diff options
| -rw-r--r-- | arch/um/Kconfig | 10 | ||||
| -rw-r--r-- | arch/um/os-Linux/signal.c | 28 |
2 files changed, 15 insertions, 23 deletions
diff --git a/arch/um/Kconfig b/arch/um/Kconfig index ec9711d068b7..41913504a56e 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -142,13 +142,17 @@ config MAGIC_SYSRQ config KERNEL_STACK_ORDER int "Kernel stack size order" - default 1 if 64BIT - range 1 10 if 64BIT - default 0 if !64BIT + default 2 if 64BIT + range 2 10 if 64BIT + default 1 if !64BIT help This option determines the size of UML kernel stacks. They will be 1 << order pages. The default is OK unless you're running Valgrind on UML, in which case, set this to 3. + It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on + older (pre-2017) CPUs. It is not recommended on newer CPUs due to the + increase in the size of the state which needs to be saved when handling + signals. config MMAPPER tristate "iomem emulation driver" diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c index bf0acb8aad8b..75b10235d369 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -31,29 +31,23 @@ void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = { static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc) { - struct uml_pt_regs *r; + struct uml_pt_regs r; int save_errno = errno; - r = uml_kmalloc(sizeof(struct uml_pt_regs), UM_GFP_ATOMIC); - if (!r) - panic("out of memory"); - - r->is_user = 0; + r.is_user = 0; if (sig == SIGSEGV) { /* For segfaults, we want the data from the sigcontext. */ - get_regs_from_mc(r, mc); - GET_FAULTINFO_FROM_MC(r->faultinfo, mc); + get_regs_from_mc(&r, mc); + GET_FAULTINFO_FROM_MC(r.faultinfo, mc); } /* enable signals if sig isn't IRQ signal */ if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGALRM)) unblock_signals(); - (*sig_info[sig])(sig, si, r); + (*sig_info[sig])(sig, si, &r); errno = save_errno; - - free(r); } /* @@ -91,17 +85,11 @@ void sig_handler(int sig, struct siginfo *si, mcontext_t *mc) static void timer_real_alarm_handler(mcontext_t *mc) { - struct uml_pt_regs *regs; - - regs = uml_kmalloc(sizeof(struct uml_pt_regs), UM_GFP_ATOMIC); - if (!regs) - panic("out of memory"); + struct uml_pt_regs regs; if (mc != NULL) - get_regs_from_mc(regs, mc); - timer_handler(SIGALRM, NULL, regs); - - free(regs); + get_regs_from_mc(®s, mc); + timer_handler(SIGALRM, NULL, ®s); } void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc) |