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Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r--arch/x86/mm/fault.c167
1 files changed, 58 insertions, 109 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 2b1519bc5381..b24eb4eb9984 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -157,79 +157,6 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
return prefetch;
}
-/*
- * A protection key fault means that the PKRU value did not allow
- * access to some PTE. Userspace can figure out what PKRU was
- * from the XSAVE state, and this function fills out a field in
- * siginfo so userspace can discover which protection key was set
- * on the PTE.
- *
- * If we get here, we know that the hardware signaled a X86_PF_PK
- * fault and that there was a VMA once we got in the fault
- * handler. It does *not* guarantee that the VMA we find here
- * was the one that we faulted on.
- *
- * 1. T1 : mprotect_key(foo, PAGE_SIZE, pkey=4);
- * 2. T1 : set PKRU to deny access to pkey=4, touches page
- * 3. T1 : faults...
- * 4. T2: mprotect_key(foo, PAGE_SIZE, pkey=5);
- * 5. T1 : enters fault handler, takes mmap_sem, etc...
- * 6. T1 : reaches here, sees vma_pkey(vma)=5, when we really
- * faulted on a pte with its pkey=4.
- */
-static void fill_sig_info_pkey(int si_signo, int si_code, siginfo_t *info,
- u32 *pkey)
-{
- /* This is effectively an #ifdef */
- if (!boot_cpu_has(X86_FEATURE_OSPKE))
- return;
-
- /* Fault not from Protection Keys: nothing to do */
- if ((si_code != SEGV_PKUERR) || (si_signo != SIGSEGV))
- return;
- /*
- * force_sig_info_fault() is called from a number of
- * contexts, some of which have a VMA and some of which
- * do not. The X86_PF_PK handing happens after we have a
- * valid VMA, so we should never reach this without a
- * valid VMA.
- */
- if (!pkey) {
- WARN_ONCE(1, "PKU fault with no VMA passed in");
- info->si_pkey = 0;
- return;
- }
- /*
- * si_pkey should be thought of as a strong hint, but not
- * absolutely guranteed to be 100% accurate because of
- * the race explained above.
- */
- info->si_pkey = *pkey;
-}
-
-static void
-force_sig_info_fault(int si_signo, int si_code, unsigned long address,
- struct task_struct *tsk, u32 *pkey, int fault)
-{
- unsigned lsb = 0;
- siginfo_t info;
-
- clear_siginfo(&info);
- info.si_signo = si_signo;
- info.si_errno = 0;
- info.si_code = si_code;
- info.si_addr = (void __user *)address;
- 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;
-
- fill_sig_info_pkey(si_signo, si_code, &info, pkey);
-
- force_sig_info(si_signo, &info, tsk);
-}
-
DEFINE_SPINLOCK(pgd_lock);
LIST_HEAD(pgd_list);
@@ -734,8 +661,8 @@ no_context(struct pt_regs *regs, unsigned long error_code,
tsk->thread.cr2 = address;
/* XXX: hwpoison faults will set the wrong code. */
- force_sig_info_fault(signal, si_code, address,
- tsk, NULL, 0);
+ force_sig_fault(signal, si_code, (void __user *)address,
+ tsk);
}
/*
@@ -862,7 +789,7 @@ static bool is_vsyscall_vaddr(unsigned long vaddr)
static void
__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, u32 *pkey, int si_code)
+ unsigned long address, u32 pkey, int si_code)
{
struct task_struct *tsk = current;
@@ -898,7 +825,10 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = X86_TRAP_PF;
- force_sig_info_fault(SIGSEGV, si_code, address, tsk, pkey, 0);
+ if (si_code == SEGV_PKUERR)
+ force_sig_pkuerr((void __user *)address, pkey);
+
+ force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk);
return;
}
@@ -911,35 +841,29 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
static noinline void
bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, u32 *pkey)
+ unsigned long address)
{
- __bad_area_nosemaphore(regs, error_code, address, pkey, SEGV_MAPERR);
+ __bad_area_nosemaphore(regs, error_code, address, 0, SEGV_MAPERR);
}
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, u32 pkey, int si_code)
{
struct mm_struct *mm = current->mm;
- u32 pkey;
-
- if (vma)
- pkey = vma_pkey(vma);
-
/*
* 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);
- __bad_area_nosemaphore(regs, error_code, address,
- (vma) ? &pkey : NULL, si_code);
+ __bad_area_nosemaphore(regs, error_code, address, pkey, si_code);
}
static noinline void
bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
{
- __bad_area(regs, error_code, address, NULL, SEGV_MAPERR);
+ __bad_area(regs, error_code, address, 0, SEGV_MAPERR);
}
static inline bool bad_area_access_from_pkeys(unsigned long error_code,
@@ -968,18 +892,40 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
* But, doing it this way allows compiler optimizations
* if pkeys are compiled out.
*/
- if (bad_area_access_from_pkeys(error_code, vma))
- __bad_area(regs, error_code, address, vma, SEGV_PKUERR);
- else
- __bad_area(regs, error_code, address, vma, SEGV_ACCERR);
+ if (bad_area_access_from_pkeys(error_code, vma)) {
+ /*
+ * A protection key fault means that the PKRU value did not allow
+ * access to some PTE. Userspace can figure out what PKRU was
+ * from the XSAVE state. This function captures the pkey from
+ * the vma and passes it to userspace so userspace can discover
+ * which protection key was set on the PTE.
+ *
+ * If we get here, we know that the hardware signaled a X86_PF_PK
+ * fault and that there was a VMA once we got in the fault
+ * handler. It does *not* guarantee that the VMA we find here
+ * was the one that we faulted on.
+ *
+ * 1. T1 : mprotect_key(foo, PAGE_SIZE, pkey=4);
+ * 2. T1 : set PKRU to deny access to pkey=4, touches page
+ * 3. T1 : faults...
+ * 4. T2: mprotect_key(foo, PAGE_SIZE, pkey=5);
+ * 5. T1 : enters fault handler, takes mmap_sem, etc...
+ * 6. T1 : reaches here, sees vma_pkey(vma)=5, when we really
+ * faulted on a pte with its pkey=4.
+ */
+ u32 pkey = vma_pkey(vma);
+
+ __bad_area(regs, error_code, address, pkey, SEGV_PKUERR);
+ } else {
+ __bad_area(regs, error_code, address, 0, SEGV_ACCERR);
+ }
}
static void
do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
- u32 *pkey, unsigned int fault)
+ unsigned int fault)
{
struct task_struct *tsk = current;
- int code = BUS_ADRERR;
/* Kernel mode? Handle exceptions or die: */
if (!(error_code & X86_PF_USER)) {
@@ -997,18 +943,25 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
#ifdef CONFIG_MEMORY_FAILURE
if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
- printk(KERN_ERR
+ unsigned lsb = 0;
+
+ pr_err(
"MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
tsk->comm, tsk->pid, address);
- code = BUS_MCEERR_AR;
+ if (fault & VM_FAULT_HWPOISON_LARGE)
+ lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
+ if (fault & VM_FAULT_HWPOISON)
+ lsb = PAGE_SHIFT;
+ force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, tsk);
+ return;
}
#endif
- force_sig_info_fault(SIGBUS, code, address, tsk, pkey, fault);
+ force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, tsk);
}
static noinline void
mm_fault_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, u32 *pkey, vm_fault_t fault)
+ unsigned long address, vm_fault_t fault)
{
if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
no_context(regs, error_code, address, 0, 0);
@@ -1032,9 +985,9 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
} else {
if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
VM_FAULT_HWPOISON_LARGE))
- do_sigbus(regs, error_code, address, pkey, fault);
+ do_sigbus(regs, error_code, address, fault);
else if (fault & VM_FAULT_SIGSEGV)
- bad_area_nosemaphore(regs, error_code, address, pkey);
+ bad_area_nosemaphore(regs, error_code, address);
else
BUG();
}
@@ -1267,7 +1220,7 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
* Don't take the mm semaphore here. If we fixup a prefetch
* fault we could otherwise deadlock:
*/
- bad_area_nosemaphore(regs, hw_error_code, address, NULL);
+ bad_area_nosemaphore(regs, hw_error_code, address);
}
NOKPROBE_SYMBOL(do_kern_addr_fault);
@@ -1283,7 +1236,6 @@ void do_user_addr_fault(struct pt_regs *regs,
struct mm_struct *mm;
vm_fault_t fault, major = 0;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
- u32 pkey;
tsk = current;
mm = tsk->mm;
@@ -1304,7 +1256,7 @@ void do_user_addr_fault(struct pt_regs *regs,
* pages in the user address space.
*/
if (unlikely(smap_violation(hw_error_code, regs))) {
- bad_area_nosemaphore(regs, hw_error_code, address, NULL);
+ bad_area_nosemaphore(regs, hw_error_code, address);
return;
}
@@ -1313,7 +1265,7 @@ void do_user_addr_fault(struct pt_regs *regs,
* in a region with pagefaults disabled then we must not take the fault
*/
if (unlikely(faulthandler_disabled() || !mm)) {
- bad_area_nosemaphore(regs, hw_error_code, address, NULL);
+ bad_area_nosemaphore(regs, hw_error_code, address);
return;
}
@@ -1403,7 +1355,7 @@ void do_user_addr_fault(struct pt_regs *regs,
* Fault from code in kernel from
* which we do not expect faults.
*/
- bad_area_nosemaphore(regs, sw_error_code, address, NULL);
+ bad_area_nosemaphore(regs, sw_error_code, address);
return;
}
retry:
@@ -1467,10 +1419,7 @@ good_area:
* (potentially after handling any pending signal during the return to
* userland). The return to userland is identified whenever
* FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in flags.
- * Thus we have to be careful about not touching vma after handling the
- * fault, so we read the pkey beforehand.
*/
- pkey = vma_pkey(vma);
fault = handle_mm_fault(vma, address, flags);
major |= fault & VM_FAULT_MAJOR;
@@ -1499,7 +1448,7 @@ good_area:
up_read(&mm->mmap_sem);
if (unlikely(fault & VM_FAULT_ERROR)) {
- mm_fault_error(regs, sw_error_code, address, &pkey, fault);
+ mm_fault_error(regs, sw_error_code, address, fault);
return;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 06:59:19 +0000