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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 <andre.przywara@arm.com>
[catalin.marinas@arm.com: s/set_segfault/arm64_notify_segfault/]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Andre Przywara 2016-06-28 18:07:31 +01:00 committed by Catalin Marinas
parent 8e2318521b
commit 390bf1773c
3 changed files with 54 additions and 36 deletions
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2
arch/arm64/include/asm/traps.h
View File

@ -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)
{

25
arch/arm64/kernel/armv8_deprecated.c
View File

@ -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(&current->mm->mmap_sem);
if (find_vma(current->mm, addr) == NULL)
info.si_code = SEGV_MAPERR;
else
info.si_code = SEGV_ACCERR;
up_read(&current->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 @@ static int swp_handler(struct pt_regs *regs, u32 instr)
return 0;
fault:
set_segfault(regs, address);
pr_debug("SWP{B} emulation: access caused memory abort!\n");
arm64_notify_segfault(regs, address);
return 0;
}

63
arch/arm64/kernel/traps.c
View File

@ -364,11 +364,59 @@ static int call_undef_hook(struct pt_regs *regs)
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;
switch (signal) {
case SIGILL:
desc = "undefined instruction";
break;
case SIGSEGV:
desc = "illegal memory access";
break;
default:
desc = "bad mode";
break;
}
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 = signal;
info.si_errno = 0;
info.si_code = code;
info.si_addr = pc;
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(&current->mm->mmap_sem);
if (find_vma(current->mm, addr) == NULL)
code = SEGV_MAPERR;
else
code = SEGV_ACCERR;
up_read(&current->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;
@ -376,18 +424,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
if (call_undef_hook(regs) == 0)
return;
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);
dump_instr(KERN_INFO, regs);
}
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLOPC;
info.si_addr = pc;
arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
}
long compat_arm_syscall(struct pt_regs *regs);