d4173023e6
Pull siginfo cleanups from Eric Biederman: "Long ago when 2.4 was just a testing release copy_siginfo_to_user was made to copy individual fields to userspace, possibly for efficiency and to ensure initialized values were not copied to userspace. Unfortunately the design was complex, it's assumptions unstated, and humans are fallible and so while it worked much of the time that design failed to ensure unitialized memory is not copied to userspace. This set of changes is part of a new design to clean up siginfo and simplify things, and hopefully make the siginfo handling robust enough that a simple inspection of the code can be made to ensure we don't copy any unitializied fields to userspace. The design is to unify struct siginfo and struct compat_siginfo into a single definition that is shared between all architectures so that anyone adding to the set of information shared with struct siginfo can see the whole picture. Hopefully ensuring all future si_code assignments are arch independent. The design is to unify copy_siginfo_to_user32 and copy_siginfo_from_user32 so that those function are complete and cope with all of the different cases documented in signinfo_layout. I don't think there was a single implementation of either of those functions that was complete and correct before my changes unified them. The design is to introduce a series of helpers including force_siginfo_fault that take the values that are needed in struct siginfo and build the siginfo structure for their callers. Ensuring struct siginfo is built correctly. The remaining work for 4.17 (unless someone thinks it is post -rc1 material) is to push usage of those helpers down into the architectures so that architecture specific code will not need to deal with the fiddly work of intializing struct siginfo, and then when struct siginfo is guaranteed to be fully initialized change copy siginfo_to_user into a simple wrapper around copy_to_user. Further there is work in progress on the issues that have been documented requires arch specific knowledge to sort out. The changes below fix or at least document all of the issues that have been found with siginfo generation. Then proceed to unify struct siginfo the 32 bit helpers that copy siginfo to and from userspace, and generally clean up anything that is not arch specific with regards to siginfo generation. It is a lot but with the unification you can of siginfo you can already see the code reduction in the kernel" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (45 commits) signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr mm/memory_failure: Remove unused trapno from memory_failure signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed signal/powerpc: Remove unnecessary signal_code parameter of do_send_trap signal: Helpers for faults with specialized siginfo layouts signal: Add send_sig_fault and force_sig_fault signal: Replace memset(info,...) with clear_siginfo for clarity signal: Don't use structure initializers for struct siginfo signal/arm64: Better isolate the COMPAT_TASK portion of ptrace_hbptriggered ptrace: Use copy_siginfo in setsiginfo and getsiginfo signal: Unify and correct copy_siginfo_to_user32 signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32 signal: Unify and correct copy_siginfo_from_user32 signal/blackfin: Remove pointless UID16_SIGINFO_COMPAT_NEEDED signal/blackfin: Move the blackfin specific si_codes to asm-generic/siginfo.h signal/tile: Move the tile specific si_codes to asm-generic/siginfo.h signal/frv: Move the frv specific si_codes to asm-generic/siginfo.h signal/ia64: Move the ia64 specific si_codes to asm-generic/siginfo.h signal/powerpc: Remove redefinition of NSIGTRAP on powerpc signal: Move addr_lsb into the _sigfault union for clarity ...
174 lines
4.4 KiB
C
174 lines
4.4 KiB
C
/*
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* Traps/Non-MMU Exception handling for ARC
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*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* vineetg: May 2011
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* -user-space unaligned access emulation
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*
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* Rahul Trivedi: Codito Technologies 2004
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*/
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#include <linux/sched/signal.h>
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#include <linux/kdebug.h>
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#include <linux/uaccess.h>
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#include <linux/ptrace.h>
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#include <linux/kprobes.h>
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#include <linux/kgdb.h>
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#include <asm/setup.h>
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#include <asm/unaligned.h>
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#include <asm/kprobes.h>
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void __init trap_init(void)
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{
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return;
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}
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void die(const char *str, struct pt_regs *regs, unsigned long address)
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{
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show_kernel_fault_diag(str, regs, address);
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/* DEAD END */
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__asm__("flag 1");
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}
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/*
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* Helper called for bulk of exceptions NOT needing specific handling
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* -for user faults enqueues requested signal
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* -for kernel, chk if due to copy_(to|from)_user, otherwise die()
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*/
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static noinline int
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unhandled_exception(const char *str, struct pt_regs *regs, siginfo_t *info)
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{
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if (user_mode(regs)) {
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struct task_struct *tsk = current;
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tsk->thread.fault_address = (__force unsigned int)info->si_addr;
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force_sig_info(info->si_signo, info, tsk);
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} else {
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/* If not due to copy_(to|from)_user, we are doomed */
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if (fixup_exception(regs))
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return 0;
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die(str, regs, (unsigned long)info->si_addr);
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}
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return 1;
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}
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#define DO_ERROR_INFO(signr, str, name, sicode) \
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int name(unsigned long address, struct pt_regs *regs) \
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{ \
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siginfo_t info; \
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\
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clear_siginfo(&info); \
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info.si_signo = signr; \
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info.si_errno = 0; \
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info.si_code = sicode; \
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info.si_addr = (void __user *)address; \
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\
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return unhandled_exception(str, regs, &info);\
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}
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/*
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* Entry points for exceptions NOT needing specific handling
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*/
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DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC)
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DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC)
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DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC)
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DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", __weak do_memory_error, BUS_ADRERR)
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DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT)
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DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN)
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DO_ERROR_INFO(SIGSEGV, "gcc generated __builtin_trap", do_trap5_error, 0)
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/*
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* Entry Point for Misaligned Data access Exception, for emulating in software
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*/
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int do_misaligned_access(unsigned long address, struct pt_regs *regs,
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struct callee_regs *cregs)
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{
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/* If emulation not enabled, or failed, kill the task */
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if (misaligned_fixup(address, regs, cregs) != 0)
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return do_misaligned_error(address, regs);
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return 0;
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}
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/*
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* Entry point for miscll errors such as Nested Exceptions
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* -Duplicate TLB entry is handled seperately though
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*/
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void do_machine_check_fault(unsigned long address, struct pt_regs *regs)
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{
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die("Unhandled Machine Check Exception", regs, address);
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}
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/*
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* Entry point for traps induced by ARCompact TRAP_S <n> insn
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* This is same family as TRAP0/SWI insn (use the same vector).
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* The only difference being SWI insn take no operand, while TRAP_S does
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* which reflects in ECR Reg as 8 bit param.
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* Thus TRAP_S <n> can be used for specific purpose
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* -1 used for software breakpointing (gdb)
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* -2 used by kprobes
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* -5 __builtin_trap() generated by gcc (2018.03 onwards) for toggle such as
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* -fno-isolate-erroneous-paths-dereference
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*/
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void do_non_swi_trap(unsigned long address, struct pt_regs *regs)
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{
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unsigned int param = regs->ecr_param;
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switch (param) {
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case 1:
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trap_is_brkpt(address, regs);
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break;
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case 2:
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trap_is_kprobe(address, regs);
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break;
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case 3:
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case 4:
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kgdb_trap(regs);
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break;
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case 5:
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do_trap5_error(address, regs);
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break;
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default:
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break;
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}
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}
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/*
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* Entry point for Instruction Error Exception
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* -For a corner case, ARC kprobes implementation resorts to using
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* this exception, hence the check
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*/
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void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs)
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{
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int rc;
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/* Check if this exception is caused by kprobes */
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rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL);
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if (rc == NOTIFY_STOP)
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return;
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insterror_is_error(address, regs);
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}
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/*
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* abort() call generated by older gcc for __builtin_trap()
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*/
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void abort(void)
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{
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__asm__ __volatile__("trap_s 5\n");
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}
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