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Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse source 
Pull x86 fixes from Ingo Molnar:
 "The biggest diffstat comes from self-test updates, plus there's entry
  code fixes, 5-level paging related fixes, console debug output fixes,
  and misc fixes"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Clean up the printk()s in show_fault_oops()
  x86/mm: Drop unneeded __always_inline for p4d page table helpers
  x86/efi: Fix efi_call_phys_epilog() with CONFIG_X86_5LEVEL=y
  selftests/x86/sigreturn: Do minor cleanups
  selftests/x86/sigreturn/64: Fix spurious failures on AMD CPUs
  x86/entry/64/compat: Fix "x86/entry/64/compat: Preserve r8-r11 in int $0x80"
  x86/mm: Don't free P4D table when it is folded at runtime
  x86/entry/32: Add explicit 'l' instruction suffix
  x86/mm: Get rid of KERN_CONT in show_fault_oops()
This commit is contained in:
Linus Torvalds 2018-06-30 11:42:14 -07:00
commit 0fbc4aeabc
8 changed files with 60 additions and 51 deletions
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2
arch/x86/entry/entry_32.S
View file

@ -477,7 +477,7 @@ ENTRY(entry_SYSENTER_32)
* whereas POPF does not.)
*/
addl $PT_EFLAGS-PT_DS, %esp /* point esp at pt_regs->flags */
btr $X86_EFLAGS_IF_BIT, (%esp)
btrl $X86_EFLAGS_IF_BIT, (%esp)
popfl
/*

16
arch/x86/entry/entry_64_compat.S
View file

@ -84,13 +84,13 @@ ENTRY(entry_SYSENTER_compat)
pushq %rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq $-ENOSYS /* pt_regs->ax */
pushq %r8 /* pt_regs->r8 */
pushq $0 /* pt_regs->r8 = 0 */
xorl %r8d, %r8d /* nospec r8 */
pushq %r9 /* pt_regs->r9 */
pushq $0 /* pt_regs->r9 = 0 */
xorl %r9d, %r9d /* nospec r9 */
pushq %r10 /* pt_regs->r10 */
pushq $0 /* pt_regs->r10 = 0 */
xorl %r10d, %r10d /* nospec r10 */
pushq %r11 /* pt_regs->r11 */
pushq $0 /* pt_regs->r11 = 0 */
xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
@ -374,13 +374,13 @@ ENTRY(entry_INT80_compat)
pushq %rcx /* pt_regs->cx */
xorl %ecx, %ecx /* nospec cx */
pushq $-ENOSYS /* pt_regs->ax */
pushq $0 /* pt_regs->r8 = 0 */
pushq %r8 /* pt_regs->r8 */
xorl %r8d, %r8d /* nospec r8 */
pushq $0 /* pt_regs->r9 = 0 */
pushq %r9 /* pt_regs->r9 */
xorl %r9d, %r9d /* nospec r9 */
pushq $0 /* pt_regs->r10 = 0 */
pushq %r10 /* pt_regs->r10*/
xorl %r10d, %r10d /* nospec r10 */
pushq $0 /* pt_regs->r11 = 0 */
pushq %r11 /* pt_regs->r11 */
xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */

3
arch/x86/include/asm/pgalloc.h
View file

@ -184,6 +184,9 @@ static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr)
static inline void p4d_free(struct mm_struct *mm, p4d_t *p4d)
{
if (!pgtable_l5_enabled())
return;
BUG_ON((unsigned long)p4d & (PAGE_SIZE-1));
free_page((unsigned long)p4d);
}

2
arch/x86/include/asm/pgtable.h
View file

@ -898,7 +898,7 @@ static inline unsigned long pgd_page_vaddr(pgd_t pgd)
#define pgd_page(pgd) pfn_to_page(pgd_pfn(pgd))
/* to find an entry in a page-table-directory. */
static __always_inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
{
if (!pgtable_l5_enabled())
return (p4d_t *)pgd;

4
arch/x86/include/asm/pgtable_64.h
View file

@ -216,7 +216,7 @@ static inline pgd_t pti_set_user_pgd(pgd_t *pgdp, pgd_t pgd)
}
#endif
static __always_inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d)
static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d)
{
pgd_t pgd;
@ -230,7 +230,7 @@ static __always_inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d)
*p4dp = native_make_p4d(native_pgd_val(pgd));
}
static __always_inline void native_p4d_clear(p4d_t *p4d)
static inline void native_p4d_clear(p4d_t *p4d)
{
native_set_p4d(p4d, native_make_p4d(0));
}

21
arch/x86/mm/fault.c
View file

@ -641,11 +641,6 @@ static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
return 0;
}
static const char nx_warning[] = KERN_CRIT
"kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n";
static const char smep_warning[] = KERN_CRIT
"unable to execute userspace code (SMEP?) (uid: %d)\n";
static void
show_fault_oops(struct pt_regs *regs, unsigned long error_code,
unsigned long address)
@ -664,20 +659,18 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code,
pte = lookup_address_in_pgd(pgd, address, &level);
if (pte && pte_present(*pte) && !pte_exec(*pte))
printk(nx_warning, from_kuid(&init_user_ns, current_uid()));
pr_crit("kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n",
from_kuid(&init_user_ns, current_uid()));
if (pte && pte_present(*pte) && pte_exec(*pte) &&
(pgd_flags(*pgd) & _PAGE_USER) &&
(__read_cr4() & X86_CR4_SMEP))
printk(smep_warning, from_kuid(&init_user_ns, current_uid()));
pr_crit("unable to execute userspace code (SMEP?) (uid: %d)\n",
from_kuid(&init_user_ns, current_uid()));
}
printk(KERN_ALERT "BUG: unable to handle kernel ");
if (address < PAGE_SIZE)
printk(KERN_CONT "NULL pointer dereference");
else
printk(KERN_CONT "paging request");
printk(KERN_CONT " at %px\n", (void *) address);
pr_alert("BUG: unable to handle kernel %s at %px\n",
address < PAGE_SIZE ? "NULL pointer dereference" : "paging request",
(void *)address);
dump_pagetable(address);
}

4
arch/x86/platform/efi/efi_64.c
View file

@ -166,14 +166,14 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
pgd = pgd_offset_k(pgd_idx * PGDIR_SIZE);
set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);
if (!(pgd_val(*pgd) & _PAGE_PRESENT))
if (!pgd_present(*pgd))
continue;
for (i = 0; i < PTRS_PER_P4D; i++) {
p4d = p4d_offset(pgd,
pgd_idx * PGDIR_SIZE + i * P4D_SIZE);
if (!(p4d_val(*p4d) & _PAGE_PRESENT))
if (!p4d_present(*p4d))
continue;
pud = (pud_t *)p4d_page_vaddr(*p4d);

59
tools/testing/selftests/x86/sigreturn.c
View file

@ -610,21 +610,41 @@ static int test_valid_sigreturn(int cs_bits, bool use_16bit_ss, int force_ss)
*/
for (int i = 0; i < NGREG; i++) {
greg_t req = requested_regs[i], res = resulting_regs[i];
if (i == REG_TRAPNO || i == REG_IP)
continue; /* don't care */
if (i == REG_SP) {
printf("\tSP: %llx -> %llx\n", (unsigned long long)req,
(unsigned long long)res);
if (i == REG_SP) {
/*
* In many circumstances, the high 32 bits of rsp
* are zeroed. For example, we could be a real
* 32-bit program, or we could hit any of a number
* of poorly-documented IRET or segmented ESP
* oddities. If this happens, it's okay.
* If we were using a 16-bit stack segment, then
* the kernel is a bit stuck: IRET only restores
* the low 16 bits of ESP/RSP if SS is 16-bit.
* The kernel uses a hack to restore bits 31:16,
* but that hack doesn't help with bits 63:32.
* On Intel CPUs, bits 63:32 end up zeroed, and, on
* AMD CPUs, they leak the high bits of the kernel
* espfix64 stack pointer. There's very little that
* the kernel can do about it.
*
* Similarly, if we are returning to a 32-bit context,
* the CPU will often lose the high 32 bits of RSP.
*/
if (res == (req & 0xFFFFFFFF))
continue; /* OK; not expected to work */
if (res == req)
continue;
if (cs_bits != 64 && ((res ^ req) & 0xFFFFFFFF) == 0) {
printf("[NOTE]\tSP: %llx -> %llx\n",
(unsigned long long)req,
(unsigned long long)res);
continue;
}
printf("[FAIL]\tSP mismatch: requested 0x%llx; got 0x%llx\n",
(unsigned long long)requested_regs[i],
(unsigned long long)resulting_regs[i]);
nerrs++;
continue;
}
bool ignore_reg = false;
@ -654,25 +674,18 @@ static int test_valid_sigreturn(int cs_bits, bool use_16bit_ss, int force_ss)
#endif
/* Sanity check on the kernel */
if (i == REG_CX && requested_regs[i] != resulting_regs[i]) {
if (i == REG_CX && req != res) {
printf("[FAIL]\tCX (saved SP) mismatch: requested 0x%llx; got 0x%llx\n",
(unsigned long long)requested_regs[i],
(unsigned long long)resulting_regs[i]);
(unsigned long long)req,
(unsigned long long)res);
nerrs++;
continue;
}
if (requested_regs[i] != resulting_regs[i] && !ignore_reg) {
/*
* SP is particularly interesting here. The
* usual cause of failures is that we hit the
* nasty IRET case of returning to a 16-bit SS,
* in which case bits 16:31 of the *kernel*
* stack pointer persist in ESP.
*/
if (req != res && !ignore_reg) {
printf("[FAIL]\tReg %d mismatch: requested 0x%llx; got 0x%llx\n",
i, (unsigned long long)requested_regs[i],
(unsigned long long)resulting_regs[i]);
i, (unsigned long long)req,
(unsigned long long)res);
nerrs++;
}
}