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

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

2 files changed, 22 insertions, 27 deletions

diff --git a/tools/perf/trace/beauty/include/uapi/linux/prctl.h b/tools/perf/trace/beauty/include/uapi/linux/prctl.h
index 55b0446fff9d..560f99bc4782 100644
--- a/tools/perf/trace/beauty/include/uapi/linux/prctl.h
+++ b/tools/perf/trace/beauty/include/uapi/linux/prctl.h
@@ -397,30 +397,24 @@ 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.
+ * Forward-edge CFI variants (excluding ARM64 BTI, which has its own
+ * prctl()s).
  */
-#define PR_SET_INDIR_BR_LP_STATUS      81
-# define PR_INDIR_BR_LP_ENABLE		   (1UL << 0)
+#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)
 
-/*
- * Prevent further changes to the specified indirect branch tracking
- * configuration.  All bits may be locked via this call, including
- * undefined bits.
- */
-#define PR_LOCK_INDIR_BR_LP_STATUS      82
 
 #endif /* _LINUX_PRCTL_H */
diff --git a/tools/testing/selftests/riscv/cfi/cfitests.c b/tools/testing/selftests/riscv/cfi/cfitests.c
index 298544854415..39d097b6881f 100644
--- a/tools/testing/selftests/riscv/cfi/cfitests.c
+++ b/tools/testing/selftests/riscv/cfi/cfitests.c
@@ -94,9 +94,9 @@ bool cfi_ptrace_test(void)
 		}
 
 		switch (ptrace_test_num) {
-#define CFI_ENABLE_MASK (PTRACE_CFI_LP_EN_STATE |	\
-			 PTRACE_CFI_SS_EN_STATE |	\
-			 PTRACE_CFI_SS_PTR_STATE)
+#define CFI_ENABLE_MASK (PTRACE_CFI_BRANCH_LANDING_PAD_EN_STATE |	\
+			 PTRACE_CFI_SHADOW_STACK_EN_STATE |		\
+			 PTRACE_CFI_SHADOW_STACK_PTR_STATE)
 		case 0:
 			if ((cfi_reg.cfi_status.cfi_state & CFI_ENABLE_MASK) != CFI_ENABLE_MASK)
 				ksft_exit_fail_msg("%s: ptrace_getregset failed, %llu\n", __func__,
@@ -106,7 +106,8 @@ bool cfi_ptrace_test(void)
 						   __func__);
 			break;
 		case 1:
-			if (!(cfi_reg.cfi_status.cfi_state & PTRACE_CFI_ELP_STATE))
+			if (!(cfi_reg.cfi_status.cfi_state &
+			      PTRACE_CFI_BRANCH_EXPECTED_LANDING_PAD_STATE))
 				ksft_exit_fail_msg("%s: elp must have been set\n", __func__);
 			/* clear elp state. not interested in anything else */
 			cfi_reg.cfi_status.cfi_state = 0;
@@ -145,11 +146,11 @@ int main(int argc, char *argv[])
 	 * pads for user mode except lighting up a bit in senvcfg via a prctl.
 	 * Enable landing pad support throughout the execution of the test binary.
 	 */
-	ret = my_syscall5(__NR_prctl, PR_GET_INDIR_BR_LP_STATUS, &lpad_status, 0, 0, 0);
+	ret = my_syscall5(__NR_prctl, PR_GET_CFI, PR_CFI_BRANCH_LANDING_PADS, &lpad_status, 0, 0);
 	if (ret)
 		ksft_exit_fail_msg("Get landing pad status failed with %d\n", ret);
 
-	if (!(lpad_status & PR_INDIR_BR_LP_ENABLE))
+	if (!(lpad_status & PR_CFI_ENABLE))
 		ksft_exit_fail_msg("Landing pad is not enabled, should be enabled via glibc\n");
 
 	ret = my_syscall5(__NR_prctl, PR_GET_SHADOW_STACK_STATUS, &ss_status, 0, 0, 0);