aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/mm/fault.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r--arch/x86/mm/fault.c110
1 files changed, 64 insertions, 46 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 4c4508e8a204..7d90ceb882a4 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -11,6 +11,7 @@
#include <linux/kprobes.h> /* __kprobes, ... */
#include <linux/mmiotrace.h> /* kmmio_handler, ... */
#include <linux/perf_event.h> /* perf_sw_event */
+#include <linux/hugetlb.h> /* hstate_index_to_shift */
#include <asm/traps.h> /* dotraplinkage, ... */
#include <asm/pgalloc.h> /* pgd_*(), ... */
@@ -160,15 +161,20 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
static void
force_sig_info_fault(int si_signo, int si_code, unsigned long address,
- struct task_struct *tsk)
+ struct task_struct *tsk, int fault)
{
+ unsigned lsb = 0;
siginfo_t info;
info.si_signo = si_signo;
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = (void __user *)address;
- info.si_addr_lsb = si_code == BUS_MCEERR_AR ? PAGE_SHIFT : 0;
+ if (fault & VM_FAULT_HWPOISON_LARGE)
+ lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
+ if (fault & VM_FAULT_HWPOISON)
+ lsb = PAGE_SHIFT;
+ info.si_addr_lsb = lsb;
force_sig_info(si_signo, &info, tsk);
}
@@ -229,7 +235,16 @@ void vmalloc_sync_all(void)
spin_lock_irqsave(&pgd_lock, flags);
list_for_each_entry(page, &pgd_list, lru) {
- if (!vmalloc_sync_one(page_address(page), address))
+ spinlock_t *pgt_lock;
+ pmd_t *ret;
+
+ pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
+
+ spin_lock(pgt_lock);
+ ret = vmalloc_sync_one(page_address(page), address);
+ spin_unlock(pgt_lock);
+
+ if (!ret)
break;
}
spin_unlock_irqrestore(&pgd_lock, flags);
@@ -251,6 +266,8 @@ static noinline __kprobes int vmalloc_fault(unsigned long address)
if (!(address >= VMALLOC_START && address < VMALLOC_END))
return -1;
+ WARN_ON_ONCE(in_nmi());
+
/*
* Synchronize this task's top level page-table
* with the 'reference' page table.
@@ -326,29 +343,7 @@ out:
void vmalloc_sync_all(void)
{
- unsigned long address;
-
- for (address = VMALLOC_START & PGDIR_MASK; address <= VMALLOC_END;
- address += PGDIR_SIZE) {
-
- const pgd_t *pgd_ref = pgd_offset_k(address);
- unsigned long flags;
- struct page *page;
-
- if (pgd_none(*pgd_ref))
- continue;
-
- spin_lock_irqsave(&pgd_lock, flags);
- list_for_each_entry(page, &pgd_list, lru) {
- pgd_t *pgd;
- pgd = (pgd_t *)page_address(page) + pgd_index(address);
- if (pgd_none(*pgd))
- set_pgd(pgd, *pgd_ref);
- else
- BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
- }
- spin_unlock_irqrestore(&pgd_lock, flags);
- }
+ sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END);
}
/*
@@ -369,6 +364,8 @@ static noinline __kprobes int vmalloc_fault(unsigned long address)
if (!(address >= VMALLOC_START && address < VMALLOC_END))
return -1;
+ WARN_ON_ONCE(in_nmi());
+
/*
* Copy kernel mappings over when needed. This can also
* happen within a race in page table update. In the later
@@ -731,7 +728,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
tsk->thread.error_code = error_code | (address >= TASK_SIZE);
tsk->thread.trap_no = 14;
- force_sig_info_fault(SIGSEGV, si_code, address, tsk);
+ force_sig_info_fault(SIGSEGV, si_code, address, tsk, 0);
return;
}
@@ -816,14 +813,14 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
tsk->thread.trap_no = 14;
#ifdef CONFIG_MEMORY_FAILURE
- if (fault & VM_FAULT_HWPOISON) {
+ if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
printk(KERN_ERR
"MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
tsk->comm, tsk->pid, address);
code = BUS_MCEERR_AR;
}
#endif
- force_sig_info_fault(SIGBUS, code, address, tsk);
+ force_sig_info_fault(SIGBUS, code, address, tsk, fault);
}
static noinline void
@@ -833,7 +830,8 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
if (fault & VM_FAULT_OOM) {
out_of_memory(regs, error_code, address);
} else {
- if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON))
+ if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
+ VM_FAULT_HWPOISON_LARGE))
do_sigbus(regs, error_code, address, fault);
else
BUG();
@@ -894,8 +892,14 @@ spurious_fault(unsigned long error_code, unsigned long address)
if (pmd_large(*pmd))
return spurious_fault_check(error_code, (pte_t *) pmd);
+ /*
+ * Note: don't use pte_present() here, since it returns true
+ * if the _PAGE_PROTNONE bit is set. However, this aliases the
+ * _PAGE_GLOBAL bit, which for kernel pages give false positives
+ * when CONFIG_DEBUG_PAGEALLOC is used.
+ */
pte = pte_offset_kernel(pmd, address);
- if (!pte_present(*pte))
+ if (!(pte_flags(*pte) & _PAGE_PRESENT))
return 0;
ret = spurious_fault_check(error_code, pte);
@@ -915,9 +919,9 @@ spurious_fault(unsigned long error_code, unsigned long address)
int show_unhandled_signals = 1;
static inline int
-access_error(unsigned long error_code, int write, struct vm_area_struct *vma)
+access_error(unsigned long error_code, struct vm_area_struct *vma)
{
- if (write) {
+ if (error_code & PF_WRITE) {
/* write, present and write, not present: */
if (unlikely(!(vma->vm_flags & VM_WRITE)))
return 1;
@@ -952,8 +956,10 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
struct task_struct *tsk;
unsigned long address;
struct mm_struct *mm;
- int write;
int fault;
+ int write = error_code & PF_WRITE;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY |
+ (write ? FAULT_FLAG_WRITE : 0);
tsk = current;
mm = tsk->mm;
@@ -1064,6 +1070,7 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
bad_area_nosemaphore(regs, error_code, address);
return;
}
+retry:
down_read(&mm->mmap_sem);
} else {
/*
@@ -1107,9 +1114,7 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
* we can handle it..
*/
good_area:
- write = error_code & PF_WRITE;
-
- if (unlikely(access_error(error_code, write, vma))) {
+ if (unlikely(access_error(error_code, vma))) {
bad_area_access_error(regs, error_code, address);
return;
}
@@ -1119,21 +1124,34 @@ good_area:
* make sure we exit gracefully rather than endlessly redo
* the fault:
*/
- fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
+ fault = handle_mm_fault(mm, vma, address, flags);
if (unlikely(fault & VM_FAULT_ERROR)) {
mm_fault_error(regs, error_code, address, fault);
return;
}
- if (fault & VM_FAULT_MAJOR) {
- tsk->maj_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0,
- regs, address);
- } else {
- tsk->min_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0,
- regs, address);
+ /*
+ * Major/minor page fault accounting is only done on the
+ * initial attempt. If we go through a retry, it is extremely
+ * likely that the page will be found in page cache at that point.
+ */
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR) {
+ tsk->maj_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0,
+ regs, address);
+ } else {
+ tsk->min_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0,
+ regs, address);
+ }
+ if (fault & VM_FAULT_RETRY) {
+ /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
+ * of starvation. */
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+ goto retry;
+ }
}
check_v8086_mode(regs, address, tsk);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.