| Message ID | 20250307130951.4816-3-philmd@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | user: Extract common MMAP API to 'user/mmap.h' | expand |
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!
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>
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;
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(-)