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Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r--arch/x86/mm/fault.c154
1 files changed, 69 insertions, 85 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index b836a7274e12..78ca9a8ee454 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1995 Linus Torvalds
* Copyright (C) 2001, 2002 Andi Kleen, SuSE Labs.
@@ -19,7 +20,6 @@
#include <asm/cpufeature.h> /* boot_cpu_has, ... */
#include <asm/traps.h> /* dotraplinkage, ... */
#include <asm/pgalloc.h> /* pgd_*(), ... */
-#include <asm/kmemcheck.h> /* kmemcheck_*(), ... */
#include <asm/fixmap.h> /* VSYSCALL_ADDR */
#include <asm/vsyscall.h> /* emulate_vsyscall */
#include <asm/vm86.h> /* struct vm86 */
@@ -29,26 +29,6 @@
#include <asm/trace/exceptions.h>
/*
- * Page fault error code bits:
- *
- * bit 0 == 0: no page found 1: protection fault
- * bit 1 == 0: read access 1: write access
- * bit 2 == 0: kernel-mode access 1: user-mode access
- * bit 3 == 1: use of reserved bit detected
- * bit 4 == 1: fault was an instruction fetch
- * bit 5 == 1: protection keys block access
- */
-enum x86_pf_error_code {
-
- PF_PROT = 1 << 0,
- PF_WRITE = 1 << 1,
- PF_USER = 1 << 2,
- PF_RSVD = 1 << 3,
- PF_INSTR = 1 << 4,
- PF_PK = 1 << 5,
-};
-
-/*
* Returns 0 if mmiotrace is disabled, or if the fault is not
* handled by mmiotrace:
*/
@@ -149,7 +129,7 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
* If it was a exec (instruction fetch) fault on NX page, then
* do not ignore the fault:
*/
- if (error_code & PF_INSTR)
+ if (error_code & X86_PF_INSTR)
return 0;
instr = (void *)convert_ip_to_linear(current, regs);
@@ -179,7 +159,7 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
* siginfo so userspace can discover which protection key was set
* on the PTE.
*
- * If we get here, we know that the hardware signaled a PF_PK
+ * 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.
@@ -192,8 +172,7 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
* 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_code, siginfo_t *info,
- struct vm_area_struct *vma)
+static void fill_sig_info_pkey(int si_code, siginfo_t *info, u32 *pkey)
{
/* This is effectively an #ifdef */
if (!boot_cpu_has(X86_FEATURE_OSPKE))
@@ -205,11 +184,11 @@ static void fill_sig_info_pkey(int si_code, siginfo_t *info,
/*
* force_sig_info_fault() is called from a number of
* contexts, some of which have a VMA and some of which
- * do not. The PF_PK handing happens after we have a
+ * 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 (!vma) {
+ if (!pkey) {
WARN_ONCE(1, "PKU fault with no VMA passed in");
info->si_pkey = 0;
return;
@@ -219,13 +198,12 @@ static void fill_sig_info_pkey(int si_code, siginfo_t *info,
* absolutely guranteed to be 100% accurate because of
* the race explained above.
*/
- info->si_pkey = vma_pkey(vma);
+ info->si_pkey = *pkey;
}
static void
force_sig_info_fault(int si_signo, int si_code, unsigned long address,
- struct task_struct *tsk, struct vm_area_struct *vma,
- int fault)
+ struct task_struct *tsk, u32 *pkey, int fault)
{
unsigned lsb = 0;
siginfo_t info;
@@ -240,7 +218,7 @@ force_sig_info_fault(int si_signo, int si_code, unsigned long address,
lsb = PAGE_SHIFT;
info.si_addr_lsb = lsb;
- fill_sig_info_pkey(si_code, &info, vma);
+ fill_sig_info_pkey(si_code, &info, pkey);
force_sig_info(si_signo, &info, tsk);
}
@@ -699,7 +677,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code,
if (!oops_may_print())
return;
- if (error_code & PF_INSTR) {
+ if (error_code & X86_PF_INSTR) {
unsigned int level;
pgd_t *pgd;
pte_t *pte;
@@ -762,8 +740,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
struct task_struct *tsk = current;
unsigned long flags;
int sig;
- /* No context means no VMA to pass down */
- struct vm_area_struct *vma = NULL;
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs, X86_TRAP_PF)) {
@@ -783,12 +759,12 @@ no_context(struct pt_regs *regs, unsigned long error_code,
*/
if (current->thread.sig_on_uaccess_err && signal) {
tsk->thread.trap_nr = X86_TRAP_PF;
- tsk->thread.error_code = error_code | PF_USER;
+ tsk->thread.error_code = error_code | X86_PF_USER;
tsk->thread.cr2 = address;
/* XXX: hwpoison faults will set the wrong code. */
force_sig_info_fault(signal, si_code, address,
- tsk, vma, 0);
+ tsk, NULL, 0);
}
/*
@@ -806,7 +782,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
if (is_vmalloc_addr((void *)address) &&
(((unsigned long)tsk->stack - 1 - address < PAGE_SIZE) ||
address - ((unsigned long)tsk->stack + THREAD_SIZE) < PAGE_SIZE)) {
- register void *__sp asm("rsp");
unsigned long stack = this_cpu_read(orig_ist.ist[DOUBLEFAULT_STACK]) - sizeof(void *);
/*
* We're likely to be running with very little stack space
@@ -821,7 +796,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
asm volatile ("movq %[stack], %%rsp\n\t"
"call handle_stack_overflow\n\t"
"1: jmp 1b"
- : "+r" (__sp)
+ : ASM_CALL_CONSTRAINT
: "D" ("kernel stack overflow (page fault)"),
"S" (regs), "d" (address),
[stack] "rm" (stack));
@@ -897,13 +872,12 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code,
static void
__bad_area_nosemaphore(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 task_struct *tsk = current;
/* User mode accesses just cause a SIGSEGV */
- if (error_code & PF_USER) {
+ if (error_code & X86_PF_USER) {
/*
* It's possible to have interrupts off here:
*/
@@ -924,7 +898,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
* Instruction fetch faults in the vsyscall page might need
* emulation.
*/
- if (unlikely((error_code & PF_INSTR) &&
+ if (unlikely((error_code & X86_PF_INSTR) &&
((address & ~0xfff) == VSYSCALL_ADDR))) {
if (emulate_vsyscall(regs, address))
return;
@@ -937,7 +911,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
* are always protection faults.
*/
if (address >= TASK_SIZE_MAX)
- error_code |= PF_PROT;
+ error_code |= X86_PF_PROT;
if (likely(show_unhandled_signals))
show_signal_msg(regs, error_code, address, tsk);
@@ -946,7 +920,7 @@ __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, vma, 0);
+ force_sig_info_fault(SIGSEGV, si_code, address, tsk, pkey, 0);
return;
}
@@ -959,9 +933,9 @@ __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, struct vm_area_struct *vma)
+ unsigned long address, u32 *pkey)
{
- __bad_area_nosemaphore(regs, error_code, address, vma, SEGV_MAPERR);
+ __bad_area_nosemaphore(regs, error_code, address, pkey, SEGV_MAPERR);
}
static void
@@ -969,6 +943,10 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
unsigned long address, struct vm_area_struct *vma, 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..
@@ -976,7 +954,8 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
*/
up_read(&mm->mmap_sem);
- __bad_area_nosemaphore(regs, error_code, address, vma, si_code);
+ __bad_area_nosemaphore(regs, error_code, address,
+ (vma) ? &pkey : NULL, si_code);
}
static noinline void
@@ -993,11 +972,11 @@ static inline bool bad_area_access_from_pkeys(unsigned long error_code,
if (!boot_cpu_has(X86_FEATURE_OSPKE))
return false;
- if (error_code & PF_PK)
+ if (error_code & X86_PF_PK)
return true;
/* this checks permission keys on the VMA: */
- if (!arch_vma_access_permitted(vma, (error_code & PF_WRITE),
- (error_code & PF_INSTR), foreign))
+ if (!arch_vma_access_permitted(vma, (error_code & X86_PF_WRITE),
+ (error_code & X86_PF_INSTR), foreign))
return true;
return false;
}
@@ -1019,13 +998,13 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
static void
do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
- struct vm_area_struct *vma, unsigned int fault)
+ u32 *pkey, unsigned int fault)
{
struct task_struct *tsk = current;
int code = BUS_ADRERR;
/* Kernel mode? Handle exceptions or die: */
- if (!(error_code & PF_USER)) {
+ if (!(error_code & X86_PF_USER)) {
no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
return;
}
@@ -1046,22 +1025,21 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
code = BUS_MCEERR_AR;
}
#endif
- force_sig_info_fault(SIGBUS, code, address, tsk, vma, fault);
+ force_sig_info_fault(SIGBUS, code, address, tsk, pkey, fault);
}
static noinline void
mm_fault_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma,
- unsigned int fault)
+ unsigned long address, u32 *pkey, unsigned int fault)
{
- if (fatal_signal_pending(current) && !(error_code & PF_USER)) {
+ if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
no_context(regs, error_code, address, 0, 0);
return;
}
if (fault & VM_FAULT_OOM) {
/* Kernel mode? Handle exceptions or die: */
- if (!(error_code & PF_USER)) {
+ if (!(error_code & X86_PF_USER)) {
no_context(regs, error_code, address,
SIGSEGV, SEGV_MAPERR);
return;
@@ -1076,9 +1054,9 @@ 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, vma, fault);
+ do_sigbus(regs, error_code, address, pkey, fault);
else if (fault & VM_FAULT_SIGSEGV)
- bad_area_nosemaphore(regs, error_code, address, vma);
+ bad_area_nosemaphore(regs, error_code, address, pkey);
else
BUG();
}
@@ -1086,16 +1064,16 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
static int spurious_fault_check(unsigned long error_code, pte_t *pte)
{
- if ((error_code & PF_WRITE) && !pte_write(*pte))
+ if ((error_code & X86_PF_WRITE) && !pte_write(*pte))
return 0;
- if ((error_code & PF_INSTR) && !pte_exec(*pte))
+ if ((error_code & X86_PF_INSTR) && !pte_exec(*pte))
return 0;
/*
* Note: We do not do lazy flushing on protection key
- * changes, so no spurious fault will ever set PF_PK.
+ * changes, so no spurious fault will ever set X86_PF_PK.
*/
- if ((error_code & PF_PK))
+ if ((error_code & X86_PF_PK))
return 1;
return 1;
@@ -1141,8 +1119,8 @@ spurious_fault(unsigned long error_code, unsigned long address)
* change, so user accesses are not expected to cause spurious
* faults.
*/
- if (error_code != (PF_WRITE | PF_PROT)
- && error_code != (PF_INSTR | PF_PROT))
+ if (error_code != (X86_PF_WRITE | X86_PF_PROT) &&
+ error_code != (X86_PF_INSTR | X86_PF_PROT))
return 0;
pgd = init_mm.pgd + pgd_index(address);
@@ -1202,19 +1180,19 @@ access_error(unsigned long error_code, struct vm_area_struct *vma)
* always an unconditional error and can never result in
* a follow-up action to resolve the fault, like a COW.
*/
- if (error_code & PF_PK)
+ if (error_code & X86_PF_PK)
return 1;
/*
* Make sure to check the VMA so that we do not perform
- * faults just to hit a PF_PK as soon as we fill in a
+ * faults just to hit a X86_PF_PK as soon as we fill in a
* page.
*/
- if (!arch_vma_access_permitted(vma, (error_code & PF_WRITE),
- (error_code & PF_INSTR), foreign))
+ if (!arch_vma_access_permitted(vma, (error_code & X86_PF_WRITE),
+ (error_code & X86_PF_INSTR), foreign))
return 1;
- if (error_code & PF_WRITE) {
+ if (error_code & X86_PF_WRITE) {
/* write, present and write, not present: */
if (unlikely(!(vma->vm_flags & VM_WRITE)))
return 1;
@@ -1222,7 +1200,7 @@ access_error(unsigned long error_code, struct vm_area_struct *vma)
}
/* read, present: */
- if (unlikely(error_code & PF_PROT))
+ if (unlikely(error_code & X86_PF_PROT))
return 1;
/* read, not present: */
@@ -1245,7 +1223,7 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs)
if (!static_cpu_has(X86_FEATURE_SMAP))
return false;
- if (error_code & PF_USER)
+ if (error_code & X86_PF_USER)
return false;
if (!user_mode(regs) && (regs->flags & X86_EFLAGS_AC))
@@ -1268,6 +1246,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
struct mm_struct *mm;
int fault, major = 0;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+ u32 pkey;
tsk = current;
mm = tsk->mm;
@@ -1276,8 +1255,6 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
* Detect and handle instructions that would cause a page fault for
* both a tracked kernel page and a userspace page.
*/
- if (kmemcheck_active(regs))
- kmemcheck_hide(regs);
prefetchw(&mm->mmap_sem);
if (unlikely(kmmio_fault(regs, address)))
@@ -1297,12 +1274,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
* protection error (error_code & 9) == 0.
*/
if (unlikely(fault_in_kernel_space(address))) {
- if (!(error_code & (PF_RSVD | PF_USER | PF_PROT))) {
+ if (!(error_code & (X86_PF_RSVD | X86_PF_USER | X86_PF_PROT))) {
if (vmalloc_fault(address) >= 0)
return;
-
- if (kmemcheck_fault(regs, address, error_code))
- return;
}
/* Can handle a stale RO->RW TLB: */
@@ -1325,7 +1299,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
if (unlikely(kprobes_fault(regs)))
return;
- if (unlikely(error_code & PF_RSVD))
+ if (unlikely(error_code & X86_PF_RSVD))
pgtable_bad(regs, error_code, address);
if (unlikely(smap_violation(error_code, regs))) {
@@ -1351,7 +1325,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
*/
if (user_mode(regs)) {
local_irq_enable();
- error_code |= PF_USER;
+ error_code |= X86_PF_USER;
flags |= FAULT_FLAG_USER;
} else {
if (regs->flags & X86_EFLAGS_IF)
@@ -1360,9 +1334,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
- if (error_code & PF_WRITE)
+ if (error_code & X86_PF_WRITE)
flags |= FAULT_FLAG_WRITE;
- if (error_code & PF_INSTR)
+ if (error_code & X86_PF_INSTR)
flags |= FAULT_FLAG_INSTRUCTION;
/*
@@ -1382,7 +1356,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
* space check, thus avoiding the deadlock:
*/
if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
- if ((error_code & PF_USER) == 0 &&
+ if (!(error_code & X86_PF_USER) &&
!search_exception_tables(regs->ip)) {
bad_area_nosemaphore(regs, error_code, address, NULL);
return;
@@ -1409,7 +1383,7 @@ retry:
bad_area(regs, error_code, address);
return;
}
- if (error_code & PF_USER) {
+ if (error_code & X86_PF_USER) {
/*
* Accessing the stack below %sp is always a bug.
* The large cushion allows instructions like enter
@@ -1441,7 +1415,17 @@ good_area:
* make sure we exit gracefully rather than endlessly redo
* the fault. Since we never set FAULT_FLAG_RETRY_NOWAIT, if
* we get VM_FAULT_RETRY back, the mmap_sem has been unlocked.
+ *
+ * Note that handle_userfault() may also release and reacquire mmap_sem
+ * (and not return with VM_FAULT_RETRY), when returning to userland to
+ * repeat the page fault later with a VM_FAULT_NOPAGE retval
+ * (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;
@@ -1470,7 +1454,7 @@ good_area:
up_read(&mm->mmap_sem);
if (unlikely(fault & VM_FAULT_ERROR)) {
- mm_fault_error(regs, error_code, address, vma, fault);
+ mm_fault_error(regs, error_code, address, &pkey, fault);
return;
}
generated by cgit (git 2.34.1) at 2024-05-04 01:32:20 +0000