kernel.git/arch/x86/um, branch linux-5.12.y

um: remove process stub VMA

2021-02-12T20:37:38Z

This mostly reverts the old commit 3963333fe676 ("uml: cover stubs with a VMA") which had added a VMA to the existing PTEs. However, there's no real reason to have the PTEs in the first place and the VMA cannot be 'fixed' in place, which leads to bugs that userspace could try to unmap them and be forcefully killed, or such. Also, there's a bit of an ugly hole in userspace's address space. Simplify all this: just install the stub code/page at the top of the (inner) address space, i.e. put it just above TASK_SIZE. The pages are simply hard-coded to be mapped in the userspace process we use to implement an mm context, and they're out of reach of the inner mmap/munmap/mprotect etc. since they're above TASK_SIZE. Getting rid of the VMA also makes vma_merge() no longer hit one of the VM_WARN_ON()s there because we installed a VMA while the code assumes the stack VMA is the first one. It also removes a lockdep warning about mmap_sem usage since we no longer have uml_setup_stubs() and thus no longer need to do any manipulation that would require mmap_sem in activate_mm(). Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger

um: rework userspace stubs to not hard-code stub location

2021-02-12T20:35:02Z

The userspace stacks mostly have a stack (and in the case of the syscall stub we can just set their stack pointer) that points to the location of the stub data page already. Rework the stubs to use the stack pointer to derive the start of the data page, rather than requiring it to be hard-coded. In the clone stub, also integrate the int3 into the stack remap, since we really must not use the stack while we remap it. This prepares for putting the stub at a variable location that's not part of the normal address space of the userspace processes running inside the UML machine. Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger

um: separate child and parent errors in clone stub

2021-02-12T20:34:33Z

If the two are mixed up, then it looks as though the parent returned an error if the child failed (before) the mmap(), and then the resulting process never gets killed. Fix this by splitting the child and parent errors, reporting and using them appropriately. Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger

arch/um: partially revert the conversion to __section() macro

2020-10-26T22:39:37Z

A couple of um files ended up not including the header file that defines the __section() macro, and the simplest fix is to just revert the change for those files. Fixes: 33def8498fdd treewide: Convert macro and uses of __section(foo) to __section("foo") Reported-and-tested-by: Guenter Roeck Cc: Joe Perches Signed-off-by: Linus Torvalds

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49Z

Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches Reviewed-by: Nick Desaulniers Reviewed-by: Miguel Ojeda Signed-off-by: Linus Torvalds

Merge tag 'for-linus-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

2020-10-18T17:03:23Z

Pull UML updates from Richard Weinberger: - Improve support for non-glibc systems - Vector: Add support for scripting and dynamic tap devices - Various fixes for the vector networking driver - Various fixes for time travel mode * tag 'for-linus-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: vector: Add dynamic tap interfaces and scripting um: Clean up stacktrace dump um: Fix incorrect assumptions about max pid length um: Remove dead usage of TIF_IA32 um: Remove redundant NULL check um: change sigio_spinlock to a mutex um: time-travel: Return the sequence number in ACK messages um: time-travel: Fix IRQ handling in time_travel_handle_message() um: Allow static linking for non-glibc implementations um: Some fixes to build UML with musl um: vector: Use GFP_ATOMIC under spin lock um: Fix null pointer dereference in vector_user_bpf

um: Remove dead usage of TIF_IA32

2020-10-11T21:19:36Z

This seems like a dead artifact since TIF_IA32 is not even defined as a TI flag for UM. Looking back in git history, it made sense in the old days, but it is apparently not used since UM was split out of the x86 arch/. It is also going away from the x86 tree soon. Also, I think the variable clean up it performs is not needed as 64-bit UML doesn't run 32-bit binaries as far as I can tell, and 32-bit UML has 32-bit ulong. Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Richard Weinberger

um: Some fixes to build UML with musl

2020-10-11T21:13:06Z

musl toolchain and headers are a bit more strict. These fixes enable building UML with musl as well as seem not to break on glibc. Signed-off-by: Ignat Korchagin Tested-by: Brendan Higgins Signed-off-by: Richard Weinberger

saner calling conventions for csum_and_copy_..._user()

2020-08-20T19:45:15Z

All callers of these primitives will * discard anything we might've copied in case of error * ignore the csum value in case of error * always pass 0xffffffff as the initial sum, so the resulting csum value (in case of success, that is) will never be 0. That suggest the following calling conventions: * don't pass err_ptr - just return 0 on error. * don't bother with zeroing destination, etc. in case of error * don't pass the initial sum - just use 0xffffffff. This commit does the minimal conversion in the instances of csum_and_copy_...(); the changes of actual asm code behind them are done later in the series. Note that this asm code is often shared with csum_partial_copy_nocheck(); the difference is that csum_partial_copy_nocheck() passes 0 for initial sum while csum_and_copy_..._user() pass 0xffffffff. Fortunately, we are free to pass 0xffffffff in all cases and subsequent patches will use that freedom without any special comments. A part that could be split off: parisc and uml/i386 claimed to have csum_and_copy_to_user() instances of their own, but those were identical to the generic one, so we simply drop them. Not sure if it's worth a separate commit... Signed-off-by: Al Viro

unify generic instances of csum_partial_copy_nocheck()

2020-08-20T19:45:14Z

quite a few architectures have the same csum_partial_copy_nocheck() - simply memcpy() the data and then return the csum of the copy. hexagon, parisc, ia64, s390, um: explicitly spelled out that way. arc, arm64, csky, h8300, m68k/nommu, microblaze, mips/GENERIC_CSUM, nds32, nios2, openrisc, riscv, unicore32: end up picking the same thing spelled out in lib/checksum.h (with varying amounts of perversions along the way). everybody else (alpha, arm, c6x, m68k/mmu, mips/!GENERIC_CSUM, powerpc, sh, sparc, x86, xtensa) have non-generic variants. For all except c6x the declaration is in their asm/checksum.h. c6x uses the wrapper from asm-generic/checksum.h that would normally lead to the lib/checksum.h instance, but in case of c6x we end up using an asm function from arch/c6x instead. Screw that mess - have architectures with private instances define _HAVE_ARCH_CSUM_AND_COPY in their asm/checksum.h and have the default one right in net/checksum.h conditional on _HAVE_ARCH_CSUM_AND_COPY *not* defined. Signed-off-by: Al Viro