[PATCH AUTOSEL 4.4 08/37] powerpc/pseries: Mark accumulate_stolen_time() as notrace

[PATCH AUTOSEL 4.4 08/37] powerpc/pseries: Mark accumulate_stolen_time() as notrace

[Sasha Levin]

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit eb8e20f89093b64f48975c74ccb114e6775cee22 ]

accumulate_stolen_time() is called prior to interrupt state being
reconciled, which can trip the warning in arch_local_irq_restore():

  WARNING: CPU: 5 PID: 1017 at arch/powerpc/kernel/irq.c:258 .arch_local_irq_restore+0x9c/0x130
  ...
  NIP .arch_local_irq_restore+0x9c/0x130
  LR  .rb_start_commit+0x38/0x80
  Call Trace:
    .ring_buffer_lock_reserve+0xe4/0x620
    .trace_function+0x44/0x210
    .function_trace_call+0x148/0x170
    .ftrace_ops_no_ops+0x180/0x1d0
    ftrace_call+0x4/0x8
    .accumulate_stolen_time+0x1c/0xb0
    decrementer_common+0x124/0x160

For now just mark it as notrace. We may change the ordering to call it
after interrupt state has been reconciled, but that is a larger
change.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191024055932.27940-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/time.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 9baba9576e998..2bcd0cfb82e0b 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -245,7 +245,7 @@ static u64 scan_dispatch_log(u64 stop_tb)
  * Accumulate stolen time by scanning the dispatch trace log.
  * Called on entry from user mode.
  */
-void accumulate_stolen_time(void)
+void notrace accumulate_stolen_time(void)
 {
 	u64 sst, ust;
 
-- 
2.20.1

[PATCH AUTOSEL 4.4 11/37] powerpc/security/book3s64: Report L1TF status in sysfs

[Sasha Levin]

From: Anthony Steinhauser <asteinhauser@google.com>

[ Upstream commit 8e6b6da91ac9b9ec5a925b6cb13f287a54bd547d ]

Some PowerPC CPUs are vulnerable to L1TF to the same extent as to
Meltdown. It is also mitigated by flushing the L1D on privilege
transition.

Currently the sysfs gives a false negative on L1TF on CPUs that I
verified to be vulnerable, a Power9 Talos II Boston 004e 1202, PowerNV
T2P9D01.

Signed-off-by: Anthony Steinhauser <asteinhauser@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[mpe: Just have cpu_show_l1tf() call cpu_show_meltdown() directly]
Link: https://lore.kernel.org/r/20191029190759.84821-1-asteinhauser@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/security.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index 156cfe6d23b09..fc5c49046aa7d 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -161,6 +161,11 @@ ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, cha
 
 	return sprintf(buf, "Vulnerable\n");
 }
+
+ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return cpu_show_meltdown(dev, attr, buf);
+}
 #endif
 
 ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
-- 
2.20.1

[PATCH AUTOSEL 4.4 22/37] powerpc/pseries/cmm: Implement release() function for sysfs device

[Sasha Levin]

From: David Hildenbrand <david@redhat.com>

[ Upstream commit 7d8212747435c534c8d564fbef4541a463c976ff ]

When unloading the module, one gets
  ------------[ cut here ]------------
  Device 'cmm0' does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.
  WARNING: CPU: 0 PID: 19308 at drivers/base/core.c:1244 .device_release+0xcc/0xf0
  ...

We only have one static fake device. There is nothing to do when
releasing the device (via cmm_exit()).

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191031142933.10779-2-david@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/cmm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index fc44ad0475f84..b126ce49ae7bb 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -391,6 +391,10 @@ static struct bus_type cmm_subsys = {
 	.dev_name = "cmm",
 };
 
+static void cmm_release_device(struct device *dev)
+{
+}
+
 /**
  * cmm_sysfs_register - Register with sysfs
  *
@@ -406,6 +410,7 @@ static int cmm_sysfs_register(struct device *dev)
 
 	dev->id = 0;
 	dev->bus = &cmm_subsys;
+	dev->release = cmm_release_device;
 
 	if ((rc = device_register(dev)))
 		goto subsys_unregister;
-- 
2.20.1

[PATCH AUTOSEL 4.4 23/37] powerpc/security: Fix wrong message when RFI Flush is disable

[Sasha Levin]

From: "Gustavo L. F. Walbon" <gwalbon@linux.ibm.com>

[ Upstream commit 4e706af3cd8e1d0503c25332b30cad33c97ed442 ]

The issue was showing "Mitigation" message via sysfs whatever the
state of "RFI Flush", but it should show "Vulnerable" when it is
disabled.

If you have "L1D private" feature enabled and not "RFI Flush" you are
vulnerable to meltdown attacks.

"RFI Flush" is the key feature to mitigate the meltdown whatever the
"L1D private" state.

SEC_FTR_L1D_THREAD_PRIV is a feature for Power9 only.

So the message should be as the truth table shows:

  CPU | L1D private | RFI Flush |                sysfs
  ----|-------------|-----------|-------------------------------------
   P9 |    False    |   False   | Vulnerable
   P9 |    False    |   True    | Mitigation: RFI Flush
   P9 |    True     |   False   | Vulnerable: L1D private per thread
   P9 |    True     |   True    | Mitigation: RFI Flush, L1D private per thread
   P8 |    False    |   False   | Vulnerable
   P8 |    False    |   True    | Mitigation: RFI Flush

Output before this fix:
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Mitigation: RFI Flush, L1D private per thread
  # echo 0 > /sys/kernel/debug/powerpc/rfi_flush
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Mitigation: L1D private per thread

Output after fix:
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Mitigation: RFI Flush, L1D private per thread
  # echo 0 > /sys/kernel/debug/powerpc/rfi_flush
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Vulnerable: L1D private per thread

Signed-off-by: Gustavo L. F. Walbon <gwalbon@linux.ibm.com>
Signed-off-by: Mauro S. M. Rodrigues <maurosr@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190502210907.42375-1-gwalbon@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/security.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index fc5c49046aa7d..45778c83038f8 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -135,26 +135,22 @@ ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, cha
 
 	thread_priv = security_ftr_enabled(SEC_FTR_L1D_THREAD_PRIV);
 
-	if (rfi_flush || thread_priv) {
+	if (rfi_flush) {
 		struct seq_buf s;
 		seq_buf_init(&s, buf, PAGE_SIZE - 1);
 
-		seq_buf_printf(&s, "Mitigation: ");
-
-		if (rfi_flush)
-			seq_buf_printf(&s, "RFI Flush");
-
-		if (rfi_flush && thread_priv)
-			seq_buf_printf(&s, ", ");
-
+		seq_buf_printf(&s, "Mitigation: RFI Flush");
 		if (thread_priv)
-			seq_buf_printf(&s, "L1D private per thread");
+			seq_buf_printf(&s, ", L1D private per thread");
 
 		seq_buf_printf(&s, "\n");
 
 		return s.len;
 	}
 
+	if (thread_priv)
+		return sprintf(buf, "Vulnerable: L1D private per thread\n");
+
 	if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
 	    !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
 		return sprintf(buf, "Not affected\n");
-- 
2.20.1

[PATCH AUTOSEL 4.4 34/37] libfdt: define INT32_MAX and UINT32_MAX in libfdt_env.h

[Sasha Levin]

From: Masahiro Yamada <yamada.masahiro@socionext.com>

[ Upstream commit a8de1304b7df30e3a14f2a8b9709bb4ff31a0385 ]

The DTC v1.5.1 added references to (U)INT32_MAX.

This is no problem for user-space programs since <stdint.h> defines
(U)INT32_MAX along with (u)int32_t.

For the kernel space, libfdt_env.h needs to be adjusted before we
pull in the changes.

In the kernel, we usually use s/u32 instead of (u)int32_t for the
fixed-width types.

Accordingly, we already have S/U32_MAX for their max values.
So, we should not add (U)INT32_MAX to <linux/limits.h> any more.

Instead, add them to the in-kernel libfdt_env.h to compile the
latest libfdt.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/boot/compressed/libfdt_env.h | 4 +++-
 arch/powerpc/boot/libfdt_env.h        | 2 ++
 include/linux/libfdt_env.h            | 3 +++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/libfdt_env.h b/arch/arm/boot/compressed/libfdt_env.h
index 005bf4ff1b4cb..f3ddd4f599e3e 100644
--- a/arch/arm/boot/compressed/libfdt_env.h
+++ b/arch/arm/boot/compressed/libfdt_env.h
@@ -1,11 +1,13 @@
 #ifndef _ARM_LIBFDT_ENV_H
 #define _ARM_LIBFDT_ENV_H
 
+#include <linux/limits.h>
 #include <linux/types.h>
 #include <linux/string.h>
 #include <asm/byteorder.h>
 
-#define INT_MAX			((int)(~0U>>1))
+#define INT32_MAX	S32_MAX
+#define UINT32_MAX	U32_MAX
 
 typedef __be16 fdt16_t;
 typedef __be32 fdt32_t;
diff --git a/arch/powerpc/boot/libfdt_env.h b/arch/powerpc/boot/libfdt_env.h
index 0b3db6322c793..5f2cb1c53e151 100644
--- a/arch/powerpc/boot/libfdt_env.h
+++ b/arch/powerpc/boot/libfdt_env.h
@@ -5,6 +5,8 @@
 #include <string.h>
 
 #define INT_MAX			((int)(~0U>>1))
+#define UINT32_MAX		((u32)~0U)
+#define INT32_MAX		((s32)(UINT32_MAX >> 1))
 
 #include "of.h"
 
diff --git a/include/linux/libfdt_env.h b/include/linux/libfdt_env.h
index 8850e243c9406..bd0a55821177a 100644
--- a/include/linux/libfdt_env.h
+++ b/include/linux/libfdt_env.h
@@ -6,6 +6,9 @@
 
 #include <asm/byteorder.h>
 
+#define INT32_MAX	S32_MAX
+#define UINT32_MAX	U32_MAX
+
 typedef __be16 fdt16_t;
 typedef __be32 fdt32_t;
 typedef __be64 fdt64_t;
-- 
2.20.1