From: Daniel Axtens <dja@axtens.net>
To: linuxppc-dev@lists.ozlabs.org
Cc: dja@axtens.net, cmr@informatik.wtf, spoorts2@in.ibm.com,
npiggin@gmail.com
Subject: [PATCH 1/7] selftests/powerpc: rfi_flush: disable entry flush if present
Date: Fri, 20 Nov 2020 10:13:27 +1100 [thread overview]
Message-ID: <20201119231333.361771-2-dja@axtens.net> (raw)
In-Reply-To: <20201119231333.361771-1-dja@axtens.net>
From: Russell Currey <ruscur@russell.cc>
We are about to add an entry flush. The rfi (exit) flush test measures
the number of L1D flushes over a syscall with the RFI flush enabled and
disabled. But if the entry flush is also enabled, the effect of enabling
and disabling the RFI flush is masked.
If there is a debugfs entry for the entry flush, disable it during the RFI
flush and restore it later.
Reported-by: Spoorthy S <spoorts2@in.ibm.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Daniel Axtens <dja@axtens.net>
---
.../selftests/powerpc/security/rfi_flush.c | 35 +++++++++++++++----
1 file changed, 29 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/powerpc/security/rfi_flush.c b/tools/testing/selftests/powerpc/security/rfi_flush.c
index 93a65bd1f231..4e7b2776c367 100644
--- a/tools/testing/selftests/powerpc/security/rfi_flush.c
+++ b/tools/testing/selftests/powerpc/security/rfi_flush.c
@@ -85,19 +85,33 @@ int rfi_flush_test(void)
__u64 l1d_misses_total = 0;
unsigned long iterations = 100000, zero_size = 24 * 1024;
unsigned long l1d_misses_expected;
- int rfi_flush_org, rfi_flush;
+ int rfi_flush_orig, rfi_flush;
+ int have_entry_flush, entry_flush_orig;
SKIP_IF(geteuid() != 0);
// The PMU event we use only works on Power7 or later
SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
- if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_org)) {
+ if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
perror("Unable to read powerpc/rfi_flush debugfs file");
SKIP_IF(1);
}
- rfi_flush = rfi_flush_org;
+ if (read_debugfs_file("powerpc/entry_flush", &entry_flush_orig) < 0) {
+ have_entry_flush = 0;
+ } else {
+ have_entry_flush = 1;
+
+ if (entry_flush_orig != 0) {
+ if (write_debugfs_file("powerpc/entry_flush", 0) < 0) {
+ perror("error writing to powerpc/entry_flush debugfs file");
+ return 1;
+ }
+ }
+ }
+
+ rfi_flush = rfi_flush_orig;
fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1);
FAIL_IF(fd < 0);
@@ -106,6 +120,7 @@ int rfi_flush_test(void)
FAIL_IF(perf_event_enable(fd));
+ // disable L1 prefetching
set_dscr(1);
iter = repetitions;
@@ -147,8 +162,8 @@ again:
repetitions * l1d_misses_expected / 2,
passes, repetitions);
- if (rfi_flush == rfi_flush_org) {
- rfi_flush = !rfi_flush_org;
+ if (rfi_flush == rfi_flush_orig) {
+ rfi_flush = !rfi_flush_orig;
if (write_debugfs_file("powerpc/rfi_flush", rfi_flush) < 0) {
perror("error writing to powerpc/rfi_flush debugfs file");
return 1;
@@ -164,11 +179,19 @@ again:
set_dscr(0);
- if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_org) < 0) {
+ if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_orig) < 0) {
perror("unable to restore original value of powerpc/rfi_flush debugfs file");
return 1;
}
+ if (have_entry_flush) {
+ if (write_debugfs_file("powerpc/entry_flush", entry_flush_orig) < 0) {
+ perror("unable to restore original value of powerpc/entry_flush "
+ "debugfs file");
+ return 1;
+ }
+ }
+
return rc;
}
--
2.25.1
next prev parent reply other threads:[~2020-11-19 23:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 23:13 [PATCH 0/7] CVE-2020-4788: Speculation on incompletely validated data on IBM Power9 Daniel Axtens
2020-11-19 23:13 ` Daniel Axtens [this message]
2020-11-19 23:13 ` [PATCH 2/7] powerpc/64s: flush L1D on kernel entry Daniel Axtens
2020-11-19 23:13 ` [PATCH 3/7] powerpc/64s: flush L1D after user accesses Daniel Axtens
2020-12-03 17:17 ` Qian Cai
2020-12-03 17:31 ` Qian Cai
2020-12-03 18:50 ` Qian Cai
2020-12-04 6:21 ` Christophe Leroy
2020-11-19 23:13 ` [PATCH 4/7] powerpc: Only include kup-radix.h for 64-bit Book3S Daniel Axtens
2020-11-19 23:13 ` [PATCH 5/7] selftests/powerpc: entry flush test Daniel Axtens
2020-11-19 23:13 ` [PATCH 6/7] selftests/powerpc: refactor entry and rfi_flush tests Daniel Axtens
2020-11-19 23:13 ` [PATCH 7/7] powerpc/64s: rename pnv|pseries_setup_rfi_flush to _setup_security_mitigations Daniel Axtens
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