kernel/linux.git/arch/powerpc/platforms/pseries, branch linux-7.1.y

pseries/papr-hvpipe: Fix style and checkpatch issues in enable_hvpipe_IRQ()

2026-05-06T02:00:25+00:00

While at it let's also fix the similar style issue in enable_hvpipe_IRQ() function. This also fixes a minor checkpatch warning which I got due to an extra space before " ==". Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/1174f60d0ae128e773dbefd11dd8d46d69e7f50e.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Refactor and simplify hvpipe_rtas_recv_msg()

2026-05-06T02:00:25+00:00

Simplify hvpipe_rtas_recv_msg() by removing three levels of nesting... if (!ret) if (buf) if (size < bytes_written) ... this refactoring of the function bails out to "out:" label first, in case of any error. This simplifies the init flow. Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/bbe7ddf8b8e25c9be8fc5e2c4aea9e5fca128bf4.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Kill task_struct pointer from struct hvpipe_source_info

2026-05-06T02:00:25+00:00

We don't really use task_struct pointer for anything meaningful. So just kill it for now, and we can bring back later if we need this for any future debug purposes. Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/895e061e45cdc95db36fa7f27aa1922b81eed867.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Simplify spin unlock usage in papr_hvpipe_handle_release()

2026-05-06T02:00:25+00:00

Once the src_info is removed from the global list, no one can access it. This simplies the usage of spin_unlock_irqrestore() in papr_hvpipe_handle_release() Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/4a980331557af3d10aada8576aaa16cddc691c65.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Fix the usage of copy_to_user()

2026-05-06T02:00:24+00:00

copy_to_user() return bytes_not_copied to the user buffer. If there was an error writing bytes into the user buffer, i.e. if copy_to_user returns a non-zero value, then we should simply return -EFAULT from the ->read() call. Otherwise, in the non-patched version, we may end up mixing "bytes_not_copied + bytes_copied (HVPIPE_HDR_LEN)" as the return value to the user in ->read() call Also let's make sure we clear the hvpipe_status flag, if we have consumed the hvpipe msg by making the rtas call. ret = -EFAULT means copy_to_user has failed but that still means that the msg was read from the hvpipe, hence for both cases, success & -EFAULT, we should clear the HVPIPE_MSG_AVAILABLE flag in hvpipe_status. Cc: stable@vger.kernel.org Fixes: cebdb522fd3edd1 ("powerpc/pseries: Receive payload with ibm,receive-hvpipe-msg RTAS") Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/8fda3212a1ad48879c174e92f67472d9b9f1c3b7.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Fix & simplify error handling in papr_hvpipe_init()

2026-05-06T02:00:24+00:00

Remove such 3 levels of nesting patterns to check success return values from function calls. ret = enable_hvpipe_IRQ() if (!ret) ret = set_hvpipe_sys_param(1) if (!ret) ret = misc_register() Instead just bail out to "out*:" labels, in case of any error. This simplifies the init flow. While at it let's also fix the following error handling logic: We have already enabled interrupt sources and enabled hvpipe to received interrupts, if misc_register() fails, we will destroy the workqueue, but the HMC might send us a msg via hvpipe which will call, queue work on the workqueue which might be destroyed. So instead, let's reverse the order of enabling set_hvpipe_sys_param(1) and in case of an error let's remove the misc dev by calling misc_deregister(). Cc: stable@vger.kernel.org Fixes: 39a08a4f94980 ("powerpc/pseries: Enable hvpipe with ibm,set-system-parameter RTAS") Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/f2141eafb80e7780395e03aa9a22e8a37be80513.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Fix null ptr deref in papr_hvpipe_dev_create_handle()

2026-05-06T02:00:24+00:00

commit 6d3789d347a7 ("papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE()"), changed the create handle to FD_PREPARE(), but it caused kernel null-ptr-deref because after call to retain_and_null_ptr(src_info), src_info is re-used for adding it to the global list. Getting the following kernel panic in papr_hvpipe_dev_create_handle() when trying to add src_info to the list. Kernel attempted to write user page (0) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on write at 0x00000000 Faulting instruction address: 0xc0000000001b44a0 Oops: Kernel access of bad area, sig: 11 [#1] ... Call Trace: papr_hvpipe_dev_ioctl+0x1f4/0x48c (unreliable) sys_ioctl+0x528/0x1064 system_call_exception+0x128/0x360 system_call_vectored_common+0x15c/0x2ec Now, the error handling with FD_PREPARE's file cleanup and __free(kfree) auto cleanup is getting too convoluted. This is mainly because we need to ensure only 1 user get the srcID handle. To simplify this, we allocate prepare the src_info in the beginning and add it to the global list under a spinlock after checking that no duplicates exist. This simplify the error handling where if the FD_ADD fails, we can simply remove the src_info from the list and consume any pending msg in hvpipe to be cleared, after src_info became visible in the global list. Cc: stable@vger.kernel.org Fixes: 6d3789d347a7 ("papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE()") Reported-by: Haren Myneni Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/31ad94bc89d44156ee700c5bd006cb47a748e3cb.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Prevent kernel stack memory leak to userspace

2026-05-06T02:00:24+00:00

The hdr variable is allocated on the stack and only hdr.version and hdr.flags are initialized explicitly. Because the struct papr_hvpipe_hdr contains reserved padding bytes (reserved[3] and reserved2[40]), these could leak the uninitialized bytes to userspace after copy_to_user(). This patch fixes that by initializing the whole struct to 0. Cc: stable@vger.kernel.org Fixes: cebdb522fd3ed ("powerpc/pseries: Receive payload with ibm,receive-hvpipe-msg RTAS") Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/7bfe03b65a282c856ed8182d1871bb973c0b78f2.1777606826.git.ritesh.list@gmail.com

pseries/papr-hvpipe: Fix race with interrupt handler

2026-05-06T02:00:24+00:00

While executing ->ioctl handler or ->release handler, if an interrupt fires on the same cpu, then we can enter into a deadlock. This patch fixes both these handlers to take spin_lock_irq{save|restore} versions of the lock to prevent this deadlock. Cc: stable@vger.kernel.org Fixes: 814ef095f12c9 ("powerpc/pseries: Add papr-hvpipe char driver for HVPIPE interfaces") Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/e4ed435c44fc191f2eb23c7907ba6f72f193e6aa.1777606826.git.ritesh.list@gmail.com

powerpc/pseries/htmdump: Add memory configuration dump support to htmdump module

2026-05-06T01:59:18+00:00

H_HTM (Hardware Trace Macro) hypervisor call has capability to capture SystemMemory Configuration. This information helps to understand the address mapping for the partitions in the system. Support dumping system memory configuration from Hardware Trace Macro (HTM) function via debugfs interface. Under debugfs folder "/sys/kernel/debug/powerpc/htmdump", add file "htmsystem_mem". The interface allows only read of this file which will present the content of HTM buffer from the hcall. The 16th offset of HTM buffer has value for the number of entries for array of processors. Use this information to copy data to the debugfs file Signed-off-by: Athira Rajeev Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260314132953.27269-1-atrajeev@linux.ibm.com