[PATCH 27/64] arch/{x86,sh,ppc}: teach bad_area() about range locking
From: Davidlohr Bueso
Date: Sun Feb 04 2018 - 20:38:07 EST
From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Such architectures will drop the mmap_sem inside __bad_area(),
which in turn calls bad_area_nosemaphore(). The rest of the
archs will implement this logic within do_page_fault(), so
they remain unchanged as we already have the mmrange.
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
arch/powerpc/mm/fault.c | 32 +++++++++++++++++---------------
arch/sh/mm/fault.c | 47 ++++++++++++++++++++++++++---------------------
arch/x86/mm/fault.c | 35 ++++++++++++++++++++---------------
3 files changed, 63 insertions(+), 51 deletions(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index d562dc88687d..80e4cf0e4c3b 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -129,7 +129,7 @@ static noinline int bad_area_nosemaphore(struct pt_regs *regs, unsigned long add
}
static int __bad_area(struct pt_regs *regs, unsigned long address, int si_code,
- int pkey)
+ int pkey, struct range_lock *mmrange)
{
struct mm_struct *mm = current->mm;
@@ -137,14 +137,15 @@ static int __bad_area(struct pt_regs *regs, unsigned long address, int si_code,
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, mmrange);
return __bad_area_nosemaphore(regs, address, si_code, pkey);
}
-static noinline int bad_area(struct pt_regs *regs, unsigned long address)
+static noinline int bad_area(struct pt_regs *regs, unsigned long address,
+ struct range_lock *mmrange)
{
- return __bad_area(regs, address, SEGV_MAPERR, 0);
+ return __bad_area(regs, address, SEGV_MAPERR, 0, mmrange);
}
static int bad_key_fault_exception(struct pt_regs *regs, unsigned long address,
@@ -153,9 +154,10 @@ static int bad_key_fault_exception(struct pt_regs *regs, unsigned long address,
return __bad_area_nosemaphore(regs, address, SEGV_PKUERR, pkey);
}
-static noinline int bad_access(struct pt_regs *regs, unsigned long address)
+static noinline int bad_access(struct pt_regs *regs, unsigned long address,
+ struct range_lock *mmrange)
{
- return __bad_area(regs, address, SEGV_ACCERR, 0);
+ return __bad_area(regs, address, SEGV_ACCERR, 0, mmrange);
}
static int do_sigbus(struct pt_regs *regs, unsigned long address,
@@ -475,12 +477,12 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
* source. If this is invalid we can skip the address space check,
* thus avoiding the deadlock.
*/
- if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
+ if (unlikely(!mm_read_trylock(mm, &mmrange))) {
if (!is_user && !search_exception_tables(regs->nip))
return bad_area_nosemaphore(regs, address);
retry:
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
} else {
/*
* The above down_read_trylock() might have succeeded in
@@ -492,23 +494,23 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
vma = find_vma(mm, address);
if (unlikely(!vma))
- return bad_area(regs, address);
+ return bad_area(regs, address, &mmrange);
if (likely(vma->vm_start <= address))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN)))
- return bad_area(regs, address);
+ return bad_area(regs, address, &mmrange);
/* The stack is being expanded, check if it's valid */
if (unlikely(bad_stack_expansion(regs, address, vma, store_update_sp)))
- return bad_area(regs, address);
+ return bad_area(regs, address, &mmrange);
/* Try to expand it */
if (unlikely(expand_stack(vma, address)))
- return bad_area(regs, address);
+ return bad_area(regs, address, &mmrange);
good_area:
if (unlikely(access_error(is_write, is_exec, vma)))
- return bad_access(regs, address);
+ return bad_access(regs, address, &mmrange);
/*
* If for any reason at all we couldn't handle the fault,
@@ -535,7 +537,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
int pkey = vma_pkey(vma);
if (likely(pkey)) {
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
return bad_key_fault_exception(regs, address, pkey);
}
}
@@ -567,7 +569,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
return is_user ? 0 : SIGBUS;
}
- up_read(¤t->mm->mmap_sem);
+ mm_read_unlock(current->mm, &mmrange);
if (unlikely(fault & VM_FAULT_ERROR))
return mm_fault_error(regs, address, fault);
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index d36106564728..a9f75dc1abb3 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -277,7 +277,8 @@ bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
static void
__bad_area(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, int si_code)
+ unsigned long address, int si_code,
+ struct range_lock *mmrange)
{
struct mm_struct *mm = current->mm;
@@ -285,31 +286,34 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, mmrange);
__bad_area_nosemaphore(regs, error_code, address, si_code);
}
static noinline void
-bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address,
+ struct range_lock *mmrange)
{
- __bad_area(regs, error_code, address, SEGV_MAPERR);
+ __bad_area(regs, error_code, address, SEGV_MAPERR, mmrange);
}
static noinline void
bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address)
+ unsigned long address,
+ struct range_lock *mmrange)
{
- __bad_area(regs, error_code, address, SEGV_ACCERR);
+ __bad_area(regs, error_code, address, SEGV_ACCERR, mmrange);
}
static void
-do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
+ struct range_lock *mmrange)
{
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, mmrange);
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs))
@@ -320,7 +324,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
static noinline int
mm_fault_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, unsigned int fault)
+ unsigned long address, unsigned int fault,
+ struct range_lock *mmrange)
{
/*
* Pagefault was interrupted by SIGKILL. We have no reason to
@@ -328,7 +333,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
*/
if (fatal_signal_pending(current)) {
if (!(fault & VM_FAULT_RETRY))
- up_read(¤t->mm->mmap_sem);
+ mm_read_unlock(current->mm, mmrange);
if (!user_mode(regs))
no_context(regs, error_code, address);
return 1;
@@ -340,11 +345,11 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
if (fault & VM_FAULT_OOM) {
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs)) {
- up_read(¤t->mm->mmap_sem);
+ mm_read_unlock(current->mm, mmrange);
no_context(regs, error_code, address);
return 1;
}
- up_read(¤t->mm->mmap_sem);
+ mm_read_unlock(current->mm, mmrange);
/*
* We ran out of memory, call the OOM killer, and return the
@@ -354,9 +359,9 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
pagefault_out_of_memory();
} else {
if (fault & VM_FAULT_SIGBUS)
- do_sigbus(regs, error_code, address);
+ do_sigbus(regs, error_code, address, mmrange);
else if (fault & VM_FAULT_SIGSEGV)
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, mmrange);
else
BUG();
}
@@ -449,21 +454,21 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
}
retry:
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
vma = find_vma(mm, address);
if (unlikely(!vma)) {
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, &mmrange);
return;
}
if (likely(vma->vm_start <= address))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, &mmrange);
return;
}
if (unlikely(expand_stack(vma, address))) {
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, &mmrange);
return;
}
@@ -473,7 +478,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
*/
good_area:
if (unlikely(access_error(error_code, vma))) {
- bad_area_access_error(regs, error_code, address);
+ bad_area_access_error(regs, error_code, address, &mmrange);
return;
}
@@ -492,7 +497,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
fault = handle_mm_fault(vma, address, flags, &mmrange);
if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
- if (mm_fault_error(regs, error_code, address, fault))
+ if (mm_fault_error(regs, error_code, address, fault, &mmrange))
return;
if (flags & FAULT_FLAG_ALLOW_RETRY) {
@@ -518,5 +523,5 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
}
}
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
}
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 93f1b8d4c88e..87bdcb26a907 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -937,7 +937,8 @@ bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
static void
__bad_area(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma, int si_code)
+ unsigned long address, struct vm_area_struct *vma, int si_code,
+ struct range_lock *mmrange)
{
struct mm_struct *mm = current->mm;
u32 pkey;
@@ -949,16 +950,17 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, mmrange);
__bad_area_nosemaphore(regs, error_code, address,
(vma) ? &pkey : NULL, si_code);
}
static noinline void
-bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address,
+ struct range_lock *mmrange)
{
- __bad_area(regs, error_code, address, NULL, SEGV_MAPERR);
+ __bad_area(regs, error_code, address, NULL, SEGV_MAPERR, mmrange);
}
static inline bool bad_area_access_from_pkeys(unsigned long error_code,
@@ -980,7 +982,8 @@ static inline bool bad_area_access_from_pkeys(unsigned long error_code,
static noinline void
bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma)
+ unsigned long address, struct vm_area_struct *vma,
+ struct range_lock *mmrange)
{
/*
* This OSPKE check is not strictly necessary at runtime.
@@ -988,9 +991,11 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
* if pkeys are compiled out.
*/
if (bad_area_access_from_pkeys(error_code, vma))
- __bad_area(regs, error_code, address, vma, SEGV_PKUERR);
+ __bad_area(regs, error_code, address, vma, SEGV_PKUERR,
+ mmrange);
else
- __bad_area(regs, error_code, address, vma, SEGV_ACCERR);
+ __bad_area(regs, error_code, address, vma, SEGV_ACCERR,
+ mmrange);
}
static void
@@ -1353,14 +1358,14 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
* validate the source. If this is invalid we can skip the address
* space check, thus avoiding the deadlock:
*/
- if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
+ if (unlikely(!mm_read_trylock(mm, &mmrange))) {
if (!(error_code & X86_PF_USER) &&
!search_exception_tables(regs->ip)) {
bad_area_nosemaphore(regs, error_code, address, NULL);
return;
}
retry:
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
} else {
/*
* The above down_read_trylock() might have succeeded in
@@ -1372,13 +1377,13 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
vma = find_vma(mm, address);
if (unlikely(!vma)) {
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, &mmrange);
return;
}
if (likely(vma->vm_start <= address))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, &mmrange);
return;
}
if (error_code & X86_PF_USER) {
@@ -1389,12 +1394,12 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
* 32 pointers and then decrements %sp by 65535.)
*/
if (unlikely(address + 65536 + 32 * sizeof(unsigned long) < regs->sp)) {
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, &mmrange);
return;
}
}
if (unlikely(expand_stack(vma, address))) {
- bad_area(regs, error_code, address);
+ bad_area(regs, error_code, address, &mmrange);
return;
}
@@ -1404,7 +1409,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
*/
good_area:
if (unlikely(access_error(error_code, vma))) {
- bad_area_access_error(regs, error_code, address, vma);
+ bad_area_access_error(regs, error_code, address, vma, &mmrange);
return;
}
@@ -1450,7 +1455,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
return;
}
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
if (unlikely(fault & VM_FAULT_ERROR)) {
mm_fault_error(regs, error_code, address, &pkey, fault);
return;
--
2.13.6