linux/kernel
Deepak Gupta 5ca243f6e3 prctl: add arch-agnostic prctl()s for indirect branch tracking
Three architectures (x86, aarch64, riscv) have support for indirect
branch tracking feature in a very similar fashion. On a very high
level, indirect branch tracking is a CPU feature where CPU tracks
branches which use a memory operand to transfer control. As part of
this tracking, during an indirect branch, the CPU expects a landing
pad instruction on the target PC, and if not found, the CPU raises
some fault (architecture-dependent).

x86 landing pad instr - 'ENDBRANCH'
arch64 landing pad instr - 'BTI'
riscv landing instr - 'lpad'

Given that three major architectures have support for indirect branch
tracking, this patch creates architecture-agnostic 'prctls' to allow
userspace to control this feature.  They are:
 - PR_GET_INDIR_BR_LP_STATUS: Get the current configured status for indirect
   branch tracking.
 - PR_SET_INDIR_BR_LP_STATUS: Set the configuration for indirect branch
   tracking.
   The following status options are allowed:
       - PR_INDIR_BR_LP_ENABLE: Enables indirect branch tracking on user
         thread.
       - PR_INDIR_BR_LP_DISABLE: Disables indirect branch tracking on user
         thread.
 - PR_LOCK_INDIR_BR_LP_STATUS: Locks configured status for indirect branch
   tracking for user thread.

Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-13-b55691eacf4f@rivosinc.com
[pjw@kernel.org: cleaned up patch description, code comments]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
2026-01-29 02:36:32 -07:00
..
bpf bpf: Reject BPF_MAP_TYPE_INSN_ARRAY in check_reg_const_str() 2026-01-07 19:03:46 -08:00
cgroup kernel: cgroup: Add LGPL-2.1 SPDX license ID to legacy_freezer.c 2026-01-15 22:03:15 -10:00
configs
debug
dma dma/pool: Avoid allocating redundant pools 2026-01-14 11:00:00 +01:00
entry
events perf: Fix refcount warning on event->mmap_count increment 2026-01-21 16:28:58 +01:00
futex Futex changes for v6.19: 2025-12-10 17:21:30 +09:00
gcov
irq treewide: Update email address 2026-01-11 06:09:11 -10:00
kcsan
livepatch
liveupdate kho: validate preserved memory map during population 2026-01-14 22:16:21 -08:00
locking
module kernel: modules: Add SPDX license identifier to kmod.c 2026-01-15 16:58:28 -08:00
power Merge branch 'pm-em' 2026-01-16 16:16:24 +01:00
printk printk fixup for 6.19 rc6 2026-01-16 09:46:59 -08:00
rcu
sched sched/fair: Revert force wakeup preemption 2026-01-23 11:53:20 +01:00
time clocksource: Reduce watchdog readout delay limit to prevent false positives 2026-01-21 11:33:11 +01:00
trace function_graph: Fix args pointer mismatch in print_graph_retval() 2026-01-23 13:34:38 -05:00
unwind
.gitignore
Kconfig.freezer
Kconfig.hz
Kconfig.kexec
Kconfig.locks
Kconfig.preempt
Makefile
acct.c
async.c
audit.c
audit.h
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cfi.c
compat.c
configs.c
context_tracking.c
cpu.c cpu: Make atomic hotplug callbacks run with interrupts disabled on UP 2025-12-10 15:49:11 +09:00
cpu_pm.c
crash_core.c
crash_core_test.c
crash_dump_dm_crypt.c
crash_reserve.c
cred.c
delayacct.c
dma.c
elfcorehdr.c
exec_domain.c
exit.c Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
exit.h
extable.c
fail_function.c
fork.c Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
freezer.c
gen_kheaders.sh
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kallsyms_internal.h
kallsyms_selftest.c
kallsyms_selftest.h
kcmp.c
kcov.c
kexec.c
kexec_core.c kernel/kexec: fix IMA when allocation happens in CMA area 2025-12-23 11:23:14 -08:00
kexec_elf.c
kexec_file.c
kexec_internal.h
kheaders.c
kprobes.c
kstack_erase.c
ksyms_common.c
ksysfs.c
kthread.c kthread: Warn if mm_struct lacks user_ns in kthread_use_mm() 2025-12-24 21:32:58 +01:00
latencytop.c
module_signature.c
notifier.c
nscommon.c
nsproxy.c
nstree.c
padata.c
panic.c panic: only warn about deprecated panic_print on write access 2026-01-19 12:30:01 -08:00
params.c
pid.c
pid_namespace.c
pid_sysctl.h
profile.c
ptrace.c
range.c
reboot.c
regset.c
relay.c
resource.c
resource_kunit.c
rseq.c
scftorture.c
scs.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stacktrace.c
static_call.c
static_call_inline.c
stop_machine.c
sys.c prctl: add arch-agnostic prctl()s for indirect branch tracking 2026-01-29 02:36:32 -07:00
sys_ni.c
sysctl-test.c
sysctl.c
task_work.c
taskstats.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
vhost_task.c
vmcore_info.c
watch_queue.c
watchdog.c powerpc/watchdog: add support for hardlockup_sys_info sysctl 2026-01-14 22:16:22 -08:00
watchdog_buddy.c
watchdog_perf.c
workqueue.c
workqueue_internal.h