aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/include/asm/processor.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/include/asm/processor.h')
-rw-r--r--arch/x86/include/asm/processor.h111
1 files changed, 59 insertions, 52 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b390ff76e58f..1f2434ee9f80 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_PROCESSOR_H
#define _ASM_X86_PROCESSOR_H
@@ -131,6 +132,7 @@ struct cpuinfo_x86 {
/* Index into per_cpu list: */
u16 cpu_index;
u32 microcode;
+ unsigned initialized : 1;
} __randomize_layout;
struct cpuid_regs {
@@ -161,9 +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);
@@ -251,6 +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 {
@@ -303,7 +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];
@@ -321,12 +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;
@@ -337,18 +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
@@ -362,6 +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
/*
@@ -430,7 +447,9 @@ typedef struct {
struct thread_struct {
/* Cached TLS descriptors: */
struct desc_struct tls_array[GDT_ENTRY_TLS_ENTRIES];
+#ifdef CONFIG_X86_32
unsigned long sp0;
+#endif
unsigned long sp;
#ifdef CONFIG_X86_32
unsigned long sysenter_cs;
@@ -517,16 +536,9 @@ static inline void native_set_iopl_mask(unsigned mask)
}
static inline void
-native_load_sp0(struct tss_struct *tss, struct thread_struct *thread)
+native_load_sp0(unsigned long sp0)
{
- tss->x86_tss.sp0 = thread->sp0;
-#ifdef CONFIG_X86_32
- /* Only happens when SEP is enabled, no need to test "SEP"arately: */
- if (unlikely(tss->x86_tss.ss1 != thread->sysenter_cs)) {
- tss->x86_tss.ss1 = thread->sysenter_cs;
- wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
- }
-#endif
+ this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
}
static inline void native_swapgs(void)
@@ -538,12 +550,18 @@ 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)
+{
+ return (unsigned long)(current_top_of_stack() -
+ current_stack_pointer) < THREAD_SIZE;
}
#ifdef CONFIG_PARAVIRT
@@ -551,10 +569,9 @@ static inline unsigned long current_top_of_stack(void)
#else
#define __cpuid native_cpuid
-static inline void load_sp0(struct tss_struct *tss,
- struct thread_struct *thread)
+static inline void load_sp0(unsigned long sp0)
{
- native_load_sp0(tss, thread);
+ native_load_sp0(sp0);
}
#define set_iopl_mask native_set_iopl_mask
@@ -803,6 +820,15 @@ static inline void spin_lock_prefetch(const void *x)
#define TOP_OF_INIT_STACK ((unsigned long)&init_stack + sizeof(init_stack) - \
TOP_OF_KERNEL_STACK_PADDING)
+#define task_top_of_stack(task) ((unsigned long)(task_pt_regs(task) + 1))
+
+#define task_pt_regs(task) \
+({ \
+ unsigned long __ptr = (unsigned long)task_stack_page(task); \
+ __ptr += THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING; \
+ ((struct pt_regs *)__ptr) - 1; \
+})
+
#ifdef CONFIG_X86_32
/*
* User space process size: 3GB (default).
@@ -822,23 +848,6 @@ static inline void spin_lock_prefetch(const void *x)
.addr_limit = KERNEL_DS, \
}
-/*
- * TOP_OF_KERNEL_STACK_PADDING reserves 8 bytes on top of the ring0 stack.
- * This is necessary to guarantee that the entire "struct pt_regs"
- * is accessible even if the CPU haven't stored the SS/ESP registers
- * on the stack (interrupt gate does not save these registers
- * when switching to the same priv ring).
- * Therefore beware: accessing the ss/esp fields of the
- * "struct pt_regs" is possible, but they may contain the
- * completely wrong values.
- */
-#define task_pt_regs(task) \
-({ \
- unsigned long __ptr = (unsigned long)task_stack_page(task); \
- __ptr += THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING; \
- ((struct pt_regs *)__ptr) - 1; \
-})
-
#define KSTK_ESP(task) (task_pt_regs(task)->sp)
#else
@@ -872,11 +881,9 @@ static inline void spin_lock_prefetch(const void *x)
#define STACK_TOP_MAX TASK_SIZE_MAX
#define INIT_THREAD { \
- .sp0 = TOP_OF_INIT_STACK, \
.addr_limit = KERNEL_DS, \
}
-#define task_pt_regs(tsk) ((struct pt_regs *)(tsk)->thread.sp0 - 1)
extern unsigned long KSTK_ESP(struct task_struct *task);
#endif /* CONFIG_X86_64 */
Powered by cgit, Gruvboxed by Blaster4385.