From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
dja@axtens.net, Spoorthy S <spoorts2@in.ibm.com>,
Russell Currey <ruscur@russell.cc>
Subject: [PATCH 5.9 01/14] selftests/powerpc: rfi_flush: disable entry flush if present
Date: Fri, 20 Nov 2020 12:03:39 +0100 [thread overview]
Message-ID: <20201120104541.238114576@linuxfoundation.org> (raw)
In-Reply-To: <20201120104541.168007611@linuxfoundation.org>
From: Russell Currey <ruscur@russell.cc>
commit fcb48454c23c5679d1a2e252f127642e91b05cbe upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/testing/selftests/powerpc/security/rfi_flush.c | 35 +++++++++++++++----
1 file changed, 29 insertions(+), 6 deletions(-)
--- a/tools/testing/selftests/powerpc/security/rfi_flush.c
+++ b/tools/testing/selftests/powerpc/security/rfi_flush.c
@@ -50,16 +50,30 @@ 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);
- 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);
@@ -68,6 +82,7 @@ int rfi_flush_test(void)
FAIL_IF(perf_event_enable(fd));
+ // disable L1 prefetching
set_dscr(1);
iter = repetitions;
@@ -109,8 +124,8 @@ 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;
@@ -126,11 +141,19 @@ 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;
}
next prev parent reply other threads:[~2020-11-20 11:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 11:03 [PATCH 5.9 00/14] 5.9.10-rc1 review Greg Kroah-Hartman
2020-11-20 11:03 ` Greg Kroah-Hartman [this message]
2020-11-20 11:03 ` [PATCH 5.9 02/14] powerpc/64s: flush L1D on kernel entry Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 03/14] powerpc/64s: flush L1D after user accesses Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 04/14] powerpc: Only include kup-radix.h for 64-bit Book3S Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 05/14] selftests/powerpc: entry flush test Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 06/14] leds: lm3697: Fix out-of-bound access Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 07/14] Input: sunkbd - avoid use-after-free in teardown paths Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 08/14] mac80211: always wind down STA state Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 09/14] can: proc: can_remove_proc(): silence remove_proc_entry warning Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 10/14] selftests/harness: prettify SKIP message whitespace again Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 11/14] powerpc/smp: Call rcu_cpu_starting() earlier Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 12/14] perf/x86/intel/uncore: Fix Add BW copypasta Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 13/14] KVM: x86: clflushopt should be treated as a no-op by emulation Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 14/14] ACPI: GED: fix -Wformat Greg Kroah-Hartman
2020-11-20 17:52 ` [PATCH 5.9 00/14] 5.9.10-rc1 review Jeffrin Jose T
2020-11-20 22:27 ` Shuah Khan
2020-11-22 9:18 ` Greg Kroah-Hartman
2020-11-21 11:12 ` Naresh Kamboju
2020-11-22 9:18 ` Greg Kroah-Hartman
[not found] ` <20201121183817.GG111877@roeck-us.net>
2020-11-22 9:19 ` Greg Kroah-Hartman
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