linux-stable.git/arch/sparc, branch linux-4.4.y

sparc64: fix pci_iounmap() when CONFIG_PCI is not set

2021-10-09T11:24:30+00:00

[ Upstream commit d8b1e10a2b8efaf71d151aa756052fbf2f3b6d57 ]

Guenter reported [1] that the pci_iounmap() changes remain problematic,
with sparc64 allnoconfig and tinyconfig still not building due to the
header file changes and confusion with the arch-specific pci_iounmap()
implementation.

I'm pretty convinced that sparc should just use GENERIC_IOMAP instead of
doing its own thing, since it turns out that the sparc64 version of
pci_iounmap() is somewhat buggy (see [2]).  But in the meantime, this
just fixes the build by avoiding the trivial re-definition of the empty
case.

Link: https://lore.kernel.org/lkml/20210920134424.GA346531@roeck-us.net/ [1]
Link: https://lore.kernel.org/lkml/CAHk-=wgheheFx9myQyy5osh79BAazvmvYURAtub2gQtMvLrhqQ@mail.gmail.com/ [2]
Reported-by: Guenter Roeck 
Cc: David Miller 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

sparc: avoid stringop-overread errors

2021-10-06T08:22:24+00:00

[ Upstream commit fc7c028dcdbfe981bca75d2a7b95f363eb691ef3 ]

The sparc mdesc code does pointer games with 'struct mdesc_hdr', but
didn't describe to the compiler how that header is then followed by the
data that the header describes.

As a result, gcc is now unhappy since it does stricter pointer range
tracking, and doesn't understand about how these things work.  This
results in various errors like:

    arch/sparc/kernel/mdesc.c: In function ‘mdesc_node_by_name’:
    arch/sparc/kernel/mdesc.c:647:22: error: ‘strcmp’ reading 1 or more bytes from a region of size 0 [-Werror=stringop-overread]
      647 |                 if (!strcmp(names + ep[ret].name_offset, name))
          |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

which are easily avoided by just describing 'struct mdesc_hdr' better,
and making the node_block() helper function look into that unsized
data[] that follows the header.

This makes the sparc64 build happy again at least for my cross-compiler
version (gcc version 11.2.1).

Link: https://lore.kernel.org/lkml/CAHk-=wi4NW3NC0xWykkw=6LnjQD6D_rtRtxY9g8gQAJXtQMi8A@mail.gmail.com/
Cc: Guenter Roeck 
Cc: David S. Miller 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

sparc32: fix a user-triggerable oops in clear_user()

2021-03-03T15:44:23+00:00

commit 7780918b36489f0b2f9a3749d7be00c2ceaec513 upstream.

Back in 2.1.29 the clear_user() guts (__bzero()) had been merged
with memset().  Unfortunately, while all exception handlers had been
copied, one of the exception table entries got lost.  As the result,
clear_user() starting at 128*n bytes before the end of page and
spanning between 8 and 127 bytes into the next page would oops when
the second page is unmapped.  It's trivial to reproduce - all
it takes is

main()
{
	int fd = open("/dev/zero", O_RDONLY);
	char *p = mmap(NULL, 16384, PROT_READ|PROT_WRITE,
			MAP_PRIVATE|MAP_ANON, -1, 0);
	munmap(p + 8192, 8192);
	read(fd, p + 8192 - 128, 192);
}

which had been oopsing since March 1997.  Says something about
the quality of test coverage... ;-/  And while today sparc32 port
is nearly dead, back in '97 it had been very much alive; in fact,
sparc64 had only been in mainline for 3 months by that point...

Cc: stable@kernel.org
Fixes: v2.1.29
Signed-off-by: Al Viro 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sparc64: only select COMPAT_BINFMT_ELF if BINFMT_ELF is set

2021-03-03T15:44:20+00:00

[ Upstream commit 80bddf5c93a99e11fc9faf7e4b575d01cecd45d3 ]

Currently COMPAT on SPARC64 selects COMPAT_BINFMT_ELF unconditionally,
even when BINFMT_ELF is not enabled. This causes a kconfig warning.

Instead, just select COMPAT_BINFMT_ELF if BINFMT_ELF is enabled.
This builds cleanly with no kconfig warnings.

WARNING: unmet direct dependencies detected for COMPAT_BINFMT_ELF
  Depends on [n]: COMPAT [=y] && BINFMT_ELF [=n]
  Selected by [y]:
  - COMPAT [=y] && SPARC64 [=y]

Fixes: 26b4c912185a ("sparc,sparc64: unify Kconfig files")
Signed-off-by: Randy Dunlap 
Cc: "David S. Miller" 
Cc: sparclinux@vger.kernel.org
Cc: Sam Ravnborg 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

sparc64: remove mm_cpumask clearing to fix kthread_use_mm race

2020-11-10T09:22:13+00:00

[ Upstream commit bafb056ce27940c9994ea905336aa8f27b4f7275 ]

The de facto (and apparently uncommented) standard for using an mm had,
thanks to this code in sparc if nothing else, been that you must have a
reference on mm_users *and that reference must have been obtained with
mmget()*, i.e., from a thread with a reference to mm_users that had used
the mm.

The introduction of mmget_not_zero() in commit d2005e3f41d4
("userfaultfd: don't pin the user memory in userfaultfd_file_create()")
allowed mm_count holders to aoperate on user mappings asynchronously
from the actual threads using the mm, but they were not to load those
mappings into their TLB (i.e., walking vmas and page tables is okay,
kthread_use_mm() is not).

io_uring 2b188cc1bb857 ("Add io_uring IO interface") added code which
does a kthread_use_mm() from a mmget_not_zero() refcount.

The problem with this is code which previously assumed mm == current->mm
and mm->mm_users == 1 implies the mm will remain single-threaded at
least until this thread creates another mm_users reference, has now
broken.

arch/sparc/kernel/smp_64.c:

    if (atomic_read(&mm->mm_users) == 1) {
        cpumask_copy(mm_cpumask(mm), cpumask_of(cpu));
        goto local_flush_and_out;
    }

vs fs/io_uring.c

    if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL) ||
                 !mmget_not_zero(ctx->sqo_mm)))
        return -EFAULT;
    kthread_use_mm(ctx->sqo_mm);

mmget_not_zero() could come in right after the mm_users == 1 test, then
kthread_use_mm() which sets its CPU in the mm_cpumask. That update could
be lost if cpumask_copy() occurs afterward.

I propose we fix this by allowing mmget_not_zero() to be a first-class
reference, and not have this obscure undocumented and unchecked
restriction.

The basic fix for sparc64 is to remove its mm_cpumask clearing code. The
optimisation could be effectively restored by sending IPIs to mm_cpumask
members and having them remove themselves from mm_cpumask. This is more
tricky so I leave it as an exercise for someone with a sparc64 SMP.
powerpc has a (currently similarly broken) example.

Signed-off-by: Nicholas Piggin 
Acked-by: David S. Miller 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200914045219.3736466-4-npiggin@gmail.com
Signed-off-by: Sasha Levin

fix a braino in "sparc32: fix register window handling in genregs32_[gs]et()"

2020-06-30T00:07:57+00:00

[ Upstream commit 9d964e1b82d8182184153b70174f445ea616f053 ]

lost npc in PTRACE_SETREGSET, breaking PTRACE_SETREGS as well

Fixes: cf51e129b968 "sparc32: fix register window handling in genregs32_[gs]et()"
Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin

sparc64: fix misuses of access_process_vm() in genregs32_[sg]et()

2020-06-30T00:07:56+00:00

[ Upstream commit 142cd25293f6a7ecbdff4fb0af17de6438d46433 ]

We do need access_process_vm() to access the target's reg_window.
However, access to caller's memory (storing the result in
genregs32_get(), fetching the new values in case of genregs32_set())
should be done by normal uaccess primitives.

Fixes: ad4f95764040 ([SPARC64]: Fix user accesses in regset code.)
Cc: stable@kernel.org
Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin

sparc32: fix register window handling in genregs32_[gs]et()

2020-06-20T08:23:24+00:00

commit cf51e129b96847f969bfb8af1ee1516a01a70b39 upstream.

It needs access_process_vm() if the traced process does not share
mm with the caller.  Solution is similar to what sparc64 does.
Note that genregs32_set() is only ever called with pos being 0
or 32 * sizeof(u32) (the latter - as part of PTRACE_SETREGS
handling).

Cc: stable@kernel.org
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

sparc32: fix struct ipc64_perm type definition

2020-02-14T21:29:53+00:00

[ Upstream commit 34ca70ef7d3a9fa7e89151597db5e37ae1d429b4 ]

As discussed in the strace issue tracker, it appears that the sparc32
sysvipc support has been broken for the past 11 years. It was however
working in compat mode, which is how it must have escaped most of the
regular testing.

The problem is that a cleanup patch inadvertently changed the uid/gid
fields in struct ipc64_perm from 32-bit types to 16-bit types in uapi
headers.

Both glibc and uclibc-ng still use the original types, so they should
work fine with compat mode, but not natively.  Change the definitions
to use __kernel_uid32_t and __kernel_gid32_t again.

Fixes: 83c86984bff2 ("sparc: unify ipcbuf.h")
Link: https://github.com/strace/strace/issues/116
Cc:  # v2.6.29
Cc: Sam Ravnborg 
Cc: "Dmitry V . Levin" 
Cc: Rich Felker 
Cc: libc-alpha@sourceware.org
Signed-off-by: Arnd Bergmann 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

sparc64: Rework xchg() definition to avoid warnings.

2019-11-28T17:25:52+00:00

[ Upstream commit 6c2fc9cddc1ffdef8ada1dc8404e5affae849953 ]

Such as:

fs/ocfs2/file.c: In function ‘ocfs2_file_write_iter’:
./arch/sparc/include/asm/cmpxchg_64.h:55:22: warning: value computed is not used [-Wunused-value]
 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

and

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c: In function ‘ixgbevf_xdp_setup’:
./arch/sparc/include/asm/cmpxchg_64.h:55:22: warning: value computed is not used [-Wunused-value]
 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin