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Diffstat (limited to 'arch/um/kernel/trap.c')
-rw-r--r--arch/um/kernel/trap.c157
1 files changed, 114 insertions, 43 deletions
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 44e49041949..5678c3571e7 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -6,15 +6,15 @@
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/hardirq.h>
+#include <linux/module.h>
#include <asm/current.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
-#include "arch.h"
-#include "as-layout.h"
-#include "kern_util.h"
-#include "os.h"
-#include "skas.h"
-#include "sysdep/sigcontext.h"
+#include <arch.h>
+#include <as-layout.h>
+#include <kern_util.h>
+#include <os.h>
+#include <skas.h>
/*
* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by
@@ -30,6 +30,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
pmd_t *pmd;
pte_t *pte;
int err = -EFAULT;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
*code_out = SEGV_MAPERR;
@@ -40,6 +41,9 @@ int handle_page_fault(unsigned long address, unsigned long ip,
if (in_atomic())
goto out_nosemaphore;
+ if (is_user)
+ flags |= FAULT_FLAG_USER;
+retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
@@ -55,20 +59,26 @@ int handle_page_fault(unsigned long address, unsigned long ip,
good_area:
*code_out = SEGV_ACCERR;
- if (is_write && !(vma->vm_flags & VM_WRITE))
- goto out;
-
- /* Don't require VM_READ|VM_EXEC for write faults! */
- if (!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC)))
- goto out;
+ if (is_write) {
+ if (!(vma->vm_flags & VM_WRITE))
+ goto out;
+ flags |= FAULT_FLAG_WRITE;
+ } else {
+ /* Don't require VM_READ|VM_EXEC for write faults! */
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+ goto out;
+ }
do {
int fault;
-survive:
- fault = handle_mm_fault(mm, vma, address, is_write);
+
+ fault = handle_mm_fault(mm, vma, address, flags);
+
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ goto out_nosemaphore;
+
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM) {
- err = -ENOMEM;
goto out_of_memory;
} else if (fault & VM_FAULT_SIGBUS) {
err = -EACCES;
@@ -76,10 +86,18 @@ survive:
}
BUG();
}
- if (fault & VM_FAULT_MAJOR)
- current->maj_flt++;
- else
- current->min_flt++;
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ current->maj_flt++;
+ else
+ current->min_flt++;
+ if (fault & VM_FAULT_RETRY) {
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+ flags |= FAULT_FLAG_TRIED;
+
+ goto retry;
+ }
+ }
pgd = pgd_offset(mm, address);
pud = pud_offset(pgd, address);
@@ -104,18 +122,38 @@ out:
out_nosemaphore:
return err;
-/*
- * We ran out of memory, or some other thing happened to us that made
- * us unable to handle the page fault gracefully.
- */
out_of_memory:
- if (is_global_init(current)) {
- up_read(&mm->mmap_sem);
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- goto out;
+ /*
+ * We ran out of memory, call the OOM killer, and return the userspace
+ * (which will retry the fault, or kill us if we got oom-killed).
+ */
+ up_read(&mm->mmap_sem);
+ if (!is_user)
+ goto out_nosemaphore;
+ pagefault_out_of_memory();
+ return 0;
+}
+EXPORT_SYMBOL(handle_page_fault);
+
+static void show_segv_info(struct uml_pt_regs *regs)
+{
+ struct task_struct *tsk = current;
+ struct faultinfo *fi = UPT_FAULTINFO(regs);
+
+ if (!unhandled_signal(tsk, SIGSEGV))
+ return;
+
+ if (!printk_ratelimit())
+ return;
+
+ printk("%s%s[%d]: segfault at %lx ip %p sp %p error %x",
+ task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+ tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi),
+ (void *)UPT_IP(regs), (void *)UPT_SP(regs),
+ fi->error_code);
+
+ print_vma_addr(KERN_CONT " in ", UPT_IP(regs));
+ printk(KERN_CONT "\n");
}
static void bad_segv(struct faultinfo fi, unsigned long ip)
@@ -141,11 +179,12 @@ void fatal_sigsegv(void)
os_dump_core();
}
-void segv_handler(int sig, struct uml_pt_regs *regs)
+void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
{
struct faultinfo * fi = UPT_FAULTINFO(regs);
if (UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)) {
+ show_segv_info(regs);
bad_segv(*fi, UPT_IP(regs));
return;
}
@@ -167,9 +206,12 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
int is_write = FAULT_WRITE(fi);
unsigned long address = FAULT_ADDRESS(fi);
+ if (!is_user && regs)
+ current->thread.segv_regs = container_of(regs, struct pt_regs, regs);
+
if (!is_user && (address >= start_vm) && (address < end_vm)) {
flush_tlb_kernel_vm();
- return 0;
+ goto out;
}
else if (current->mm == NULL) {
show_regs(container_of(regs, struct pt_regs, regs));
@@ -191,7 +233,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
catcher = current->thread.fault_catcher;
if (!err)
- return 0;
+ goto out;
else if (catcher != NULL) {
current->thread.fault_addr = (void *) address;
UML_LONGJMP(catcher, 1);
@@ -199,7 +241,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
else if (current->thread.fault_addr != NULL)
panic("fault_addr set but no fault catcher");
else if (!is_user && arch_fixup(ip, regs))
- return 0;
+ goto out;
if (!is_user) {
show_regs(container_of(regs, struct pt_regs, regs));
@@ -207,6 +249,8 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
address, ip);
}
+ show_segv_info(regs);
+
if (err == -EACCES) {
si.si_signo = SIGBUS;
si.si_errno = 0;
@@ -214,9 +258,6 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
si.si_addr = (void __user *)address;
current->thread.arch.faultinfo = fi;
force_sig_info(SIGBUS, &si, current);
- } else if (err == -ENOMEM) {
- printk(KERN_INFO "VM: killing process %s\n", current->comm);
- do_exit(SIGKILL);
} else {
BUG_ON(err != -EFAULT);
si.si_signo = SIGSEGV;
@@ -224,11 +265,19 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
current->thread.arch.faultinfo = fi;
force_sig_info(SIGSEGV, &si, current);
}
+
+out:
+ if (regs)
+ current->thread.segv_regs = NULL;
+
return 0;
}
-void relay_signal(int sig, struct uml_pt_regs *regs)
+void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
{
+ struct faultinfo *fi;
+ struct siginfo clean_si;
+
if (!UPT_IS_USER(regs)) {
if (sig == SIGBUS)
printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
@@ -238,18 +287,40 @@ void relay_signal(int sig, struct uml_pt_regs *regs)
arch_examine_signal(sig, regs);
- current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
- force_sig(sig, current);
+ memset(&clean_si, 0, sizeof(clean_si));
+ clean_si.si_signo = si->si_signo;
+ clean_si.si_errno = si->si_errno;
+ clean_si.si_code = si->si_code;
+ switch (sig) {
+ case SIGILL:
+ case SIGFPE:
+ case SIGSEGV:
+ case SIGBUS:
+ case SIGTRAP:
+ fi = UPT_FAULTINFO(regs);
+ clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi);
+ current->thread.arch.faultinfo = *fi;
+#ifdef __ARCH_SI_TRAPNO
+ clean_si.si_trapno = si->si_trapno;
+#endif
+ break;
+ default:
+ printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
+ sig, si->si_code);
+ }
+
+ force_sig_info(sig, &clean_si, current);
}
-void bus_handler(int sig, struct uml_pt_regs *regs)
+void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs)
{
if (current->thread.fault_catcher != NULL)
UML_LONGJMP(current->thread.fault_catcher, 1);
- else relay_signal(sig, regs);
+ else
+ relay_signal(sig, si, regs);
}
-void winch(int sig, struct uml_pt_regs *regs)
+void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
{
do_IRQ(WINCH_IRQ, regs);
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-06 22:51:01 +0000