From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- Documentation/ABI/testing/debugfs-tpmi | 40 ++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-tpmi (limited to 'Documentation/ABI/testing/debugfs-tpmi') diff --git a/Documentation/ABI/testing/debugfs-tpmi b/Documentation/ABI/testing/debugfs-tpmi new file mode 100644 index 000000000..c493a1403 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-tpmi @@ -0,0 +1,40 @@ +What: /sys/kernel/debug/tpmi-/pfs_dump +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +The PFS (PM Feature Structure) table, shows details of each power +management feature. This includes: +tpmi_id, number of entries, entry size, offset, vsec offset, lock status +and disabled status. +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-/tpmi-id-/mem_dump +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +Shows the memory dump of the MMIO region for a TPMI ID. +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-/tpmi-id-/mem_write +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +Allows to write at any offset. It doesn't check for Read/Write access +as hardware will not allow to write at read-only memory. This write is +at offset multiples of 4. The format is instance,offset,contents. +Example: +echo 0,0x20,0xff > mem_write +echo 1,64,64 > mem_write +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-/plr/domain/status +Date: Aug 2024 +KernelVersion: 6.11 +Contact: Tero Kristo +Description: +Shows the currently active Performance Limit Reasons for die level and the +individual CPUs under the die. The contents of this file are sticky, and +clearing all the statuses can be done by writing "0\n" to this file. -- cgit v1.3.1