Merge tag 'riscv-for-linus-v7.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linuxHEADmaster

Pull RISC-V updates from Paul Walmsley:
 "Before v7.0 is released, fix a few issues with the CFI patchset,
  merged earlier in v7.0-rc, that primarily affect interfaces to
  non-kernel code:

   - Improve the prctl() interface for per-task indirect branch landing
     pad control to expand abbreviations and to resemble the speculation
     control prctl() interface

   - Expand the "LP" and "SS" abbreviations in the ptrace uapi header
     file to "branch landing pad" and "shadow stack", to improve
     readability

   - Fix a typo in a CFI-related macro name in the ptrace uapi header
     file

   - Ensure that the indirect branch tracking state and shadow stack
     state are unlocked immediately after an exec() on the new task so
     that libc subsequently can control it

   - While working in this area, clean up the kernel-internal,
     cross-architecture prctl() function names by expanding the
     abbreviations mentioned above"

* tag 'riscv-for-linus-v7.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  prctl: cfi: change the branch landing pad prctl()s to be more descriptive
  riscv: ptrace: cfi: expand "SS" references to "shadow stack" in uapi headers
  prctl: rename branch landing pad implementation functions to be more explicit
  riscv: ptrace: expand "LP" references to "branch landing pads" in uapi headers
  riscv: cfi: clear CFI lock status in start_thread()
  riscv: ptrace: cfi: fix "PRACE" typo in uapi header

1 files changed, 15 insertions, 22 deletions

diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 55b0446fff9d..b6ec6f693719 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -397,30 +397,23 @@ struct prctl_mm_map {
 # define PR_RSEQ_SLICE_EXT_ENABLE		0x01
 
 /*
- * Get the current indirect branch tracking configuration for the current
- * thread, this will be the value configured via PR_SET_INDIR_BR_LP_STATUS.
+ * Get or set the control flow integrity (CFI) configuration for the
+ * current thread.
+ *
+ * Some per-thread control flow integrity settings are not yet
+ * controlled through this prctl(); see for example
+ * PR_{GET,SET,LOCK}_SHADOW_STACK_STATUS
  */
-#define PR_GET_INDIR_BR_LP_STATUS      80
-
+#define PR_GET_CFI	80
+#define PR_SET_CFI	81
 /*
- * Set the indirect branch tracking configuration. PR_INDIR_BR_LP_ENABLE will
- * enable cpu feature for user thread, to track all indirect branches and ensure
- * they land on arch defined landing pad instruction.
- * x86 - If enabled, an indirect branch must land on an ENDBRANCH instruction.
- * arch64 - If enabled, an indirect branch must land on a BTI instruction.
- * riscv - If enabled, an indirect branch must land on an lpad instruction.
- * PR_INDIR_BR_LP_DISABLE will disable feature for user thread and indirect
- * branches will no more be tracked by cpu to land on arch defined landing pad
- * instruction.
- */
-#define PR_SET_INDIR_BR_LP_STATUS      81
-# define PR_INDIR_BR_LP_ENABLE		   (1UL << 0)
-
-/*
- * Prevent further changes to the specified indirect branch tracking
- * configuration.  All bits may be locked via this call, including
- * undefined bits.
+ * Forward-edge CFI variants (excluding ARM64 BTI, which has its own
+ * prctl()s).
  */
-#define PR_LOCK_INDIR_BR_LP_STATUS      82
+#define PR_CFI_BRANCH_LANDING_PADS	0
+/* Return and control values for PR_{GET,SET}_CFI */
+# define PR_CFI_ENABLE		_BITUL(0)
+# define PR_CFI_DISABLE		_BITUL(1)
+# define PR_CFI_LOCK		_BITUL(2)
 
 #endif /* _LINUX_PRCTL_H */