On 13/08/2019 17:27, Dave Martin wrote:
> On Fri, Aug 02, 2019 at 06:03:00PM +0100, Cristian Marussi wrote:
>> Added a simple fake_sigreturn testcase which places a valid
>
> Add
>
Ok
>> sigframe on a non-16 bytes aligned SP.
>> fake_sigretrun() helper function has been patched accordingly
>> to support placing a sigframe on a non-16 bytes aligned address.
>> Expects a SIGSEGV on test PASS.
>>
>> Adds also a test TODO lists holding some further test ideas.
>
> Adds -> Also add
> lists -> list
>
Removed together with the TODO.
>> Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
>> ---
>> Re-added this text after fixing the forced misaglinment procedure in
>> fake_sigreturn() itself: require a ZERO alignment and you'll get
>> your sigframe placed on a misaligned SP (2-bytes off the 16-align)
>> ---
>> .../testing/selftests/arm64/signal/signals.S | 21 +++++++++----
>> .../arm64/signal/testcases/TODO.readme | 8 +++++
>> .../testcases/fake_sigreturn_misaligned_sp.c | 30 +++++++++++++++++++
>> 3 files changed, 53 insertions(+), 6 deletions(-)
>> create mode 100644 tools/testing/selftests/arm64/signal/testcases/TODO.readme
>> create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
>>
>> diff --git a/tools/testing/selftests/arm64/signal/signals.S b/tools/testing/selftests/arm64/signal/signals.S
>> index 6262b877400b..2099871176ed 100644
>> --- a/tools/testing/selftests/arm64/signal/signals.S
>> +++ b/tools/testing/selftests/arm64/signal/signals.S
>> @@ -13,19 +13,28 @@ call_fmt:
>>
>> .globl fake_sigreturn
>>
>> -/* fake_sigreturn x0:&sigframe, x1:sigframe_size, x2:alignment_SP */
>> +/* fake_sigreturn x0:&sigframe, x1:sigframe_sz, x2:align */
>> fake_sigreturn:
>> - mov x20, x0
>> - mov x21, x1
>> - mov x22, x2
>> - mov x23, sp
>>
>> - /* create space on the stack for fake sigframe..."x22"-aligned */
>> + /* Save args and decide which aligment to enforce */
>> + mov x23, sp
>> + mov x20, x0
>> + mov x21, x1
>> + /* x22 and x24 used for forcing alignment or misalignment */
>> + mov x22, x2
>> + mov x24, #0
>> + cbnz x22, 1f
>> + mov x22, #16
>> + mov x24, #2
>> +
>> +1: /* create space on the stack for fake sigframe..."x22"-aligned */
>> mov x0, #0
>> add x0, x21, x22
>> sub x22, x22, #1
>> bic x0, x0, x22
>> sub x23, x23, x0
>> + /* force misaligned by x24 bytes if required alignment was zero */
>> + add x23, x23, x24
>>
>> ldr x0, =call_fmt
>> mov x1, x21
>
> Would it be simpler for the third argument to specify a number of bytes
> to subtract from SP after allocating 16-byte aligned storage to
> accommodate sigframe_sz?
>
> Then 0 gives an aligned frame, 1 gives a frame misaligned by 1 byte,
> etc.
>
>
> Also if all this is a fix to the original fake_sigreturn, can we merge
> it into the original patch instead?
>
Yes simplified and merged into 6/11
>> diff --git a/tools/testing/selftests/arm64/signal/testcases/TODO.readme b/tools/testing/selftests/arm64/signal/testcases/TODO.readme
>> new file mode 100644
>> index 000000000000..5c949492e7ab
>> --- /dev/null
>> +++ b/tools/testing/selftests/arm64/signal/testcases/TODO.readme
>> @@ -0,0 +1,8 @@
>> +Some more possible ideas for signals tests:
>> +
>> +- fake_sigreturn_unmapped_sp
>> +- fake_sigreturn_kernelspace_sp
>> +- fake_sigreturn_sve_bad_extra_context
>> +- mangle_sve_invalid_extra_context
>> +- mangle_pstate_invalid_el for H modes (+ macroization ?)
>> +- fake_sigreturn_overflow_reserved
>
> This seems a reasonable list, but it occurs to me that it will tend to
> go out of sync as tests get added. So maybe just put this list in the
> cover letter instead of including it in the patch.
>
> We should probably have a one-line description of each proposed test,
> since the names are a bit cryptic.
Moving to cover letter with description.
>
>> diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
>> new file mode 100644
>> index 000000000000..3ee8c500c7d1
>> --- /dev/null
>> +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
>> @@ -0,0 +1,30 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/* Copyright (C) 2019 ARM Limited */
>> +
>
> signal.h?
ok
>
>> +#include <ucontext.h>
>> +
>> +#include "test_signals_utils.h"
>> +#include "testcases.h"
>> +
>> +struct fake_sigframe sf;
>> +
>> +static int fake_sigreturn_misaligned_run(struct tdescr *td,
>> + siginfo_t *si, ucontext_t *uc)
>> +{
>> + /* just to fill the ucontext_t with something real */
>> + if (!get_current_context(td, &sf.uc))
>> + return 1;
>> +
>> + /* Forcing sigframe on misaligned (=!16) SP */
>> + fake_sigreturn(&sf, sizeof(sf), 0);
>> +
>> + return 1;
>> +}
>
> [...]
>
> Cheers
> ---Dave
>
Cheers
Cristian
