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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-20 19:34:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-20 19:34:09 -0800
commitae821d2107e378bb086a02afcce82d0f43c29a6f (patch)
tree7aa005e882110d6e70ccaf46abea3def9a2ce9dd /arch/x86
parent1255f44017c02d14e3ad5b63cdf619a734d765a1 (diff)
parent40c1fa52cdb7c13ef88232e374b4b8ac8d820c4f (diff)
downloadlinux-ae821d2107e378bb086a02afcce82d0f43c29a6f.tar.gz
Merge tag 'x86_mm_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm cleanups from Borislav Petkov: - PTRACE_GETREGS/PTRACE_PUTREGS regset selection cleanup - Another initial cleanup - more to follow - to the fault handling code. - Other minor cleanups and corrections. * tag 'x86_mm_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) x86/{fault,efi}: Fix and rename efi_recover_from_page_fault() x86/fault: Don't run fixups for SMAP violations x86/fault: Don't look for extable entries for SMEP violations x86/fault: Rename no_context() to kernelmode_fixup_or_oops() x86/fault: Bypass no_context() for implicit kernel faults from usermode x86/fault: Split the OOPS code out from no_context() x86/fault: Improve kernel-executing-user-memory handling x86/fault: Correct a few user vs kernel checks wrt WRUSS x86/fault: Document the locking in the fault_signal_pending() path x86/fault/32: Move is_f00f_bug() to do_kern_addr_fault() x86/fault: Fold mm_fault_error() into do_user_addr_fault() x86/fault: Skip the AMD erratum #91 workaround on unaffected CPUs x86/fault: Fix AMD erratum #91 errata fixup for user code x86/Kconfig: Remove HPET_EMULATE_RTC depends on RTC x86/asm: Fixup TASK_SIZE_MAX comment x86/ptrace: Clean up PTRACE_GETREGS/PTRACE_PUTREGS regset selection x86/vm86/32: Remove VM86_SCREEN_BITMAP support x86: Remove definition of DEBUG x86/entry: Remove now unused do_IRQ() declaration x86/mm: Remove duplicate definition of _PAGE_PAT_LARGE ...
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/Kconfig2
-rw-r--r--arch/x86/include/asm/efi.h2
-rw-r--r--arch/x86/include/asm/irq.h2
-rw-r--r--arch/x86/include/asm/page_64_types.h2
-rw-r--r--arch/x86/include/asm/pgtable_types.h2
-rw-r--r--arch/x86/include/asm/vm86.h1
-rw-r--r--arch/x86/include/uapi/asm/vm86.h4
-rw-r--r--arch/x86/kernel/cpu/mtrr/cleanup.c4
-rw-r--r--arch/x86/kernel/cpu/mtrr/generic.c1
-rw-r--r--arch/x86/kernel/cpu/mtrr/mtrr.c2
-rw-r--r--arch/x86/kernel/pci-iommu_table.c3
-rw-r--r--arch/x86/kernel/ptrace.c46
-rw-r--r--arch/x86/kernel/sys_x86_64.c8
-rw-r--r--arch/x86/kernel/vm86_32.c62
-rw-r--r--arch/x86/mm/fault.c403
-rw-r--r--arch/x86/mm/init.c19
-rw-r--r--arch/x86/mm/mmio-mod.c2
-rw-r--r--arch/x86/platform/efi/quirks.c16
18 files changed, 298 insertions, 283 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9989db3a9bf5..3d498caca1ea 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -890,7 +890,7 @@ config HPET_TIMER
config HPET_EMULATE_RTC
def_bool y
- depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
+ depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
config APB_TIMER
def_bool y if X86_INTEL_MID
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 1328b7959b72..627347af343a 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -139,7 +139,7 @@ extern void __init efi_dump_pagetable(void);
extern void __init efi_apply_memmap_quirks(void);
extern int __init efi_reuse_config(u64 tables, int nr_tables);
extern void efi_delete_dummy_variable(void);
-extern void efi_recover_from_page_fault(unsigned long phys_addr);
+extern void efi_crash_gracefully_on_page_fault(unsigned long phys_addr);
extern void efi_free_boot_services(void);
void efi_enter_mm(void);
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 528c8a71fe7f..76d389691b5b 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -40,8 +40,6 @@ extern void native_init_IRQ(void);
extern void __handle_irq(struct irq_desc *desc, struct pt_regs *regs);
-extern __visible void do_IRQ(struct pt_regs *regs, unsigned long vector);
-
extern void init_ISA_irqs(void);
extern void __init init_IRQ(void);
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 645bd1d0ee07..64297eabad63 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -66,7 +66,7 @@
* On Intel CPUs, if a SYSCALL instruction is at the highest canonical
* address, then that syscall will enter the kernel with a
* non-canonical return address, and SYSRET will explode dangerously.
- * We avoid this particular problem by preventing anything executable
+ * We avoid this particular problem by preventing anything
* from being mapped at the maximum canonical address.
*
* On AMD CPUs in the Ryzen family, there's a nasty bug in which the
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 394757ee030a..f24d7ef8fffa 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -177,8 +177,6 @@ enum page_cache_mode {
#define __pgprot(x) ((pgprot_t) { (x) } )
#define __pg(x) __pgprot(x)
-#define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
-
#define PAGE_NONE __pg( 0| 0| 0|___A| 0| 0| 0|___G)
#define PAGE_SHARED __pg(__PP|__RW|_USR|___A|__NX| 0| 0| 0)
#define PAGE_SHARED_EXEC __pg(__PP|__RW|_USR|___A| 0| 0| 0| 0)
diff --git a/arch/x86/include/asm/vm86.h b/arch/x86/include/asm/vm86.h
index 26efbec94448..9e8ac5073ecb 100644
--- a/arch/x86/include/asm/vm86.h
+++ b/arch/x86/include/asm/vm86.h
@@ -36,7 +36,6 @@ struct vm86 {
unsigned long saved_sp0;
unsigned long flags;
- unsigned long screen_bitmap;
unsigned long cpu_type;
struct revectored_struct int_revectored;
struct revectored_struct int21_revectored;
diff --git a/arch/x86/include/uapi/asm/vm86.h b/arch/x86/include/uapi/asm/vm86.h
index d2ee4e307ef8..18909b8050bc 100644
--- a/arch/x86/include/uapi/asm/vm86.h
+++ b/arch/x86/include/uapi/asm/vm86.h
@@ -97,7 +97,7 @@ struct revectored_struct {
struct vm86_struct {
struct vm86_regs regs;
unsigned long flags;
- unsigned long screen_bitmap;
+ unsigned long screen_bitmap; /* unused, preserved by vm86() */
unsigned long cpu_type;
struct revectored_struct int_revectored;
struct revectored_struct int21_revectored;
@@ -106,7 +106,7 @@ struct vm86_struct {
/*
* flags masks
*/
-#define VM86_SCREEN_BITMAP 0x0001
+#define VM86_SCREEN_BITMAP 0x0001 /* no longer supported */
struct vm86plus_info_struct {
unsigned long force_return_for_pic:1;
diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
index 5bd011737272..9231640782fa 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -537,9 +537,9 @@ static void __init print_out_mtrr_range_state(void)
if (!size_base)
continue;
- size_base = to_size_factor(size_base, &size_factor),
+ size_base = to_size_factor(size_base, &size_factor);
start_base = range_state[i].base_pfn << (PAGE_SHIFT - 10);
- start_base = to_size_factor(start_base, &start_factor),
+ start_base = to_size_factor(start_base, &start_factor);
type = range_state[i].type;
pr_debug("reg %d, base: %ld%cB, range: %ld%cB, type %s\n",
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index a29997e6cf9e..b90f3f437765 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -3,7 +3,6 @@
* This only handles 32bit MTRR on 32bit hosts. This is strictly wrong
* because MTRRs can span up to 40 bits (36bits on most modern x86)
*/
-#define DEBUG
#include <linux/export.h>
#include <linux/init.h>
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 61eb26edc6d2..28c8a23aa42e 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -31,8 +31,6 @@
System Programming Guide; Section 9.11. (1997 edition - PPro).
*/
-#define DEBUG
-
#include <linux/types.h> /* FIXME: kvm_para.h needs this */
#include <linux/stop_machine.h>
diff --git a/arch/x86/kernel/pci-iommu_table.c b/arch/x86/kernel/pci-iommu_table.c
index 2e9006c1e240..42e92ec62973 100644
--- a/arch/x86/kernel/pci-iommu_table.c
+++ b/arch/x86/kernel/pci-iommu_table.c
@@ -4,9 +4,6 @@
#include <linux/string.h>
#include <linux/kallsyms.h>
-
-#define DEBUG 1
-
static struct iommu_table_entry * __init
find_dependents_of(struct iommu_table_entry *start,
struct iommu_table_entry *finish,
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index bedca011459c..87a4143aa7d7 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -704,6 +704,9 @@ void ptrace_disable(struct task_struct *child)
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
static const struct user_regset_view user_x86_32_view; /* Initialized below. */
#endif
+#ifdef CONFIG_X86_64
+static const struct user_regset_view user_x86_64_view; /* Initialized below. */
+#endif
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
@@ -711,6 +714,14 @@ long arch_ptrace(struct task_struct *child, long request,
int ret;
unsigned long __user *datap = (unsigned long __user *)data;
+#ifdef CONFIG_X86_64
+ /* This is native 64-bit ptrace() */
+ const struct user_regset_view *regset_view = &user_x86_64_view;
+#else
+ /* This is native 32-bit ptrace() */
+ const struct user_regset_view *regset_view = &user_x86_32_view;
+#endif
+
switch (request) {
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
@@ -749,28 +760,28 @@ long arch_ptrace(struct task_struct *child, long request,
case PTRACE_GETREGS: /* Get all gp regs from the child. */
return copy_regset_to_user(child,
- task_user_regset_view(current),
+ regset_view,
REGSET_GENERAL,
0, sizeof(struct user_regs_struct),
datap);
case PTRACE_SETREGS: /* Set all gp regs in the child. */
return copy_regset_from_user(child,
- task_user_regset_view(current),
+ regset_view,
REGSET_GENERAL,
0, sizeof(struct user_regs_struct),
datap);
case PTRACE_GETFPREGS: /* Get the child FPU state. */
return copy_regset_to_user(child,
- task_user_regset_view(current),
+ regset_view,
REGSET_FP,
0, sizeof(struct user_i387_struct),
datap);
case PTRACE_SETFPREGS: /* Set the child FPU state. */
return copy_regset_from_user(child,
- task_user_regset_view(current),
+ regset_view,
REGSET_FP,
0, sizeof(struct user_i387_struct),
datap);
@@ -1152,28 +1163,28 @@ static long x32_arch_ptrace(struct task_struct *child,
case PTRACE_GETREGS: /* Get all gp regs from the child. */
return copy_regset_to_user(child,
- task_user_regset_view(current),
+ &user_x86_64_view,
REGSET_GENERAL,
0, sizeof(struct user_regs_struct),
datap);
case PTRACE_SETREGS: /* Set all gp regs in the child. */
return copy_regset_from_user(child,
- task_user_regset_view(current),
+ &user_x86_64_view,
REGSET_GENERAL,
0, sizeof(struct user_regs_struct),
datap);
case PTRACE_GETFPREGS: /* Get the child FPU state. */
return copy_regset_to_user(child,
- task_user_regset_view(current),
+ &user_x86_64_view,
REGSET_FP,
0, sizeof(struct user_i387_struct),
datap);
case PTRACE_SETFPREGS: /* Set the child FPU state. */
return copy_regset_from_user(child,
- task_user_regset_view(current),
+ &user_x86_64_view,
REGSET_FP,
0, sizeof(struct user_i387_struct),
datap);
@@ -1309,6 +1320,25 @@ void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask)
xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask;
}
+/*
+ * This is used by the core dump code to decide which regset to dump. The
+ * core dump code writes out the resulting .e_machine and the corresponding
+ * regsets. This is suboptimal if the task is messing around with its CS.L
+ * field, but at worst the core dump will end up missing some information.
+ *
+ * Unfortunately, it is also used by the broken PTRACE_GETREGSET and
+ * PTRACE_SETREGSET APIs. These APIs look at the .regsets field but have
+ * no way to make sure that the e_machine they use matches the caller's
+ * expectations. The result is that the data format returned by
+ * PTRACE_GETREGSET depends on the returned CS field (and even the offset
+ * of the returned CS field depends on its value!) and the data format
+ * accepted by PTRACE_SETREGSET is determined by the old CS value. The
+ * upshot is that it is basically impossible to use these APIs correctly.
+ *
+ * The best way to fix it in the long run would probably be to add new
+ * improved ptrace() APIs to read and write registers reliably, possibly by
+ * allowing userspace to select the ELF e_machine variant that they expect.
+ */
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_IA32_EMULATION
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 504fa5425bce..660b78827638 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -90,14 +90,10 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, off)
{
- long error;
- error = -EINVAL;
if (off & ~PAGE_MASK)
- goto out;
+ return -EINVAL;
- error = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
-out:
- return error;
+ return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
}
static void find_start_end(unsigned long addr, unsigned long flags,
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 764573de3996..e5a7a10a0164 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -134,7 +134,11 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
unsafe_put_user(regs->ds, &user->regs.ds, Efault_end);
unsafe_put_user(regs->fs, &user->regs.fs, Efault_end);
unsafe_put_user(regs->gs, &user->regs.gs, Efault_end);
- unsafe_put_user(vm86->screen_bitmap, &user->screen_bitmap, Efault_end);
+
+ /*
+ * Don't write screen_bitmap in case some user had a value there
+ * and expected it to remain unchanged.
+ */
user_access_end();
@@ -160,49 +164,6 @@ Efault:
do_exit(SIGSEGV);
}
-static void mark_screen_rdonly(struct mm_struct *mm)
-{
- struct vm_area_struct *vma;
- spinlock_t *ptl;
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- int i;
-
- mmap_write_lock(mm);
- pgd = pgd_offset(mm, 0xA0000);
- if (pgd_none_or_clear_bad(pgd))
- goto out;
- p4d = p4d_offset(pgd, 0xA0000);
- if (p4d_none_or_clear_bad(p4d))
- goto out;
- pud = pud_offset(p4d, 0xA0000);
- if (pud_none_or_clear_bad(pud))
- goto out;
- pmd = pmd_offset(pud, 0xA0000);
-
- if (pmd_trans_huge(*pmd)) {
- vma = find_vma(mm, 0xA0000);
- split_huge_pmd(vma, pmd, 0xA0000);
- }
- if (pmd_none_or_clear_bad(pmd))
- goto out;
- pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl);
- for (i = 0; i < 32; i++) {
- if (pte_present(*pte))
- set_pte(pte, pte_wrprotect(*pte));
- pte++;
- }
- pte_unmap_unlock(pte, ptl);
-out:
- mmap_write_unlock(mm);
- flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, PAGE_SHIFT, false);
-}
-
-
-
static int do_vm86_irq_handling(int subfunction, int irqnumber);
static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus);
@@ -282,6 +243,15 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
offsetof(struct vm86_struct, int_revectored)))
return -EFAULT;
+
+ /* VM86_SCREEN_BITMAP had numerous bugs and appears to have no users. */
+ if (v.flags & VM86_SCREEN_BITMAP) {
+ char comm[TASK_COMM_LEN];
+
+ pr_info_once("vm86: '%s' uses VM86_SCREEN_BITMAP, which is no longer supported\n", get_task_comm(comm, current));
+ return -EINVAL;
+ }
+
memset(&vm86regs, 0, sizeof(vm86regs));
vm86regs.pt.bx = v.regs.ebx;
@@ -302,7 +272,6 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
vm86regs.gs = v.regs.gs;
vm86->flags = v.flags;
- vm86->screen_bitmap = v.screen_bitmap;
vm86->cpu_type = v.cpu_type;
if (copy_from_user(&vm86->int_revectored,
@@ -370,9 +339,6 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
update_task_stack(tsk);
preempt_enable();
- if (vm86->flags & VM86_SCREEN_BITMAP)
- mark_screen_rdonly(tsk->mm);
-
memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs));
return regs->ax;
}
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index f1f1b5a0956a..525197381baa 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -16,7 +16,7 @@
#include <linux/prefetch.h> /* prefetchw */
#include <linux/context_tracking.h> /* exception_enter(), ... */
#include <linux/uaccess.h> /* faulthandler_disabled() */
-#include <linux/efi.h> /* efi_recover_from_page_fault()*/
+#include <linux/efi.h> /* efi_crash_gracefully_on_page_fault()*/
#include <linux/mm_types.h>
#include <asm/cpufeature.h> /* boot_cpu_has, ... */
@@ -25,7 +25,7 @@
#include <asm/vsyscall.h> /* emulate_vsyscall */
#include <asm/vm86.h> /* struct vm86 */
#include <asm/mmu_context.h> /* vma_pkey() */
-#include <asm/efi.h> /* efi_recover_from_page_fault()*/
+#include <asm/efi.h> /* efi_crash_gracefully_on_page_fault()*/
#include <asm/desc.h> /* store_idt(), ... */
#include <asm/cpu_entry_area.h> /* exception stack */
#include <asm/pgtable_areas.h> /* VMALLOC_START, ... */
@@ -54,7 +54,7 @@ kmmio_fault(struct pt_regs *regs, unsigned long addr)
* 32-bit mode:
*
* Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
- * Check that here and ignore it.
+ * Check that here and ignore it. This is AMD erratum #91.
*
* 64-bit mode:
*
@@ -83,11 +83,7 @@ check_prefetch_opcode(struct pt_regs *regs, unsigned char *instr,
#ifdef CONFIG_X86_64
case 0x40:
/*
- * In AMD64 long mode 0x40..0x4F are valid REX prefixes
- * Need to figure out under what instruction mode the
- * instruction was issued. Could check the LDT for lm,
- * but for now it's good enough to assume that long
- * mode only uses well known segments or kernel.
+ * In 64-bit mode 0x40..0x4F are valid REX prefixes
*/
return (!user_mode(regs) || user_64bit_mode(regs));
#endif
@@ -110,6 +106,15 @@ check_prefetch_opcode(struct pt_regs *regs, unsigned char *instr,
}
}
+static bool is_amd_k8_pre_npt(void)
+{
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+
+ return unlikely(IS_ENABLED(CONFIG_CPU_SUP_AMD) &&
+ c->x86_vendor == X86_VENDOR_AMD &&
+ c->x86 == 0xf && c->x86_model < 0x40);
+}
+
static int
is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
{
@@ -117,6 +122,10 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
unsigned char *instr;
int prefetch = 0;
+ /* Erratum #91 affects AMD K8, pre-NPT CPUs */
+ if (!is_amd_k8_pre_npt())
+ return 0;
+
/*
* If it was a exec (instruction fetch) fault on NX page, then
* do not ignore the fault:
@@ -127,20 +136,31 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
instr = (void *)convert_ip_to_linear(current, regs);
max_instr = instr + 15;
- if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE_MAX)
- return 0;
+ /*
+ * This code has historically always bailed out if IP points to a
+ * not-present page (e.g. due to a race). No one has ever
+ * complained about this.
+ */
+ pagefault_disable();
while (instr < max_instr) {
unsigned char opcode;
- if (get_kernel_nofault(opcode, instr))
- break;
+ if (user_mode(regs)) {
+ if (get_user(opcode, instr))
+ break;
+ } else {
+ if (get_kernel_nofault(opcode, instr))
+ break;
+ }
instr++;
if (!check_prefetch_opcode(regs, instr, opcode, &prefetch))
break;
}
+
+ pagefault_enable();
return prefetch;
}
@@ -262,25 +282,6 @@ void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
}
}
-/*
- * Did it hit the DOS screen memory VA from vm86 mode?
- */
-static inline void
-check_v8086_mode(struct pt_regs *regs, unsigned long address,
- struct task_struct *tsk)
-{
-#ifdef CONFIG_VM86
- unsigned long bit;
-
- if (!v8086_mode(regs) || !tsk->thread.vm86)
- return;
-
- bit = (address - 0xA0000) >> PAGE_SHIFT;
- if (bit < 32)
- tsk->thread.vm86->screen_bitmap |= 1 << bit;
-#endif
-}
-
static bool low_pfn(unsigned long pfn)
{
return pfn < max_low_pfn;
@@ -335,15 +336,6 @@ KERN_ERR
"******* Disabling USB legacy in the BIOS may also help.\n";
#endif
-/*
- * No vm86 mode in 64-bit mode:
- */
-static inline void
-check_v8086_mode(struct pt_regs *regs, unsigned long address,
- struct task_struct *tsk)
-{
-}
-
static int bad_address(void *p)
{
unsigned long dummy;
@@ -427,6 +419,9 @@ static int is_errata93(struct pt_regs *regs, unsigned long address)
|| boot_cpu_data.x86 != 0xf)
return 0;
+ if (user_mode(regs))
+ return 0;
+
if (address != regs->ip)
return 0;
@@ -462,10 +457,12 @@ static int is_errata100(struct pt_regs *regs, unsigned long address)
}
/* Pentium F0 0F C7 C8 bug workaround: */
-static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
+static int is_f00f_bug(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
{
#ifdef CONFIG_X86_F00F_BUG
- if (boot_cpu_has_bug(X86_BUG_F00F) && idt_is_f00f_address(address)) {
+ if (boot_cpu_has_bug(X86_BUG_F00F) && !(error_code & X86_PF_USER) &&
+ idt_is_f00f_address(address)) {
handle_invalid_op(regs);
return 1;
}
@@ -630,53 +627,20 @@ static void set_signal_archinfo(unsigned long address,
}
static noinline void
-no_context(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, int signal, int si_code)
+page_fault_oops(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
{
- struct task_struct *tsk = current;
unsigned long flags;
int sig;
if (user_mode(regs)) {
/*
- * This is an implicit supervisor-mode access from user
- * mode. Bypass all the kernel-mode recovery code and just
- * OOPS.
+ * Implicit kernel access from user mode? Skip the stack
+ * overflow and EFI special cases.
*/
goto oops;
}
- /* Are we prepared to handle this kernel fault? */
- if (fixup_exception(regs, X86_TRAP_PF, error_code, address)) {
- /*
- * Any interrupt that takes a fault gets the fixup. This makes
- * the below recursive fault logic only apply to a faults from
- * task context.
- */
- if (in_interrupt())
- return;
-
- /*
- * Per the above we're !in_interrupt(), aka. task context.
- *
- * In this case we need to make sure we're not recursively
- * faulting through the emulate_vsyscall() logic.
- */
- if (current->thread.sig_on_uaccess_err && signal) {
- sanitize_error_code(address, &error_code);
-
- set_signal_archinfo(address, error_code);
-
- /* XXX: hwpoison faults will set the wrong code. */
- force_sig_fault(signal, si_code, (void __user *)address);
- }
-
- /*
- * Barring that, we can do the fixup and be happy.
- */
- return;
- }
-
#ifdef CONFIG_VMAP_STACK
/*
* Stack overflow? During boot, we can fault near the initial
@@ -684,8 +648,8 @@ no_context(struct pt_regs *regs, unsigned long error_code,
* that we're in vmalloc space to avoid this.
*/
if (is_vmalloc_addr((void *)address) &&
- (((unsigned long)tsk->stack - 1 - address < PAGE_SIZE) ||
- address - ((unsigned long)tsk->stack + THREAD_SIZE) < PAGE_SIZE)) {
+ (((unsigned long)current->stack - 1 - address < PAGE_SIZE) ||
+ address - ((unsigned long)current->stack + THREAD_SIZE) < PAGE_SIZE)) {
unsigned long stack = __this_cpu_ist_top_va(DF) - sizeof(void *);
/*
* We're likely to be running with very little stack space
@@ -709,28 +673,12 @@ no_context(struct pt_regs *regs, unsigned long error_code,
#endif
/*
- * 32-bit:
- *
- * Valid to do another page fault here, because if this fault
- * had been triggered by is_prefetch fixup_exception would have
- * handled it.
- *
- * 64-bit:
- *
- * Hall of shame of CPU/BIOS bugs.
- */
- if (is_prefetch(regs, error_code, address))
- return;
-
- if (is_errata93(regs, address))
- return;
-
- /*
- * Buggy firmware could access regions which might page fault, try to
- * recover from such faults.
+ * Buggy firmware could access regions which might page fault. If
+ * this happens, EFI has a special OOPS path that will try to
+ * avoid hanging the system.
*/
if (IS_ENABLED(CONFIG_EFI))
- efi_recover_from_page_fault(address);
+ efi_crash_gracefully_on_page_fault(address);
oops:
/*
@@ -741,7 +689,7 @@ oops:
show_fault_oops(regs, error_code, address);
- if (task_stack_end_corrupted(tsk))
+ if (task_stack_end_corrupted(current))
printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
sig = SIGKILL;
@@ -754,6 +702,53 @@ oops:
oops_end(flags, regs, sig);
}
+static noinline void
+kernelmode_fixup_or_oops(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, int signal, int si_code)
+{
+ WARN_ON_ONCE(user_mode(regs));
+
+ /* Are we prepared to handle this kernel fault? */
+ if (fixup_exception(regs, X86_TRAP_PF, error_code, address)) {
+ /*
+ * Any interrupt that takes a fault gets the fixup. This makes
+ * the below recursive fault logic only apply to a faults from
+ * task context.
+ */
+ if (in_interrupt())
+ return;
+
+ /*
+ * Per the above we're !in_interrupt(), aka. task context.
+ *
+ * In this case we need to make sure we're not recursively
+ * faulting through the emulate_vsyscall() logic.
+ */
+ if (current->thread.sig_on_uaccess_err && signal) {
+ sanitize_error_code(address, &error_code);
+
+ set_signal_archinfo(address, error_code);
+
+ /* XXX: hwpoison faults will set the wrong code. */
+ force_sig_fault(signal, si_code, (void __user *)address);
+ }
+
+ /*
+ * Barring that, we can do the fixup and be happy.
+ */
+ return;
+ }
+
+ /*
+ * AMD erratum #91 manifests as a spurious page fault on a PREFETCH
+ * instruction.
+ */
+ if (is_prefetch(regs, error_code, address))
+ return;
+
+ page_fault_oops(regs, error_code, address);
+}
+
/*
* Print out info about fatal segfaults, if the show_unhandled_signals
* sysctl is set:
@@ -796,47 +791,49 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
{
struct task_struct *tsk = current;
- /* User mode accesses just cause a SIGSEGV */
- if (user_mode(regs) && (error_code & X86_PF_USER)) {
- /*
- * It's possible to have interrupts off here:
- */
- local_irq_enable();
-
- /*
- * Valid to do another page fault here because this one came
- * from user space:
- */
- if (is_prefetch(regs, error_code, address))
- return;
+ if (!user_mode(regs)) {
+ kernelmode_fixup_or_oops(regs, error_code, address, pkey, si_code);
+ return;
+ }
- if (is_errata100(regs, address))
- return;
+ if (!(error_code & X86_PF_USER)) {
+ /* Implicit user access to kernel memory -- just oops */
+ page_fault_oops(regs, error_code, address);
+ return;
+ }
- sanitize_error_code(address, &error_code);
+ /*
+ * User mode accesses just cause a SIGSEGV.
+ * It's possible to have interrupts off here:
+ */
+ local_irq_enable();
- if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
- return;
+ /*
+ * Valid to do another page fault here because this one came
+ * from user space:
+ */
+ if (is_prefetch(regs, error_code, address))
+ return;
- if (likely(show_unhandled_signals))
- show_signal_msg(regs, error_code, address, tsk);
+ if (is_errata100(regs, address))
+ return;
- set_signal_archinfo(address, error_code);
+ sanitize_error_code(address, &error_code);
- if (si_code == SEGV_PKUERR)
- force_sig_pkuerr((void __user *)address, pkey);
+ if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
+ return;
- force_sig_fault(SIGSEGV, si_code, (void __user *)address);
+ if (likely(show_unhandled_signals))
+ show_signal_msg(regs, error_code, address, tsk);
- local_irq_disable();
+ set_signal_archinfo(address, error_code);
- return;
- }
+ if (si_code == SEGV_PKUERR)
+ force_sig_pkuerr((void __user *)address, pkey);
- if (is_f00f_bug(regs, address))
- return;
+ force_sig_fault(SIGSEGV, si_code, (void __user *)address);
- no_context(regs, error_code, address, SIGSEGV, si_code);
+ local_irq_disable();
}
static noinline void
@@ -926,8 +923,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
vm_fault_t fault)
{
/* Kernel mode? Handle exceptions or die: */
- if (!(error_code & X86_PF_USER)) {
- no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
+ if (!user_mode(regs)) {
+ kernelmode_fixup_or_oops(regs, error_code, address, SIGBUS, BUS_ADRERR);
return;
}
@@ -961,40 +958,6 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
}
-static noinline void
-mm_fault_error(struct pt_regs *regs, unsigned long error_code,
- 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);
- return;
- }
-
- if (fault & VM_FAULT_OOM) {
- /* Kernel mode? Handle exceptions or die: */
- if (!(error_code & X86_PF_USER)) {
- no_context(regs, error_code, address,
- SIGSEGV, SEGV_MAPERR);
- return;
- }
-
- /*
- * We ran out of memory, call the OOM killer, and return the
- * userspace (which will retry the fault, or kill us if we got
- * oom-killed):
- */
- pagefault_out_of_memory();
- } else {
- if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
- VM_FAULT_HWPOISON_LARGE))
- do_sigbus(regs, error_code, address, fault);
- else if (fault & VM_FAULT_SIGSEGV)
- bad_area_nosemaphore(regs, error_code, address);
- else
- BUG();
- }
-}
-
static int spurious_kernel_fault_check(unsigned long error_code, pte_t *pte)
{
if ((error_code & X86_PF_WRITE) && !pte_write(*pte))
@@ -1209,6 +1172,9 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
}
#endif
+ if (is_f00f_bug(regs, hw_error_code, address))
+ return;
+
/* Was the fault spurious, caused by lazy TLB invalidation? */
if (spurious_kernel_fault(hw_error_code, address))
return;
@@ -1229,10 +1195,17 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
}
NOKPROBE_SYMBOL(do_kern_addr_fault);
-/* Handle faults in the user portion of the address space */
+/*
+ * Handle faults in the user portion of the address space. Nothing in here
+ * should check X86_PF_USER without a specific justification: for almost
+ * all purposes, we should treat a normal kernel access to user memory
+ * (e.g. get_user(), put_user(), etc.) the same as the WRUSS instruction.
+ * The one exception is AC flag handling, which is, per the x86
+ * architecture, special for WRUSS.
+ */
static inline
void do_user_addr_fault(struct pt_regs *regs,
- unsigned long hw_error_code,
+ unsigned long error_code,
unsigned long address)
{
struct vm_area_struct *vma;
@@ -1244,6 +1217,21 @@ void do_user_addr_fault(struct pt_regs *regs,
tsk = current;
mm = tsk->mm;
+ if (unlikely((error_code & (X86_PF_USER | X86_PF_INSTR)) == X86_PF_INSTR)) {
+ /*
+ * Whoops, this is kernel mode code trying to execute from
+ * user memory. Unless this is AMD erratum #93, which
+ * corrupts RIP such that it looks like a user address,
+ * this is unrecoverable. Don't even try to look up the
+ * VMA or look for extable entries.
+ */
+ if (is_errata93(regs, address))
+ return;
+
+ page_fault_oops(regs, error_code, address);
+ return;
+ }
+
/* kprobes don't want to hook the spurious faults: */
if (unlikely(kprobe_page_fault(regs, X86_TRAP_PF)))
return;
@@ -1252,8 +1240,8 @@ void do_user_addr_fault(struct pt_regs *regs,
* Reserved bits are never expected to be set on
* entries in the user portion of the page tables.
*/
- if (unlikely(hw_error_code & X86_PF_RSVD))
- pgtable_bad(regs, hw_error_code, address);
+ if (unlikely(error_code & X86_PF_RSVD))
+ pgtable_bad(regs, error_code, address);
/*
* If SMAP is on, check for invalid kernel (supervisor) access to user
@@ -1263,10 +1251,13 @@ void do_user_addr_fault(struct pt_regs *regs,
* enforcement appears to be consistent with the USER bit.
*/
if (unlikely(cpu_feature_enabled(X86_FEATURE_SMAP) &&
- !(hw_error_code & X86_PF_USER) &&
- !(regs->flags & X86_EFLAGS_AC)))
- {
- bad_area_nosemaphore(regs, hw_error_code, address);
+ !(error_code & X86_PF_USER) &&
+ !(regs->flags & X86_EFLAGS_AC))) {
+ /*
+ * No extable entry here. This was a kernel access to an
+ * invalid pointer. get_kernel_nofault() will not get here.
+ */
+ page_fault_oops(regs, error_code, address);
return;
}
@@ -1275,7 +1266,7 @@ 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);
+ bad_area_nosemaphore(regs, error_code, address);
return;
}
@@ -1296,9 +1287,9 @@ void do_user_addr_fault(struct pt_regs *regs,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
- if (hw_error_code & X86_PF_WRITE)
+ if (error_code & X86_PF_WRITE)
flags |= FAULT_FLAG_WRITE;
- if (hw_error_code & X86_PF_INSTR)
+ if (error_code & X86_PF_INSTR)
flags |= FAULT_FLAG_INSTRUCTION;
#ifdef CONFIG_X86_64
@@ -1314,7 +1305,7 @@ void do_user_addr_fault(struct pt_regs *regs,
* to consider the PF_PK bit.
*/
if (is_vsyscall_vaddr(address)) {
- if (emulate_vsyscall(hw_error_code, regs, address))
+ if (emulate_vsyscall(error_code, regs, address))
return;
}
#endif
@@ -1337,7 +1328,7 @@ 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, hw_error_code, address);
+ bad_area_nosemaphore(regs, error_code, address);
return;
}
retry:
@@ -1353,17 +1344,17 @@ retry:
vma = find_vma(mm, address);
if (unlikely(!vma)) {
- bad_area(regs, hw_error_code, address);
+ bad_area(regs, error_code, address);
return;
}
if (likely(vma->vm_start <= address))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
- bad_area(regs, hw_error_code, address);
+ bad_area(regs, error_code, address);
return;
}
if (unlikely(expand_stack(vma, address))) {
- bad_area(regs, hw_error_code, address);
+ bad_area(regs, error_code, address);
return;
}
@@ -1372,8 +1363,8 @@ retry:
* we can handle it..
*/
good_area:
- if (unlikely(access_error(hw_error_code, vma))) {
- bad_area_access_error(regs, hw_error_code, address, vma);
+ if (unlikely(access_error(error_code, vma))) {
+ bad_area_access_error(regs, error_code, address, vma);
return;
}
@@ -1392,11 +1383,14 @@ good_area:
*/
fault = handle_mm_fault(vma, address, flags, regs);
- /* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
+ /*
+ * Quick path to respond to signals. The core mm code
+ * has unlocked the mm for us if we get here.
+ */
if (!user_mode(regs))
- no_context(regs, hw_error_code, address, SIGBUS,
- BUS_ADRERR);
+ kernelmode_fixup_or_oops(regs, error_code, address,
+ SIGBUS, BUS_ADRERR);
return;
}
@@ -1412,12 +1406,37 @@ good_area:
}
mmap_read_unlock(mm);
- if (unlikely(fault & VM_FAULT_ERROR)) {
- mm_fault_error(regs, hw_error_code, address, fault);
+ if (likely(!(fault & VM_FAULT_ERROR)))
+ return;
+
+ if (fatal_signal_pending(current) && !user_mode(regs)) {
+ kernelmode_fixup_or_oops(regs, error_code, address, 0, 0);
return;
}
- check_v8086_mode(regs, address, tsk);
+ if (fault & VM_FAULT_OOM) {
+ /* Kernel mode? Handle exceptions or die: */
+ if (!user_mode(regs)) {
+ kernelmode_fixup_or_oops(regs, error_code, address,
+ SIGSEGV, SEGV_MAPERR);
+ return;
+ }
+
+ /*
+ * We ran out of memory, call the OOM killer, and return the
+ * userspace (which will retry the fault, or kill us if we got
+ * oom-killed):
+ */
+ pagefault_out_of_memory();
+ } else {
+ if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
+ VM_FAULT_HWPOISON_LARGE))
+ do_sigbus(regs, error_code, address, fault);
+ else if (fault & VM_FAULT_SIGSEGV)
+ bad_area_nosemaphore(regs, error_code, address);
+ else
+ BUG();
+ }
}
NOKPROBE_SYMBOL(do_user_addr_fault);
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index e26f5c5c6565..dd694fb93916 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -157,16 +157,25 @@ __ref void *alloc_low_pages(unsigned int num)
}
/*
- * By default need 3 4k for initial PMD_SIZE, 3 4k for 0-ISA_END_ADDRESS.
- * With KASLR memory randomization, depending on the machine e820 memory
- * and the PUD alignment. We may need twice more pages when KASLR memory
+ * By default need to be able to allocate page tables below PGD firstly for
+ * the 0-ISA_END_ADDRESS range and secondly for the initial PMD_SIZE mapping.
+ * With KASLR memory randomization, depending on the machine e820 memory and the
+ * PUD alignment, twice that many pages may be needed when KASLR memory
* randomization is enabled.
*/
+
+#ifndef CONFIG_X86_5LEVEL
+#define INIT_PGD_PAGE_TABLES 3
+#else
+#define INIT_PGD_PAGE_TABLES 4
+#endif
+
#ifndef CONFIG_RANDOMIZE_MEMORY
-#define INIT_PGD_PAGE_COUNT 6
+#define INIT_PGD_PAGE_COUNT (2 * INIT_PGD_PAGE_TABLES)
#else
-#define INIT_PGD_PAGE_COUNT 12
+#define INIT_PGD_PAGE_COUNT (4 * INIT_PGD_PAGE_TABLES)
#endif
+
#define INIT_PGT_BUF_SIZE (INIT_PGD_PAGE_COUNT * PAGE_SIZE)
RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);
void __init early_alloc_pgt_buf(void)
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index bd7aff5c51f7..cd768dafca9e 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -10,8 +10,6 @@
#define pr_fmt(fmt) "mmiotrace: " fmt
-#define DEBUG 1
-
#include <linux/moduleparam.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 5a40fe411ebd..67d93a243c35 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -687,15 +687,25 @@ int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
* @return: Returns, if the page fault is not handled. This function
* will never return if the page fault is handled successfully.
*/
-void efi_recover_from_page_fault(unsigned long phys_addr)
+void efi_crash_gracefully_on_page_fault(unsigned long phys_addr)
{
if (!IS_ENABLED(CONFIG_X86_64))
return;
/*
+ * If we get an interrupt/NMI while processing an EFI runtime service
+ * then this is a regular OOPS, not an EFI failure.
+ */
+ if (in_interrupt())
+ return;
+
+ /*
* Make sure that an efi runtime service caused the page fault.
+ * READ_ONCE() because we might be OOPSing in a different thread,
+ * and we don't want to trip KTSAN while trying to OOPS.
*/
- if (efi_rts_work.efi_rts_id == EFI_NONE)
+ if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE ||
+ current_work() != &efi_rts_work.work)
return;
/*
@@ -747,6 +757,4 @@ void efi_recover_from_page_fault(unsigned long phys_addr)
set_current_state(TASK_IDLE);
schedule();
}
-
- return;
}