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arm64: signal: Make force_signal_inject more robust

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force_signal_inject is a little flakey:

  * It only knows about SIGILL and SIGSEGV, so can potentially deliver
    other signals based on a partially initialised siginfo_t

  * It sets si_addr to point at the PC for SIGSEGV

  * It always operates on current, so doesn't need the regs argument

This patch fixes these issues by always assigning the si_addr field to
the address parameter of the function and updates the callers (including
those that indirectly call via arm64_notify_segfault) accordingly.

Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2018-02-20 14:16:29 +00:00
parent e0f6429dc1
commit 2c9120f3a8
4 changed files with 17 additions and 19 deletions
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6
arch/arm64/include/asm/traps.h
View File

@ -35,10 +35,8 @@ struct undef_hook {
void register_undef_hook(struct undef_hook *hook);
void unregister_undef_hook(struct undef_hook *hook);
void force_signal_inject(int signal, int code, struct pt_regs *regs,
unsigned long address);
void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr);
void force_signal_inject(int signal, int code, unsigned long address);
void arm64_notify_segfault(unsigned long addr);
/*
* Move regs->pc to next instruction and do necessary setup before it

2
arch/arm64/kernel/armv8_deprecated.c
View File

@ -429,7 +429,7 @@ static int swp_handler(struct pt_regs *regs, u32 instr)
fault:
pr_debug("SWP{B} emulation: access caused memory abort!\n");
arm64_notify_segfault(regs, address);
arm64_notify_segfault(address);
return 0;
}

5
arch/arm64/kernel/fpsimd.c
View File

@ -285,8 +285,7 @@ static void task_fpsimd_save(void)
* re-enter user with corrupt state.
* There's no way to recover, so kill it:
*/
force_signal_inject(
SIGKILL, 0, current_pt_regs(), 0);
force_signal_inject(SIGKILL, 0, 0);
return;
}
@ -831,7 +830,7 @@ asmlinkage void do_sve_acc(unsigned int esr, struct pt_regs *regs)
{
/* Even if we chose not to use SVE, the hardware could still trap: */
if (unlikely(!system_supports_sve()) || WARN_ON(is_compat_task())) {
force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
return;
}

23
arch/arm64/kernel/traps.c
View File

@ -311,12 +311,13 @@ static int call_undef_hook(struct pt_regs *regs)
return fn ? fn(regs, instr) : 1;
}
void force_signal_inject(int signal, int code, struct pt_regs *regs,
unsigned long address)
void force_signal_inject(int signal, int code, unsigned long address)
{
siginfo_t info;
void __user *pc = (void __user *)instruction_pointer(regs);
const char *desc;
struct pt_regs *regs = current_pt_regs();
clear_siginfo(&info);
switch (signal) {
case SIGILL:
@ -332,15 +333,15 @@ void force_signal_inject(int signal, int code, struct pt_regs *regs,
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);
pr_info("%s[%d]: %s: pc=%08llx\n",
current->comm, task_pid_nr(current), desc, regs->pc);
dump_instr(KERN_INFO, regs);
}
info.si_signo = signal;
info.si_errno = 0;
info.si_code = code;
info.si_addr = pc;
info.si_addr = (void __user *)address;
arm64_notify_die(desc, regs, &info, 0);
}
@ -348,7 +349,7 @@ void force_signal_inject(int signal, int code, struct pt_regs *regs,
/*
* Set up process info to signal segmentation fault - called on access error.
*/
void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
void arm64_notify_segfault(unsigned long addr)
{
int code;
@ -359,7 +360,7 @@ void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
code = SEGV_ACCERR;
up_read(&current->mm->mmap_sem);
force_signal_inject(SIGSEGV, code, regs, addr);
force_signal_inject(SIGSEGV, code, addr);
}
asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
@ -371,7 +372,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
if (call_undef_hook(regs) == 0)
return;
force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
}
int cpu_enable_cache_maint_trap(void *__unused)
@ -426,12 +427,12 @@ static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
__user_cache_maint("ic ivau", address, ret);
break;
default:
force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
return;
}
if (ret)
arm64_notify_segfault(regs, address);
arm64_notify_segfault(address);
else
arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
}