Re: [PATCH 23/25] powerpc: Deliver SEGV signal on pkey violation
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2017-10-24 15:46:51
Ram Pai [off-list ref] writes:
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index ec74e20..f2a310d 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c@@ -265,6 +266,15 @@ void user_single_step_siginfo(struct task_struct *tsk, info->si_addr = (void __user *)regs->nip; } +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS +static void fill_sig_info_pkey(int si_code, siginfo_t *info, unsigned long addr) +{ + if (info->si_signo != SIGSEGV || si_code != SEGV_PKUERR)
Just checking si_code is sufficient there I think.
+ return; + info->si_pkey = get_paca()->paca_pkey; +} +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
This should define an empty version in the #else case, so we don't need the ifdef below.
quoted hunk ↗ jump to hunk
@@ -292,6 +302,18 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr) info.si_signo = signr; info.si_code = code; info.si_addr = (void __user *) addr; + +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS + /* + * update the thread's pkey related fields. + * core-dump handlers and other sub-systems + * depend on those values. + */ + thread_pkey_regs_save(¤t->thread);
You shouldn't need to do this. We're not putting any of the pkey regs in the signal frame, so you don't need to save before we do that. [And if you did the right place to do it would be in setup_sigcontext() (or the TM version).] For ptrace and coredumps it should happen in pkey_get(), see eg. fpr_get() which does flush_fp_to_thread() as an example.
+ /* update the violated-key value */ + fill_sig_info_pkey(code, &info, addr); +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
+ force_sig_info(signr, &info, current); }
cheers