diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 4838037f97f6..bd8b57a5c874 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -941,7 +941,8 @@ ENTRY(debug)
movl %esp, %eax # pt_regs pointer
/* Are we currently on the SYSENTER stack? */
- PER_CPU(cpu_tss + CPU_TSS_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx)
+ movl PER_CPU_VAR(cpu_entry_area), %ecx
+ addl $CPU_ENTRY_AREA_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
subl %eax, %ecx /* ecx = (end of SYSENTER_stack) - esp */
cmpl $SIZEOF_SYSENTER_stack, %ecx
jb .Ldebug_from_sysenter_stack
@@ -984,7 +985,8 @@ ENTRY(nmi)
movl %esp, %eax # pt_regs pointer
/* Are we currently on the SYSENTER stack? */
- PER_CPU(cpu_tss + CPU_TSS_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx)
+ movl PER_CPU_VAR(cpu_entry_area), %ecx
+ addl $CPU_ENTRY_AREA_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
subl %eax, %ecx /* ecx = (end of SYSENTER_stack) - esp */
cmpl $SIZEOF_SYSENTER_stack, %ecx
jb .Lnmi_from_sysenter_stack
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index f81d50d7ceac..423885bee398 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -140,6 +140,64 @@ END(native_usergs_sysret64)
* with them due to bugs in both AMD and Intel CPUs.
*/
+ .pushsection .entry_trampoline, "ax"
+
+/*
+ * The code in here gets remapped into cpu_entry_area's trampoline. This means
+ * that the assembler and linker have the wrong idea as to where this code
+ * lives (and, in fact, it's mapped more than once, so it's not even at a
+ * fixed address). So we can't reference any symbols outside the entry
+ * trampoline and expect it to work.
+ *
+ * Instead, we carefully abuse %rip-relative addressing.
+ * _entry_trampoline(%rip) refers to the start of the remapped) entry
+ * trampoline. We can thus find cpu_entry_area with this macro:
+ */
+
+#define CPU_ENTRY_AREA \
+ _entry_trampoline - CPU_ENTRY_AREA_entry_trampoline(%rip)
+
+/* The top word of the SYSENTER stack is hot and is usable as scratch space. */
+#define RSP_SCRATCH CPU_ENTRY_AREA_SYSENTER_stack + \
+ SIZEOF_SYSENTER_stack - 8 + CPU_ENTRY_AREA
+
+ENTRY(entry_SYSCALL_64_trampoline)
+ UNWIND_HINT_EMPTY
+ swapgs
+
+ /* Stash the user RSP. */
+ movq %rsp, RSP_SCRATCH
+
+ /* Load the top of the task stack into RSP */
+ movq CPU_ENTRY_AREA_tss + TSS_sp1 + CPU_ENTRY_AREA, %rsp
+
+ /* Start building the simulated IRET frame. */
+ pushq $__USER_DS /* pt_regs->ss */
+ pushq RSP_SCRATCH /* pt_regs->sp */
+ pushq %r11 /* pt_regs->flags */
+ pushq $__USER_CS /* pt_regs->cs */
+ pushq %rcx /* pt_regs->ip */
+
+ /*
+ * x86 lacks a near absolute jump, and we can't jump to the real
+ * entry text with a relative jump. We could push the target
+ * address and then use retq, but this destroys the pipeline on
+ * many CPUs (wasting over 20 cycles on Sandy Bridge). Instead,
+ * spill RDI and restore it in a second-stage trampoline.
+ */
+ pushq %rdi
+ movq $entry_SYSCALL_64_stage2, %rdi
+ jmp *%rdi
+END(entry_SYSCALL_64_trampoline)
+
+ .popsection
+
+ENTRY(entry_SYSCALL_64_stage2)
+ UNWIND_HINT_EMPTY
+ popq %rdi
+ jmp entry_SYSCALL_64_after_hwframe
+END(entry_SYSCALL_64_stage2)
+
ENTRY(entry_SYSCALL_64)
UNWIND_HINT_EMPTY
/*
@@ -330,8 +388,24 @@ syscall_return_via_sysret:
popq %rsi /* skip rcx */
popq %rdx
popq %rsi
+
+ /*
+ * Now all regs are restored except RSP and RDI.
+ * Save old stack pointer and switch to trampoline stack.
+ */
+ movq %rsp, %rdi
+ movq PER_CPU_VAR(cpu_tss_rw + TSS_sp0), %rsp
+
+ pushq RSP-RDI(%rdi) /* RSP */
+ pushq (%rdi) /* RDI */
+
+ /*
+ * We are on the trampoline stack. All regs except RDI are live.
+ * We can do future final exit work right here.
+ */
+
popq %rdi
- movq RSP-ORIG_RAX(%rsp), %rsp
+ popq %rsp
USERGS_SYSRET64
END(entry_SYSCALL_64)
@@ -466,12 +540,13 @@ END(irq_entries_start)
.macro DEBUG_ENTRY_ASSERT_IRQS_OFF
#ifdef CONFIG_DEBUG_ENTRY
- pushfq
- testl $X86_EFLAGS_IF, (%rsp)
+ pushq %rax
+ SAVE_FLAGS(CLBR_RAX)
+ testl $X86_EFLAGS_IF, %eax
jz .Lokay_\@
ud2
.Lokay_\@:
- addq $8, %rsp
+ popq %rax
#endif
.endm
@@ -563,6 +638,13 @@ END(irq_entries_start)
/* 0(%rsp): ~(interrupt number) */
.macro interrupt func
cld
+
+ testb $3, CS-ORIG_RAX(%rsp)
+ jz 1f
+ SWAPGS
+ call switch_to_thread_stack
+1:
+
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
@@ -572,12 +654,8 @@ END(irq_entries_start)
jz 1f
/*
- * IRQ from user mode. Switch to kernel gsbase and inform context
- * tracking that we're in kernel mode.
- */
- SWAPGS
-
- /*
+ * IRQ from user mode.
+ *
* We need to tell lockdep that IRQs are off. We can't do this until
* we fix gsbase, and we should do it before enter_from_user_mode
* (which can take locks). Since TRACE_IRQS_OFF idempotent,
@@ -630,10 +708,41 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode)
ud2
1:
#endif
- SWAPGS
POP_EXTRA_REGS
- POP_C_REGS
- addq $8, %rsp /* skip regs->orig_ax */
+ popq %r11
+ popq %r10
+ popq %r9
+ popq %r8
+ popq %rax
+ popq %rcx
+ popq %rdx
+ popq %rsi
+
+ /*
+ * The stack is now user RDI, orig_ax, RIP, CS, EFLAGS, RSP, SS.
+ * Save old stack pointer and switch to trampoline stack.
+ */
+ movq %rsp, %rdi
+ movq PER_CPU_VAR(cpu_tss_rw + TSS_sp0), %rsp
+
+ /* Copy the IRET frame to the trampoline stack. */
+ pushq 6*8(%rdi) /* SS */
+ pushq 5*8(%rdi) /* RSP */
+ pushq 4*8(%rdi) /* EFLAGS */
+ pushq 3*8(%rdi) /* CS */
+ pushq 2*8(%rdi) /* RIP */
+
+ /* Push user RDI on the trampoline stack. */
+ pushq (%rdi)
+
+ /*
+ * We are on the trampoline stack. All regs except RDI are live.
+ * We can do future final exit work right here.
+ */
+
+ /* Restore RDI. */
+ popq %rdi
+ SWAPGS
INTERRUPT_RETURN
@@ -829,7 +938,33 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt
/*
* Exception entry points.
*/
-#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss) + (TSS_ist + ((x) - 1) * 8)
+#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + ((x) - 1) * 8)
+
+/*
+ * Switch to the thread stack. This is called with the IRET frame and
+ * orig_ax on the stack. (That is, RDI..R12 are not on the stack and
+ * space has not been allocated for them.)
+ */
+ENTRY(switch_to_thread_stack)
+ UNWIND_HINT_FUNC
+
+ pushq %rdi
+ movq %rsp, %rdi
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+ UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
+
+ pushq 7*8(%rdi) /* regs->ss */
+ pushq 6*8(%rdi) /* regs->rsp */
+ pushq 5*8(%rdi) /* regs->eflags */
+ pushq 4*8(%rdi) /* regs->cs */
+ pushq 3*8(%rdi) /* regs->ip */
+ pushq 2*8(%rdi) /* regs->orig_ax */
+ pushq 8(%rdi) /* return address */
+ UNWIND_HINT_FUNC
+
+ movq (%rdi), %rdi
+ ret
+END(switch_to_thread_stack)
.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
ENTRY(\sym)
@@ -848,11 +983,12 @@ ENTRY(\sym)
ALLOC_PT_GPREGS_ON_STACK
- .if \paranoid
- .if \paranoid == 1
+ .if \paranoid < 2
testb $3, CS(%rsp) /* If coming from userspace, switch stacks */
- jnz 1f
+ jnz .Lfrom_usermode_switch_stack_\@
.endif
+
+ .if \paranoid
call paranoid_entry
.else
call error_entry
@@ -894,20 +1030,15 @@ ENTRY(\sym)
jmp error_exit
.endif
- .if \paranoid == 1
+ .if \paranoid < 2
/*
- * Paranoid entry from userspace. Switch stacks and treat it
+ * Entry from userspace. Switch stacks and treat it
* as a normal entry. This means that paranoid handlers
* run in real process context if user_mode(regs).
*/
-1:
+.Lfrom_usermode_switch_stack_\@:
call error_entry
-
- movq %rsp, %rdi /* pt_regs pointer */
- call sync_regs
- movq %rax, %rsp /* switch stack */
-
movq %rsp, %rdi /* pt_regs pointer */
.if \has_error_code
@@ -1170,6 +1301,14 @@ ENTRY(error_entry)
SWAPGS
.Lerror_entry_from_usermode_after_swapgs:
+ /* Put us onto the real thread stack. */
+ popq %r12 /* save return addr in %12 */
+ movq %rsp, %rdi /* arg0 = pt_regs pointer */
+ call sync_regs
+ movq %rax, %rsp /* switch stack */
+ ENCODE_FRAME_POINTER
+ pushq %r12
+
/*
* We need to tell lockdep that IRQs are off. We can't do this until
* we fix gsbase, and we should do it before enter_from_user_mode
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 568e130d932c..95ad40eb7eff 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -48,7 +48,7 @@
*/
ENTRY(entry_SYSENTER_compat)
/* Interrupts are off on entry. */
- SWAPGS_UNSAFE_STACK
+ SWAPGS
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
/*
@@ -306,8 +306,11 @@ ENTRY(entry_INT80_compat)
*/
movl %eax, %eax
- /* Construct struct pt_regs on stack (iret frame is already on stack) */
pushq %rax /* pt_regs->orig_ax */
+
+ /* switch to thread stack expects orig_ax to be pushed */
+ call switch_to_thread_stack
+
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
pushq %rdx /* pt_regs->dx */
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index bf6a76202a77..ea9a7dde62e5 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -135,6 +135,8 @@ extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
set_bit(bit, (unsigned long *)cpu_caps_set); \
} while (0)
+#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
+
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_X86_FAST_FEATURE_TESTS)
/*
* Static testing of CPU features. Used the same as boot_cpu_has().
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 4011cb03ef08..aab4fe9f49f8 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -60,17 +60,10 @@ static inline struct desc_struct *get_current_gdt_rw(void)
return this_cpu_ptr(&gdt_page)->gdt;
}
-/* Get the fixmap index for a specific processor */
-static inline unsigned int get_cpu_gdt_ro_index(int cpu)
-{
- return FIX_GDT_REMAP_BEGIN + cpu;
-}
-
/* Provide the fixmap address of the remapped GDT */
static inline struct desc_struct *get_cpu_gdt_ro(int cpu)
{
- unsigned int idx = get_cpu_gdt_ro_index(cpu);
- return (struct desc_struct *)__fix_to_virt(idx);
+ return (struct desc_struct *)&get_cpu_entry_area(cpu)->gdt;
}
/* Provide the current read-only GDT */
@@ -185,7 +178,7 @@ static inline void set_tssldt_descriptor(void *d, unsigned long addr,
#endif
}
-static inline void __set_tss_desc(unsigned cpu, unsigned int entry, void *addr)
+static inline void __set_tss_desc(unsigned cpu, unsigned int entry, struct x86_hw_tss *addr)
{
struct desc_struct *d = get_cpu_gdt_rw(cpu);
tss_desc tss;
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index b0c505fe9a95..94fc4fa14127 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -44,6 +44,45 @@ extern unsigned long __FIXADDR_TOP;
PAGE_SIZE)
#endif
+/*
+ * cpu_entry_area is a percpu region in the fixmap that contains things
+ * needed by the CPU and early entry/exit code. Real types aren't used
+ * for all fields here to avoid circular header dependencies.
+ *
+ * Every field is a virtual alias of some other allocated backing store.
+ * There is no direct allocation of a struct cpu_entry_area.
+ */
+struct cpu_entry_area {
+ char gdt[PAGE_SIZE];
+
+ /*
+ * The GDT is just below SYSENTER_stack and thus serves (on x86_64) as
+ * a a read-only guard page.
+ */
+ struct SYSENTER_stack_page SYSENTER_stack_page;
+
+ /*
+ * On x86_64, the TSS is mapped RO. On x86_32, it's mapped RW because
+ * we need task switches to work, and task switches write to the TSS.
+ */
+ struct tss_struct tss;
+
+ char entry_trampoline[PAGE_SIZE];
+
+#ifdef CONFIG_X86_64
+ /*
+ * Exception stacks used for IST entries.
+ *
+ * In the future, this should have a separate slot for each stack
+ * with guard pages between them.
+ */
+ char exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ];
+#endif
+};
+
+#define CPU_ENTRY_AREA_PAGES (sizeof(struct cpu_entry_area) / PAGE_SIZE)
+
+extern void setup_cpu_entry_areas(void);
/*
* Here we define all the compile-time 'special' virtual
@@ -101,8 +140,8 @@ enum fixed_addresses {
FIX_LNW_VRTC,
#endif
/* Fixmap entries to remap the GDTs, one per processor. */
- FIX_GDT_REMAP_BEGIN,
- FIX_GDT_REMAP_END = FIX_GDT_REMAP_BEGIN + NR_CPUS - 1,
+ FIX_CPU_ENTRY_AREA_TOP,
+ FIX_CPU_ENTRY_AREA_BOTTOM = FIX_CPU_ENTRY_AREA_TOP + (CPU_ENTRY_AREA_PAGES * NR_CPUS) - 1,
#ifdef CONFIG_ACPI_APEI_GHES
/* Used for GHES mapping from assorted contexts */
@@ -191,5 +230,30 @@ void __init *early_memremap_decrypted_wp(resource_size_t phys_addr,
void __early_set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t flags);
+static inline unsigned int __get_cpu_entry_area_page_index(int cpu, int page)
+{
+ BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0);
+
+ return FIX_CPU_ENTRY_AREA_BOTTOM - cpu*CPU_ENTRY_AREA_PAGES - page;
+}
+
+#define __get_cpu_entry_area_offset_index(cpu, offset) ({ \
+ BUILD_BUG_ON(offset % PAGE_SIZE != 0); \
+ __get_cpu_entry_area_page_index(cpu, offset / PAGE_SIZE); \
+ })
+
+#define get_cpu_entry_area_index(cpu, field) \
+ __get_cpu_entry_area_offset_index((cpu), offsetof(struct cpu_entry_area, field))
+
+static inline struct cpu_entry_area *get_cpu_entry_area(int cpu)
+{
+ return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0));
+}
+
+static inline struct SYSENTER_stack *cpu_SYSENTER_stack(int cpu)
+{
+ return &get_cpu_entry_area(cpu)->SYSENTER_stack_page.stack;
+}
+
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_X86_FIXMAP_H */
diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 1b0a5abcd8ae..96aa6b9884dc 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -20,16 +20,7 @@
#ifndef _ASM_X86_HYPERVISOR_H
#define _ASM_X86_HYPERVISOR_H
-#ifdef CONFIG_HYPERVISOR_GUEST
-
-#include <asm/kvm_para.h>
-#include <asm/x86_init.h>
-#include <asm/xen/hypervisor.h>
-
-/*
- * x86 hypervisor information
- */
-
+/* x86 hypervisor types */
enum x86_hypervisor_type {
X86_HYPER_NATIVE = 0,
X86_HYPER_VMWARE,
@@ -39,6 +30,12 @@ enum x86_hypervisor_type {
X86_HYPER_KVM,
};
+#ifdef CONFIG_HYPERVISOR_GUEST
+
+#include <asm/kvm_para.h>
+#include <asm/x86_init.h>
+#include <asm/xen/hypervisor.h>
+
struct hypervisor_x86 {
/* Hypervisor name */
const char *name;
@@ -58,7 +55,15 @@ struct hypervisor_x86 {
extern enum x86_hypervisor_type x86_hyper_type;
extern void init_hypervisor_platform(void);
+static inline bool hypervisor_is_type(enum x86_hypervisor_type type)
+{
+ return x86_hyper_type == type;
+}
#else
static inline void init_hypervisor_platform(void) { }
+static inline bool hypervisor_is_type(enum x86_hypervisor_type type)
+{
+ return type == X86_HYPER_NATIVE;
+}
#endif /* CONFIG_HYPERVISOR_GUEST */
#endif /* _ASM_X86_HYPERVISOR_H */
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index c8ef23f2c28f..89f08955fff7 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -142,6 +142,9 @@ static inline notrace unsigned long arch_local_irq_save(void)
swapgs; \
sysretl
+#ifdef CONFIG_DEBUG_ENTRY
+#define SAVE_FLAGS(x) pushfq; popq %rax
+#endif
#else
#define INTERRUPT_RETURN iret
#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit
diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h
index f86a8caa561e..395c9631e000 100644
--- a/arch/x86/include/asm/kdebug.h
+++ b/arch/x86/include/asm/kdebug.h
@@ -26,6 +26,7 @@ extern void die(const char *, struct pt_regs *,long);
extern int __must_check __die(const char *, struct pt_regs *, long);
extern void show_stack_regs(struct pt_regs *regs);
extern void __show_regs(struct pt_regs *regs, int all);
+extern void show_iret_regs(struct pt_regs *regs);
extern unsigned long oops_begin(void);
extern void oops_end(unsigned long, struct pt_regs *, int signr);
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 283efcaac8af..892df375b615 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -927,6 +927,15 @@ extern void default_banner(void);
PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret64), \
CLBR_NONE, \
jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usergs_sysret64))
+
+#ifdef CONFIG_DEBUG_ENTRY
+#define SAVE_FLAGS(clobbers) \
+ PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_save_fl), clobbers, \
+ PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
+ call PARA_INDIRECT(pv_irq_ops+PV_IRQ_save_fl); \
+ PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
+#endif
+
#endif /* CONFIG_X86_32 */
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index cc16fa882e3e..1f2434ee9f80 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -163,9 +163,9 @@ enum cpuid_regs_idx {
extern struct cpuinfo_x86 boot_cpu_data;
extern struct cpuinfo_x86 new_cpu_data;
-extern struct tss_struct doublefault_tss;
-extern __u32 cpu_caps_cleared[NCAPINTS];
-extern __u32 cpu_caps_set[NCAPINTS];
+extern struct x86_hw_tss doublefault_tss;
+extern __u32 cpu_caps_cleared[NCAPINTS + NBUGINTS];
+extern __u32 cpu_caps_set[NCAPINTS + NBUGINTS];
#ifdef CONFIG_SMP
DECLARE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
@@ -253,6 +253,11 @@ static inline void load_cr3(pgd_t *pgdir)
write_cr3(__sme_pa(pgdir));
}
+/*
+ * Note that while the legacy 'TSS' name comes from 'Task State Segment',
+ * on modern x86 CPUs the TSS also holds information important to 64-bit mode,
+ * unrelated to the task-switch mechanism:
+ */
#ifdef CONFIG_X86_32
/* This is the TSS defined by the hardware. */
struct x86_hw_tss {
@@ -305,7 +310,13 @@ struct x86_hw_tss {
struct x86_hw_tss {
u32 reserved1;
u64 sp0;
+
+ /*
+ * We store cpu_current_top_of_stack in sp1 so it's always accessible.
+ * Linux does not use ring 1, so sp1 is not otherwise needed.
+ */
u64 sp1;
+
u64 sp2;
u64 reserved2;
u64 ist[7];
@@ -323,12 +334,22 @@ struct x86_hw_tss {
#define IO_BITMAP_BITS 65536
#define IO_BITMAP_BYTES (IO_BITMAP_BITS/8)
#define IO_BITMAP_LONGS (IO_BITMAP_BYTES/sizeof(long))
-#define IO_BITMAP_OFFSET offsetof(struct tss_struct, io_bitmap)
+#define IO_BITMAP_OFFSET (offsetof(struct tss_struct, io_bitmap) - offsetof(struct tss_struct, x86_tss))
#define INVALID_IO_BITMAP_OFFSET 0x8000
+struct SYSENTER_stack {
+ unsigned long words[64];
+};
+
+struct SYSENTER_stack_page {
+ struct SYSENTER_stack stack;
+} __aligned(PAGE_SIZE);
+
struct tss_struct {
/*
- * The hardware state:
+ * The fixed hardware portion. This must not cross a page boundary
+ * at risk of violating the SDM's advice and potentially triggering
+ * errata.
*/
struct x86_hw_tss x86_tss;
@@ -339,18 +360,9 @@ struct tss_struct {
* be within the limit.
*/
unsigned long io_bitmap[IO_BITMAP_LONGS + 1];
+} __aligned(PAGE_SIZE);
-#ifdef CONFIG_X86_32
- /*
- * Space for the temporary SYSENTER stack.
- */
- unsigned long SYSENTER_stack_canary;
- unsigned long SYSENTER_stack[64];
-#endif
-
-} ____cacheline_aligned;
-
-DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
+DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw);
/*
* sizeof(unsigned long) coming from an extra "long" at the end
@@ -364,6 +376,9 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
#ifdef CONFIG_X86_32
DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
+#else
+/* The RO copy can't be accessed with this_cpu_xyz(), so use the RW copy. */
+#define cpu_current_top_of_stack cpu_tss_rw.x86_tss.sp1
#endif
/*
@@ -523,7 +538,7 @@ static inline void native_set_iopl_mask(unsigned mask)
static inline void
native_load_sp0(unsigned long sp0)
{
- this_cpu_write(cpu_tss.x86_tss.sp0, sp0);
+ this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
}
static inline void native_swapgs(void)
@@ -535,12 +550,12 @@ static inline void native_swapgs(void)
static inline unsigned long current_top_of_stack(void)
{
-#ifdef CONFIG_X86_64
- return this_cpu_read_stable(cpu_tss.x86_tss.sp0);
-#else
- /* sp0 on x86_32 is special in and around vm86 mode. */
+ /*
+ * We can't read directly from tss.sp0: sp0 on x86_32 is special in
+ * and around vm86 mode and sp0 on x86_64 is special because of the
+ * entry trampoline.
+ */
return this_cpu_read_stable(cpu_current_top_of_stack);
-#endif
}
static inline bool on_thread_stack(void)
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index 8da111b3c342..f8062bfd43a0 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -16,6 +16,7 @@ enum stack_type {
STACK_TYPE_TASK,
STACK_TYPE_IRQ,
STACK_TYPE_SOFTIRQ,
+ STACK_TYPE_SYSENTER,
STACK_TYPE_EXCEPTION,
STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1,
};
@@ -28,6 +29,8 @@ struct stack_info {
bool in_task_stack(unsigned long *stack, struct task_struct *task,
struct stack_info *info);
+bool in_sysenter_stack(unsigned long *stack, struct stack_info *info);
+
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask);
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index 8c6bd6863db9..9b6df68d8fd1 100644
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -79,10 +79,10 @@ do { \
static inline void refresh_sysenter_cs(struct thread_struct *thread)
{
/* Only happens when SEP is enabled, no need to test "SEP"arately: */
- if (unlikely(this_cpu_read(cpu_tss.x86_tss.ss1) == thread->sysenter_cs))
+ if (unlikely(this_cpu_read(cpu_tss_rw.x86_tss.ss1) == thread->sysenter_cs))
return;
- this_cpu_write(cpu_tss.x86_tss.ss1, thread->sysenter_cs);
+ this_cpu_write(cpu_tss_rw.x86_tss.ss1, thread->sysenter_cs);
wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
}
#endif
@@ -90,10 +90,12 @@ static inline void refresh_sysenter_cs(struct thread_struct *thread)
/* This is used when switching tasks or entering/exiting vm86 mode. */
static inline void update_sp0(struct task_struct *task)
{
+ /* On x86_64, sp0 always points to the entry trampoline stack, which is constant: */
#ifdef CONFIG_X86_32
load_sp0(task->thread.sp0);
#else
- load_sp0(task_top_of_stack(task));
+ if (static_cpu_has(X86_FEATURE_XENPV))
+ load_sp0(task_top_of_stack(task));
#endif
}
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 70f425947dc5..00223333821a 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -207,7 +207,7 @@ static inline int arch_within_stack_frames(const void * const stack,
#else /* !__ASSEMBLY__ */
#ifdef CONFIG_X86_64
-# define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
+# define cpu_current_top_of_stack (cpu_tss_rw + TSS_sp1)
#endif
#endif
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 1fadd310ff68..31051f35cbb7 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -75,7 +75,6 @@ dotraplinkage void do_segment_not_present(struct pt_regs *, long);
dotraplinkage void do_stack_segment(struct pt_regs *, long);
#ifdef CONFIG_X86_64
dotraplinkage void do_double_fault(struct pt_regs *, long);
-asmlinkage struct pt_regs *sync_regs(struct pt_regs *);
#endif
dotraplinkage void do_general_protection(struct pt_regs *, long);
dotraplinkage void do_page_fault(struct pt_regs *, unsigned long);
diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
index e9cc6fe1fc6f..c1688c2d0a12 100644
--- a/arch/x86/include/asm/unwind.h
+++ b/arch/x86/include/asm/unwind.h
@@ -7,6 +7,9 @@
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
+#define IRET_FRAME_OFFSET (offsetof(struct pt_regs, ip))
+#define IRET_FRAME_SIZE (sizeof(struct pt_regs) - IRET_FRAME_OFFSET)
+
struct unwind_state {
struct stack_info stack_info;
unsigned long stack_mask;
@@ -52,6 +55,10 @@ void unwind_start(struct unwind_state *state, struct task_struct *task,
}
#if defined(CONFIG_UNWINDER_ORC) || defined(CONFIG_UNWINDER_FRAME_POINTER)
+/*
+ * WARNING: The entire pt_regs may not be safe to dereference. In some cases,
+ * only the iret frame registers are accessible. Use with caution!
+ */
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
if (unwind_done(state))
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 8ea78275480d..cd360a5e0dca 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -93,4 +93,10 @@ void common(void) {
BLANK();
DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
+
+ /* Layout info for cpu_entry_area */
+ OFFSET(CPU_ENTRY_AREA_tss, cpu_entry_area, tss);
+ OFFSET(CPU_ENTRY_AREA_entry_trampoline, cpu_entry_area, entry_trampoline);
+ OFFSET(CPU_ENTRY_AREA_SYSENTER_stack, cpu_entry_area, SYSENTER_stack_page);
+ DEFINE(SIZEOF_SYSENTER_stack, sizeof(struct SYSENTER_stack));
}
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index dedf428b20b6..7d20d9c0b3d6 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -47,13 +47,8 @@ void foo(void)
BLANK();
/* Offset from the sysenter stack to tss.sp0 */
- DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) -
- offsetofend(struct tss_struct, SYSENTER_stack));
-
- /* Offset from cpu_tss to SYSENTER_stack */
- OFFSET(CPU_TSS_SYSENTER_stack, tss_struct, SYSENTER_stack);
- /* Size of SYSENTER_stack */
- DEFINE(SIZEOF_SYSENTER_stack, sizeof(((struct tss_struct *)0)->SYSENTER_stack));
+ DEFINE(TSS_sysenter_sp0, offsetof(struct cpu_entry_area, tss.x86_tss.sp0) -
+ offsetofend(struct cpu_entry_area, SYSENTER_stack_page.stack));
#ifdef CONFIG_CC_STACKPROTECTOR
BLANK();
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 630212fa9b9d..bf51e51d808d 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -23,6 +23,9 @@ int main(void)
#ifdef CONFIG_PARAVIRT
OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64);
OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs);
+#ifdef CONFIG_DEBUG_ENTRY
+ OFFSET(PV_IRQ_save_fl, pv_irq_ops, save_fl);
+#endif
BLANK();
#endif
@@ -63,6 +66,7 @@ int main(void)
OFFSET(TSS_ist, tss_struct, x86_tss.ist);
OFFSET(TSS_sp0, tss_struct, x86_tss.sp0);
+ OFFSET(TSS_sp1, tss_struct, x86_tss.sp1);
BLANK();
#ifdef CONFIG_CC_STACKPROTECTOR
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index fa998ca8aa5a..7416da3ec4df 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -476,8 +476,8 @@ static const char *table_lookup_model(struct cpuinfo_x86 *c)
return NULL; /* Not found */
}
-__u32 cpu_caps_cleared[NCAPINTS];
-__u32 cpu_caps_set[NCAPINTS];
+__u32 cpu_caps_cleared[NCAPINTS + NBUGINTS];
+__u32 cpu_caps_set[NCAPINTS + NBUGINTS];
void load_percpu_segment(int cpu)
{
@@ -490,27 +490,116 @@ void load_percpu_segment(int cpu)
load_stack_canary_segment();
}
-/* Setup the fixmap mapping only once per-processor */
-static inline void setup_fixmap_gdt(int cpu)
+#ifdef CONFIG_X86_32
+/* The 32-bit entry code needs to find cpu_entry_area. */
+DEFINE_PER_CPU(struct cpu_entry_area *, cpu_entry_area);
+#endif
+
+#ifdef CONFIG_X86_64
+/*
+ * Special IST stacks which the CPU switches to when it calls
+ * an IST-marked descriptor entry. Up to 7 stacks (hardware
+ * limit), all of them are 4K, except the debug stack which
+ * is 8K.
+ */
+static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
+ [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
+ [DEBUG_STACK - 1] = DEBUG_STKSZ
+};
+
+static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
+ [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
+#endif
+
+static DEFINE_PER_CPU_PAGE_ALIGNED(struct SYSENTER_stack_page,
+ SYSENTER_stack_storage);
+
+static void __init
+set_percpu_fixmap_pages(int idx, void *ptr, int pages, pgprot_t prot)
+{
+ for ( ; pages; pages--, idx--, ptr += PAGE_SIZE)
+ __set_fixmap(idx, per_cpu_ptr_to_phys(ptr), prot);
+}
+
+/* Setup the fixmap mappings only once per-processor */
+static void __init setup_cpu_entry_area(int cpu)
{
#ifdef CONFIG_X86_64
- /* On 64-bit systems, we use a read-only fixmap GDT. */
- pgprot_t prot = PAGE_KERNEL_RO;
+ extern char _entry_trampoline[];
+
+ /* On 64-bit systems, we use a read-only fixmap GDT and TSS. */
+ pgprot_t gdt_prot = PAGE_KERNEL_RO;
+ pgprot_t tss_prot = PAGE_KERNEL_RO;
#else
/*
* On native 32-bit systems, the GDT cannot be read-only because
* our double fault handler uses a task gate, and entering through
- * a task gate needs to change an available TSS to busy. If the GDT
- * is read-only, that will triple fault.
+ * a task gate needs to change an available TSS to busy. If the
+ * GDT is read-only, that will triple fault. The TSS cannot be
+ * read-only because the CPU writes to it on task switches.
*
- * On Xen PV, the GDT must be read-only because the hypervisor requires
- * it.
+ * On Xen PV, the GDT must be read-only because the hypervisor
+ * requires it.
*/
- pgprot_t prot = boot_cpu_has(X86_FEATURE_XENPV) ?
+ pgprot_t gdt_prot = boot_cpu_has(X86_FEATURE_XENPV) ?
PAGE_KERNEL_RO : PAGE_KERNEL;
+ pgprot_t tss_prot = PAGE_KERNEL;
#endif
- __set_fixmap(get_cpu_gdt_ro_index(cpu), get_cpu_gdt_paddr(cpu), prot);
+ __set_fixmap(get_cpu_entry_area_index(cpu, gdt), get_cpu_gdt_paddr(cpu), gdt_prot);
+ set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, SYSENTER_stack_page),
+ per_cpu_ptr(&SYSENTER_stack_storage, cpu), 1,
+ PAGE_KERNEL);
+
+ /*
+ * The Intel SDM says (Volume 3, 7.2.1):
+ *
+ * Avoid placing a page boundary in the part of the TSS that the
+ * processor reads during a task switch (the first 104 bytes). The
+ * processor may not correctly perform address translations if a
+ * boundary occurs in this area. During a task switch, the processor
+ * reads and writes into the first 104 bytes of each TSS (using
+ * contiguous physical addresses beginning with the physical address
+ * of the first byte of the TSS). So, after TSS access begins, if
+ * part of the 104 bytes is not physically contiguous, the processor
+ * will access incorrect information without generating a page-fault
+ * exception.
+ *
+ * There are also a lot of errata involving the TSS spanning a page
+ * boundary. Assert that we're not doing that.
+ */
+ BUILD_BUG_ON((offsetof(struct tss_struct, x86_tss) ^
+ offsetofend(struct tss_struct, x86_tss)) & PAGE_MASK);
+ BUILD_BUG_ON(sizeof(struct tss_struct) % PAGE_SIZE != 0);
+ set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, tss),
+ &per_cpu(cpu_tss_rw, cpu),
+ sizeof(struct tss_struct) / PAGE_SIZE,
+ tss_prot);
+
+#ifdef CONFIG_X86_32
+ per_cpu(cpu_entry_area, cpu) = get_cpu_entry_area(cpu);
+#endif
+
+#ifdef CONFIG_X86_64
+ BUILD_BUG_ON(sizeof(exception_stacks) % PAGE_SIZE != 0);
+ BUILD_BUG_ON(sizeof(exception_stacks) !=
+ sizeof(((struct cpu_entry_area *)0)->exception_stacks));
+ set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, exception_stacks),
+ &per_cpu(exception_stacks, cpu),
+ sizeof(exception_stacks) / PAGE_SIZE,
+ PAGE_KERNEL);
+
+ __set_fixmap(get_cpu_entry_area_index(cpu, entry_trampoline),
+ __pa_symbol(_entry_trampoline), PAGE_KERNEL_RX);
+#endif
+}
+
+void __init setup_cpu_entry_areas(void)
+{
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu)
+ setup_cpu_entry_area(cpu);
}
/* Load the original GDT from the per-cpu structure */
@@ -747,7 +836,7 @@ static void apply_forced_caps(struct cpuinfo_x86 *c)
{
int i;
- for (i = 0; i < NCAPINTS; i++) {
+ for (i = 0; i < NCAPINTS + NBUGINTS; i++) {
c->x86_capability[i] &= ~cpu_caps_cleared[i];
c->x86_capability[i] |= cpu_caps_set[i];
}
@@ -1250,7 +1339,7 @@ void enable_sep_cpu(void)
return;
cpu = get_cpu();
- tss = &per_cpu(cpu_tss, cpu);
+ tss = &per_cpu(cpu_tss_rw, cpu);
/*
* We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
@@ -1259,11 +1348,7 @@ void enable_sep_cpu(void)
tss->x86_tss.ss1 = __KERNEL_CS;
wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0);
-
- wrmsr(MSR_IA32_SYSENTER_ESP,
- (unsigned long)tss + offsetofend(struct tss_struct, SYSENTER_stack),
- 0);
-
+ wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1), 0);
wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);
put_cpu();
@@ -1357,25 +1442,19 @@ DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1;
DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
EXPORT_PER_CPU_SYMBOL(__preempt_count);
-/*
- * Special IST stacks which the CPU switches to when it calls
- * an IST-marked descriptor entry. Up to 7 stacks (hardware
- * limit), all of them are 4K, except the debug stack which
- * is 8K.
- */
-static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
- [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
- [DEBUG_STACK - 1] = DEBUG_STKSZ
-};
-
-static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
- [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
-
/* May not be marked __init: used by software suspend */
void syscall_init(void)
{
+ extern char _entry_trampoline[];
+ extern char entry_SYSCALL_64_trampoline[];
+
+ int cpu = smp_processor_id();
+ unsigned long SYSCALL64_entry_trampoline =
+ (unsigned long)get_cpu_entry_area(cpu)->entry_trampoline +
+ (entry_SYSCALL_64_trampoline - _entry_trampoline);
+
wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
- wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);
+ wrmsrl(MSR_LSTAR, SYSCALL64_entry_trampoline);
#ifdef CONFIG_IA32_EMULATION
wrmsrl(MSR_CSTAR, (unsigned long)entry_SYSCALL_compat);
@@ -1386,7 +1465,7 @@ void syscall_init(void)
* AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
*/
wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
- wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
+ wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1));
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
#else
wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret);
@@ -1530,7 +1609,7 @@ void cpu_init(void)
if (cpu)
load_ucode_ap();
- t = &per_cpu(cpu_tss, cpu);
+ t = &per_cpu(cpu_tss_rw, cpu);
oist = &per_cpu(orig_ist, cpu);
#ifdef CONFIG_NUMA
@@ -1569,7 +1648,7 @@ void cpu_init(void)
* set up and load the per-CPU TSS
*/
if (!oist->ist[0]) {
- char *estacks = per_cpu(exception_stacks, cpu);
+ char *estacks = get_cpu_entry_area(cpu)->exception_stacks;
for (v = 0; v < N_EXCEPTION_STACKS; v++) {
estacks += exception_stack_sizes[v];
@@ -1580,7 +1659,7 @@ void cpu_init(void)
}
}
- t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
+ t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
/*
* <= is required because the CPU will access up to
@@ -1596,11 +1675,12 @@ void cpu_init(void)
enter_lazy_tlb(&init_mm, me);
/*
- * Initialize the TSS. Don't bother initializing sp0, as the initial
- * task never enters user mode.
+ * Initialize the TSS. sp0 points to the entry trampoline stack
+ * regardless of what task is running.
*/
- set_tss_desc(cpu, t);
+ set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
load_TR_desc();
+ load_sp0((unsigned long)(cpu_SYSENTER_stack(cpu) + 1));
load_mm_ldt(&init_mm);
@@ -1612,7 +1692,6 @@ void cpu_init(void)
if (is_uv_system())
uv_cpu_init();
- setup_fixmap_gdt(cpu);
load_fixmap_gdt(cpu);
}
@@ -1622,7 +1701,7 @@ void cpu_init(void)
{
int cpu = smp_processor_id();
struct task_struct *curr = current;
- struct tss_struct *t = &per_cpu(cpu_tss, cpu);
+ struct tss_struct *t = &per_cpu(cpu_tss_rw, cpu);
wait_for_master_cpu(cpu);
@@ -1657,12 +1736,12 @@ void cpu_init(void)
* Initialize the TSS. Don't bother initializing sp0, as the initial
* task never enters user mode.
*/
- set_tss_desc(cpu, t);
+ set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
load_TR_desc();
load_mm_ldt(&init_mm);
- t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
+ t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
#ifdef CONFIG_DOUBLEFAULT
/* Set up doublefault TSS pointer in the GDT */
@@ -1674,7 +1753,6 @@ void cpu_init(void)
fpu__init_cpu();
- setup_fixmap_gdt(cpu);
load_fixmap_gdt(cpu);
}
#endif
diff --git a/arch/x86/kernel/doublefault.c b/arch/x86/kernel/doublefault.c
index 0e662c55ae90..0b8cedb20d6d 100644
--- a/arch/x86/kernel/doublefault.c
+++ b/arch/x86/kernel/doublefault.c
@@ -50,25 +50,23 @@ static void doublefault_fn(void)
cpu_relax();
}
-struct tss_struct doublefault_tss __cacheline_aligned = {
- .x86_tss = {
- .sp0 = STACK_START,
- .ss0 = __KERNEL_DS,
- .ldt = 0,
- .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
+struct x86_hw_tss doublefault_tss __cacheline_aligned = {
+ .sp0 = STACK_START,
+ .ss0 = __KERNEL_DS,
+ .ldt = 0,
+ .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
- .ip = (unsigned long) doublefault_fn,
- /* 0x2 bit is always set */
- .flags = X86_EFLAGS_SF | 0x2,
- .sp = STACK_START,
- .es = __USER_DS,
- .cs = __KERNEL_CS,
- .ss = __KERNEL_DS,
- .ds = __USER_DS,
- .fs = __KERNEL_PERCPU,
+ .ip = (unsigned long) doublefault_fn,
+ /* 0x2 bit is always set */
+ .flags = X86_EFLAGS_SF | 0x2,
+ .sp = STACK_START,
+ .es = __USER_DS,
+ .cs = __KERNEL_CS,
+ .ss = __KERNEL_DS,
+ .ds = __USER_DS,
+ .fs = __KERNEL_PERCPU,
- .__cr3 = __pa_nodebug(swapper_pg_dir),
- }
+ .__cr3 = __pa_nodebug(swapper_pg_dir),
};
/* dummy for do_double_fault() call */
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index f13b4c00a5de..bbd6d986e2d0 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -43,6 +43,24 @@ bool in_task_stack(unsigned long *stack, struct task_struct *task,
return true;
}
+bool in_sysenter_stack(unsigned long *stack, struct stack_info *info)
+{
+ struct SYSENTER_stack *ss = cpu_SYSENTER_stack(smp_processor_id());
+
+ void *begin = ss;
+ void *end = ss + 1;
+
+ if ((void *)stack < begin || (void *)stack >= end)
+ return false;
+
+ info->type = STACK_TYPE_SYSENTER;
+ info->begin = begin;
+ info->end = end;
+ info->next_sp = NULL;
+
+ return true;
+}
+
static void printk_stack_address(unsigned long address, int reliable,
char *log_lvl)
{
@@ -50,6 +68,28 @@ static void printk_stack_address(unsigned long address, int reliable,
printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
}
+void show_iret_regs(struct pt_regs *regs)
+{
+ printk(KERN_DEFAULT "RIP: %04x:%pS\n", (int)regs->cs, (void *)regs->ip);
+ printk(KERN_DEFAULT "RSP: %04x:%016lx EFLAGS: %08lx", (int)regs->ss,
+ regs->sp, regs->flags);
+}
+
+static void show_regs_safe(struct stack_info *info, struct pt_regs *regs)
+{
+ if (on_stack(info, regs, sizeof(*regs)))
+ __show_regs(regs, 0);
+ else if (on_stack(info, (void *)regs + IRET_FRAME_OFFSET,
+ IRET_FRAME_SIZE)) {
+ /*
+ * When an interrupt or exception occurs in entry code, the
+ * full pt_regs might not have been saved yet. In that case
+ * just print the iret frame.
+ */
+ show_iret_regs(regs);
+ }
+}
+
void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, char *log_lvl)
{
@@ -71,31 +111,35 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
* - task stack
* - interrupt stack
* - HW exception stacks (double fault, nmi, debug, mce)
+ * - SYSENTER stack
*
- * x86-32 can have up to three stacks:
+ * x86-32 can have up to four stacks:
* - task stack
* - softirq stack
* - hardirq stack
+ * - SYSENTER stack
*/
for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
const char *stack_name;
- /*
- * If we overflowed the task stack into a guard page, jump back
- * to the bottom of the usable stack.
- */
- if (task_stack_page(task) - (void *)stack < PAGE_SIZE)
- stack = task_stack_page(task);
-
- if (get_stack_info(stack, task, &stack_info, &visit_mask))
- break;
+ if (get_stack_info(stack, task, &stack_info, &visit_mask)) {
+ /*
+ * We weren't on a valid stack. It's possible that
+ * we overflowed a valid stack into a guard page.
+ * See if the next page up is valid so that we can
+ * generate some kind of backtrace if this happens.
+ */
+ stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack);
+ if (get_stack_info(stack, task, &stack_info, &visit_mask))
+ break;
+ }
stack_name = stack_type_name(stack_info.type);
if (stack_name)
printk("%s <%s>\n", log_lvl, stack_name);
- if (regs && on_stack(&stack_info, regs, sizeof(*regs)))
- __show_regs(regs, 0);
+ if (regs)
+ show_regs_safe(&stack_info, regs);
/*
* Scan the stack, printing any text addresses we find. At the
@@ -119,7 +163,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
/*
* Don't print regs->ip again if it was already printed
- * by __show_regs() below.
+ * by show_regs_safe() below.
*/
if (regs && stack == ®s->ip)
goto next;
@@ -155,8 +199,8 @@ next:
/* if the frame has entry regs, print them */
regs = unwind_get_entry_regs(&state);
- if (regs && on_stack(&stack_info, regs, sizeof(*regs)))
- __show_regs(regs, 0);
+ if (regs)
+ show_regs_safe(&stack_info, regs);
}
if (stack_name)
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index daefae83a3aa..5ff13a6b3680 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -26,6 +26,9 @@ const char *stack_type_name(enum stack_type type)
if (type == STACK_TYPE_SOFTIRQ)
return "SOFTIRQ";
+ if (type == STACK_TYPE_SYSENTER)
+ return "SYSENTER";
+
return NULL;
}
@@ -93,6 +96,9 @@ int get_stack_info(unsigned long *stack, struct task_struct *task,
if (task != current)
goto unknown;
+ if (in_sysenter_stack(stack, info))
+ goto recursion_check;
+
if (in_hardirq_stack(stack, info))
goto recursion_check;
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 88ce2ffdb110..abc828f8c297 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -37,6 +37,9 @@ const char *stack_type_name(enum stack_type type)
if (type == STACK_TYPE_IRQ)
return "IRQ";
+ if (type == STACK_TYPE_SYSENTER)
+ return "SYSENTER";
+
if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
return exception_stack_names[type - STACK_TYPE_EXCEPTION];
@@ -115,6 +118,9 @@ int get_stack_info(unsigned long *stack, struct task_struct *task,
if (in_irq_stack(stack, info))
goto recursion_check;
+ if (in_sysenter_stack(stack, info))
+ goto recursion_check;
+
goto unknown;
recursion_check:
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index 3feb648781c4..2f723301eb58 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -67,7 +67,7 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
* because the ->io_bitmap_max value must match the bitmap
* contents:
*/
- tss = &per_cpu(cpu_tss, get_cpu());
+ tss = &per_cpu(cpu_tss_rw, get_cpu());
if (turn_on)
bitmap_clear(t->io_bitmap_ptr, from, num);
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 49cfd9fe7589..68e1867cca80 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -219,18 +219,6 @@ __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
/* high bit used in ret_from_ code */
unsigned vector = ~regs->orig_ax;
- /*
- * NB: Unlike exception entries, IRQ entries do not reliably
- * handle context tracking in the low-level entry code. This is
- * because syscall entries execute briefly with IRQs on before
- * updating context tracking state, so we can take an IRQ from
- * kernel mode with CONTEXT_USER. The low-level entry code only
- * updates the context if we came from user mode, so we won't
- * switch to CONTEXT_KERNEL. We'll fix that once the syscall
- * code is cleaned up enough that we can cleanly defer enabling
- * IRQs.
- */
-
entering_irq();
/* entering_irq() tells RCU that we're not quiescent. Check it. */
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 020efbf5786b..d86e344f5b3d 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -57,10 +57,10 @@ static inline void stack_overflow_check(struct pt_regs *regs)
if (regs->sp >= estack_top && regs->sp <= estack_bottom)
return;
- WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n",
+ WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx,ip:%pF)\n",
current->comm, curbase, regs->sp,
irq_stack_top, irq_stack_bottom,
- estack_top, estack_bottom);
+ estack_top, estack_bottom, (void *)regs->ip);
if (sysctl_panic_on_stackoverflow)
panic("low stack detected by irq handler - check messages\n");
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index ac0be8283325..9edadabf04f6 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -10,7 +10,6 @@ DEF_NATIVE(pv_irq_ops, save_fl, "pushfq; popq %rax");
DEF_NATIVE(pv_mmu_ops, read_cr2, "movq %cr2, %rax");
DEF_NATIVE(pv_mmu_ops, read_cr3, "movq %cr3, %rax");
DEF_NATIVE(pv_mmu_ops, write_cr3, "movq %rdi, %cr3");
-DEF_NATIVE(pv_mmu_ops, flush_tlb_single, "invlpg (%rdi)");
DEF_NATIVE(pv_cpu_ops, wbinvd, "wbinvd");
DEF_NATIVE(pv_cpu_ops, usergs_sysret64, "swapgs; sysretq");
@@ -60,7 +59,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
PATCH_SITE(pv_mmu_ops, read_cr2);
PATCH_SITE(pv_mmu_ops, read_cr3);
PATCH_SITE(pv_mmu_ops, write_cr3);
- PATCH_SITE(pv_mmu_ops, flush_tlb_single);
PATCH_SITE(pv_cpu_ops, wbinvd);
#if defined(CONFIG_PARAVIRT_SPINLOCKS)
case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index bb988a24db92..aed9d94bd46f 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -47,7 +47,7 @@
* section. Since TSS's are completely CPU-local, we want them
* on exact cacheline boundaries, to eliminate cacheline ping-pong.
*/
-__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
+__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss_rw) = {
.x86_tss = {
/*
* .sp0 is only used when entering ring 0 from a lower
@@ -56,6 +56,16 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
* Poison it.
*/
.sp0 = (1UL << (BITS_PER_LONG-1)) + 1,
+
+#ifdef CONFIG_X86_64
+ /*
+ * .sp1 is cpu_current_top_of_stack. The init task never
+ * runs user code, but cpu_current_top_of_stack should still
+ * be well defined before the first context switch.
+ */
+ .sp1 = TOP_OF_INIT_STACK,
+#endif
+
#ifdef CONFIG_X86_32
.ss0 = __KERNEL_DS,
.ss1 = __KERNEL_CS,
@@ -71,11 +81,8 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
*/
.io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 },
#endif
-#ifdef CONFIG_X86_32
- .SYSENTER_stack_canary = STACK_END_MAGIC,
-#endif
};
-EXPORT_PER_CPU_SYMBOL(cpu_tss);
+EXPORT_PER_CPU_SYMBOL(cpu_tss_rw);
DEFINE_PER_CPU(bool, __tss_limit_invalid);
EXPORT_PER_CPU_SYMBOL_GPL(__tss_limit_invalid);
@@ -104,7 +111,7 @@ void exit_thread(struct task_struct *tsk)
struct fpu *fpu = &t->fpu;
if (bp) {
- struct tss_struct *tss = &per_cpu(cpu_tss, get_cpu());
+ struct tss_struct *tss = &per_cpu(cpu_tss_rw, get_cpu());
t->io_bitmap_ptr = NULL;
clear_thread_flag(TIF_IO_BITMAP);
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 45bf0c5f93e1..5224c6099184 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -234,7 +234,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
struct fpu *prev_fpu = &prev->fpu;
struct fpu *next_fpu = &next->fpu;
int cpu = smp_processor_id();
- struct tss_struct *tss = &per_cpu(cpu_tss, cpu);
+ struct tss_struct *tss = &per_cpu(cpu_tss_rw, cpu);
/* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index eeeb34f85c25..c75466232016 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -69,9 +69,8 @@ void __show_regs(struct pt_regs *regs, int all)
unsigned int fsindex, gsindex;
unsigned int ds, cs, es;
- printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs, (void *)regs->ip);
- printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx", regs->ss,
- regs->sp, regs->flags);
+ show_iret_regs(regs);
+
if (regs->orig_ax != -1)
pr_cont(" ORIG_RAX: %016lx\n", regs->orig_ax);
else
@@ -88,6 +87,9 @@ void __show_regs(struct pt_regs *regs, int all)
printk(KERN_DEFAULT "R13: %016lx R14: %016lx R15: %016lx\n",
regs->r13, regs->r14, regs->r15);
+ if (!all)
+ return;
+
asm("movl %%ds,%0" : "=r" (ds));
asm("movl %%cs,%0" : "=r" (cs));
asm("movl %%es,%0" : "=r" (es));
@@ -98,9 +100,6 @@ void __show_regs(struct pt_regs *regs, int all)
rdmsrl(MSR_GS_BASE, gs);
rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
- if (!all)
- return;
-
cr0 = read_cr0();
cr2 = read_cr2();
cr3 = __read_cr3();
@@ -400,7 +399,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
struct fpu *prev_fpu = &prev->fpu;
struct fpu *next_fpu = &next->fpu;
int cpu = smp_processor_id();
- struct tss_struct *tss = &per_cpu(cpu_tss, cpu);
+ struct tss_struct *tss = &per_cpu(cpu_tss_rw, cpu);
WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) &&
this_cpu_read(irq_count) != -1);
@@ -462,6 +461,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* Switch the PDA and FPU contexts.
*/
this_cpu_write(current_task, next_p);
+ this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p));
/* Reload sp0. */
update_sp0(next_p);
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 989514c94a55..e98f8b66a460 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -348,9 +348,15 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
/*
* If IRET takes a non-IST fault on the espfix64 stack, then we
- * end up promoting it to a doublefault. In that case, modify
- * the stack to make it look like we just entered the #GP
- * handler from user space, similar to bad_iret.
+ * end up promoting it to a doublefault. In that case, take
+ * advantage of the fact that we're not using the normal (TSS.sp0)
+ * stack right now. We can write a fake #GP(0) frame at TSS.sp0
+ * and then modify our own IRET frame so that, when we return,
+ * we land directly at the #GP(0) vector with the stack already
+ * set up according to its expectations.
+ *
+ * The net result is that our #GP handler will think that we
+ * entered from usermode with the bad user context.
*
* No need for ist_enter here because we don't use RCU.
*/
@@ -358,13 +364,26 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
regs->cs == __KERNEL_CS &&
regs->ip == (unsigned long)native_irq_return_iret)
{
- struct pt_regs *normal_regs = task_pt_regs(current);
+ struct pt_regs *gpregs = (struct pt_regs *)this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1;
- /* Fake a #GP(0) from userspace. */
- memmove(&normal_regs->ip, (void *)regs->sp, 5*8);
- normal_regs->orig_ax = 0; /* Missing (lost) #GP error code */
+ /*
+ * regs->sp points to the failing IRET frame on the
+ * ESPFIX64 stack. Copy it to the entry stack. This fills
+ * in gpregs->ss through gpregs->ip.
+ *
+ */
+ memmove(&gpregs->ip, (void *)regs->sp, 5*8);
+ gpregs->orig_ax = 0; /* Missing (lost) #GP error code */
+
+ /*
+ * Adjust our frame so that we return straight to the #GP
+ * vector with the expected RSP value. This is safe because
+ * we won't enable interupts or schedule before we invoke
+ * general_protection, so nothing will clobber the stack
+ * frame we just set up.
+ */
regs->ip = (unsigned long)general_protection;
- regs->sp = (unsigned long)&normal_regs->orig_ax;
+ regs->sp = (unsigned long)&gpregs->orig_ax;
return;
}
@@ -389,7 +408,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
*
* Processors update CR2 whenever a page fault is detected. If a
* second page fault occurs while an earlier page fault is being
- * deliv- ered, the faulting linear address of the second fault will
+ * delivered, the faulting linear address of the second fault will
* overwrite the contents of CR2 (replacing the previous
* address). These updates to CR2 occur even if the page fault
* results in a double fault or occurs during the delivery of a
@@ -605,14 +624,15 @@ NOKPROBE_SYMBOL(do_int3);
#ifdef CONFIG_X86_64
/*
- * Help handler running on IST stack to switch off the IST stack if the
- * interrupted code was in user mode. The actual stack switch is done in
- * entry_64.S
+ * Help handler running on a per-cpu (IST or entry trampoline) stack
+ * to switch to the normal thread stack if the interrupted code was in
+ * user mode. The actual stack switch is done in entry_64.S
*/
asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs)
{
- struct pt_regs *regs = task_pt_regs(current);
- *regs = *eregs;
+ struct pt_regs *regs = (struct pt_regs *)this_cpu_read(cpu_current_top_of_stack) - 1;
+ if (regs != eregs)
+ *regs = *eregs;
return regs;
}
NOKPROBE_SYMBOL(sync_regs);
@@ -628,13 +648,13 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
/*
* This is called from entry_64.S early in handling a fault
* caused by a bad iret to user mode. To handle the fault
- * correctly, we want move our stack frame to task_pt_regs
- * and we want to pretend that the exception came from the
- * iret target.
+ * correctly, we want to move our stack frame to where it would
+ * be had we entered directly on the entry stack (rather than
+ * just below the IRET frame) and we want to pretend that the
+ * exception came from the IRET target.
*/
struct bad_iret_stack *new_stack =
- container_of(task_pt_regs(current),
- struct bad_iret_stack, regs);
+ (struct bad_iret_stack *)this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1;
/* Copy the IRET target to the new stack. */
memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8);
@@ -795,14 +815,6 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
debug_stack_usage_dec();
exit:
-#if defined(CONFIG_X86_32)
- /*
- * This is the most likely code path that involves non-trivial use
- * of the SYSENTER stack. Check that we haven't overrun it.
- */
- WARN(this_cpu_read(cpu_tss.SYSENTER_stack_canary) != STACK_END_MAGIC,
- "Overran or corrupted SYSENTER stack\n");
-#endif
ist_exit(regs);
}
NOKPROBE_SYMBOL(do_debug);
@@ -929,6 +941,9 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
void __init trap_init(void)
{
+ /* Init cpu_entry_area before IST entries are set up */
+ setup_cpu_entry_areas();
+
idt_setup_traps();
/*
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index a3f973b2c97a..be86a865087a 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -253,22 +253,15 @@ unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
return NULL;
}
-static bool stack_access_ok(struct unwind_state *state, unsigned long addr,
+static bool stack_access_ok(struct unwind_state *state, unsigned long _addr,
size_t len)
{
struct stack_info *info = &state->stack_info;
+ void *addr = (void *)_addr;
- /*
- * If the address isn't on the current stack, switch to the next one.
- *
- * We may have to traverse multiple stacks to deal with the possibility
- * that info->next_sp could point to an empty stack and the address
- * could be on a subsequent stack.
- */
- while (!on_stack(info, (void *)addr, len))
- if (get_stack_info(info->next_sp, state->task, info,
- &state->stack_mask))
- return false;
+ if (!on_stack(info, addr, len) &&
+ (get_stack_info(addr, state->task, info, &state->stack_mask)))
+ return false;
return true;
}
@@ -283,42 +276,32 @@ static bool deref_stack_reg(struct unwind_state *state, unsigned long addr,
return true;
}
-#define REGS_SIZE (sizeof(struct pt_regs))
-#define SP_OFFSET (offsetof(struct pt_regs, sp))
-#define IRET_REGS_SIZE (REGS_SIZE - offsetof(struct pt_regs, ip))
-#define IRET_SP_OFFSET (SP_OFFSET - offsetof(struct pt_regs, ip))
-
static bool deref_stack_regs(struct unwind_state *state, unsigned long addr,
- unsigned long *ip, unsigned long *sp, bool full)
+ unsigned long *ip, unsigned long *sp)
{
- size_t regs_size = full ? REGS_SIZE : IRET_REGS_SIZE;
- size_t sp_offset = full ? SP_OFFSET : IRET_SP_OFFSET;
- struct pt_regs *regs = (struct pt_regs *)(addr + regs_size - REGS_SIZE);
+ struct pt_regs *regs = (struct pt_regs *)addr;
- if (IS_ENABLED(CONFIG_X86_64)) {
- if (!stack_access_ok(state, addr, regs_size))
- return false;
+ /* x86-32 support will be more complicated due to the ®s->sp hack */
+ BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_32));
- *ip = regs->ip;
- *sp = regs->sp;
-
- return true;
- }
-
- if (!stack_access_ok(state, addr, sp_offset))
+ if (!stack_access_ok(state, addr, sizeof(struct pt_regs)))
return false;
*ip = regs->ip;
+ *sp = regs->sp;
+ return true;
+}
- if (user_mode(regs)) {
- if (!stack_access_ok(state, addr + sp_offset,
- REGS_SIZE - SP_OFFSET))
- return false;
+static bool deref_stack_iret_regs(struct unwind_state *state, unsigned long addr,
+ unsigned long *ip, unsigned long *sp)
+{
+ struct pt_regs *regs = (void *)addr - IRET_FRAME_OFFSET;
- *sp = regs->sp;
- } else
- *sp = (unsigned long)®s->sp;
+ if (!stack_access_ok(state, addr, IRET_FRAME_SIZE))
+ return false;
+ *ip = regs->ip;
+ *sp = regs->sp;
return true;
}
@@ -327,7 +310,6 @@ bool unwind_next_frame(struct unwind_state *state)
unsigned long ip_p, sp, orig_ip, prev_sp = state->sp;
enum stack_type prev_type = state->stack_info.type;
struct orc_entry *orc;
- struct pt_regs *ptregs;
bool indirect = false;
if (unwind_done(state))
@@ -435,7 +417,7 @@ bool unwind_next_frame(struct unwind_state *state)
break;
case ORC_TYPE_REGS:
- if (!deref_stack_regs(state, sp, &state->ip, &state->sp, true)) {
+ if (!deref_stack_regs(state, sp, &state->ip, &state->sp)) {
orc_warn("can't dereference registers at %p for ip %pB\n",
(void *)sp, (void *)orig_ip);
goto done;
@@ -447,20 +429,14 @@ bool unwind_next_frame(struct unwind_state *state)
break;
case ORC_TYPE_REGS_IRET:
- if (!deref_stack_regs(state, sp, &state->ip, &state->sp, false)) {
+ if (!deref_stack_iret_regs(state, sp, &state->ip, &state->sp)) {
orc_warn("can't dereference iret registers at %p for ip %pB\n",
(void *)sp, (void *)orig_ip);
goto done;
}
- ptregs = container_of((void *)sp, struct pt_regs, ip);
- if ((unsigned long)ptregs >= prev_sp &&
- on_stack(&state->stack_info, ptregs, REGS_SIZE)) {
- state->regs = ptregs;
- state->full_regs = false;
- } else
- state->regs = NULL;
-
+ state->regs = (void *)sp - IRET_FRAME_OFFSET;
+ state->full_regs = false;
state->signal = true;
break;
@@ -553,8 +529,18 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
}
if (get_stack_info((unsigned long *)state->sp, state->task,
- &state->stack_info, &state->stack_mask))
- return;
+ &state->stack_info, &state->stack_mask)) {
+ /*
+ * We weren't on a valid stack. It's possible that
+ * we overflowed a valid stack into a guard page.
+ * See if the next page up is valid so that we can
+ * generate some kind of backtrace if this happens.
+ */
+ void *next_page = (void *)PAGE_ALIGN((unsigned long)state->sp);
+ if (get_stack_info(next_page, state->task, &state->stack_info,
+ &state->stack_mask))
+ return;
+ }
/*
* The caller can provide the address of the first frame directly
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index a4009fb9be87..d2a8b5a24a44 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -107,6 +107,15 @@ SECTIONS
SOFTIRQENTRY_TEXT
*(.fixup)
*(.gnu.warning)
+
+#ifdef CONFIG_X86_64
+ . = ALIGN(PAGE_SIZE);
+ _entry_trampoline = .;
+ *(.entry_trampoline)
+ . = ALIGN(PAGE_SIZE);
+ ASSERT(. - _entry_trampoline == PAGE_SIZE, "entry trampoline is too big");
+#endif
+
/* End of text section */
_etext = .;
} :text = 0x9090
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8eba631c4dbd..023afa0c8887 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2302,7 +2302,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
* processors. See 22.2.4.
*/
vmcs_writel(HOST_TR_BASE,
- (unsigned long)this_cpu_ptr(&cpu_tss));
+ (unsigned long)&get_cpu_entry_area(cpu)->tss.x86_tss);
vmcs_writel(HOST_GDTR_BASE, (unsigned long)gdt); /* 22.2.4 */
/*
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
index 553f8fd23cc4..4846eff7e4c8 100644
--- a/arch/x86/lib/delay.c
+++ b/arch/x86/lib/delay.c
@@ -107,10 +107,10 @@ static void delay_mwaitx(unsigned long __loops)
delay = min_t(u64, MWAITX_MAX_LOOPS, loops);
/*
- * Use cpu_tss as a cacheline-aligned, seldomly
+ * Use cpu_tss_rw as a cacheline-aligned, seldomly
* accessed per-cpu variable as the monitor target.
*/
- __monitorx(raw_cpu_ptr(&cpu_tss), 0, 0);
+ __monitorx(raw_cpu_ptr(&cpu_tss_rw), 0, 0);
/*
* AMD, like Intel, supports the EAX hint and EAX=0xf
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 99dfed6dfef8..9ec70d780f1f 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -277,6 +277,7 @@ void __init kasan_early_init(void)
void __init kasan_init(void)
{
int i;
+ void *shadow_cpu_entry_begin, *shadow_cpu_entry_end;
#ifdef CONFIG_KASAN_INLINE
register_die_notifier(&kasan_die_notifier);
@@ -329,8 +330,23 @@ void __init kasan_init(void)
(unsigned long)kasan_mem_to_shadow(_end),
early_pfn_to_nid(__pa(_stext)));
+ shadow_cpu_entry_begin = (void *)__fix_to_virt(FIX_CPU_ENTRY_AREA_BOTTOM);
+ shadow_cpu_entry_begin = kasan_mem_to_shadow(shadow_cpu_entry_begin);
+ shadow_cpu_entry_begin = (void *)round_down((unsigned long)shadow_cpu_entry_begin,
+ PAGE_SIZE);
+
+ shadow_cpu_entry_end = (void *)(__fix_to_virt(FIX_CPU_ENTRY_AREA_TOP) + PAGE_SIZE);
+ shadow_cpu_entry_end = kasan_mem_to_shadow(shadow_cpu_entry_end);
+ shadow_cpu_entry_end = (void *)round_up((unsigned long)shadow_cpu_entry_end,
+ PAGE_SIZE);
+
kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
- (void *)KASAN_SHADOW_END);
+ shadow_cpu_entry_begin);
+
+ kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
+ (unsigned long)shadow_cpu_entry_end, 0);
+
+ kasan_populate_zero_shadow(shadow_cpu_entry_end, (void *)KASAN_SHADOW_END);
load_cr3(init_top_pgt);
__flush_tlb_all();
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 36a28eddb435..a7d966964c6f 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -152,17 +152,19 @@ static void do_fpu_end(void)
static void fix_processor_context(void)
{
int cpu = smp_processor_id();
- struct tss_struct *t = &per_cpu(cpu_tss, cpu);
#ifdef CONFIG_X86_64
struct desc_struct *desc = get_cpu_gdt_rw(cpu);
tss_desc tss;
#endif
- set_tss_desc(cpu, t); /*
- * This just modifies memory; should not be
- * necessary. But... This is necessary, because
- * 386 hardware has concept of busy TSS or some
- * similar stupidity.
- */
+
+ /*
+ * We need to reload TR, which requires that we change the
+ * GDT entry to indicate "available" first.
+ *
+ * XXX: This could probably all be replaced by a call to
+ * force_reload_TR().
+ */
+ set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
#ifdef CONFIG_X86_64
memcpy(&tss, &desc[GDT_ENTRY_TSS], sizeof(tss_desc));
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index f2414c6c5e7c..7beeee1443b3 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -826,7 +826,7 @@ static void xen_load_sp0(unsigned long sp0)
mcs = xen_mc_entry(0);
MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0);
xen_mc_issue(PARAVIRT_LAZY_CPU);
- this_cpu_write(cpu_tss.x86_tss.sp0, sp0);
+ this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
}
void xen_set_iopl_mask(unsigned mask)
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index fc048ec686e7..6cf801ca1142 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2272,7 +2272,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
#endif
case FIX_TEXT_POKE0:
case FIX_TEXT_POKE1:
- case FIX_GDT_REMAP_BEGIN ... FIX_GDT_REMAP_END:
+ case FIX_CPU_ENTRY_AREA_TOP ... FIX_CPU_ENTRY_AREA_BOTTOM:
/* All local page mappings */
pte = pfn_pte(phys, prot);
break;