From: Michael Ellerman <mpe@ellerman•id.au>
To: Thiago Jung Bauermann <bauerman@linux•vnet.ibm.com>,
Ram Pai <linuxram@us•ibm.com>
Cc: linuxppc-dev@lists•ozlabs.org, benh@kernel•crashing.org,
paulus@samba•org, khandual@linux•vnet.ibm.com,
aneesh.kumar@linux•vnet.ibm.com, bsingharora@gmail•com,
hbabu@us•ibm.com, bauerman@linux•vnet.ibm.com, mhocko@kernel•org
Subject: Re: [RFC v7 24/25] powerpc: Deliver SEGV signal on pkey violation
Date: Fri, 11 Aug 2017 20:26:30 +1000 [thread overview]
Message-ID: <87a836csdl.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <87378zkuil.fsf@linux.vnet.ibm.com>
Thiago Jung Bauermann <bauerman@linux•vnet.ibm.com> writes:
> Ram Pai <linuxram@us•ibm.com> writes:
>
>> The value of the AMR register at the time of exception
>> is made available in gp_regs[PT_AMR] of the siginfo.
>>
>> The value of the pkey, whose protection got violated,
>> is made available in si_pkey field of the siginfo structure.
>
> Should the IAMR also be made available?
>
> Also, should the AMR and IAMR be accesible to userspace (e.g., to GDB)
> via ptrace and the core file?
Yes if they're part of the thread's context they should be accessible
via ptrace and in core files.
>> --- a/arch/powerpc/kernel/signal_32.c
>> +++ b/arch/powerpc/kernel/signal_32.c
>> @@ -500,6 +500,11 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
>> (unsigned long) &frame->tramp[2]);
>> }
>>
>> +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
>> + if (__put_user(get_paca()->paca_amr, &frame->mc_gregs[PT_AMR]))
>> + return 1;
>> +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
>> +
>> return 0;
>> }
>
> frame->mc_gregs[PT_AMR] has 32 bits, but paca_amr has 64 bits. Does this
> work as intended?
I don't understand why we are putting it in there at all?
Is there some special handling of the actual register on signals? I
haven't seen it. In which case the process can get the value of AMR by
reading the register. ??
cheers
next prev parent reply other threads:[~2017-08-11 10:26 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 0:12 [RFC v7 00/25] powerpc: Memory Protection Keys Ram Pai
2017-07-31 0:12 ` [RFC v7 01/25] powerpc: define an additional vma bit for protection keys Ram Pai
2017-07-31 0:12 ` [RFC v7 02/25] powerpc: track allocation status of all pkeys Ram Pai
2017-08-10 20:25 ` Thiago Jung Bauermann
2017-08-11 5:39 ` Michael Ellerman
2017-08-17 16:00 ` Ram Pai
2017-08-17 15:48 ` Ram Pai
2017-08-17 20:40 ` Thiago Jung Bauermann
2017-10-18 2:42 ` Balbir Singh
2017-10-18 3:40 ` Ram Pai
2017-10-18 16:08 ` Laurent Dufour
2017-10-18 22:04 ` Ram Pai
2017-07-31 0:12 ` [RFC v7 03/25] powerpc: helper function to read, write AMR, IAMR, UAMOR registers Ram Pai
2017-07-31 0:12 ` [RFC v7 04/25] powerpc: helper functions to initialize AMR, IAMR and " Ram Pai
2017-07-31 0:12 ` [RFC v7 05/25] powerpc: cleaup AMR, iAMR when a key is allocated or freed Ram Pai
2017-07-31 0:12 ` [RFC v7 06/25] powerpc: implementation for arch_set_user_pkey_access() Ram Pai
2017-07-31 0:12 ` [RFC v7 07/25] powerpc: sys_pkey_alloc() and sys_pkey_free() system calls Ram Pai
2017-07-31 0:12 ` [RFC v7 08/25] powerpc: ability to create execute-disabled pkeys Ram Pai
2017-07-31 0:12 ` [RFC v7 09/25] powerpc: store and restore the pkey state across context switches Ram Pai
2017-08-10 20:46 ` Thiago Jung Bauermann
2017-08-11 6:34 ` Michael Ellerman
2017-08-17 16:41 ` Ram Pai
2017-07-31 0:12 ` [RFC v7 10/25] powerpc: introduce execute-only pkey Ram Pai
2017-07-31 0:12 ` [RFC v7 11/25] powerpc: ability to associate pkey to a vma Ram Pai
2017-07-31 0:12 ` [RFC v7 12/25] powerpc: implementation for arch_override_mprotect_pkey() Ram Pai
2017-10-18 15:58 ` Laurent Dufour
2017-10-18 21:37 ` Ram Pai
2017-07-31 0:12 ` [RFC v7 13/25] powerpc: map vma key-protection bits to pte key bits Ram Pai
2017-07-31 0:12 ` [RFC v7 14/25] powerpc: sys_pkey_mprotect() system call Ram Pai
2017-07-31 0:12 ` [RFC v7 15/25] powerpc: Program HPTE key protection bits Ram Pai
2017-10-18 16:15 ` Laurent Dufour
2017-10-18 22:12 ` Ram Pai
2017-10-19 5:12 ` Michael Ellerman
2017-07-31 0:12 ` [RFC v7 16/25] powerpc: helper to validate key-access permissions of a pte Ram Pai
2017-10-18 16:08 ` Laurent Dufour
2017-10-18 21:56 ` Ram Pai
2017-10-19 5:13 ` Michael Ellerman
2017-07-31 0:12 ` [RFC v7 17/25] powerpc: check key protection for user page access Ram Pai
2017-07-31 0:12 ` [RFC v7 18/25] powerpc: Macro the mask used for checking DSI exception Ram Pai
2017-07-31 0:12 ` [RFC v7 19/25] powerpc: implementation for arch_vma_access_permitted() Ram Pai
2017-07-31 0:12 ` [RFC v7 20/25] powerpc: Handle exceptions caused by pkey violation Ram Pai
2017-07-31 0:12 ` [RFC v7 21/25] powerpc: capture AMR register content on " Ram Pai
2017-07-31 0:12 ` [RFC v7 22/25] powerpc: introduce get_pte_pkey() helper Ram Pai
2017-07-31 0:12 ` [RFC v7 23/25] powerpc: capture the violated protection key on fault Ram Pai
2017-07-31 0:12 ` [RFC v7 24/25] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2017-08-10 21:00 ` Thiago Jung Bauermann
2017-08-11 10:26 ` Michael Ellerman [this message]
2017-08-17 17:14 ` Ram Pai
2017-08-18 4:48 ` Michael Ellerman
2017-08-18 17:04 ` Ram Pai
2017-08-18 21:54 ` Benjamin Herrenschmidt
2017-08-18 22:36 ` Ram Pai
2017-10-18 2:25 ` Balbir Singh
2017-10-18 3:01 ` Ram Pai
2017-08-18 22:49 ` Ram Pai
2017-08-19 8:23 ` Benjamin Herrenschmidt
2017-07-31 0:12 ` [RFC v7 25/25] powerpc: Enable pkey subsystem Ram Pai
2017-08-10 21:27 ` Thiago Jung Bauermann
2017-08-17 17:40 ` Ram Pai
2017-08-17 20:30 ` Thiago Jung Bauermann
2017-08-17 23:48 ` Ram Pai
2017-08-18 5:07 ` Michael Ellerman
2017-08-18 15:26 ` Thiago Jung Bauermann
2017-08-18 16:32 ` Ram Pai
2017-08-11 17:34 ` [RFC v7 26/25] mm/mprotect, powerpc/mm/pkeys, x86/mm/pkeys: Add sysfs interface Thiago Jung Bauermann
2017-08-18 0:25 ` Ram Pai
2017-08-18 23:19 ` Thiago Jung Bauermann
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