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Message-Id: <20200817102330.777537-3-ravi.bangoria@linux.ibm.com>
Date: Mon, 17 Aug 2020 15:53:26 +0530
From: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To: mpe@...erman.id.au, christophe.leroy@....fr
Cc: ravi.bangoria@...ux.ibm.com, mikey@...ling.org, paulus@...ba.org,
naveen.n.rao@...ux.vnet.ibm.com, pedromfc@...ibm.com,
rogealve@...ibm.com, jniethe5@...il.com,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH v4 2/6] powerpc/watchpoint: Move DAWR detection logic outside of hw_breakpoint.c
Power10 hw has multiple DAWRs but hw doesn't tell which DAWR caused
the exception. So we have a sw logic to detect that in hw_breakpoint.c.
But hw_breakpoint.c gets compiled only with CONFIG_HAVE_HW_BREAKPOINT=Y.
Move DAWR detection logic outside of hw_breakpoint.c so that it can be
reused when CONFIG_HAVE_HW_BREAKPOINT is not set.
Signed-off-by: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
---
arch/powerpc/include/asm/hw_breakpoint.h | 8 +
arch/powerpc/kernel/Makefile | 3 +-
arch/powerpc/kernel/hw_breakpoint.c | 149 +----------------
.../kernel/hw_breakpoint_constraints.c | 152 ++++++++++++++++++
4 files changed, 164 insertions(+), 148 deletions(-)
create mode 100644 arch/powerpc/kernel/hw_breakpoint_constraints.c
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index db206a7f38e2..f71f08a7e2e0 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -10,6 +10,7 @@
#define _PPC_BOOK3S_64_HW_BREAKPOINT_H
#include <asm/cpu_has_feature.h>
+#include <asm/inst.h>
#ifdef __KERNEL__
struct arch_hw_breakpoint {
@@ -51,6 +52,13 @@ static inline int nr_wp_slots(void)
return cpu_has_feature(CPU_FTR_DAWR1) ? 2 : 1;
}
+bool wp_check_constraints(struct pt_regs *regs, struct ppc_inst instr,
+ unsigned long ea, int type, int size,
+ struct arch_hw_breakpoint *info);
+
+void wp_get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
+ int *type, int *size, unsigned long *ea);
+
#ifdef CONFIG_HAVE_HW_BREAKPOINT
#include <linux/kdebug.h>
#include <asm/reg.h>
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index d4d5946224f8..286f85a103de 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -45,7 +45,8 @@ obj-y := cputable.o syscalls.o \
signal.o sysfs.o cacheinfo.o time.o \
prom.o traps.o setup-common.o \
udbg.o misc.o io.o misc_$(BITS).o \
- of_platform.o prom_parse.o firmware.o
+ of_platform.o prom_parse.o firmware.o \
+ hw_breakpoint_constraints.o
obj-y += ptrace/
obj-$(CONFIG_PPC64) += setup_64.o \
paca.o nvram_64.o note.o syscall_64.o
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 1f4a1efa0074..f4e8f21046f5 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -494,151 +494,6 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
}
}
-static bool dar_in_user_range(unsigned long dar, struct arch_hw_breakpoint *info)
-{
- return ((info->address <= dar) && (dar - info->address < info->len));
-}
-
-static bool ea_user_range_overlaps(unsigned long ea, int size,
- struct arch_hw_breakpoint *info)
-{
- return ((ea < info->address + info->len) &&
- (ea + size > info->address));
-}
-
-static bool dar_in_hw_range(unsigned long dar, struct arch_hw_breakpoint *info)
-{
- unsigned long hw_start_addr, hw_end_addr;
-
- hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE);
- hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);
-
- return ((hw_start_addr <= dar) && (hw_end_addr > dar));
-}
-
-static bool ea_hw_range_overlaps(unsigned long ea, int size,
- struct arch_hw_breakpoint *info)
-{
- unsigned long hw_start_addr, hw_end_addr;
-
- hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE);
- hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);
-
- return ((ea < hw_end_addr) && (ea + size > hw_start_addr));
-}
-
-/*
- * If hw has multiple DAWR registers, we also need to check all
- * dawrx constraint bits to confirm this is _really_ a valid event.
- * If type is UNKNOWN, but privilege level matches, consider it as
- * a positive match.
- */
-static bool check_dawrx_constraints(struct pt_regs *regs, int type,
- struct arch_hw_breakpoint *info)
-{
- if (OP_IS_LOAD(type) && !(info->type & HW_BRK_TYPE_READ))
- return false;
-
- /*
- * The Cache Management instructions other than dcbz never
- * cause a match. i.e. if type is CACHEOP, the instruction
- * is dcbz, and dcbz is treated as Store.
- */
- if ((OP_IS_STORE(type) || type == CACHEOP) && !(info->type & HW_BRK_TYPE_WRITE))
- return false;
-
- if (is_kernel_addr(regs->nip) && !(info->type & HW_BRK_TYPE_KERNEL))
- return false;
-
- if (user_mode(regs) && !(info->type & HW_BRK_TYPE_USER))
- return false;
-
- return true;
-}
-
-/*
- * Return true if the event is valid wrt dawr configuration,
- * including extraneous exception. Otherwise return false.
- */
-static bool check_constraints(struct pt_regs *regs, struct ppc_inst instr,
- unsigned long ea, int type, int size,
- struct arch_hw_breakpoint *info)
-{
- bool in_user_range = dar_in_user_range(regs->dar, info);
- bool dawrx_constraints;
-
- /*
- * 8xx supports only one breakpoint and thus we can
- * unconditionally return true.
- */
- if (IS_ENABLED(CONFIG_PPC_8xx)) {
- if (!in_user_range)
- info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
- return true;
- }
-
- if (unlikely(ppc_inst_equal(instr, ppc_inst(0)))) {
- if (cpu_has_feature(CPU_FTR_ARCH_31) &&
- !dar_in_hw_range(regs->dar, info))
- return false;
-
- return true;
- }
-
- dawrx_constraints = check_dawrx_constraints(regs, type, info);
-
- if (type == UNKNOWN) {
- if (cpu_has_feature(CPU_FTR_ARCH_31) &&
- !dar_in_hw_range(regs->dar, info))
- return false;
-
- return dawrx_constraints;
- }
-
- if (ea_user_range_overlaps(ea, size, info))
- return dawrx_constraints;
-
- if (ea_hw_range_overlaps(ea, size, info)) {
- if (dawrx_constraints) {
- info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
- return true;
- }
- }
- return false;
-}
-
-static int cache_op_size(void)
-{
-#ifdef __powerpc64__
- return ppc64_caches.l1d.block_size;
-#else
- return L1_CACHE_BYTES;
-#endif
-}
-
-static void get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
- int *type, int *size, unsigned long *ea)
-{
- struct instruction_op op;
-
- if (__get_user_instr_inatomic(*instr, (void __user *)regs->nip))
- return;
-
- analyse_instr(&op, regs, *instr);
- *type = GETTYPE(op.type);
- *ea = op.ea;
-#ifdef __powerpc64__
- if (!(regs->msr & MSR_64BIT))
- *ea &= 0xffffffffUL;
-#endif
-
- *size = GETSIZE(op.type);
- if (*type == CACHEOP) {
- *size = cache_op_size();
- *ea &= ~(*size - 1);
- }
-}
-
static bool is_larx_stcx_instr(int type)
{
return type == LARX || type == STCX;
@@ -722,7 +577,7 @@ int hw_breakpoint_handler(struct die_args *args)
rcu_read_lock();
if (!IS_ENABLED(CONFIG_PPC_8xx))
- get_instr_detail(regs, &instr, &type, &size, &ea);
+ wp_get_instr_detail(regs, &instr, &type, &size, &ea);
for (i = 0; i < nr_wp_slots(); i++) {
bp[i] = __this_cpu_read(bp_per_reg[i]);
@@ -732,7 +587,7 @@ int hw_breakpoint_handler(struct die_args *args)
info[i] = counter_arch_bp(bp[i]);
info[i]->type &= ~HW_BRK_TYPE_EXTRANEOUS_IRQ;
- if (check_constraints(regs, instr, ea, type, size, info[i])) {
+ if (wp_check_constraints(regs, instr, ea, type, size, info[i])) {
if (!IS_ENABLED(CONFIG_PPC_8xx) &&
ppc_inst_equal(instr, ppc_inst(0))) {
handler_error(bp[i], info[i]);
diff --git a/arch/powerpc/kernel/hw_breakpoint_constraints.c b/arch/powerpc/kernel/hw_breakpoint_constraints.c
new file mode 100644
index 000000000000..a4f13026d2e0
--- /dev/null
+++ b/arch/powerpc/kernel/hw_breakpoint_constraints.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/sched.h>
+#include <asm/hw_breakpoint.h>
+#include <asm/sstep.h>
+#include <asm/cache.h>
+
+static bool dar_in_user_range(unsigned long dar, struct arch_hw_breakpoint *info)
+{
+ return ((info->address <= dar) && (dar - info->address < info->len));
+}
+
+static bool ea_user_range_overlaps(unsigned long ea, int size,
+ struct arch_hw_breakpoint *info)
+{
+ return ((ea < info->address + info->len) &&
+ (ea + size > info->address));
+}
+
+static bool dar_in_hw_range(unsigned long dar, struct arch_hw_breakpoint *info)
+{
+ unsigned long hw_start_addr, hw_end_addr;
+
+ hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE);
+ hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);
+
+ return ((hw_start_addr <= dar) && (hw_end_addr > dar));
+}
+
+static bool ea_hw_range_overlaps(unsigned long ea, int size,
+ struct arch_hw_breakpoint *info)
+{
+ unsigned long hw_start_addr, hw_end_addr;
+
+ hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE);
+ hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);
+
+ return ((ea < hw_end_addr) && (ea + size > hw_start_addr));
+}
+
+/*
+ * If hw has multiple DAWR registers, we also need to check all
+ * dawrx constraint bits to confirm this is _really_ a valid event.
+ * If type is UNKNOWN, but privilege level matches, consider it as
+ * a positive match.
+ */
+static bool check_dawrx_constraints(struct pt_regs *regs, int type,
+ struct arch_hw_breakpoint *info)
+{
+ if (OP_IS_LOAD(type) && !(info->type & HW_BRK_TYPE_READ))
+ return false;
+
+ /*
+ * The Cache Management instructions other than dcbz never
+ * cause a match. i.e. if type is CACHEOP, the instruction
+ * is dcbz, and dcbz is treated as Store.
+ */
+ if ((OP_IS_STORE(type) || type == CACHEOP) && !(info->type & HW_BRK_TYPE_WRITE))
+ return false;
+
+ if (is_kernel_addr(regs->nip) && !(info->type & HW_BRK_TYPE_KERNEL))
+ return false;
+
+ if (user_mode(regs) && !(info->type & HW_BRK_TYPE_USER))
+ return false;
+
+ return true;
+}
+
+/*
+ * Return true if the event is valid wrt dawr configuration,
+ * including extraneous exception. Otherwise return false.
+ */
+bool wp_check_constraints(struct pt_regs *regs, struct ppc_inst instr,
+ unsigned long ea, int type, int size,
+ struct arch_hw_breakpoint *info)
+{
+ bool in_user_range = dar_in_user_range(regs->dar, info);
+ bool dawrx_constraints;
+
+ /*
+ * 8xx supports only one breakpoint and thus we can
+ * unconditionally return true.
+ */
+ if (IS_ENABLED(CONFIG_PPC_8xx)) {
+ if (!in_user_range)
+ info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+ return true;
+ }
+
+ if (unlikely(ppc_inst_equal(instr, ppc_inst(0)))) {
+ if (cpu_has_feature(CPU_FTR_ARCH_31) &&
+ !dar_in_hw_range(regs->dar, info))
+ return false;
+
+ return true;
+ }
+
+ dawrx_constraints = check_dawrx_constraints(regs, type, info);
+
+ if (type == UNKNOWN) {
+ if (cpu_has_feature(CPU_FTR_ARCH_31) &&
+ !dar_in_hw_range(regs->dar, info))
+ return false;
+
+ return dawrx_constraints;
+ }
+
+ if (ea_user_range_overlaps(ea, size, info))
+ return dawrx_constraints;
+
+ if (ea_hw_range_overlaps(ea, size, info)) {
+ if (dawrx_constraints) {
+ info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+ return true;
+ }
+ }
+ return false;
+}
+
+static int cache_op_size(void)
+{
+#ifdef __powerpc64__
+ return ppc64_caches.l1d.block_size;
+#else
+ return L1_CACHE_BYTES;
+#endif
+}
+
+void wp_get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
+ int *type, int *size, unsigned long *ea)
+{
+ struct instruction_op op;
+
+ if (__get_user_instr_inatomic(*instr, (void __user *)regs->nip))
+ return;
+
+ analyse_instr(&op, regs, *instr);
+ *type = GETTYPE(op.type);
+ *ea = op.ea;
+#ifdef __powerpc64__
+ if (!(regs->msr & MSR_64BIT))
+ *ea &= 0xffffffffUL;
+#endif
+
+ *size = GETSIZE(op.type);
+ if (*type == CACHEOP) {
+ *size = cache_op_size();
+ *ea &= ~(*size - 1);
+ }
+}
--
2.26.2
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