-/* ptrace expects control registers to be formatted as follows:
-
- 31 13 5 3 1 0
- +--------------------------------+----------+------+------+----+
- | RESERVED (SBZ) | LENGTH | TYPE | PRIV | EN |
- +--------------------------------+----------+------+------+----+
-
- The TYPE field is ignored for breakpoints. */
-
-#define DR_CONTROL_ENABLED(ctrl) (((ctrl) & 0x1) == 1)
-#define DR_CONTROL_LENGTH(ctrl) (((ctrl) >> 5) & 0xff)
-
-/* Utility function that returns the length in bytes of a watchpoint
- according to the content of a hardware debug control register CTRL.
- Note that the kernel currently only supports the following Byte
- Address Select (BAS) values: 0x1, 0x3, 0xf and 0xff, which means
- that for a hardware watchpoint, its valid length can only be 1
- byte, 2 bytes, 4 bytes or 8 bytes. */
-
-static inline unsigned int
-aarch64_watchpoint_length (unsigned int ctrl)
-{
- switch (DR_CONTROL_LENGTH (ctrl))
- {
- case 0x01:
- return 1;
- case 0x03:
- return 2;
- case 0x0f:
- return 4;
- case 0xff:
- return 8;
- default:
- return 0;
- }
-}
-
-/* Given the hardware breakpoint or watchpoint type TYPE and its
- length LEN, return the expected encoding for a hardware
- breakpoint/watchpoint control register. */
-
-static unsigned int
-aarch64_point_encode_ctrl_reg (enum target_hw_bp_type type, int len)
-{
- unsigned int ctrl, ttype;
-
- /* type */
- switch (type)
- {
- case hw_write:
- ttype = 2;
- break;
- case hw_read:
- ttype = 1;
- break;
- case hw_access:
- ttype = 3;
- break;
- case hw_execute:
- ttype = 0;
- break;
- default:
- perror_with_name (_("Unrecognized breakpoint/watchpoint type"));
- }
-
- /* type */
- ctrl = ttype << 3;
- /* length bitmask */
- ctrl |= ((1 << len) - 1) << 5;
- /* enabled at el0 */
- ctrl |= (2 << 1) | 1;
-
- return ctrl;
-}
-
-/* Addresses to be written to the hardware breakpoint and watchpoint
- value registers need to be aligned; the alignment is 4-byte and
- 8-type respectively. Linux kernel rejects any non-aligned address
- it receives from the related ptrace call. Furthermore, the kernel
- currently only supports the following Byte Address Select (BAS)
- values: 0x1, 0x3, 0xf and 0xff, which means that for a hardware
- watchpoint to be accepted by the kernel (via ptrace call), its
- valid length can only be 1 byte, 2 bytes, 4 bytes or 8 bytes.
- Despite these limitations, the unaligned watchpoint is supported in
- this gdbserver port.
-
- Return 0 for any non-compliant ADDR and/or LEN; return 1 otherwise. */
-
-static int
-aarch64_point_is_aligned (int is_watchpoint, CORE_ADDR addr, int len)
-{
- unsigned int alignment = is_watchpoint ? AARCH64_HWP_ALIGNMENT
- : AARCH64_HBP_ALIGNMENT;
-
- if (addr & (alignment - 1))
- return 0;
-
- if (len != 8 && len != 4 && len != 2 && len != 1)
- return 0;
-
- return 1;
-}
-
-/* Given the (potentially unaligned) watchpoint address in ADDR and
- length in LEN, return the aligned address and aligned length in
- *ALIGNED_ADDR_P and *ALIGNED_LEN_P, respectively. The returned
- aligned address and length will be valid to be written to the
- hardware watchpoint value and control registers. See the comment
- above aarch64_point_is_aligned for the information about the
- alignment requirement. The given watchpoint may get truncated if
- more than one hardware register is needed to cover the watched
- region. *NEXT_ADDR_P and *NEXT_LEN_P, if non-NULL, will return the
- address and length of the remaining part of the watchpoint (which
- can be processed by calling this routine again to generate another
- aligned address and length pair.
-
- Essentially, unaligned watchpoint is achieved by minimally
- enlarging the watched area to meet the alignment requirement, and
- if necessary, splitting the watchpoint over several hardware
- watchpoint registers. The trade-off is that there will be
- false-positive hits for the read-type or the access-type hardware
- watchpoints; for the write type, which is more commonly used, there
- will be no such issues, as the higher-level breakpoint management
- in gdb always examines the exact watched region for any content
- change, and transparently resumes a thread from a watchpoint trap
- if there is no change to the watched region.
-
- Another limitation is that because the watched region is enlarged,
- the watchpoint fault address returned by
- aarch64_stopped_data_address may be outside of the original watched
- region, especially when the triggering instruction is accessing a
- larger region. When the fault address is not within any known
- range, watchpoints_triggered in gdb will get confused, as the
- higher-level watchpoint management is only aware of original
- watched regions, and will think that some unknown watchpoint has
- been triggered. In such a case, gdb may stop without displaying
- any detailed information.
-
- Once the kernel provides the full support for Byte Address Select
- (BAS) in the hardware watchpoint control register, these
- limitations can be largely relaxed with some further work. */
-
-static void
-aarch64_align_watchpoint (CORE_ADDR addr, int len, CORE_ADDR *aligned_addr_p,
- int *aligned_len_p, CORE_ADDR *next_addr_p,
- int *next_len_p)
-{
- int aligned_len;
- unsigned int offset;
- CORE_ADDR aligned_addr;
- const unsigned int alignment = AARCH64_HWP_ALIGNMENT;
- const unsigned int max_wp_len = AARCH64_HWP_MAX_LEN_PER_REG;
-
- /* As assumed by the algorithm. */
- gdb_assert (alignment == max_wp_len);
-
- if (len <= 0)
- return;
-
- /* Address to be put into the hardware watchpoint value register
- must be aligned. */
- offset = addr & (alignment - 1);
- aligned_addr = addr - offset;
-
- gdb_assert (offset >= 0 && offset < alignment);
- gdb_assert (aligned_addr >= 0 && aligned_addr <= addr);
- gdb_assert ((offset + len) > 0);
-
- if (offset + len >= max_wp_len)
- {
- /* Need more than one watchpoint registers; truncate it at the
- alignment boundary. */
- aligned_len = max_wp_len;
- len -= (max_wp_len - offset);
- addr += (max_wp_len - offset);
- gdb_assert ((addr & (alignment - 1)) == 0);
- }
- else
- {
- /* Find the smallest valid length that is large enough to
- accommodate this watchpoint. */
- static const unsigned char
- aligned_len_array[AARCH64_HWP_MAX_LEN_PER_REG] =
- { 1, 2, 4, 4, 8, 8, 8, 8 };
-
- aligned_len = aligned_len_array[offset + len - 1];
- addr += len;
- len = 0;
- }
-
- if (aligned_addr_p != NULL)
- *aligned_addr_p = aligned_addr;
- if (aligned_len_p != NULL)
- *aligned_len_p = aligned_len;
- if (next_addr_p != NULL)
- *next_addr_p = addr;
- if (next_len_p != NULL)
- *next_len_p = len;
-}
-
-/* Call ptrace to set the thread TID's hardware breakpoint/watchpoint
- registers with data from *STATE. */
-
-static void
-aarch64_linux_set_debug_regs (const struct aarch64_debug_reg_state *state,
- int tid, int watchpoint)
-{
- int i, count;
- struct iovec iov;
- struct user_hwdebug_state regs;
- const CORE_ADDR *addr;
- const unsigned int *ctrl;
-
- memset (®s, 0, sizeof (regs));
- iov.iov_base = ®s;
- count = watchpoint ? aarch64_num_wp_regs : aarch64_num_bp_regs;
- addr = watchpoint ? state->dr_addr_wp : state->dr_addr_bp;
- ctrl = watchpoint ? state->dr_ctrl_wp : state->dr_ctrl_bp;
- if (count == 0)
- return;
- iov.iov_len = (offsetof (struct user_hwdebug_state, dbg_regs[count - 1])
- + sizeof (regs.dbg_regs [count - 1]));
-
- for (i = 0; i < count; i++)
- {
- regs.dbg_regs[i].addr = addr[i];
- regs.dbg_regs[i].ctrl = ctrl[i];
- }
-
- if (ptrace (PTRACE_SETREGSET, tid,
- watchpoint ? NT_ARM_HW_WATCH : NT_ARM_HW_BREAK,
- (void *) &iov))
- error (_("Unexpected error setting hardware debug registers"));
-}
-