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 --- tools/perf/util/smt.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 tools/perf/util/smt.c (limited to 'tools/perf/util/smt.c') diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c new file mode 100644 index 000000000..650e804d0 --- /dev/null +++ b/tools/perf/util/smt.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include "api/fs/fs.h" +#include "cputopo.h" +#include "smt.h" + +bool smt_on(void) +{ + static bool cached; + static bool cached_result; + int fs_value; + + if (cached) + return cached_result; + + if (sysfs__read_int("devices/system/cpu/smt/active", &fs_value) >= 0) + cached_result = (fs_value == 1); + else + cached_result = cpu_topology__smt_on(online_topology()); + + cached = true; + return cached_result; +} + +bool core_wide(bool system_wide, const char *user_requested_cpu_list) +{ + /* If not everything running on a core is being recorded then we can't use core_wide. */ + if (!system_wide) + return false; + + /* Cheap case that SMT is disabled and therefore we're inherently core_wide. */ + if (!smt_on()) + return true; + + return cpu_topology__core_wide(online_topology(), user_requested_cpu_list); +} -- cgit v1.3.1