From 390bf1773c7eba3b45df62ae82b3d2be911185b7 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Tue, 28 Jun 2016 18:07:31 +0100 Subject: [PATCH] arm64: consolidate signal injection on emulation errors The code for injecting a signal into userland if a trapped instruction fails emulation due to a _userland_ error (like an illegal address) will be used more often with the next patch. Factor out the core functionality into a separate function and use that both for the existing trap handler and for the deprecated instructions emulation. Signed-off-by: Andre Przywara [catalin.marinas@arm.com: s/set_segfault/arm64_notify_segfault/] Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/traps.h | 2 + arch/arm64/kernel/armv8_deprecated.c | 25 +---------- arch/arm64/kernel/traps.c | 63 ++++++++++++++++++++++------ 3 files changed, 54 insertions(+), 36 deletions(-) diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index 0cc2f29bf9da..9cd03f3e812f 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -34,6 +34,8 @@ struct undef_hook { void register_undef_hook(struct undef_hook *hook); void unregister_undef_hook(struct undef_hook *hook); +void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr); + #ifdef CONFIG_FUNCTION_GRAPH_TRACER static inline int __in_irqentry_text(unsigned long ptr) { diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index c37202c0c838..fab5603f57ea 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -316,28 +316,6 @@ static void __init register_insn_emulation_sysctl(struct ctl_table *table) */ #define TYPE_SWPB (1 << 22) -/* - * Set up process info to signal segmentation fault - called on access error. - */ -static void set_segfault(struct pt_regs *regs, unsigned long addr) -{ - siginfo_t info; - - down_read(¤t->mm->mmap_sem); - if (find_vma(current->mm, addr) == NULL) - info.si_code = SEGV_MAPERR; - else - info.si_code = SEGV_ACCERR; - up_read(¤t->mm->mmap_sem); - - info.si_signo = SIGSEGV; - info.si_errno = 0; - info.si_addr = (void *) instruction_pointer(regs); - - pr_debug("SWP{B} emulation: access caused memory abort!\n"); - arm64_notify_die("Illegal memory access", regs, &info, 0); -} - static int emulate_swpX(unsigned int address, unsigned int *data, unsigned int type) { @@ -430,7 +408,8 @@ ret: return 0; fault: - set_segfault(regs, address); + pr_debug("SWP{B} emulation: access caused memory abort!\n"); + arm64_notify_segfault(regs, address); return 0; } diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index a4250a59f2b9..d8a5366dcc24 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -364,30 +364,67 @@ exit: return fn ? fn(regs, instr) : 1; } -asmlinkage void __exception do_undefinstr(struct pt_regs *regs) +static void force_signal_inject(int signal, int code, struct pt_regs *regs, + unsigned long address) { siginfo_t info; void __user *pc = (void __user *)instruction_pointer(regs); + const char *desc; - /* check for AArch32 breakpoint instructions */ - if (!aarch32_break_handler(regs)) - return; - - if (call_undef_hook(regs) == 0) - return; + switch (signal) { + case SIGILL: + desc = "undefined instruction"; + break; + case SIGSEGV: + desc = "illegal memory access"; + break; + default: + desc = "bad mode"; + break; + } - if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) { - pr_info("%s[%d]: undefined instruction: pc=%p\n", - current->comm, task_pid_nr(current), pc); + if (unhandled_signal(current, signal) && + show_unhandled_signals_ratelimited()) { + pr_info("%s[%d]: %s: pc=%p\n", + current->comm, task_pid_nr(current), desc, pc); dump_instr(KERN_INFO, regs); } - info.si_signo = SIGILL; + info.si_signo = signal; info.si_errno = 0; - info.si_code = ILL_ILLOPC; + info.si_code = code; info.si_addr = pc; - arm64_notify_die("Oops - undefined instruction", regs, &info, 0); + arm64_notify_die(desc, regs, &info, 0); +} + +/* + * Set up process info to signal segmentation fault - called on access error. + */ +void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr) +{ + int code; + + down_read(¤t->mm->mmap_sem); + if (find_vma(current->mm, addr) == NULL) + code = SEGV_MAPERR; + else + code = SEGV_ACCERR; + up_read(¤t->mm->mmap_sem); + + force_signal_inject(SIGSEGV, code, regs, addr); +} + +asmlinkage void __exception do_undefinstr(struct pt_regs *regs) +{ + /* check for AArch32 breakpoint instructions */ + if (!aarch32_break_handler(regs)) + return; + + if (call_undef_hook(regs) == 0) + return; + + force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0); } long compat_arm_syscall(struct pt_regs *regs); -- 2.20.1