From 2f04304587544dd14277413ebff12fa0f4fc932c Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Tue, 13 Aug 2013 10:45:19 +0100 Subject: arm64: kernel: refactor code to install/uninstall breakpoints 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 Signed-off-by: Lorenzo Pieralisi --- arch/arm64/kernel/hw_breakpoint.c | 142 +++++++++++++++++++++++--------------- 1 file changed, 88 insertions(+), 54 deletions(-) (limited to 'arch/arm64/kernel/hw_breakpoint.c') diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index ff516f6..e894591 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -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 = ¤t->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; - if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot")) - return -ENOSPC; + switch (ops) { + case HW_BREAKPOINT_INSTALL: + /* + * Ensure debug monitors are enabled at the correct exception + * level. + */ + enable_debug_monitors(dbg_el); - /* 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 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); - /* Setup the control register. */ - ctrl = encode_ctrl_reg(info->ctrl); - write_wb_reg(ctrl_reg, i, reg_enable ? ctrl | 0x1 : ctrl & ~0x1); + /* + * Release the debug monitors for the correct exception + * level. + */ + disable_debug_monitors(dbg_el); + break; + } return 0; } -void arch_uninstall_hw_breakpoint(struct perf_event *bp) +/* + * Install a perf counter breakpoint. + */ +int arch_install_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); + return hw_breakpoint_control(bp, HW_BREAKPOINT_INSTALL); +} - /* Release the debug monitors for the correct exception level. */ - disable_debug_monitors(debug_exception_level(info->ctrl.privilege)); +void arch_uninstall_hw_breakpoint(struct perf_event *bp) +{ + hw_breakpoint_control(bp, HW_BREAKPOINT_UNINSTALL); } static int get_hbp_len(u8 hbp_len) -- cgit v1.1