selftests/powerpc: Move set_dscr() into rfi_flush.c

This version of set_dscr() was added for the RFI flush test, and is
fairly specific to it. It also clashes with the version of set_dscr()
in dscr/dscr.h. So move it into the RFI flush test where it's used.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200819015727.1977134-3-mpe@ellerman.id.au

1 files changed, 35 insertions, 0 deletions

diff --git a/tools/testing/selftests/powerpc/security/rfi_flush.c b/tools/testing/selftests/powerpc/security/rfi_flush.c
index 0a7d0afb26b8..fd37ff9b1c45 100644
--- a/tools/testing/selftests/powerpc/security/rfi_flush.c
+++ b/tools/testing/selftests/powerpc/security/rfi_flush.c
@@ -10,6 +10,7 @@
 #include <stdint.h>
 #include <malloc.h>
 #include <unistd.h>
+#include <signal.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ -41,6 +42,40 @@ static void syscall_loop(char *p, unsigned long iterations,
 	}
 }
 
+static void sigill_handler(int signr, siginfo_t *info, void *unused)
+{
+	static int warned = 0;
+	ucontext_t *ctx = (ucontext_t *)unused;
+	unsigned long *pc = &UCONTEXT_NIA(ctx);
+
+	/* mtspr 3,RS to check for move to DSCR below */
+	if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) {
+		if (!warned++)
+			printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n");
+		*pc += 4;
+	} else {
+		printf("SIGILL at %p\n", pc);
+		abort();
+	}
+}
+
+static void set_dscr(unsigned long val)
+{
+	static int init = 0;
+	struct sigaction sa;
+
+	if (!init) {
+		memset(&sa, 0, sizeof(sa));
+		sa.sa_sigaction = sigill_handler;
+		sa.sa_flags = SA_SIGINFO;
+		if (sigaction(SIGILL, &sa, NULL))
+			perror("sigill_handler");
+		init = 1;
+	}
+
+	asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
+}
+
 int rfi_flush_test(void)
 {
 	char *p;