[PATCH 06/12] arm64: Implement hw_breakpoint_arch_parse()

From: Frederic Weisbecker
Date: Fri Jun 01 2018 - 10:32:59 EST


Migrate to the new API in order to remove arch_validate_hwbkpt_settings()
that clumsily mixes up architecture validation and commit.

Acked-by: Will Deacon <will.deacon@xxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Joel Fernandes <joel.opensrc@xxxxxxxxx>
---
arch/arm64/include/asm/hw_breakpoint.h | 6 ++-
arch/arm64/kernel/hw_breakpoint.c | 79 +++++++++++++++++-----------------
2 files changed, 45 insertions(+), 40 deletions(-)

diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h
index 9f4a3d4..bf9c305 100644
--- a/arch/arm64/include/asm/hw_breakpoint.h
+++ b/arch/arm64/include/asm/hw_breakpoint.h
@@ -119,13 +119,17 @@ static inline void decode_ctrl_reg(u32 reg,

struct task_struct;
struct notifier_block;
+struct perf_event_attr;
struct perf_event;
struct pmu;

extern int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl,
int *gen_len, int *gen_type, int *offset);
extern int arch_check_bp_in_kernelspace(struct arch_hw_breakpoint *hw);
-extern int arch_validate_hwbkpt_settings(struct perf_event *bp);
+extern int hw_breakpoint_arch_parse(struct perf_event *bp,
+ const struct perf_event_attr *attr,
+ struct arch_hw_breakpoint *hw);
+#define hw_breakpoint_arch_parse hw_breakpoint_arch_parse
extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
unsigned long val, void *data);

diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index 92c6973..6114660 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -421,53 +421,53 @@ int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl,
/*
* Construct an arch_hw_breakpoint from a perf_event.
*/
-static int arch_build_bp_info(struct perf_event *bp)
+static int arch_build_bp_info(struct perf_event *bp,
+ const struct perf_event_attr *attr,
+ struct arch_hw_breakpoint *hw)
{
- struct arch_hw_breakpoint *info = counter_arch_bp(bp);
-
/* Type */
- switch (bp->attr.bp_type) {
+ switch (attr->bp_type) {
case HW_BREAKPOINT_X:
- info->ctrl.type = ARM_BREAKPOINT_EXECUTE;
+ hw->ctrl.type = ARM_BREAKPOINT_EXECUTE;
break;
case HW_BREAKPOINT_R:
- info->ctrl.type = ARM_BREAKPOINT_LOAD;
+ hw->ctrl.type = ARM_BREAKPOINT_LOAD;
break;
case HW_BREAKPOINT_W:
- info->ctrl.type = ARM_BREAKPOINT_STORE;
+ hw->ctrl.type = ARM_BREAKPOINT_STORE;
break;
case HW_BREAKPOINT_RW:
- info->ctrl.type = ARM_BREAKPOINT_LOAD | ARM_BREAKPOINT_STORE;
+ hw->ctrl.type = ARM_BREAKPOINT_LOAD | ARM_BREAKPOINT_STORE;
break;
default:
return -EINVAL;
}

/* Len */
- switch (bp->attr.bp_len) {
+ switch (attr->bp_len) {
case HW_BREAKPOINT_LEN_1:
- info->ctrl.len = ARM_BREAKPOINT_LEN_1;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_1;
break;
case HW_BREAKPOINT_LEN_2:
- info->ctrl.len = ARM_BREAKPOINT_LEN_2;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_2;
break;
case HW_BREAKPOINT_LEN_3:
- info->ctrl.len = ARM_BREAKPOINT_LEN_3;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_3;
break;
case HW_BREAKPOINT_LEN_4:
- info->ctrl.len = ARM_BREAKPOINT_LEN_4;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_4;
break;
case HW_BREAKPOINT_LEN_5:
- info->ctrl.len = ARM_BREAKPOINT_LEN_5;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_5;
break;
case HW_BREAKPOINT_LEN_6:
- info->ctrl.len = ARM_BREAKPOINT_LEN_6;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_6;
break;
case HW_BREAKPOINT_LEN_7:
- info->ctrl.len = ARM_BREAKPOINT_LEN_7;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_7;
break;
case HW_BREAKPOINT_LEN_8:
- info->ctrl.len = ARM_BREAKPOINT_LEN_8;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_8;
break;
default:
return -EINVAL;
@@ -478,37 +478,37 @@ static int arch_build_bp_info(struct perf_event *bp)
* AArch32 also requires breakpoints of length 2 for Thumb.
* Watchpoints can be of length 1, 2, 4 or 8 bytes.
*/
- if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
+ if (hw->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
if (is_compat_bp(bp)) {
- if (info->ctrl.len != ARM_BREAKPOINT_LEN_2 &&
- info->ctrl.len != ARM_BREAKPOINT_LEN_4)
+ if (hw->ctrl.len != ARM_BREAKPOINT_LEN_2 &&
+ hw->ctrl.len != ARM_BREAKPOINT_LEN_4)
return -EINVAL;
- } else if (info->ctrl.len != ARM_BREAKPOINT_LEN_4) {
+ } else if (hw->ctrl.len != ARM_BREAKPOINT_LEN_4) {
/*
* FIXME: Some tools (I'm looking at you perf) assume
* that breakpoints should be sizeof(long). This
* is nonsense. For now, we fix up the parameter
* but we should probably return -EINVAL instead.
*/
- info->ctrl.len = ARM_BREAKPOINT_LEN_4;
+ hw->ctrl.len = ARM_BREAKPOINT_LEN_4;
}
}

/* Address */
- info->address = bp->attr.bp_addr;
+ hw->address = attr->bp_addr;

/*
* Privilege
* Note that we disallow combined EL0/EL1 breakpoints because
* that would complicate the stepping code.
*/
- if (arch_check_bp_in_kernelspace(info))
- info->ctrl.privilege = AARCH64_BREAKPOINT_EL1;
+ if (arch_check_bp_in_kernelspace(hw))
+ hw->ctrl.privilege = AARCH64_BREAKPOINT_EL1;
else
- info->ctrl.privilege = AARCH64_BREAKPOINT_EL0;
+ hw->ctrl.privilege = AARCH64_BREAKPOINT_EL0;

/* Enabled? */
- info->ctrl.enabled = !bp->attr.disabled;
+ hw->ctrl.enabled = !attr->disabled;

return 0;
}
@@ -516,14 +516,15 @@ static int arch_build_bp_info(struct perf_event *bp)
/*
* Validate the arch-specific HW Breakpoint register settings.
*/
-int arch_validate_hwbkpt_settings(struct perf_event *bp)
+int hw_breakpoint_arch_parse(struct perf_event *bp,
+ const struct perf_event_attr *attr,
+ struct arch_hw_breakpoint *hw)
{
- struct arch_hw_breakpoint *info = counter_arch_bp(bp);
int ret;
u64 alignment_mask, offset;

/* Build the arch_hw_breakpoint. */
- ret = arch_build_bp_info(bp);
+ ret = arch_build_bp_info(bp, attr, hw);
if (ret)
return ret;

@@ -537,42 +538,42 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
* that here.
*/
if (is_compat_bp(bp)) {
- if (info->ctrl.len == ARM_BREAKPOINT_LEN_8)
+ if (hw->ctrl.len == ARM_BREAKPOINT_LEN_8)
alignment_mask = 0x7;
else
alignment_mask = 0x3;
- offset = info->address & alignment_mask;
+ offset = hw->address & alignment_mask;
switch (offset) {
case 0:
/* Aligned */
break;
case 1:
/* Allow single byte watchpoint. */
- if (info->ctrl.len == ARM_BREAKPOINT_LEN_1)
+ if (hw->ctrl.len == ARM_BREAKPOINT_LEN_1)
break;
case 2:
/* Allow halfword watchpoints and breakpoints. */
- if (info->ctrl.len == ARM_BREAKPOINT_LEN_2)
+ if (hw->ctrl.len == ARM_BREAKPOINT_LEN_2)
break;
default:
return -EINVAL;
}
} else {
- if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE)
+ if (hw->ctrl.type == ARM_BREAKPOINT_EXECUTE)
alignment_mask = 0x3;
else
alignment_mask = 0x7;
- offset = info->address & alignment_mask;
+ offset = hw->address & alignment_mask;
}

- info->address &= ~alignment_mask;
- info->ctrl.len <<= offset;
+ hw->address &= ~alignment_mask;
+ hw->ctrl.len <<= offset;

/*
* Disallow per-task kernel breakpoints since these would
* complicate the stepping code.
*/
- if (info->ctrl.privilege == AARCH64_BREAKPOINT_EL1 && bp->hw.target)
+ if (hw->ctrl.privilege == AARCH64_BREAKPOINT_EL1 && bp->hw.target)
return -EINVAL;

return 0;
--
2.7.4