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| author | Frans Kaashoek <kaashoek@mit.edu> | 2022-08-10 20:35:42 -0400 |
|---|---|---|
| committer | Frans Kaashoek <kaashoek@mit.edu> | 2022-08-10 20:35:42 -0400 |
| commit | 4087a6e7fc773ba4eb217dfc196dfe1eee84b25d (patch) | |
| tree | a77a5b04944ed3f83ea10875aa32b1322e4224c6 /kernel/trap.c | |
| parent | b1fd09335ae1c112a01cedad0a6abd584fe8dca7 (diff) | |
| download | xv6-labs-2022-4087a6e7fc773ba4eb217dfc196dfe1eee84b25d.tar.xz xv6-labs-2022-4087a6e7fc773ba4eb217dfc196dfe1eee84b25d.zip | |
Read and write p->killed using atomics
Diffstat (limited to 'kernel/trap.c')
| -rw-r--r-- | kernel/trap.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/trap.c b/kernel/trap.c index 75fb3ec..b879f01 100644 --- a/kernel/trap.c +++ b/kernel/trap.c @@ -53,7 +53,7 @@ usertrap(void) if(r_scause() == 8){ // system call - if(p->killed) + if(__sync_add_and_fetch(&p->killed, 0)) exit(-1); // sepc points to the ecall instruction, @@ -70,10 +70,10 @@ usertrap(void) } else { printf("usertrap(): unexpected scause %p pid=%d\n", r_scause(), p->pid); printf(" sepc=%p stval=%p\n", r_sepc(), r_stval()); - p->killed = 1; + __sync_bool_compare_and_swap(&p->killed, 0, 1); } - if(p->killed) + if(__sync_add_and_fetch(&p->killed, 0)) exit(-1); // give up the CPU if this is a timer interrupt. |