abi_ulong alignment);
void mmap_reserve(abi_ulong start, abi_ulong size);
void TSA_NO_TSA mmap_fork_start(void);
void TSA_NO_TSA mmap_fork_end(int child);
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index 28d7e387a20..da22fcc7c41 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -275,8 +275,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size,
* It must be called with mmap_lock() held.
* Return -1 if error.
*/
-static abi_ulong mmap_find_vma_aligned(abi_ulong start, abi_ulong size,
- abi_ulong alignment)
+abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size, abi_ulong alignment)
{
void *ptr, *prev;
abi_ulong addr;
@@ -395,11 +394,6 @@ static abi_ulong mmap_find_vma_aligned(abi_ulong start, abi_ulong size,
}
}
-abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
-{
- return mmap_find_vma_aligned(start, size, 0);
-}
-
/* NOTE: all the constants are the HOST ones */
abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
int flags, int fd, off_t offset)
@@ -496,7 +490,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
if ((flags & MAP_ALIGNMENT_MASK) != 0) {
alignment = (flags & MAP_ALIGNMENT_MASK) >> MAP_ALIGNMENT_SHIFT;
}
- start = mmap_find_vma_aligned(real_start, host_len, alignment);
+ start = mmap_find_vma(real_start, host_len, alignment);
if (start == (abi_ulong)-1) {
errno = ENOMEM;
goto fail;
--
2.47.1
On Fri, Mar 7, 2025 at 6:10 AM Philippe Mathieu-Daudé <philmd@linaro.org> wrote: > Propagate the alignment to mmap_find_vma(), effectively > embedding mmap_find_vma_aligned() within mmap_find_vma(). > > Since we ignore the alignment in do_bsd_shmat(), leave a > FIXME comment. > > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> > --- > bsd-user/bsd-mem.h | 2 +- > bsd-user/qemu.h | 2 +- > bsd-user/mmap.c | 10 ++-------- > 3 files changed, 4 insertions(+), 10 deletions(-) > Reviewed-by: Warner Losh <imp@bsdimp.com>
On 3/7/25 05:09, Philippe Mathieu-Daudé wrote:
> Propagate the alignment to mmap_find_vma(), effectively
> embedding mmap_find_vma_aligned() within mmap_find_vma().
>
> Since we ignore the alignment in do_bsd_shmat(), leave a
> FIXME comment.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> bsd-user/bsd-mem.h | 2 +-
> bsd-user/qemu.h | 2 +-
> bsd-user/mmap.c | 10 ++--------
> 3 files changed, 4 insertions(+), 10 deletions(-)
>
> diff --git a/bsd-user/bsd-mem.h b/bsd-user/bsd-mem.h
> index f5ec0de24ca..87219da2919 100644
> --- a/bsd-user/bsd-mem.h
> +++ b/bsd-user/bsd-mem.h
> @@ -372,7 +372,7 @@ static inline abi_long do_bsd_shmat(int shmid, abi_ulong shmaddr, int shmflg)
> } else {
> abi_ulong mmap_start;
>
> - mmap_start = mmap_find_vma(0, shm_info.shm_segsz);
> + mmap_start = mmap_find_vma(0, shm_info.shm_segsz, 0 /* FIXME??? */);
It's not really ignoring the alignment, but not requiring alignment above page size.
Traditionally, the alignment for shmat should be SHMLBA.
But in current freebsd sources,
sys/sys/shm.h:#define SHMLBA PAGE_SIZE /* Segment low boundary address multiple */
there are no crazy broken old architectures to worry about.
r~
On 7/3/25 17:08, Richard Henderson wrote:
> On 3/7/25 05:09, Philippe Mathieu-Daudé wrote:
>> Propagate the alignment to mmap_find_vma(), effectively
>> embedding mmap_find_vma_aligned() within mmap_find_vma().
>>
>> Since we ignore the alignment in do_bsd_shmat(), leave a
>> FIXME comment.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>> bsd-user/bsd-mem.h | 2 +-
>> bsd-user/qemu.h | 2 +-
>> bsd-user/mmap.c | 10 ++--------
>> 3 files changed, 4 insertions(+), 10 deletions(-)
>>
>> diff --git a/bsd-user/bsd-mem.h b/bsd-user/bsd-mem.h
>> index f5ec0de24ca..87219da2919 100644
>> --- a/bsd-user/bsd-mem.h
>> +++ b/bsd-user/bsd-mem.h
>> @@ -372,7 +372,7 @@ static inline abi_long do_bsd_shmat(int shmid,
>> abi_ulong shmaddr, int shmflg)
>> } else {
>> abi_ulong mmap_start;
>> - mmap_start = mmap_find_vma(0, shm_info.shm_segsz);
>> + mmap_start = mmap_find_vma(0, shm_info.shm_segsz, 0 /*
>> FIXME??? */);
>
> It's not really ignoring the alignment, but not requiring alignment
> above page size.
>
> Traditionally, the alignment for shmat should be SHMLBA.
> But in current freebsd sources,
>
> sys/sys/shm.h:#define SHMLBA PAGE_SIZE /* Segment low boundary
> address multiple */
>
> there are no crazy broken old architectures to worry about.
OK, thank you for checking!
© 2016 - 2025 Red Hat, Inc.