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authorJeff Dike <jdike@addtoit.com>2007-05-06 17:51:40 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 15:13:03 -0400
commit77f6af778dc23514d897f4fdc7935329285ecb1b (patch)
treeb800f241f3d49dce3ef79c7ec2e6cf8ff04e07a7 /arch/um
parent63843c265fd0e0c7894f713e0db5777560e756ae (diff)
uml: don't try to handle signals on initial process stack
Code running on the initial UML stack can't receive or process signals since current must be valid when IRQs are handled, and there is no current for this stack. So, instead of using UML_LONGJMP and UML_SETJMP, which are careful to save and restore signal state, and, as a side-effect, handle any deferred signals, start_idle_thread must use the bare equivalents, which don't do anything with signals. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/os-Linux/skas/process.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 5b1943dc15e9..1f39f2bf7ce9 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -494,7 +494,15 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
494 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 494 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
495 SIGVTALRM, -1); 495 SIGVTALRM, -1);
496 496
497 n = UML_SETJMP(&initial_jmpbuf); 497 /*
498 * Can't use UML_SETJMP or UML_LONGJMP here because they save
499 * and restore signals, with the possible side-effect of
500 * trying to handle any signals which came when they were
501 * blocked, which can't be done on this stack.
502 * Signals must be blocked when jumping back here and restored
503 * after returning to the jumper.
504 */
505 n = setjmp(initial_jmpbuf);
498 switch(n){ 506 switch(n){
499 case INIT_JMP_NEW_THREAD: 507 case INIT_JMP_NEW_THREAD:
500 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler; 508 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
@@ -504,7 +512,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
504 break; 512 break;
505 case INIT_JMP_CALLBACK: 513 case INIT_JMP_CALLBACK:
506 (*cb_proc)(cb_arg); 514 (*cb_proc)(cb_arg);
507 UML_LONGJMP(cb_back, 1); 515 longjmp(*cb_back, 1);
508 break; 516 break;
509 case INIT_JMP_HALT: 517 case INIT_JMP_HALT:
510 kmalloc_ok = 0; 518 kmalloc_ok = 0;
@@ -515,7 +523,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
515 default: 523 default:
516 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); 524 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
517 } 525 }
518 UML_LONGJMP(switch_buf, 1); 526 longjmp(*switch_buf, 1);
519} 527}
520 528
521void initial_thread_cb_skas(void (*proc)(void *), void *arg) 529void initial_thread_cb_skas(void (*proc)(void *), void *arg)