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-rw-r--r--arch/um/Kconfig3
-rw-r--r--arch/um/defconfig2
-rw-r--r--arch/um/include/common-offsets.h2
-rw-r--r--arch/um/include/kern_util.h3
-rw-r--r--arch/um/include/os.h1
-rw-r--r--arch/um/kernel/dyn.lds.S2
-rw-r--r--arch/um/kernel/init_task.c30
-rw-r--r--arch/um/kernel/irq.c115
-rw-r--r--arch/um/kernel/skas/process.c4
-rw-r--r--arch/um/kernel/tt/exec_kern.c2
-rw-r--r--arch/um/kernel/tt/process_kern.c2
-rw-r--r--arch/um/kernel/um_arch.c2
-rw-r--r--arch/um/kernel/uml.lds.S2
-rw-r--r--arch/um/os-Linux/signal.c50
-rw-r--r--arch/um/os-Linux/skas/process.c13
-rw-r--r--arch/um/os-Linux/sys-i386/signal.c8
-rw-r--r--arch/um/os-Linux/sys-x86_64/signal.c6
-rw-r--r--arch/um/os-Linux/util.c23
18 files changed, 206 insertions, 64 deletions
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index b9c0f307a8f..c504312219b 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -277,7 +277,8 @@ config HIGHMEM
config KERNEL_STACK_ORDER
int "Kernel stack size order"
- default 2
+ default 1 if 64BIT
+ default 0 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
diff --git a/arch/um/defconfig b/arch/um/defconfig
index f938fa82214..a54d0efecae 100644
--- a/arch/um/defconfig
+++ b/arch/um/defconfig
@@ -86,7 +86,7 @@ CONFIG_MCONSOLE=y
# CONFIG_MAGIC_SYSRQ is not set
CONFIG_NEST_LEVEL=0
# CONFIG_HIGHMEM is not set
-CONFIG_KERNEL_STACK_ORDER=2
+CONFIG_KERNEL_STACK_ORDER=0
CONFIG_UML_REAL_TIME_CLOCK=y
#
diff --git a/arch/um/include/common-offsets.h b/arch/um/include/common-offsets.h
index 5593a802708..541f4a8ca51 100644
--- a/arch/um/include/common-offsets.h
+++ b/arch/um/include/common-offsets.h
@@ -28,3 +28,5 @@ DEFINE(UM_NR_CPUS, NR_CPUS);
/* For crypto assembler code. */
DEFINE(crypto_tfm_ctx_offset, offsetof(struct crypto_tfm, __crt_ctx));
+
+DEFINE(UM_THREAD_SIZE, THREAD_SIZE);
diff --git a/arch/um/include/kern_util.h b/arch/um/include/kern_util.h
index 50a49691e0e..8d7f7c1cb9c 100644
--- a/arch/um/include/kern_util.h
+++ b/arch/um/include/kern_util.h
@@ -117,4 +117,7 @@ extern void sigio_handler(int sig, union uml_pt_regs *regs);
extern void copy_sc(union uml_pt_regs *regs, void *from);
+unsigned long to_irq_stack(int sig, unsigned long *mask_out);
+unsigned long from_irq_stack(int nested);
+
#endif
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 688d181b5f8..4d9fb26387d 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -272,7 +272,6 @@ extern void do_longjmp(void *p, int val);
/* util.c */
extern void stack_protections(unsigned long address);
-extern void task_protections(unsigned long address);
extern int raw(int fd);
extern void setup_machinename(char *machine_out);
extern void setup_hostinfo(char *buf, int len);
diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S
index e36f92b463c..87a4e4427d8 100644
--- a/arch/um/kernel/dyn.lds.S
+++ b/arch/um/kernel/dyn.lds.S
@@ -97,6 +97,8 @@ SECTIONS
.data : {
. = ALIGN(KERNEL_STACK_SIZE); /* init_task */
*(.data.init_task)
+ . = ALIGN(KERNEL_STACK_SIZE);
+ *(.data.init_irqstack)
*(.data .data.* .gnu.linkonce.d.*)
SORT(CONSTRUCTORS)
}
diff --git a/arch/um/kernel/init_task.c b/arch/um/kernel/init_task.c
index cda91aa8e70..d4f1d1ab252 100644
--- a/arch/um/kernel/init_task.c
+++ b/arch/um/kernel/init_task.c
@@ -1,5 +1,5 @@
-/*
- * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,intel.linux}.com)
* Licensed under the GPL
*/
@@ -33,28 +33,20 @@ EXPORT_SYMBOL(init_task);
/*
* Initial thread structure.
*
- * We need to make sure that this is 16384-byte aligned due to the
+ * We need to make sure that this is aligned due to the
* way process stacks are handled. This is done by having a special
* "init_task" linker map entry..
*/
-union thread_union init_thread_union
-__attribute__((__section__(".data.init_task"))) =
-{ INIT_THREAD_INFO(init_task) };
+union thread_union init_thread_union
+ __attribute__((__section__(".data.init_task"))) =
+ { INIT_THREAD_INFO(init_task) };
+
+union thread_union cpu0_irqstack
+ __attribute__((__section__(".data.init_irqstack"))) =
+ { INIT_THREAD_INFO(init_task) };
void unprotect_stack(unsigned long stack)
{
- os_protect_memory((void *) stack, (1 << CONFIG_KERNEL_STACK_ORDER) * PAGE_SIZE,
- 1, 1, 0);
+ os_protect_memory((void *) stack, THREAD_SIZE, 1, 1, 0);
}
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 8f2ed369031..dba04d88b43 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -1,4 +1,4 @@
-/*
+/*
* Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
* Derived (i.e. mostly copied) from arch/i386/kernel/irq.c:
@@ -32,6 +32,7 @@
#include "sigio.h"
#include "um_malloc.h"
#include "misc_constants.h"
+#include "as-layout.h"
/*
* Generic, controller-independent functions:
@@ -53,7 +54,7 @@ int show_interrupts(struct seq_file *p, void *v)
if (i < NR_IRQS) {
spin_lock_irqsave(&irq_desc[i].lock, flags);
action = irq_desc[i].action;
- if (!action)
+ if (!action)
goto skip;
seq_printf(p, "%3d: ",i);
#ifndef CONFIG_SMP
@@ -468,3 +469,113 @@ int init_aio_irq(int irq, char *name, irq_handler_t handler)
out:
return err;
}
+
+/*
+ * 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(int sig, unsigned long *mask_out)
+{
+ struct thread_info *ti;
+ unsigned long mask, old;
+ int nested;
+
+ mask = xchg(&pending_mask, 1 << sig);
+ 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 = 1 << sig;
+ 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/skas/process.c b/arch/um/kernel/skas/process.c
index a96ae1a0610..2a69a7ce579 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -163,8 +163,12 @@ static int start_kernel_proc(void *unused)
extern int userspace_pid[];
+extern char cpu0_irqstack[];
+
int start_uml_skas(void)
{
+ stack_protections((unsigned long) &cpu0_irqstack);
+ set_sigstack(cpu0_irqstack, THREAD_SIZE);
if(proc_mm)
userspace_pid[0] = start_userspace(0);
diff --git a/arch/um/kernel/tt/exec_kern.c b/arch/um/kernel/tt/exec_kern.c
index 98e21743e60..40126cb5180 100644
--- a/arch/um/kernel/tt/exec_kern.c
+++ b/arch/um/kernel/tt/exec_kern.c
@@ -57,7 +57,7 @@ void flush_thread_tt(void)
enable_timer();
free_page(stack);
protect_memory(uml_reserved, high_physmem - uml_reserved, 1, 1, 0, 1);
- task_protections((unsigned long) current_thread);
+ stack_protections((unsigned long) current_thread);
force_flush_all();
unblock_signals();
}
diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c
index c631303cb80..74347adf81b 100644
--- a/arch/um/kernel/tt/process_kern.c
+++ b/arch/um/kernel/tt/process_kern.c
@@ -209,7 +209,7 @@ void finish_fork_handler(int sig)
if(current->mm != current->parent->mm)
protect_memory(uml_reserved, high_physmem - uml_reserved, 1,
1, 0, 1);
- task_protections((unsigned long) current_thread);
+ stack_protections((unsigned long) current_thread);
free_page(current->thread.temp_stack);
local_irq_disable();
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 1cf954a47fd..ecc458fe51b 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -459,7 +459,7 @@ int __init linux_main(int argc, char **argv)
uml_postsetup();
- task_protections((unsigned long) &init_thread_info);
+ stack_protections((unsigned long) &init_thread_info);
os_flush_stdout();
return CHOOSE_MODE(start_uml_tt(), start_uml_skas());
diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S
index f6301274cf3..bc59f97e34d 100644
--- a/arch/um/kernel/uml.lds.S
+++ b/arch/um/kernel/uml.lds.S
@@ -59,6 +59,8 @@ SECTIONS
{
. = ALIGN(KERNEL_STACK_SIZE); /* init_task */
*(.data.init_task)
+ . = ALIGN(KERNEL_STACK_SIZE);
+ *(.data.init_irqstack)
*(.data)
*(.gnu.linkonce.d*)
CONSTRUCTORS
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 48d49341530..18e5c8b67eb 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -61,15 +61,19 @@ void sig_handler(int sig, struct sigcontext *sc)
static void real_alarm_handler(int sig, struct sigcontext *sc)
{
+ union uml_pt_regs regs;
+
if(sig == SIGALRM)
switch_timers(0);
- CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
- sig, sc);
+ if(sc != NULL)
+ copy_sc(&regs, sc);
+ regs.skas.is_user = 0;
+ unblock_signals();
+ timer_handler(sig, &regs);
if(sig == SIGALRM)
switch_timers(1);
-
}
void alarm_handler(int sig, struct sigcontext *sc)
@@ -113,6 +117,46 @@ void remove_sigstack(void)
void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
+void handle_signal(int sig, struct sigcontext *sc)
+{
+ unsigned long pending = 0;
+
+ 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(sig, &pending);
+ if(bail)
+ return;
+
+ nested = pending & 1;
+ pending &= ~1;
+
+ while((sig = ffs(pending)) != 0){
+ sig--;
+ pending &= ~(1 << sig);
+ (*handlers[sig])(sig, sc);
+ }
+
+ /* 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);
+}
+
extern void hard_handler(int sig);
void set_handler(int sig, void (*handler)(int), int flags, ...)
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 6a0e466d01e..f9d2f8545af 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -288,7 +288,8 @@ int start_userspace(unsigned long stub_stack)
void userspace(union uml_pt_regs *regs)
{
int err, status, op, pid = userspace_pid[0];
- int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
+ /* To prevent races if using_sysemu changes under us.*/
+ int local_using_sysemu;
while(1){
restore_registers(pid, regs);
@@ -296,7 +297,8 @@ void userspace(union uml_pt_regs *regs)
/* Now we set local_using_sysemu to be used for one loop */
local_using_sysemu = get_using_sysemu();
- op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL));
+ op = SELECT_PTRACE_OPERATION(local_using_sysemu,
+ singlestepping(NULL));
err = ptrace(op, pid, 0, 0);
if(err)
@@ -490,8 +492,8 @@ void map_stub_pages(int fd, unsigned long code,
void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
{
(*buf)[0].JB_IP = (unsigned long) handler;
- (*buf)[0].JB_SP = (unsigned long) stack +
- (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) - sizeof(void *);
+ (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
+ sizeof(void *);
}
#define INIT_JMP_NEW_THREAD 0
@@ -533,8 +535,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
case INIT_JMP_NEW_THREAD:
(*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
(*switch_buf)[0].JB_SP = (unsigned long) stack +
- (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) -
- sizeof(void *);
+ UM_THREAD_SIZE - sizeof(void *);
break;
case INIT_JMP_CALLBACK:
(*cb_proc)(cb_arg);
diff --git a/arch/um/os-Linux/sys-i386/signal.c b/arch/um/os-Linux/sys-i386/signal.c
index 0d3eae51835..f311609f93d 100644
--- a/arch/um/os-Linux/sys-i386/signal.c
+++ b/arch/um/os-Linux/sys-i386/signal.c
@@ -1,15 +1,13 @@
/*
- * Copyright (C) 2006 Jeff Dike (jdike@addtoit.com)
+ * Copyright (C) 2006 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <signal.h>
-extern void (*handlers[])(int sig, struct sigcontext *sc);
+extern void handle_signal(int sig, struct sigcontext *sc);
void hard_handler(int sig)
{
- struct sigcontext *sc = (struct sigcontext *) (&sig + 1);
-
- (*handlers[sig])(sig, sc);
+ handle_signal(sig, (struct sigcontext *) (&sig + 1));
}
diff --git a/arch/um/os-Linux/sys-x86_64/signal.c b/arch/um/os-Linux/sys-x86_64/signal.c
index 3f369e5f976..82a388822cd 100644
--- a/arch/um/os-Linux/sys-x86_64/signal.c
+++ b/arch/um/os-Linux/sys-x86_64/signal.c
@@ -1,16 +1,16 @@
/*
- * Copyright (C) 2006 Jeff Dike (jdike@addtoit.com)
+ * Copyright (C) 2006 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <signal.h>
-extern void (*handlers[])(int sig, struct sigcontext *sc);
+extern void handle_signal(int sig, struct sigcontext *sc);
void hard_handler(int sig)
{
struct ucontext *uc;
asm("movq %%rdx, %0" : "=r" (uc));
- (*handlers[sig])(sig, (struct sigcontext *) &uc->uc_mcontext);
+ handle_signal(sig, (struct sigcontext *) &uc->uc_mcontext);
}
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index c307a89ed25..7cbcf484e13 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -33,25 +33,8 @@
void stack_protections(unsigned long address)
{
- int prot = PROT_READ | PROT_WRITE | PROT_EXEC;
-
- if(mprotect((void *) address, UM_KERN_PAGE_SIZE, prot) < 0)
- panic("protecting stack failed, errno = %d", errno);
-}
-
-void task_protections(unsigned long address)
-{
- unsigned long guard = address + UM_KERN_PAGE_SIZE;
- unsigned long stack = guard + UM_KERN_PAGE_SIZE;
- int prot = 0, pages;
-
-#ifdef notdef
- if(mprotect((void *) stack, UM_KERN_PAGE_SIZE, prot) < 0)
- panic("protecting guard page failed, errno = %d", errno);
-#endif
- pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER) - 2;
- prot = PROT_READ | PROT_WRITE | PROT_EXEC;
- if(mprotect((void *) stack, pages * UM_KERN_PAGE_SIZE, prot) < 0)
+ if(mprotect((void *) address, UM_THREAD_SIZE,
+ PROT_READ | PROT_WRITE | PROT_EXEC) < 0)
panic("protecting stack failed, errno = %d", errno);
}
@@ -72,7 +55,7 @@ int raw(int fd)
/* XXX tcsetattr could have applied only some changes
* (and cfmakeraw() is a set of changes) */
- return(0);
+ return 0;
}
void setup_machinename(char *machine_out)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 18:09:53 +0000