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arm64: kernel: refactor code to install/uninstall breakpoints

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Most of the code executed to install and uninstall breakpoints is
common and can be factored out in a function that through a runtime
operations type provides the requested implementation.

This patch creates a common function that can be used to install/uninstall
breakpoints and defines the set of operations that can be carried out
through it.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
This commit is contained in:
Lorenzo Pieralisi 2013-08-13 10:45:19 +01:00
parent 1fcf7ce0c6
commit 2f04304587
1 changed files with 91 additions and 57 deletions
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148
arch/arm64/kernel/hw_breakpoint.c
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@ -169,15 +169,63 @@ static enum debug_el debug_exception_level(int privilege)
}
}
/*
* Install a perf counter breakpoint.
enum hw_breakpoint_ops {
HW_BREAKPOINT_INSTALL,
HW_BREAKPOINT_UNINSTALL
};
/**
* hw_breakpoint_slot_setup - Find and setup a perf slot according to
* operations
*
* @slots: pointer to array of slots
* @max_slots: max number of slots
* @bp: perf_event to setup
* @ops: operation to be carried out on the slot
*
* Return:
* slot index on success
* -ENOSPC if no slot is available/matches
* -EINVAL on wrong operations parameter
*/
int arch_install_hw_breakpoint(struct perf_event *bp)
static int hw_breakpoint_slot_setup(struct perf_event **slots, int max_slots,
struct perf_event *bp,
enum hw_breakpoint_ops ops)
{
int i;
struct perf_event **slot;
for (i = 0; i < max_slots; ++i) {
slot = &slots[i];
switch (ops) {
case HW_BREAKPOINT_INSTALL:
if (!*slot) {
*slot = bp;
return i;
}
break;
case HW_BREAKPOINT_UNINSTALL:
if (*slot == bp) {
*slot = NULL;
return i;
}
break;
default:
pr_warn_once("Unhandled hw breakpoint ops %d\n", ops);
return -EINVAL;
}
}
return -ENOSPC;
}
static int hw_breakpoint_control(struct perf_event *bp,
enum hw_breakpoint_ops ops)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
struct perf_event **slot, **slots;
struct perf_event **slots;
struct debug_info *debug_info = &current->thread.debug;
int i, max_slots, ctrl_reg, val_reg, reg_enable;
enum debug_el dbg_el = debug_exception_level(info->ctrl.privilege);
u32 ctrl;
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
@ -196,67 +244,53 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
reg_enable = !debug_info->wps_disabled;
}
for (i = 0; i < max_slots; ++i) {
slot = &slots[i];
i = hw_breakpoint_slot_setup(slots, max_slots, bp, ops);
if (!*slot) {
*slot = bp;
break;
}
if (WARN_ONCE(i < 0, "Can't find any breakpoint slot"))
return i;
switch (ops) {
case HW_BREAKPOINT_INSTALL:
/*
* Ensure debug monitors are enabled at the correct exception
* level.
*/
enable_debug_monitors(dbg_el);
/* Setup the address register. */
write_wb_reg(val_reg, i, info->address);
/* Setup the control register. */
ctrl = encode_ctrl_reg(info->ctrl);
write_wb_reg(ctrl_reg, i,
reg_enable ? ctrl | 0x1 : ctrl & ~0x1);
break;
case HW_BREAKPOINT_UNINSTALL:
/* Reset the control register. */
write_wb_reg(ctrl_reg, i, 0);
/*
* Release the debug monitors for the correct exception
* level.
*/
disable_debug_monitors(dbg_el);
break;
}
if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
return -ENOSPC;
/* Ensure debug monitors are enabled at the correct exception level. */
enable_debug_monitors(debug_exception_level(info->ctrl.privilege));
/* Setup the address register. */
write_wb_reg(val_reg, i, info->address);
/* Setup the control register. */
ctrl = encode_ctrl_reg(info->ctrl);
write_wb_reg(ctrl_reg, i, reg_enable ? ctrl | 0x1 : ctrl & ~0x1);
return 0;
}
/*
* Install a perf counter breakpoint.
*/
int arch_install_hw_breakpoint(struct perf_event *bp)
{
return hw_breakpoint_control(bp, HW_BREAKPOINT_INSTALL);
}
void arch_uninstall_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
struct perf_event **slot, **slots;
int i, max_slots, base;
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
/* Breakpoint */
base = AARCH64_DBG_REG_BCR;
slots = this_cpu_ptr(bp_on_reg);
max_slots = core_num_brps;
} else {
/* Watchpoint */
base = AARCH64_DBG_REG_WCR;
slots = this_cpu_ptr(wp_on_reg);
max_slots = core_num_wrps;
}
/* Remove the breakpoint. */
for (i = 0; i < max_slots; ++i) {
slot = &slots[i];
if (*slot == bp) {
*slot = NULL;
break;
}
}
if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
return;
/* Reset the control register. */
write_wb_reg(base, i, 0);
/* Release the debug monitors for the correct exception level. */
disable_debug_monitors(debug_exception_level(info->ctrl.privilege));
hw_breakpoint_control(bp, HW_BREAKPOINT_UNINSTALL);
}
static int get_hbp_len(u8 hbp_len)