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* um: mark rodata read-only and implement _nofault accessesJohannes Berg2025-03-181-4/+8
| | | | | | | | | | | | | | | | | | | | | | | Mark read-only data actually read-only (simple mprotect), and to be able to test it also implement _nofault accesses. This works by setting up a new "segv_continue" pointer in current, and then when we hit a segfault we change the signal return context so that we continue at that address. The code using this sets it up so that it jumps to a label and then aborts the access that way, returning -EFAULT. It's possible to optimize the ___backtrack_faulted() thing by using asm goto (compiler version dependent) and/or gcc's (not sure if clang has it) &&label extension, but at least in one attempt I made the && caused the compiler to not load -EFAULT into the register in case of jumping to the &&label from the fault handler. So leave it like this for now. Signed-off-by: Johannes Berg <[email protected]> Co-developed-by: Benjamin Berg <[email protected]> Signed-off-by: Benjamin Berg <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Johannes Berg <[email protected]>
* um: remove fault_catcher infrastructureJohannes Berg2024-10-231-1/+0
| | | | | | | | | | | This was perhaps intended to do _nofault copies, but the real reason is lost to history. Remove this, it's not needed, and using longjmp() out of the middle of the signal handler with all the state it has modified is not going to be a good idea anyway. Link: https://patch.msgid.link/20241010224513.901c4d390b3e.Ia74742668b44603c1ca23dd36f90e964e6e7ee55@changeid Signed-off-by: Johannes Berg <[email protected]>
* um: Remove unused ncpus variableTiwei Bie2024-07-031-1/+0
| | | | | | | | It's no longer used. And uml_ncpus_setup doesn't exist anymore. Signed-off-by: Tiwei Bie <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Johannes Berg <[email protected]>
* um: Fix the declaration of kasan_map_memoryTiwei Bie2024-04-301-0/+2
| | | | | | | | | | Make it match its definition (size_t vs unsigned long). And declare it in a shared header to fix the -Wmissing-prototypes warning, as it is defined in the user code and called in the kernel code. Fixes: 5b301409e8bc ("UML: add support for KASAN under x86_64") Signed-off-by: Tiwei Bie <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: Move declarations to proper headersTiwei Bie2024-04-221-0/+1
| | | | | | | | | | | | | | | | | | This will address below -Wmissing-prototypes warnings: arch/um/kernel/initrd.c:18:12: warning: no previous prototype for ‘read_initrd’ [-Wmissing-prototypes] arch/um/kernel/um_arch.c:408:19: warning: no previous prototype for ‘read_initrd’ [-Wmissing-prototypes] arch/um/os-Linux/start_up.c:301:12: warning: no previous prototype for ‘parse_iomem’ [-Wmissing-prototypes] arch/x86/um/ptrace_32.c:15:6: warning: no previous prototype for ‘arch_switch_to’ [-Wmissing-prototypes] arch/x86/um/ptrace_32.c:101:5: warning: no previous prototype for ‘poke_user’ [-Wmissing-prototypes] arch/x86/um/ptrace_32.c:153:5: warning: no previous prototype for ‘peek_user’ [-Wmissing-prototypes] arch/x86/um/ptrace_64.c:111:5: warning: no previous prototype for ‘poke_user’ [-Wmissing-prototypes] arch/x86/um/ptrace_64.c:171:5: warning: no previous prototype for ‘peek_user’ [-Wmissing-prototypes] arch/x86/um/syscalls_64.c:48:6: warning: no previous prototype for ‘arch_switch_to’ [-Wmissing-prototypes] arch/x86/um/tls_32.c:184:5: warning: no previous prototype for ‘arch_switch_tls’ [-Wmissing-prototypes] Signed-off-by: Tiwei Bie <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: Drop support for hosts without SYSEMU_SINGLESTEP supportBenjamin Berg2024-01-041-2/+1
| | | | | | | | | | | | | | | These features have existed since Linux 2.6.14 and can be considered widely available at this point. Also drop the backward compatibility code for PTRACE_SETOPTIONS. Signed-off-by: Benjamin Berg <[email protected]> ---- v2: * Continue to define PTRACE_SYSEMU_SINGLESTEP as glibc only added it in version 2.27. Signed-off-by: Richard Weinberger <[email protected]>
* um: Fix naming clash between UML and schedulerAnton Ivanov2024-01-041-1/+1
| | | | | | | | | __cant_sleep was already used and exported by the scheduler. The name had to be changed to a UML specific one. Signed-off-by: Anton Ivanov <[email protected]> Reviewed-by: Peter Lafreniere <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: remove a dangling extern of syscall_trace()Al Viro2021-12-211-1/+0
| | | | | | | the function had been gone since 2012... Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: kill unused cpu()Al Viro2021-12-211-1/+0
| | | | | Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: remove unused smp_sigio_handler() declarationJohannes Berg2021-06-171-1/+0
| | | | | | | | This function doesn't exist, remove its declaration. Signed-off-by: Johannes Berg <[email protected]> Acked-By: Anton Ivanov <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* Revert "um: allocate a guard page to helper threads"Johannes Berg2021-01-261-1/+1
| | | | | | | | | | | | | | | | | | | | | This reverts commit ef4459a6da09 ("um: allocate a guard page to helper threads"), it's broken in multiple ways: 1) the free no longer matches the alloc; and 2) more importantly, the set_memory_ro() causes allocation of page tables for the normal memory that doesn't have any, and that later causes corruption and crashes (usually but not always in vfree()). We could fix the first bug and use vmalloc() to work around the second, but set_memory_ro() actually doesn't do anything either so I'll just revert that as well. Reported-by: Benjamin Berg <[email protected]> Fixes: ef4459a6da09 ("um: allocate a guard page to helper threads") Signed-off-by: Johannes Berg <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: allocate a guard page to helper threadsJohannes Berg2020-12-131-1/+1
| | | | | | | | | | | | | | | | We've been running into stack overflows in helper threads corrupting memory (e.g. because somebody put printf() or os_info() there), so to avoid those causing hard-to-debug issues later on, allocate a guard page for helper thread stacks and mark it read-only. Unfortunately, the crash dump at that point is useless as the stack tracer will try to backtrace the *kernel* thread, not the helper thread, but at least we don't survive to a random issue caused by corruption. Signed-off-by: Johannes Berg <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: Support suspend to RAMJohannes Berg2020-12-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | With all the previous bits in place, we can now also support suspend to RAM, in the sense that everything is suspended, not just most, including userspace, processes like in s2idle. Since um_idle_sleep() now waits forever, we can simply call that to "suspend" the system. As before, you can wake it up using SIGUSR1 since we're just in a pause() call that only needs to return. In order to implement selective resume from certain devices, and not have any arbitrary device interrupt wake up, suspend interrupts by removing SIGIO notification (O_ASYNC) from all the FDs that are not supposed to wake up the system. However, swap out the handler so we don't actually handle the SIGIO as an interrupt. Since we're in pause(), the mere act of receiving SIGIO wakes us up, and then after things have been restored enough, re-set O_ASYNC for all previously suspended FDs, reinstall the proper SIGIO handler, and send SIGIO to self to process anything that might now be pending. Signed-off-by: Johannes Berg <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: Allow PM with suspend-to-idleJohannes Berg2020-12-131-0/+2
| | | | | | | | | | | In order to be able to experiment with suspend in UML, add the minimal work to be able to suspend (s2idle) an instance of UML, and be able to wake it back up from that state with the USR1 signal sent to the main UML process. Signed-off-by: Johannes Berg <[email protected]> Acked-By: Anton Ivanov <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: Add SPDX headers for files in arch/um/includeAlex Dewar2019-09-151-1/+1
| | | | | | | Convert files to use SPDX header. All files are licensed under the GPLv2. Signed-off-by: Alex Dewar <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: Fix do_signal() prototypeIngo Molnar2015-07-071-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Once x86 exports its do_signal(), the prototypes will clash. Fix the clash and also improve the code a bit: remove the unnecessary kern_do_signal() indirection. This allows interrupt_end() to share the 'regs' parameter calculation. Also remove the unused return code to match x86. Minimally build and boot tested. Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Andy Lutomirski <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Richard Weinberger <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/67c57eac09a589bac3c6c5ff22f9623ec55a184a.1435952415.git.luto@kernel.org Signed-off-by: Ingo Molnar <[email protected]>
* um: get rid of pointless include "..." where include <...> will doAl Viro2012-10-091-2/+2
| | | | | Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: pass siginfo to guest processMartin Pärtel2012-08-011-6/+7
| | | | | | | | | UML guest processes now get correct siginfo_t for SIGTRAP, SIGFPE, SIGILL and SIGBUS. Specifically, si_addr and si_code are now correct where previously they were si_addr = NULL and si_code = 128. Signed-off-by: Martin Pärtel <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: kill HOST_TASK_PIDAl Viro2012-03-241-1/+1
| | | | | | | | just provide get_current_pid() to the userland side of things instead of get_current() + manual poking in its results Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* um: make copy_sc() staticAl Viro2011-11-021-1/+0
| | | | | | | ... and kill it in amd64 - not used. Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
* x86, um: take arch/um/include/* out of the wayAl Viro2008-10-231-0/+69
We can't just plop asm/* into it - userland helpers are built with it in search path and seeing asm/* show up there suddenly would be a bad idea. Signed-off-by: Al Viro <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
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