LoongArch: ptrace: Expose hardware breakpoints to debuggers
Implement the regset-based ptrace interface that exposes hardware breakpoints to user-space debuggers to query and set instruction and data breakpoints. Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Qing Zhang
Huacai Chen
parent
edffa33c7b
commit
1a69f7a161
@ -46,6 +46,15 @@ struct user_fp_state {
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uint32_t fcsr;
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};
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struct user_watch_state {
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uint16_t dbg_info;
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struct {
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uint64_t addr;
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uint64_t mask;
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uint32_t ctrl;
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} dbg_regs[8];
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};
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#define PTRACE_SYSEMU 0x1f
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#define PTRACE_SYSEMU_SINGLESTEP 0x20
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@ -20,7 +20,9 @@
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#include <linux/context_tracking.h>
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#include <linux/elf.h>
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#include <linux/errno.h>
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#include <linux/hw_breakpoint.h>
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#include <linux/mm.h>
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#include <linux/nospec.h>
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#include <linux/ptrace.h>
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#include <linux/regset.h>
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#include <linux/sched.h>
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@ -246,6 +248,384 @@ static int cfg_set(struct task_struct *target,
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return 0;
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}
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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/*
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* Handle hitting a HW-breakpoint.
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*/
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static void ptrace_hbptriggered(struct perf_event *bp,
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struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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int i;
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struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
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for (i = 0; i < LOONGARCH_MAX_BRP; ++i)
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if (current->thread.hbp_break[i] == bp)
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break;
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for (i = 0; i < LOONGARCH_MAX_WRP; ++i)
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if (current->thread.hbp_watch[i] == bp)
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break;
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force_sig_ptrace_errno_trap(i, (void __user *)bkpt->address);
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}
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static struct perf_event *ptrace_hbp_get_event(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx)
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{
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struct perf_event *bp;
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switch (note_type) {
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case NT_LOONGARCH_HW_BREAK:
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if (idx >= LOONGARCH_MAX_BRP)
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return ERR_PTR(-EINVAL);
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idx = array_index_nospec(idx, LOONGARCH_MAX_BRP);
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bp = tsk->thread.hbp_break[idx];
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break;
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case NT_LOONGARCH_HW_WATCH:
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if (idx >= LOONGARCH_MAX_WRP)
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return ERR_PTR(-EINVAL);
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idx = array_index_nospec(idx, LOONGARCH_MAX_WRP);
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bp = tsk->thread.hbp_watch[idx];
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break;
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}
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return bp;
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}
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static int ptrace_hbp_set_event(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx,
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struct perf_event *bp)
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{
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switch (note_type) {
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case NT_LOONGARCH_HW_BREAK:
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if (idx >= LOONGARCH_MAX_BRP)
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return -EINVAL;
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idx = array_index_nospec(idx, LOONGARCH_MAX_BRP);
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tsk->thread.hbp_break[idx] = bp;
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break;
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case NT_LOONGARCH_HW_WATCH:
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if (idx >= LOONGARCH_MAX_WRP)
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return -EINVAL;
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idx = array_index_nospec(idx, LOONGARCH_MAX_WRP);
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tsk->thread.hbp_watch[idx] = bp;
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break;
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}
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return 0;
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}
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static struct perf_event *ptrace_hbp_create(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx)
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{
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int err, type;
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struct perf_event *bp;
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struct perf_event_attr attr;
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switch (note_type) {
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case NT_LOONGARCH_HW_BREAK:
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type = HW_BREAKPOINT_X;
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break;
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case NT_LOONGARCH_HW_WATCH:
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type = HW_BREAKPOINT_RW;
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break;
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default:
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return ERR_PTR(-EINVAL);
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}
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ptrace_breakpoint_init(&attr);
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/*
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* Initialise fields to sane defaults
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* (i.e. values that will pass validation).
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*/
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attr.bp_addr = 0;
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attr.bp_len = HW_BREAKPOINT_LEN_4;
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attr.bp_type = type;
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attr.disabled = 1;
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bp = register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL, tsk);
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if (IS_ERR(bp))
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return bp;
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err = ptrace_hbp_set_event(note_type, tsk, idx, bp);
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if (err)
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return ERR_PTR(err);
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return bp;
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}
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static int ptrace_hbp_fill_attr_ctrl(unsigned int note_type,
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struct arch_hw_breakpoint_ctrl ctrl,
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struct perf_event_attr *attr)
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{
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int err, len, type, offset;
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err = arch_bp_generic_fields(ctrl, &len, &type, &offset);
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if (err)
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return err;
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switch (note_type) {
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case NT_LOONGARCH_HW_BREAK:
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if ((type & HW_BREAKPOINT_X) != type)
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return -EINVAL;
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break;
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case NT_LOONGARCH_HW_WATCH:
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if ((type & HW_BREAKPOINT_RW) != type)
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return -EINVAL;
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break;
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default:
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return -EINVAL;
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}
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attr->bp_len = len;
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attr->bp_type = type;
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attr->bp_addr += offset;
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return 0;
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}
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static int ptrace_hbp_get_resource_info(unsigned int note_type, u16 *info)
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{
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u8 num;
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u16 reg = 0;
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switch (note_type) {
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case NT_LOONGARCH_HW_BREAK:
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num = hw_breakpoint_slots(TYPE_INST);
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break;
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case NT_LOONGARCH_HW_WATCH:
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num = hw_breakpoint_slots(TYPE_DATA);
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break;
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default:
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return -EINVAL;
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}
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*info = reg | num;
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return 0;
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}
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static struct perf_event *ptrace_hbp_get_initialised_bp(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx)
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{
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struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
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if (!bp)
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bp = ptrace_hbp_create(note_type, tsk, idx);
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return bp;
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}
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static int ptrace_hbp_get_ctrl(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx, u32 *ctrl)
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{
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struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
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if (IS_ERR(bp))
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return PTR_ERR(bp);
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*ctrl = bp ? encode_ctrl_reg(counter_arch_bp(bp)->ctrl) : 0;
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return 0;
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}
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static int ptrace_hbp_get_mask(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx, u64 *mask)
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{
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struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
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if (IS_ERR(bp))
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return PTR_ERR(bp);
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*mask = bp ? counter_arch_bp(bp)->mask : 0;
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return 0;
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}
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static int ptrace_hbp_get_addr(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx, u64 *addr)
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{
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struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
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if (IS_ERR(bp))
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return PTR_ERR(bp);
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*addr = bp ? counter_arch_bp(bp)->address : 0;
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return 0;
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}
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static int ptrace_hbp_set_ctrl(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx, u32 uctrl)
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{
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int err;
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struct perf_event *bp;
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struct perf_event_attr attr;
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struct arch_hw_breakpoint_ctrl ctrl;
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bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
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if (IS_ERR(bp))
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return PTR_ERR(bp);
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attr = bp->attr;
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decode_ctrl_reg(uctrl, &ctrl);
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err = ptrace_hbp_fill_attr_ctrl(note_type, ctrl, &attr);
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if (err)
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return err;
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return modify_user_hw_breakpoint(bp, &attr);
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}
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static int ptrace_hbp_set_mask(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx, u64 mask)
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{
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struct perf_event *bp;
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struct perf_event_attr attr;
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struct arch_hw_breakpoint *info;
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bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
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if (IS_ERR(bp))
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return PTR_ERR(bp);
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attr = bp->attr;
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info = counter_arch_bp(bp);
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info->mask = mask;
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return modify_user_hw_breakpoint(bp, &attr);
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}
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static int ptrace_hbp_set_addr(unsigned int note_type,
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struct task_struct *tsk,
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unsigned long idx, u64 addr)
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{
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struct perf_event *bp;
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struct perf_event_attr attr;
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bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
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if (IS_ERR(bp))
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return PTR_ERR(bp);
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attr = bp->attr;
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attr.bp_addr = addr;
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return modify_user_hw_breakpoint(bp, &attr);
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}
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#define PTRACE_HBP_CTRL_SZ sizeof(u32)
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#define PTRACE_HBP_ADDR_SZ sizeof(u64)
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#define PTRACE_HBP_MASK_SZ sizeof(u64)
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static int hw_break_get(struct task_struct *target,
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const struct user_regset *regset,
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struct membuf to)
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{
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u16 info;
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u32 ctrl;
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u64 addr, mask;
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int ret, idx = 0;
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unsigned int note_type = regset->core_note_type;
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/* Resource info */
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ret = ptrace_hbp_get_resource_info(note_type, &info);
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if (ret)
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return ret;
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membuf_write(&to, &info, sizeof(info));
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/* (address, ctrl) registers */
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while (to.left) {
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ret = ptrace_hbp_get_addr(note_type, target, idx, &addr);
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if (ret)
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return ret;
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ret = ptrace_hbp_get_mask(note_type, target, idx, &mask);
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if (ret)
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return ret;
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ret = ptrace_hbp_get_ctrl(note_type, target, idx, &ctrl);
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if (ret)
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return ret;
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membuf_store(&to, addr);
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membuf_store(&to, mask);
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membuf_store(&to, ctrl);
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idx++;
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}
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return 0;
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}
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static int hw_break_set(struct task_struct *target,
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const struct user_regset *regset,
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unsigned int pos, unsigned int count,
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const void *kbuf, const void __user *ubuf)
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{
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u32 ctrl;
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u64 addr, mask;
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int ret, idx = 0, offset, limit;
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unsigned int note_type = regset->core_note_type;
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/* Resource info */
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offset = offsetof(struct user_watch_state, dbg_regs);
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user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, offset);
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/* (address, ctrl) registers */
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limit = regset->n * regset->size;
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while (count && offset < limit) {
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if (count < PTRACE_HBP_ADDR_SZ)
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return -EINVAL;
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
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offset, offset + PTRACE_HBP_ADDR_SZ);
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if (ret)
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return ret;
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ret = ptrace_hbp_set_addr(note_type, target, idx, addr);
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if (ret)
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return ret;
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offset += PTRACE_HBP_ADDR_SZ;
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if (!count)
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break;
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &mask,
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offset, offset + PTRACE_HBP_ADDR_SZ);
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if (ret)
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return ret;
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ret = ptrace_hbp_set_mask(note_type, target, idx, mask);
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if (ret)
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return ret;
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offset += PTRACE_HBP_MASK_SZ;
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &mask,
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offset, offset + PTRACE_HBP_MASK_SZ);
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if (ret)
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return ret;
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ret = ptrace_hbp_set_ctrl(note_type, target, idx, ctrl);
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if (ret)
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return ret;
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offset += PTRACE_HBP_CTRL_SZ;
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idx++;
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}
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return 0;
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}
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#endif
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struct pt_regs_offset {
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const char *name;
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int offset;
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@ -319,6 +699,10 @@ enum loongarch_regset {
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REGSET_GPR,
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REGSET_FPR,
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REGSET_CPUCFG,
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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REGSET_HW_BREAK,
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REGSET_HW_WATCH,
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#endif
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};
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static const struct user_regset loongarch64_regsets[] = {
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@ -346,6 +730,24 @@ static const struct user_regset loongarch64_regsets[] = {
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.regset_get = cfg_get,
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.set = cfg_set,
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},
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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[REGSET_HW_BREAK] = {
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.core_note_type = NT_LOONGARCH_HW_BREAK,
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.n = sizeof(struct user_watch_state) / sizeof(u32),
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.size = sizeof(u32),
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.align = sizeof(u32),
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.regset_get = hw_break_get,
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.set = hw_break_set,
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},
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[REGSET_HW_WATCH] = {
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.core_note_type = NT_LOONGARCH_HW_WATCH,
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.n = sizeof(struct user_watch_state) / sizeof(u32),
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.size = sizeof(u32),
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.align = sizeof(u32),
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.regset_get = hw_break_get,
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.set = hw_break_set,
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},
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#endif
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};
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static const struct user_regset_view user_loongarch64_view = {
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@ -444,6 +444,8 @@ typedef struct elf64_shdr {
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#define NT_LOONGARCH_LSX 0xa02 /* LoongArch Loongson SIMD Extension registers */
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#define NT_LOONGARCH_LASX 0xa03 /* LoongArch Loongson Advanced SIMD Extension registers */
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#define NT_LOONGARCH_LBT 0xa04 /* LoongArch Loongson Binary Translation registers */
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#define NT_LOONGARCH_HW_BREAK 0xa05 /* LoongArch hardware breakpoint registers */
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#define NT_LOONGARCH_HW_WATCH 0xa06 /* LoongArch hardware watchpoint registers */
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/* Note types with note name "GNU" */
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#define NT_GNU_PROPERTY_TYPE_0 5
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