linux/arch/loongarch
Hui Li f63a47b34b LoongArch: Fix watchpoint setting error
In the current code, when debugging the following code using gdb,
"invalid argument ..." message will be displayed.

lihui@bogon:~$ cat test.c
  #include <stdio.h>
  int a = 0;
  int main()
  {
	a = 1;
	return 0;
  }
lihui@bogon:~$ gcc -g test.c -o test
lihui@bogon:~$ gdb test
...
(gdb) watch a
Hardware watchpoint 1: a
(gdb) r
...
Invalid argument setting hardware debug registers

There are mainly two types of issues.

1. Some incorrect judgment condition existed in user_watch_state
   argument parsing, causing -EINVAL to be returned.

When setting up a watchpoint, gdb uses the ptrace interface,
ptrace(PTRACE_SETREGSET, tid, NT_LOONGARCH_HW_WATCH, (void *) &iov)).
Register values in user_watch_state as follows:

  addr[0] = 0x0, mask[0] = 0x0, ctrl[0] = 0x0
  addr[1] = 0x0, mask[1] = 0x0, ctrl[1] = 0x0
  addr[2] = 0x0, mask[2] = 0x0, ctrl[2] = 0x0
  addr[3] = 0x0, mask[3] = 0x0, ctrl[3] = 0x0
  addr[4] = 0x0, mask[4] = 0x0, ctrl[4] = 0x0
  addr[5] = 0x0, mask[5] = 0x0, ctrl[5] = 0x0
  addr[6] = 0x0, mask[6] = 0x0, ctrl[6] = 0x0
  addr[7] = 0x12000803c, mask[7] = 0x0, ctrl[7] = 0x610

In arch_bp_generic_fields(), return -EINVAL when ctrl.len is
LOONGARCH_BREAKPOINT_LEN_8(0b00). So delete the incorrect judgment here.

In ptrace_hbp_fill_attr_ctrl(), when note_type is NT_LOONGARCH_HW_WATCH
and ctrl[0] == 0x0, if ((type & HW_BREAKPOINT_RW) != type) will return
-EINVAL. Here ctrl.type should be set based on note_type, and unnecessary
judgments can be removed.

2. The watchpoint argument was not set correctly due to unnecessary
   offset and alignment_mask.

Modify ptrace_hbp_fill_attr_ctrl() and hw_breakpoint_arch_parse(), which
ensure the watchpont argument is set correctly.

All changes according to the LoongArch Reference Manual:
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#control-and-status-registers-related-to-watchpoints

Cc: stable@vger.kernel.org
Signed-off-by: Hui Li <lihui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-06-21 10:18:40 +08:00
..
boot LoongArch: Fix GMAC's phy-mode definitions in dts 2024-06-03 15:45:53 +08:00
configs LoongArch changes for v6.10 2024-05-22 09:43:07 -07:00
crypto LoongArch/crypto: Clean up useless assignment operations 2024-03-19 15:50:34 +08:00
include LoongArch: Fix watchpoint setting error 2024-06-21 10:18:40 +08:00
kernel LoongArch: Fix watchpoint setting error 2024-06-21 10:18:40 +08:00
kvm Kbuild updates for v6.10 2024-05-18 12:39:20 -07:00
lib LoongArch: Select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 2024-05-14 12:24:18 +08:00
mm LoongArch changes for v6.10 2024-05-22 09:43:07 -07:00
net bpf: Take return from set_memory_rox() into account with bpf_jit_binary_lock_ro() 2024-03-14 19:28:52 -07:00
pci LoongArch: Add FDT booting support from efi system table 2022-12-14 08:41:53 +08:00
power LoongArch: Give a chance to build with !CONFIG_SMP 2024-05-14 12:24:18 +08:00
vdso Makefile: remove redundant tool coverage variables 2024-05-14 23:35:48 +09:00
Kbuild LoongArch: Allow device trees be built into the kernel 2024-01-17 12:43:00 +08:00
Kconfig LoongArch: Only allow OBJTOOL & ORC unwinder if toolchain supports -mthin-add-sub 2024-06-21 10:18:40 +08:00
Kconfig.debug LoongArch: Only allow OBJTOOL & ORC unwinder if toolchain supports -mthin-add-sub 2024-06-21 10:18:40 +08:00
Makefile - A series ("kbuild: enable more warnings by default") from Arnd 2024-05-22 18:59:29 -07:00