diff options
| -rw-r--r-- | arch/um/Kconfig | 1 | ||||
| -rw-r--r-- | arch/um/include/asm/Kbuild | 1 | ||||
| -rw-r--r-- | arch/um/include/asm/current.h | 23 | ||||
| -rw-r--r-- | arch/um/include/asm/thread_info.h | 16 | ||||
| -rw-r--r-- | arch/um/include/shared/as-layout.h | 7 | ||||
| -rw-r--r-- | arch/um/kernel/dyn.lds.S | 2 | ||||
| -rw-r--r-- | arch/um/kernel/irq.c | 112 | ||||
| -rw-r--r-- | arch/um/kernel/process.c | 5 | ||||
| -rw-r--r-- | arch/um/kernel/skas/process.c | 4 | ||||
| -rw-r--r-- | arch/um/kernel/um_arch.c | 7 | ||||
| -rw-r--r-- | arch/um/kernel/uml.lds.S | 2 | ||||
| -rw-r--r-- | arch/um/os-Linux/signal.c | 37 |
12 files changed, 34 insertions, 183 deletions
diff --git a/arch/um/Kconfig b/arch/um/Kconfig index a9876bdb5bf9..18051b1cfce0 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -34,6 +34,7 @@ config UML select HAVE_RUST select ARCH_HAS_UBSAN select HAVE_ARCH_TRACEHOOK + select THREAD_INFO_IN_TASK config MMU bool diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild index 18f902da8e99..428f2c5158c2 100644 --- a/arch/um/include/asm/Kbuild +++ b/arch/um/include/asm/Kbuild @@ -1,7 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 generic-y += bug.h generic-y += compat.h -generic-y += current.h generic-y += device.h generic-y += dma-mapping.h generic-y += emergency-restart.h diff --git a/arch/um/include/asm/current.h b/arch/um/include/asm/current.h new file mode 100644 index 000000000000..de64e032d66c --- /dev/null +++ b/arch/um/include/asm/current.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_CURRENT_H +#define __ASM_CURRENT_H + +#include <linux/compiler.h> +#include <linux/threads.h> + +#ifndef __ASSEMBLY__ + +struct task_struct; +extern struct task_struct *cpu_tasks[NR_CPUS]; + +static __always_inline struct task_struct *get_current(void) +{ + return cpu_tasks[0]; +} + + +#define current get_current() + +#endif /* __ASSEMBLY__ */ + +#endif /* __ASM_CURRENT_H */ diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h index 4d2a768246bc..f9ad06fcc991 100644 --- a/arch/um/include/asm/thread_info.h +++ b/arch/um/include/asm/thread_info.h @@ -17,33 +17,17 @@ #include <sysdep/ptrace_user.h> struct thread_info { - struct task_struct *task; /* main task structure */ unsigned long flags; /* low level flags */ __u32 cpu; /* current CPU */ int preempt_count; /* 0 => preemptable, <0 => BUG */ - struct thread_info *real_thread; /* Points to non-IRQ stack */ }; #define INIT_THREAD_INFO(tsk) \ { \ - .task = &tsk, \ .flags = 0, \ .cpu = 0, \ .preempt_count = INIT_PREEMPT_COUNT, \ - .real_thread = NULL, \ -} - -/* how to get the thread information struct from C */ -static inline struct thread_info *current_thread_info(void) -{ - struct thread_info *ti; - unsigned long mask = THREAD_SIZE - 1; - void *p; - - asm volatile ("" : "=r" (p) : "0" (&ti)); - ti = (struct thread_info *) (((unsigned long)p) & ~mask); - return ti; } #endif diff --git a/arch/um/include/shared/as-layout.h b/arch/um/include/shared/as-layout.h index d9679c911e54..ea65f151bf48 100644 --- a/arch/um/include/shared/as-layout.h +++ b/arch/um/include/shared/as-layout.h @@ -30,11 +30,8 @@ #include <sysdep/ptrace.h> -struct cpu_task { - void *task; -}; - -extern struct cpu_task cpu_tasks[]; +struct task_struct; +extern struct task_struct *cpu_tasks[]; extern unsigned long long physmem_size; diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S index dc9d9a68af55..a36b7918a011 100644 --- a/arch/um/kernel/dyn.lds.S +++ b/arch/um/kernel/dyn.lds.S @@ -116,8 +116,6 @@ SECTIONS .fini_array : { *(.fini_array) } .data : { INIT_TASK_DATA(KERNEL_STACK_SIZE) - . = ALIGN(KERNEL_STACK_SIZE); - *(.data..init_irqstack) DATA_DATA *(.data.* .gnu.linkonce.d.*) SORT(CONSTRUCTORS) diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c index 534e91797f89..338450741aac 100644 --- a/arch/um/kernel/irq.c +++ b/arch/um/kernel/irq.c @@ -674,115 +674,3 @@ void __init init_IRQ(void) /* Initialize EPOLL Loop */ os_setup_epoll(); } - -/* - * IRQ stack entry and exit: - * - * Unlike i386, UML doesn't receive IRQs on the normal kernel stack - * and switch over to the IRQ stack after some preparation. We use - * sigaltstack to receive signals on a separate stack from the start. - * These two functions make sure the rest of the kernel won't be too - * upset by being on a different stack. The IRQ stack has a - * thread_info structure at the bottom so that current et al continue - * to work. - * - * to_irq_stack copies the current task's thread_info to the IRQ stack - * thread_info and sets the tasks's stack to point to the IRQ stack. - * - * from_irq_stack copies the thread_info struct back (flags may have - * been modified) and resets the task's stack pointer. - * - * Tricky bits - - * - * What happens when two signals race each other? UML doesn't block - * signals with sigprocmask, SA_DEFER, or sa_mask, so a second signal - * could arrive while a previous one is still setting up the - * thread_info. - * - * There are three cases - - * The first interrupt on the stack - sets up the thread_info and - * handles the interrupt - * A nested interrupt interrupting the copying of the thread_info - - * can't handle the interrupt, as the stack is in an unknown state - * A nested interrupt not interrupting the copying of the - * thread_info - doesn't do any setup, just handles the interrupt - * - * The first job is to figure out whether we interrupted stack setup. - * This is done by xchging the signal mask with thread_info->pending. - * If the value that comes back is zero, then there is no setup in - * progress, and the interrupt can be handled. If the value is - * non-zero, then there is stack setup in progress. In order to have - * the interrupt handled, we leave our signal in the mask, and it will - * be handled by the upper handler after it has set up the stack. - * - * Next is to figure out whether we are the outer handler or a nested - * one. As part of setting up the stack, thread_info->real_thread is - * set to non-NULL (and is reset to NULL on exit). This is the - * nesting indicator. If it is non-NULL, then the stack is already - * set up and the handler can run. - */ - -static unsigned long pending_mask; - -unsigned long to_irq_stack(unsigned long *mask_out) -{ - struct thread_info *ti; - unsigned long mask, old; - int nested; - - mask = xchg(&pending_mask, *mask_out); - if (mask != 0) { - /* - * If any interrupts come in at this point, we want to - * make sure that their bits aren't lost by our - * putting our bit in. So, this loop accumulates bits - * until xchg returns the same value that we put in. - * When that happens, there were no new interrupts, - * and pending_mask contains a bit for each interrupt - * that came in. - */ - old = *mask_out; - do { - old |= mask; - mask = xchg(&pending_mask, old); - } while (mask != old); - return 1; - } - - ti = current_thread_info(); - nested = (ti->real_thread != NULL); - if (!nested) { - struct task_struct *task; - struct thread_info *tti; - - task = cpu_tasks[ti->cpu].task; - tti = task_thread_info(task); - - *ti = *tti; - ti->real_thread = tti; - task->stack = ti; - } - - mask = xchg(&pending_mask, 0); - *mask_out |= mask | nested; - return 0; -} - -unsigned long from_irq_stack(int nested) -{ - struct thread_info *ti, *to; - unsigned long mask; - - ti = current_thread_info(); - - pending_mask = 1; - - to = ti->real_thread; - current->stack = to; - ti->real_thread = NULL; - *to = *ti; - - mask = xchg(&pending_mask, 0); - return mask & ~1; -} - diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c index 56e7e525fc91..30bdc0a87dc8 100644 --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -43,7 +43,8 @@ * cares about its entry, so it's OK if another processor is modifying its * entry. */ -struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { NULL } }; +struct task_struct *cpu_tasks[NR_CPUS]; +EXPORT_SYMBOL(cpu_tasks); void free_stack(unsigned long stack, int order) { @@ -64,7 +65,7 @@ unsigned long alloc_stack(int order, int atomic) static inline void set_current(struct task_struct *task) { - cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task) { task }); + cpu_tasks[task_thread_info(task)->cpu] = task; } struct task_struct *__switch_to(struct task_struct *from, struct task_struct *to) diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c index 68657988c8d1..05dcdc057af9 100644 --- a/arch/um/kernel/skas/process.c +++ b/arch/um/kernel/skas/process.c @@ -22,15 +22,13 @@ static int __init start_kernel_proc(void *unused) { block_signals_trace(); - cpu_tasks[0].task = current; - start_kernel(); return 0; } extern int userspace_pid[]; -extern char cpu0_irqstack[]; +static char cpu0_irqstack[THREAD_SIZE] __aligned(THREAD_SIZE); int __init start_uml(void) { diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index ec17576ce9fc..62ddb865eb91 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -65,9 +65,6 @@ struct cpuinfo_um boot_cpu_data = { EXPORT_SYMBOL(boot_cpu_data); -union thread_union cpu0_irqstack - __section(".data..init_irqstack") = - { .thread_info = INIT_THREAD_INFO(init_task) }; /* Changed in setup_arch, which is called in early boot */ static char host_info[(__NEW_UTS_LEN + 1) * 5]; @@ -244,6 +241,8 @@ static struct notifier_block panic_exit_notifier = { void uml_finishsetup(void) { + cpu_tasks[0] = &init_task; + atomic_notifier_chain_register(&panic_notifier_list, &panic_exit_notifier); @@ -418,7 +417,7 @@ void __init setup_arch(char **cmdline_p) { u8 rng_seed[32]; - stack_protections((unsigned long) &init_thread_info); + stack_protections((unsigned long) init_task.stack); setup_physmem(uml_physmem, uml_reserved, physmem_size); mem_total_pages(physmem_size, iomem_size); uml_dtb_init(); diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S index 5c92d58a78e8..a409d4b66114 100644 --- a/arch/um/kernel/uml.lds.S +++ b/arch/um/kernel/uml.lds.S @@ -77,8 +77,6 @@ SECTIONS .data : { INIT_TASK_DATA(KERNEL_STACK_SIZE) - . = ALIGN(KERNEL_STACK_SIZE); - *(.data..init_irqstack) DATA_DATA *(.gnu.linkonce.d*) CONSTRUCTORS diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c index 52852018a3ad..9ea7269ffb77 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -190,43 +190,8 @@ static void hard_handler(int sig, siginfo_t *si, void *p) { ucontext_t *uc = p; mcontext_t *mc = &uc->uc_mcontext; - unsigned long pending = 1UL << sig; - do { - int nested, bail; - - /* - * pending comes back with one bit set for each - * interrupt that arrived while setting up the stack, - * plus a bit for this interrupt, plus the zero bit is - * set if this is a nested interrupt. - * If bail is true, then we interrupted another - * handler setting up the stack. In this case, we - * have to return, and the upper handler will deal - * with this interrupt. - */ - bail = to_irq_stack(&pending); - if (bail) - return; - - nested = pending & 1; - pending &= ~1; - - while ((sig = ffs(pending)) != 0){ - sig--; - pending &= ~(1 << sig); - (*handlers[sig])(sig, (struct siginfo *)si, mc); - } - - /* - * Again, pending comes back with a mask of signals - * that arrived while tearing down the stack. If this - * is non-zero, we just go back, set up the stack - * again, and handle the new interrupts. - */ - if (!nested) - pending = from_irq_stack(nested); - } while (pending); + (*handlers[sig])(sig, (struct siginfo *)si, mc); } void set_handler(int sig) |