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-rw-r--r--arch/powerpc/include/asm/hw_breakpoint.h8
-rw-r--r--arch/powerpc/kernel/hw_breakpoint.c62
-rw-r--r--arch/powerpc/kernel/process.c9
-rw-r--r--arch/powerpc/kernel/ptrace.c3
-rw-r--r--arch/powerpc/kvm/book3s_hv.c3
-rw-r--r--arch/powerpc/kvm/book3s_hv_rmhandlers.S23
6 files changed, 91 insertions, 17 deletions
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index ece4dc89c90b..0fe8c1e46bbc 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -90,10 +90,18 @@ 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;
+}
+
#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 */
#endif /* __KERNEL__ */
#endif /* _PPC_BOOK3S_64_HW_BREAKPOINT_H */
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index fec8a6773119..da307dd93ee3 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -29,11 +29,15 @@
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
+#include <linux/debugfs.h>
+#include <linux/init.h>
#include <asm/hw_breakpoint.h>
#include <asm/processor.h>
#include <asm/sstep.h>
#include <asm/debug.h>
+#include <asm/debugfs.h>
+#include <asm/hvcall.h>
#include <linux/uaccess.h>
/*
@@ -174,7 +178,7 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
if (!ppc_breakpoint_available())
return -ENODEV;
length_max = 8; /* DABR */
- if (cpu_has_feature(CPU_FTR_DAWR)) {
+ if (dawr_enabled()) {
length_max = 512 ; /* 64 doublewords */
/* DAWR region can't cross 512 boundary */
if ((attr->bp_addr >> 9) !=
@@ -376,3 +380,59 @@ 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/kernel/process.c b/arch/powerpc/kernel/process.c
index dd9e0d5386ee..225705aac814 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -67,6 +67,7 @@
#include <asm/cpu_has_feature.h>
#include <asm/asm-prototypes.h>
#include <asm/stacktrace.h>
+#include <asm/hw_breakpoint.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
@@ -784,7 +785,7 @@ static inline int set_dabr(struct arch_hw_breakpoint *brk)
return __set_dabr(dabr, dabrx);
}
-static inline int set_dawr(struct arch_hw_breakpoint *brk)
+int set_dawr(struct arch_hw_breakpoint *brk)
{
unsigned long dawr, dawrx, mrd;
@@ -816,7 +817,7 @@ void __set_breakpoint(struct arch_hw_breakpoint *brk)
{
memcpy(this_cpu_ptr(&current_brk), brk, sizeof(*brk));
- if (cpu_has_feature(CPU_FTR_DAWR))
+ if (dawr_enabled())
// Power8 or later
set_dawr(brk);
else if (!cpu_has_feature(CPU_FTR_ARCH_207S))
@@ -830,8 +831,8 @@ void __set_breakpoint(struct arch_hw_breakpoint *brk)
/* Check if we have DAWR or DABR hardware */
bool ppc_breakpoint_available(void)
{
- if (cpu_has_feature(CPU_FTR_DAWR))
- return true; /* POWER8 DAWR */
+ if (dawr_enabled())
+ return true; /* POWER8 DAWR or POWER9 forced DAWR */
if (cpu_has_feature(CPU_FTR_ARCH_207S))
return false; /* POWER9 with DAWR disabled */
/* DABR: Everything but POWER8 and POWER9 */
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index d9ac7d94656e..684b0b315c32 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -43,6 +43,7 @@
#include <asm/tm.h>
#include <asm/asm-prototypes.h>
#include <asm/debug.h>
+#include <asm/hw_breakpoint.h>
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
@@ -3088,7 +3089,7 @@ long arch_ptrace(struct task_struct *child, long request,
dbginfo.sizeof_condition = 0;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
dbginfo.features = PPC_DEBUG_FEATURE_DATA_BP_RANGE;
- if (cpu_has_feature(CPU_FTR_DAWR))
+ if (dawr_enabled())
dbginfo.features |= PPC_DEBUG_FEATURE_DATA_BP_DAWR;
#else
dbginfo.features = 0;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 06964350b97a..0fab0a201027 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -74,6 +74,7 @@
#include <asm/opal.h>
#include <asm/xics.h>
#include <asm/xive.h>
+#include <asm/hw_breakpoint.h>
#include "book3s.h"
@@ -3374,7 +3375,7 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
mtspr(SPRN_PURR, vcpu->arch.purr);
mtspr(SPRN_SPURR, vcpu->arch.spurr);
- if (cpu_has_feature(CPU_FTR_DAWR)) {
+ if (dawr_enabled()) {
mtspr(SPRN_DAWR, vcpu->arch.dawr);
mtspr(SPRN_DAWRX, vcpu->arch.dawrx);
}
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 3a5e719ef032..139027c62dc2 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -822,18 +822,21 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
mtspr SPRN_IAMR, r5
mtspr SPRN_PSPB, r6
mtspr SPRN_FSCR, r7
- ld r5, VCPU_DAWR(r4)
- ld r6, VCPU_DAWRX(r4)
- ld r7, VCPU_CIABR(r4)
- ld r8, VCPU_TAR(r4)
/*
* Handle broken DAWR case by not writing it. This means we
* can still store the DAWR register for migration.
*/
-BEGIN_FTR_SECTION
+ LOAD_REG_ADDR(r5, dawr_force_enable)
+ lbz r5, 0(r5)
+ cmpdi r5, 0
+ beq 1f
+ ld r5, VCPU_DAWR(r4)
+ ld r6, VCPU_DAWRX(r4)
mtspr SPRN_DAWR, r5
mtspr SPRN_DAWRX, r6
-END_FTR_SECTION_IFSET(CPU_FTR_DAWR)
+1:
+ ld r7, VCPU_CIABR(r4)
+ ld r8, VCPU_TAR(r4)
mtspr SPRN_CIABR, r7
mtspr SPRN_TAR, r8
ld r5, VCPU_IC(r4)
@@ -2513,11 +2516,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
blr
2:
-BEGIN_FTR_SECTION
- /* POWER9 with disabled DAWR */
+ LOAD_REG_ADDR(r11, dawr_force_enable)
+ lbz r11, 0(r11)
+ cmpdi r11, 0
li r3, H_HARDWARE
- blr
-END_FTR_SECTION_IFCLR(CPU_FTR_DAWR)
+ beqlr
/* Emulate H_SET_DABR/X on P8 for the sake of compat mode guests */
rlwimi r5, r4, 5, DAWRX_DR | DAWRX_DW
rlwimi r5, r4, 2, DAWRX_WT
generated by cgit (git 2.34.1) at 2025-04-07 03:56:47 +0000