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Marchesi" , Beau Belgrave , Linus Torvalds , Andrew Morton , Florian Weimer , Kees Cook , "Carlos O'Donell" , Sam James , Dylan Hatch Subject: Re: [RFC PATCH v3 13/17] s390/ptrace: Provide frame_pointer() Message-ID: <20251210151902.40732D1a-hca@linux.ibm.com> References: <20251208171559.2029709-1-jremus@linux.ibm.com> <20251208171559.2029709-14-jremus@linux.ibm.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251208171559.2029709-14-jremus@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-GUID: a_BuvdF9hZClqgXyowAYhzzpkuXFdamT X-Proofpoint-ORIG-GUID: 8FikjVBgtVE8byOpez3eQKOpzihoHr3U X-Authority-Analysis: v=2.4 cv=aY9sXBot c=1 sm=1 tr=0 ts=69398f6f cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=wP3pNCr1ah4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=NEAV23lmAAAA:8 a=VnNF1IyMAAAA:8 a=0Va_bqAEYgpgdbXSXcAA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMjA2MDAwNyBTYWx0ZWRfX81GjcufygHRk w5Fj2uQ0wOdB8YITtX3NTtr7vcOADSfxBAChZ31n2RheVvMPfHoBa8unHgQUIrmc1w41p3IdAuC lmiYE6pTJwiXLk1LD5e/AA8dza8yQMtWH18ViY7ImPEfztwXksFqVmvZY97puW1JU0rW4XaGUj9 hskij6li5fKnkZldbPKLxfLn5qbHiCd4chTpmDhCxvoyOCjQ8WkeJK2Mh+87BLM2Rgk+aBEwuSN LNC/iedTyHDF6XvvqZzavqHZDr8UpTK6HuRX2q24Ujq7HduOhpKiQuGsQl+PbLshQpKa2IOPCdV RqQuKIJfAVR3I7quWQDbwETGW18lGGU0VbUOBd1d5zgZrnvEbgIFPGzGtAXPGGoyzSFN02I/RfM i0gMHULkRKc3mynhvFu7hRqMrQUiVA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-12-10_01,2025-12-09_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 clxscore=1015 phishscore=0 lowpriorityscore=0 bulkscore=0 adultscore=0 impostorscore=0 malwarescore=0 priorityscore=1501 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2512060007 On Mon, Dec 08, 2025 at 06:15:55PM +0100, Jens Remus wrote: > On s390 64-bit the s390x ELF ABI [1] designates register 11 as the > "preferred" frame pointer (FP) register in user space. > > While at it convert instruction_pointer() and user_stack_pointer() > from macros to inline functions, to align their definition with > x86 and arm64. > > Use const qualifier on struct pt_regs pointers to prevent compiler > warnings: > > arch/s390/kernel/stacktrace.c: In function ‘arch_stack_walk_user_common’: > arch/s390/kernel/stacktrace.c:114:34: warning: passing argument 1 of > ‘instruction_pointer’ discards ‘const’ qualifier from pointer target > type [-Wdiscarded-qualifiers] > ... > arch/s390/kernel/stacktrace.c:117:48: warning: passing argument 1 of > ‘user_stack_pointer’ discards ‘const’ qualifier from pointer target > type [-Wdiscarded-qualifiers] > ... > > [1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases > > Signed-off-by: Jens Remus > --- > > Notes (jremus): > Changes in RFC v2: > - Separate provide frame_pointer() into this new commit. > > arch/s390/include/asm/ptrace.h | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h > index dfa770b15fad..455c119167fc 100644 > --- a/arch/s390/include/asm/ptrace.h > +++ b/arch/s390/include/asm/ptrace.h > @@ -212,8 +212,6 @@ void update_cr_regs(struct task_struct *task); > #define arch_has_block_step() (1) > > #define user_mode(regs) (((regs)->psw.mask & PSW_MASK_PSTATE) != 0) > -#define instruction_pointer(regs) ((regs)->psw.addr) > -#define user_stack_pointer(regs)((regs)->gprs[15]) > #define profile_pc(regs) instruction_pointer(regs) "while at it", and then you don't convert user_mode() to a function? :) Please provide a stand-alone patch for the "while at it" stuff, so it can go independently.