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LoongArch defines hardware watchpoint functions for fetch operations.
After the software configures the watchpoints for fetch, the processor
hardware will monitor the access addresses of the fetch operations and
trigger a watchpoint exception when the watchpoint setting conditions
are met.
Hardware watchpoints for fetch operations is used to implement hardware
breakpoint function on LoongArch. Refer to the following document for
hardware breakpoint.
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#control-and-status-registers-related-to-watchpoints
A simple test is as follows:
lihui@bogon:~$ cat test.c
#include <stdio.h>
int a = 0;
int main()
{
printf("start test\n");
a = 1;
printf("a = %d\n", a);
printf("end test\n");
return 0;
}
lihui@bogon:~$ gcc -g test.c -o test
without this patch:
lihui@bogon:~$ gdb test
...
(gdb) start
...
Temporary breakpoint 1, main () at test.c:5
5 printf("start test\n");
(gdb) hbreak 8
No hardware breakpoint support in the target.
with this patch:
lihui@bogon:~$ gdb test
...
(gdb) start
...
Temporary breakpoint 1, main () at test.c:5
5 printf("start test\n");
(gdb) hbreak 8
Hardware assisted breakpoint 2 at 0x1200006ec: file test.c, line 8.
(gdb) c
Continuing.
start test
a = 1
Breakpoint 2, main () at test.c:8
8 printf("end test\n");
(gdb) c
Continuing.
end test
[Inferior 1 (process 25378) exited normally]
Signed-off-by: Hui Li <lihui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
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LoongArch defines hardware watchpoint functions for load/store
operations. After the software configures the watchpoints for
load/store, the processor hardware will monitor the access
addresses of the load/store operations and trigger watchpoint
exception when the watchpoint setting conditions are met.
After this patch, watch/rwatch/awatch command are supported. Refer to the
following document for hardware watchpoint.
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#control-and-status-registers-related-to-watchpoints
A simple test is as follows:
lihui@bogon:~$ cat test.c
#include <stdio.h>
int a = 0;
int main()
{
printf("start test\n");
a = 1;
printf("a = %d\n", a);
printf("end test\n");
return 0;
}
lihui@bogon:~$ gcc -g test.c -o test
without this patch:
lihui@bogon:~$ gdb test
...
(gdb) start
...
Temporary breakpoint 1, main () at test.c:5
5 printf("start test\n");
(gdb) awatch a
Target does not support this type of hardware watchpoint.
...
with this patch:
lihui@bogon:~$ gdb test
...
(gdb) start
...
Temporary breakpoint 1, main () at test.c:5
5 printf("start test\n");
(gdb) awatch a
Hardware access (read/write) watchpoint 2: a
(gdb) c
Continuing.
start test
Hardware access (read/write) watchpoint 2: a
Old value = 0
New value = 1
main () at test.c:7
7 printf("a = %d\n", a);
(gdb) c
Continuing.
Hardware access (read/write) watchpoint 2: a
Value = 1
0x00000001200006e0 in main () at test.c:7
7 printf("a = %d\n", a);
(gdb) c
Continuing.
a = 1
end test
[Inferior 1 (process 22250) exited normally]
Signed-off-by: Hui Li <lihui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
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