kernel/git/stable/linux.git/arch/powerpc, branch linux-4.14.y

powerpc/ftrace: Fix stack teardown in ftrace_no_trace

2023-12-20T14:32:39+00:00

commit 4b3338aaa74d7d4ec5b6734dc298f0db94ec83d2 upstream. Commit 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") added use of a new stack frame on ftrace entry to fix stack unwind. However, the commit missed updating the offset used while tearing down the ftrace stack when ftrace is disabled. Fix the same. In addition, the commit missed saving the correct stack pointer in pt_regs. Update the same. Fixes: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") Cc: stable@vger.kernel.org # v6.5+ Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/20231130065947.2188860-1-naveen@kernel.org Signed-off-by: Greg Kroah-Hartman

powerpc/ftrace: Create a dummy stackframe to fix stack unwind

2023-12-20T14:32:39+00:00

commit 41a506ef71eb38d94fe133f565c87c3e06ccc072 upstream. With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable@vger.kernel.org Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org Signed-off-by: Greg Kroah-Hartman

powerpc: Don't clobber f0/vs0 during fp|altivec register save

2023-12-08T07:42:00+00:00

commit 5e1d824f9a283cbf90f25241b66d1f69adb3835b upstream. During floating point and vector save to thread data f0/vs0 are clobbered by the FPSCR/VSCR store routine. This has been obvserved to lead to userspace register corruption and application data corruption with io-uring. Fix it by restoring f0/vs0 after FPSCR/VSCR store has completed for all the FP, altivec, VMX register save paths. Tested under QEMU in kvm mode, running on a Talos II workstation with dual POWER9 DD2.2 CPUs. Additional detail (mpe): Typically save_fpu() is called from __giveup_fpu() which saves the FP regs and also *turns off FP* in the tasks MSR, meaning the kernel will reload the FP regs from the thread struct before letting the task use FP again. So in that case save_fpu() is free to clobber f0 because the FP regs no longer hold live values for the task. There is another case though, which is the path via: sys_clone() ... copy_process() dup_task_struct() arch_dup_task_struct() flush_all_to_thread() save_all() That path saves the FP regs but leaves them live. That's meant as an optimisation for a process that's using FP/VSX and then calls fork(), leaving the regs live means the parent process doesn't have to take a fault after the fork to get its FP regs back. The optimisation was added in commit 8792468da5e1 ("powerpc: Add the ability to save FPU without giving it up"). That path does clobber f0, but f0 is volatile across function calls, and typically programs reach copy_process() from userspace via a syscall wrapper function. So in normal usage f0 being clobbered across a syscall doesn't cause visible data corruption. But there is now a new path, because io-uring can call copy_process() via create_io_thread() from the signal handling path. That's OK if the signal is handled as part of syscall return, but it's not OK if the signal is handled due to some other interrupt. That path is: interrupt_return_srr_user() interrupt_exit_user_prepare() interrupt_exit_user_prepare_main() do_notify_resume() get_signal() task_work_run() create_worker_cb() create_io_worker() copy_process() dup_task_struct() arch_dup_task_struct() flush_all_to_thread() save_all() if (tsk->thread.regs->msr & MSR_FP) save_fpu() # f0 is clobbered and potentially live in userspace Note the above discussion applies equally to save_altivec(). Fixes: 8792468da5e1 ("powerpc: Add the ability to save FPU without giving it up") Cc: stable@vger.kernel.org # v4.6+ Closes: https://lore.kernel.org/all/480932026.45576726.1699374859845.JavaMail.zimbra@raptorengineeringinc.com/ Closes: https://lore.kernel.org/linuxppc-dev/480221078.47953493.1700206777956.JavaMail.zimbra@raptorengineeringinc.com/ Tested-by: Timothy Pearson Tested-by: Jens Axboe Signed-off-by: Timothy Pearson [mpe: Reword change log to describe exact path of corruption & other minor tweaks] Signed-off-by: Michael Ellerman Link: https://msgid.link/1921539696.48534988.1700407082933.JavaMail.zimbra@raptorengineeringinc.com Signed-off-by: Greg Kroah-Hartman

powerpc/perf/hv-24x7: Update domain value check

2023-10-10T19:43:38+00:00

[ Upstream commit 4ff3ba4db5943cac1045e3e4a3c0463ea10f6930 ] Valid domain value is in range 1 to HV_PERF_DOMAIN_MAX. Current code has check for domain value greater than or equal to HV_PERF_DOMAIN_MAX. But the check for domain value 0 is missing. Fix this issue by adding check for domain value 0. Before: # ./perf stat -v -e hv_24x7/CPM_ADJUNCT_INST,domain=0,core=1/ sleep 1 Using CPUID 00800200 Control descriptor is not initialized Error: The sys_perf_event_open() syscall returned with 5 (Input/output error) for event (hv_24x7/CPM_ADJUNCT_INST,domain=0,core=1/). /bin/dmesg | grep -i perf may provide additional information. Result from dmesg: [ 37.819387] hv-24x7: hcall failed: [0 0x60040000 0x100 0] => ret 0xfffffffffffffffc (-4) detail=0x2000000 failing ix=0 After: # ./perf stat -v -e hv_24x7/CPM_ADJUNCT_INST,domain=0,core=1/ sleep 1 Using CPUID 00800200 Control descriptor is not initialized Warning: hv_24x7/CPM_ADJUNCT_INST,domain=0,core=1/ event is not supported by the kernel. failed to read counter hv_24x7/CPM_ADJUNCT_INST,domain=0,core=1/ Fixes: ebd4a5a3ebd9 ("powerpc/perf/hv-24x7: Minor improvements") Reported-by: Krishan Gopal Sarawast Signed-off-by: Kajol Jain Tested-by: Disha Goel Signed-off-by: Michael Ellerman Link: https://msgid.link/20230825055601.360083-1-kjain@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/pseries: fix possible memory leak in ibmebus_bus_init()

2023-09-23T08:47:04+00:00

[ Upstream commit afda85b963c12947e298ad85d757e333aa40fd74 ] If device_register() returns error in ibmebus_bus_init(), name of kobject which is allocated in dev_set_name() called in device_add() is leaked. As comment of device_add() says, it should call put_device() to drop the reference count that was set in device_initialize() when it fails, so the name can be freed in kobject_cleanup(). Signed-off-by: ruanjinjie Signed-off-by: Michael Ellerman Link: https://msgid.link/20221110011929.3709774-1-ruanjinjie@huawei.com Signed-off-by: Sasha Levin

powerpc/iommu: Fix notifiers being shared by PCI and VIO buses

2023-09-23T08:46:57+00:00

[ Upstream commit c37b6908f7b2bd24dcaaf14a180e28c9132b9c58 ] fail_iommu_setup() registers the fail_iommu_bus_notifier struct to both PCI and VIO buses. struct notifier_block is a linked list node, so this causes any notifiers later registered to either bus type to also be registered to the other since they share the same node. This causes issues in (at least) the vgaarb code, which registers a notifier for PCI buses. pci_notify() ends up being called on a vio device, converted with to_pci_dev() even though it's not a PCI device, and finally makes a bad access in vga_arbiter_add_pci_device() as discovered with KASAN: BUG: KASAN: slab-out-of-bounds in vga_arbiter_add_pci_device+0x60/0xe00 Read of size 4 at addr c000000264c26fdc by task swapper/0/1 Call Trace: dump_stack_lvl+0x1bc/0x2b8 (unreliable) print_report+0x3f4/0xc60 kasan_report+0x244/0x698 __asan_load4+0xe8/0x250 vga_arbiter_add_pci_device+0x60/0xe00 pci_notify+0x88/0x444 notifier_call_chain+0x104/0x320 blocking_notifier_call_chain+0xa0/0x140 device_add+0xac8/0x1d30 device_register+0x58/0x80 vio_register_device_node+0x9ac/0xce0 vio_bus_scan_register_devices+0xc4/0x13c __machine_initcall_pseries_vio_device_init+0x94/0xf0 do_one_initcall+0x12c/0xaa8 kernel_init_freeable+0xa48/0xba8 kernel_init+0x64/0x400 ret_from_kernel_thread+0x5c/0x64 Fix this by creating separate notifier_block structs for each bus type. Fixes: d6b9a81b2a45 ("powerpc: IOMMU fault injection") Reported-by: Nageswara R Sastry Signed-off-by: Russell Currey Tested-by: Nageswara R Sastry Reviewed-by: Andrew Donnellan [mpe: Add #ifdef to fix CONFIG_IBMVIO=n build] Signed-off-by: Michael Ellerman Link: https://msgid.link/20230322035322.328709-1-ruscur@russell.cc Signed-off-by: Sasha Levin

powerpc/32s: Fix assembler warning about r0

2023-09-23T08:46:54+00:00

commit b51ba4fe2e134b631f9c8f45423707aab71449b5 upstream. The assembler says: arch/powerpc/kernel/head_32.S:1095: Warning: invalid register expression It's objecting to the use of r0 as the RA argument. That's because when RA = 0 the literal value 0 is used, rather than the content of r0, making the use of r0 in the source potentially confusing. Fix it to use a literal 0, the generated code is identical. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/2b69ac8e1cddff6f808fc7415907179eab4aae9e.1596693679.git.christophe.leroy@csgroup.eu Signed-off-by: Greg Kroah-Hartman

powerpc/32: Include .branch_lt in data section

2023-09-23T08:46:54+00:00

commit 98ecc6768e8fdba95da1fc1efa0ef2d769e7fe1c upstream. When building a 32 bit powerpc kernel with Binutils 2.31.1 this warning is emitted: powerpc-linux-gnu-ld: warning: orphan section `.branch_lt' from `arch/powerpc/kernel/head_44x.o' being placed in section `.branch_lt' As of binutils commit 2d7ad24e8726 ("Support PLT16 relocs against local symbols")[1], 32 bit targets can produce .branch_lt sections in their output. Include these symbols in the .data section as the ppc64 kernel does. [1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=2d7ad24e8726ba4c45c9e67be08223a146a837ce Signed-off-by: Joel Stanley Reviewed-by: Alan Modra Signed-off-by: Michael Ellerman Cc: Christophe Leroy Signed-off-by: Greg Kroah-Hartman

word-at-a-time: use the same return type for has_zero regardless of endianness

2023-08-11T09:33:54+00:00

[ Upstream commit 79e8328e5acbe691bbde029a52c89d70dcbc22f3 ] Compiling big-endian targets with Clang produces the diagnostic: fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical] } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants))); ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ || fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning It appears that when has_zero was introduced, two definitions were produced with different signatures (in particular different return types). Looking at the usage in hash_name() in fs/namei.c, I suspect that has_zero() is meant to be invoked twice per while loop iteration; using logical-or would not update `bdata` when `a` did not have zeros. So I think it's preferred to always return an unsigned long rather than a bool than update the while loop in hash_name() to use a logical-or rather than bitwise-or. [ Also changed powerpc version to do the same - Linus ] Link: https://github.com/ClangBuiltLinux/linux/issues/1832 Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/ Fixes: 36126f8f2ed8 ("word-at-a-time: make the interfaces truly generic") Debugged-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Acked-by: Heiko Carstens Cc: Arnd Bergmann Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

powerpc: allow PPC_EARLY_DEBUG_CPM only when SERIAL_CPM=y

2023-08-11T09:33:40+00:00

[ Upstream commit 39f49684036d24af800ff194c33c7b2653c591d7 ] In a randconfig with CONFIG_SERIAL_CPM=m and CONFIG_PPC_EARLY_DEBUG_CPM=y, there is a build error: ERROR: modpost: "udbg_putc" [drivers/tty/serial/cpm_uart/cpm_uart.ko] undefined! Prevent the build error by allowing PPC_EARLY_DEBUG_CPM only when SERIAL_CPM=y. Fixes: c374e00e17f1 ("[POWERPC] Add early debug console for CPM serial ports.") Signed-off-by: Randy Dunlap Reviewed-by: Pali Rohár Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/20230701054714.30512-1-rdunlap@infradead.org Signed-off-by: Sasha Levin