diff options
Diffstat (limited to 'arch/powerpc/kernel/hw_breakpoint.c')
| -rw-r--r-- | arch/powerpc/kernel/hw_breakpoint.c | 119 |
1 files changed, 78 insertions, 41 deletions
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index 1007ec36b4cb..58ce3d37c2a3 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -127,15 +127,58 @@ int arch_bp_generic_fields(int type, int *gen_bp_type) } /* + * Watchpoint match range is always doubleword(8 bytes) aligned on + * powerpc. If the given range is crossing doubleword boundary, we + * need to increase the length such that next doubleword also get + * covered. Ex, + * + * address len = 6 bytes + * |=========. + * |------------v--|------v--------| + * | | | | | | | | | | | | | | | | | + * |---------------|---------------| + * <---8 bytes---> + * + * In this case, we should configure hw as: + * start_addr = address & ~HW_BREAKPOINT_ALIGN + * len = 16 bytes + * + * @start_addr and @end_addr are inclusive. + */ +static int hw_breakpoint_validate_len(struct arch_hw_breakpoint *hw) +{ + u16 max_len = DABR_MAX_LEN; + u16 hw_len; + unsigned long start_addr, end_addr; + + start_addr = hw->address & ~HW_BREAKPOINT_ALIGN; + end_addr = (hw->address + hw->len - 1) | HW_BREAKPOINT_ALIGN; + hw_len = end_addr - start_addr + 1; + + if (dawr_enabled()) { + max_len = DAWR_MAX_LEN; + /* DAWR region can't cross 512 bytes boundary */ + if ((start_addr >> 9) != (end_addr >> 9)) + return -EINVAL; + } + + if (hw_len > max_len) + return -EINVAL; + + hw->hw_len = hw_len; + return 0; +} + +/* * Validate the arch-specific HW Breakpoint register settings */ int hw_breakpoint_arch_parse(struct perf_event *bp, const struct perf_event_attr *attr, struct arch_hw_breakpoint *hw) { - int ret = -EINVAL, length_max; + int ret = -EINVAL; - if (!bp) + if (!bp || !attr->bp_len) return ret; hw->type = HW_BRK_TYPE_TRANSLATE; @@ -155,26 +198,10 @@ int hw_breakpoint_arch_parse(struct perf_event *bp, hw->address = attr->bp_addr; hw->len = attr->bp_len; - /* - * Since breakpoint length can be a maximum of HW_BREAKPOINT_LEN(8) - * and breakpoint addresses are aligned to nearest double-word - * HW_BREAKPOINT_ALIGN by rounding off to the lower address, the - * 'symbolsize' should satisfy the check below. - */ if (!ppc_breakpoint_available()) return -ENODEV; - length_max = 8; /* DABR */ - if (dawr_enabled()) { - length_max = 512 ; /* 64 doublewords */ - /* DAWR region can't cross 512 boundary */ - if ((attr->bp_addr >> 9) != - ((attr->bp_addr + attr->bp_len - 1) >> 9)) - return -EINVAL; - } - if (hw->len > - (length_max - (hw->address & HW_BREAKPOINT_ALIGN))) - return -EINVAL; - return 0; + + return hw_breakpoint_validate_len(hw); } /* @@ -195,33 +222,49 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs) tsk->thread.last_hit_ubp = NULL; } -static bool is_larx_stcx_instr(struct pt_regs *regs, unsigned int instr) +static bool dar_within_range(unsigned long dar, struct arch_hw_breakpoint *info) { - int ret, type; - struct instruction_op op; + return ((info->address <= dar) && (dar - info->address < info->len)); +} - ret = analyse_instr(&op, regs, instr); - type = GETTYPE(op.type); - return (!ret && (type == LARX || type == STCX)); +static bool +dar_range_overlaps(unsigned long dar, int size, struct arch_hw_breakpoint *info) +{ + return ((dar <= info->address + info->len - 1) && + (dar + size - 1 >= info->address)); } /* * Handle debug exception notifications. */ static bool stepping_handler(struct pt_regs *regs, struct perf_event *bp, - unsigned long addr) + struct arch_hw_breakpoint *info) { unsigned int instr = 0; + int ret, type, size; + struct instruction_op op; + unsigned long addr = info->address; if (__get_user_inatomic(instr, (unsigned int *)regs->nip)) goto fail; - if (is_larx_stcx_instr(regs, instr)) { + ret = analyse_instr(&op, regs, instr); + type = GETTYPE(op.type); + size = GETSIZE(op.type); + + if (!ret && (type == LARX || type == STCX)) { printk_ratelimited("Breakpoint hit on instruction that can't be emulated." " Breakpoint at 0x%lx will be disabled.\n", addr); goto disable; } + /* + * If it's extraneous event, we still need to emulate/single- + * step the instruction, but we don't generate an event. + */ + if (size && !dar_range_overlaps(regs->dar, size, info)) + info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ; + /* Do not emulate user-space instructions, instead single-step them */ if (user_mode(regs)) { current->thread.last_hit_ubp = bp; @@ -253,7 +296,6 @@ int hw_breakpoint_handler(struct die_args *args) struct perf_event *bp; struct pt_regs *regs = args->regs; struct arch_hw_breakpoint *info; - unsigned long dar = regs->dar; /* Disable breakpoints during exception handling */ hw_breakpoint_disable(); @@ -285,19 +327,14 @@ int hw_breakpoint_handler(struct die_args *args) goto out; } - /* - * Verify if dar lies within the address range occupied by the symbol - * being watched to filter extraneous exceptions. If it doesn't, - * we still need to single-step the instruction, but we don't - * generate an event. - */ info->type &= ~HW_BRK_TYPE_EXTRANEOUS_IRQ; - if (!((bp->attr.bp_addr <= dar) && - (dar - bp->attr.bp_addr < bp->attr.bp_len))) - info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ; - - if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address)) - goto out; + if (IS_ENABLED(CONFIG_PPC_8xx)) { + if (!dar_within_range(regs->dar, info)) + info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ; + } else { + if (!stepping_handler(regs, bp, info)) + goto out; + } /* * As a policy, the callback is invoked in a 'trigger-after-execute' |