Le 13/05/2019 à 09:17, Michael Neuling a écrit :
If you compile with KVM but without CONFIG_HAVE_HW_BREAKPOINT you fail
at linking with:
arch/powerpc/kvm/book3s_hv_rmhandlers.o:(.text+0x708): undefined reference
to `dawr_force_enable'
This was caused by commit c1fe190c0672 ("powerpc: Add force enable of
DAWR on P9 option").
This puts more of the dawr infrastructure in a new file.
I think you are doing a bit more than that. I think you should explain
that you define a new CONFIG_ option, when it is selected, etc ...
The commit you are referring to is talking about P9. It looks like your
patch covers a lot more, so it should be mentionned her I guess.
Signed-off-by: Michael Neuling <mi...@neuling.org>
You should add a Fixes: tag, ie:
Fixes: c1fe190c0672 ("powerpc: Add force enable of DAWR on P9 option")
--
v2:
Fixes based on Christophe Leroy's comments:
- Fix commit message formatting
- Move more DAWR code into dawr.c
---
arch/powerpc/Kconfig | 5 ++
arch/powerpc/include/asm/hw_breakpoint.h | 20 ++++---
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/dawr.c | 75 ++++++++++++++++++++++++
arch/powerpc/kernel/hw_breakpoint.c | 56 ------------------
arch/powerpc/kvm/Kconfig | 1 +
6 files changed, 94 insertions(+), 64 deletions(-)
create mode 100644 arch/powerpc/kernel/dawr.c
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2711aac246..f4b19e48cc 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -242,6 +242,7 @@ config PPC
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
select VIRT_TO_BUS if !PPC64
+ select PPC_DAWR_FORCE_ENABLE if PPC64 || PERF
What's PERF ? Did you mean PERF_EVENTS ?
Then what you mean is:
- Selected all the time for PPC64
- Selected for PPC32 when PERF is also selected.
Is that what you want ? At first I thought it was linked to P9.
And ... did you read below statement ?
#
# Please keep this list sorted alphabetically.
#
@@ -369,6 +370,10 @@ config PPC_ADV_DEBUG_DAC_RANGE
depends on PPC_ADV_DEBUG_REGS && 44x
default y
+config PPC_DAWR_FORCE_ENABLE
+ bool
+ default y
+
Why defaulting it to y. Then how is it set to n ?
config ZONE_DMA
bool
default y if PPC_BOOK3E_64
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h
b/arch/powerpc/include/asm/hw_breakpoint.h
index 0fe8c1e46b..ffbc8eab41 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -47,6 +47,8 @@ struct arch_hw_breakpoint {
#define HW_BRK_TYPE_PRIV_ALL (HW_BRK_TYPE_USER | HW_BRK_TYPE_KERNEL | \
HW_BRK_TYPE_HYP)
+extern int set_dawr(struct arch_hw_breakpoint *brk);
+
#ifdef CONFIG_HAVE_HW_BREAKPOINT
#include <linux/kdebug.h>
#include <asm/reg.h>
@@ -90,18 +92,20 @@ static inline void hw_breakpoint_disable(void)
extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);
int hw_breakpoint_handler(struct die_args *args);
-extern int set_dawr(struct arch_hw_breakpoint *brk);
-extern bool dawr_force_enable;
-static inline bool dawr_enabled(void)
-{
- return dawr_force_enable;
-}
-
That's a very simple function, why not keep it here (or in another .h)
as 'static inline' ?
#else /* CONFIG_HAVE_HW_BREAKPOINT */
static inline void hw_breakpoint_disable(void) { }
static inline void thread_change_pc(struct task_struct *tsk,
struct pt_regs *regs) { }
-static inline bool dawr_enabled(void) { return false; }
+
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+
+extern bool dawr_force_enable;
+
+#ifdef CONFIG_PPC_DAWR_FORCE_ENABLE
+extern bool dawr_enabled(void);
Functions should not be 'extern'. I'm sure checkpatch --strict will tell
you.
+#else
+#define dawr_enabled() true
true by default ?
Previously it was false by default.
And why a #define ? That's better to keep a static inline.
+#endif
+
#endif /* __KERNEL__ */
#endif /* _PPC_BOOK3S_64_HW_BREAKPOINT_H */
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 0ea6c4aa3a..a9c497c34f 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_PPC64) += setup_64.o sys_ppc32.o \
obj-$(CONFIG_VDSO32) += vdso32/
obj-$(CONFIG_PPC_WATCHDOG) += watchdog.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
+obj-$(CONFIG_PPC_DAWR_FORCE_ENABLE) += dawr.o
obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_ppc970.o cpu_setup_pa6t.o
obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_power.o
obj-$(CONFIG_PPC_BOOK3S_64) += mce.o mce_power.o
diff --git a/arch/powerpc/kernel/dawr.c b/arch/powerpc/kernel/dawr.c
new file mode 100644
index 0000000000..cf1d02fe1e
--- /dev/null
+++ b/arch/powerpc/kernel/dawr.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// DAWR infrastructure
+//
+// Copyright 2019, Michael Neuling, IBM Corporation.
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <asm/debugfs.h>
+#include <asm/machdep.h>
+#include <asm/hvcall.h>
+
+bool dawr_force_enable;
+EXPORT_SYMBOL_GPL(dawr_force_enable);
+
+extern bool dawr_enabled(void)
extern ????
+{
+ return dawr_force_enable;
+}
+EXPORT_SYMBOL_GPL(dawr_enabled);
Since dawr_force_enable is also exported, I see no point in having such
a tiny function as an exported function, was better as a 'static inline'.
+
+static ssize_t dawr_write_file_bool(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct arch_hw_breakpoint null_brk = {0, 0, 0};
+ size_t rc;
+
+ /* Send error to user if they hypervisor won't allow us to write DAWR */
+ if ((!dawr_force_enable) &&
+ (firmware_has_feature(FW_FEATURE_LPAR)) &&
+ (set_dawr(&null_brk) != H_SUCCESS))
The above is not real clear.
set_dabr() returns 0, H_SUCCESS is not used there.
+ return -1;
+
+ rc = debugfs_write_file_bool(file, user_buf, count, ppos);
+ if (rc)
+ return rc;
+
+ /* If we are clearing, make sure all CPUs have the DAWR cleared */
+ if (!dawr_force_enable)
+ smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
+
+ return rc;
+}
+
+static const struct file_operations dawr_enable_fops = {
+ .read = debugfs_read_file_bool,
+ .write = dawr_write_file_bool,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
+static int __init dawr_force_setup(void)
+{
+ dawr_force_enable = false;
The above is not needed, the BSS is zeroised at kernel startup.
+
+ if (cpu_has_feature(CPU_FTR_DAWR)) {
+ /* Don't setup sysfs file for user control on P8 */
+ dawr_force_enable = true;
Strange comment, word "don't" doesn't really fit with a 'true'
+ return 0;
+ }
+
+ if (PVR_VER(mfspr(SPRN_PVR)) == PVR_POWER9) {
You could use pvr_version_is(PVR_POWER9) instead of open codiing.
+ /* Turn DAWR off by default, but allow admin to turn it on */
+ dawr_force_enable = false;
+ debugfs_create_file_unsafe("dawr_enable_dangerous", 0600,
+ powerpc_debugfs_root,
+ &dawr_force_enable,
+ &dawr_enable_fops);
+ }
+ return 0;
+}
+arch_initcall(dawr_force_setup);
Wouldn't it also make sense to move set_dawr() from process.c to here ?
diff --git a/arch/powerpc/kernel/hw_breakpoint.c
b/arch/powerpc/kernel/hw_breakpoint.c
index da307dd93e..95605a9c9a 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -380,59 +380,3 @@ void hw_breakpoint_pmu_read(struct perf_event *bp)
{
/* TODO */
}
-
-bool dawr_force_enable;
-EXPORT_SYMBOL_GPL(dawr_force_enable);
-
-static ssize_t dawr_write_file_bool(struct file *file,
- const char __user *user_buf,
- size_t count, loff_t *ppos)
-{
- struct arch_hw_breakpoint null_brk = {0, 0, 0};
- size_t rc;
-
- /* Send error to user if they hypervisor won't allow us to write DAWR */
- if ((!dawr_force_enable) &&
- (firmware_has_feature(FW_FEATURE_LPAR)) &&
- (set_dawr(&null_brk) != H_SUCCESS))
- return -1;
-
- rc = debugfs_write_file_bool(file, user_buf, count, ppos);
- if (rc)
- return rc;
-
- /* If we are clearing, make sure all CPUs have the DAWR cleared */
- if (!dawr_force_enable)
- smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
-
- return rc;
-}
-
-static const struct file_operations dawr_enable_fops = {
- .read = debugfs_read_file_bool,
- .write = dawr_write_file_bool,
- .open = simple_open,
- .llseek = default_llseek,
-};
-
-static int __init dawr_force_setup(void)
-{
- dawr_force_enable = false;
-
- if (cpu_has_feature(CPU_FTR_DAWR)) {
- /* Don't setup sysfs file for user control on P8 */
- dawr_force_enable = true;
- return 0;
- }
-
- if (PVR_VER(mfspr(SPRN_PVR)) == PVR_POWER9) {
- /* Turn DAWR off by default, but allow admin to turn it on */
- dawr_force_enable = false;
- debugfs_create_file_unsafe("dawr_enable_dangerous", 0600,
- powerpc_debugfs_root,
- &dawr_force_enable,
- &dawr_enable_fops);
- }
- return 0;
-}
-arch_initcall(dawr_force_setup);
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index bfdde04e49..9c0d315108 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -39,6 +39,7 @@ config KVM_BOOK3S_32_HANDLER
config KVM_BOOK3S_64_HANDLER
bool
select KVM_BOOK3S_HANDLER
+ select PPC_DAWR_FORCE_ENABLE
config KVM_BOOK3S_PR_POSSIBLE
bool
Christophe
