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-rw-r--r--arch/x86/entry/entry_64.S13
-rw-r--r--arch/x86/include/asm/asm.h2
-rw-r--r--arch/x86/include/asm/mmu.h15
-rw-r--r--arch/x86/include/asm/mmu_context.h5
-rw-r--r--arch/x86/include/asm/nospec-branch.h37
-rw-r--r--arch/x86/include/asm/tlbflush.h2
-rw-r--r--arch/x86/kernel/apic/vector.c14
-rw-r--r--arch/x86/kvm/svm.c9
-rw-r--r--arch/x86/kvm/vmx.c9
-rw-r--r--arch/x86/mm/tlb.c33
-rw-r--r--arch/x86/net/bpf_jit_comp.c9
-rw-r--r--arch/x86/oprofile/nmi_int.c2
-rw-r--r--arch/x86/platform/intel-mid/intel-mid.c2
-rw-r--r--arch/x86/xen/suspend.c16
14 files changed, 145 insertions, 23 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index db5009ce065a..8d7e4d48db0d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -176,13 +176,26 @@ GLOBAL(entry_SYSCALL_64_after_swapgs)
pushq %r8 /* pt_regs->r8 */
pushq %r9 /* pt_regs->r9 */
pushq %r10 /* pt_regs->r10 */
+ /*
+ * Clear extra registers that a speculation attack might
+ * otherwise want to exploit. Interleave XOR with PUSH
+ * for better uop scheduling:
+ */
+ xorq %r10, %r10 /* nospec r10 */
pushq %r11 /* pt_regs->r11 */
+ xorq %r11, %r11 /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
+ xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp */
+ xorl %ebp, %ebp /* nospec rbp */
pushq %r12 /* pt_regs->r12 */
+ xorq %r12, %r12 /* nospec r12 */
pushq %r13 /* pt_regs->r13 */
+ xorq %r13, %r13 /* nospec r13 */
pushq %r14 /* pt_regs->r14 */
+ xorq %r14, %r14 /* nospec r14 */
pushq %r15 /* pt_regs->r15 */
+ xorq %r15, %r15 /* nospec r15 */
/* IRQs are off. */
movq %rsp, %rdi
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 7bb29a416b77..f35f246a26bf 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -128,6 +128,7 @@
#endif
#ifndef __ASSEMBLY__
+#ifndef __BPF__
/*
* This output constraint should be used for any inline asm which has a "call"
* instruction. Otherwise the asm may be inserted before the frame pointer
@@ -137,5 +138,6 @@
register unsigned long current_stack_pointer asm(_ASM_SP);
#define ASM_CALL_CONSTRAINT "+r" (current_stack_pointer)
#endif
+#endif
#endif /* _ASM_X86_ASM_H */
diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index 8b272a08d1a8..e2e09347ee3c 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -3,12 +3,18 @@
#include <linux/spinlock.h>
#include <linux/mutex.h>
+#include <linux/atomic.h>
/*
- * The x86 doesn't have a mmu context, but
- * we put the segment information here.
+ * x86 has arch-specific MMU state beyond what lives in mm_struct.
*/
typedef struct {
+ /*
+ * ctx_id uniquely identifies this mm_struct. A ctx_id will never
+ * be reused, and zero is not a valid ctx_id.
+ */
+ u64 ctx_id;
+
#ifdef CONFIG_MODIFY_LDT_SYSCALL
struct ldt_struct *ldt;
#endif
@@ -33,6 +39,11 @@ typedef struct {
#endif
} mm_context_t;
+#define INIT_MM_CONTEXT(mm) \
+ .context = { \
+ .ctx_id = 1, \
+ }
+
void leave_mm(int cpu);
#endif /* _ASM_X86_MMU_H */
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index d23e35584f15..5a295bb97103 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -12,6 +12,9 @@
#include <asm/tlbflush.h>
#include <asm/paravirt.h>
#include <asm/mpx.h>
+
+extern atomic64_t last_mm_ctx_id;
+
#ifndef CONFIG_PARAVIRT
static inline void paravirt_activate_mm(struct mm_struct *prev,
struct mm_struct *next)
@@ -106,6 +109,8 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
static inline int init_new_context(struct task_struct *tsk,
struct mm_struct *mm)
{
+ mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id);
+
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
if (cpu_feature_enabled(X86_FEATURE_OSPKE)) {
/* pkey 0 is the default and always allocated */
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 76b058533e47..81a1be326571 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -177,4 +177,41 @@ static inline void indirect_branch_prediction_barrier(void)
}
#endif /* __ASSEMBLY__ */
+
+/*
+ * Below is used in the eBPF JIT compiler and emits the byte sequence
+ * for the following assembly:
+ *
+ * With retpolines configured:
+ *
+ * callq do_rop
+ * spec_trap:
+ * pause
+ * lfence
+ * jmp spec_trap
+ * do_rop:
+ * mov %rax,(%rsp)
+ * retq
+ *
+ * Without retpolines configured:
+ *
+ * jmp *%rax
+ */
+#ifdef CONFIG_RETPOLINE
+# define RETPOLINE_RAX_BPF_JIT_SIZE 17
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT1_off32(0xE8, 7); /* callq do_rop */ \
+ /* spec_trap: */ \
+ EMIT2(0xF3, 0x90); /* pause */ \
+ EMIT3(0x0F, 0xAE, 0xE8); /* lfence */ \
+ EMIT2(0xEB, 0xF9); /* jmp spec_trap */ \
+ /* do_rop: */ \
+ EMIT4(0x48, 0x89, 0x04, 0x24); /* mov %rax,(%rsp) */ \
+ EMIT1(0xC3); /* retq */
+#else
+# define RETPOLINE_RAX_BPF_JIT_SIZE 2
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT2(0xFF, 0xE0); /* jmp *%rax */
+#endif
+
#endif /* _ASM_X86_NOSPEC_BRANCH_H_ */
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 94146f665a3c..99185a064978 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -68,6 +68,8 @@ static inline void invpcid_flush_all_nonglobals(void)
struct tlb_state {
struct mm_struct *active_mm;
int state;
+ /* last user mm's ctx id */
+ u64 last_ctx_id;
/*
* Access to this CR4 shadow and to H/W CR4 is protected by
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index b5229abd1629..4922ab66fd29 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -93,8 +93,12 @@ out_data:
return NULL;
}
-static void free_apic_chip_data(struct apic_chip_data *data)
+static void free_apic_chip_data(unsigned int virq, struct apic_chip_data *data)
{
+#ifdef CONFIG_X86_IO_APIC
+ if (virq < nr_legacy_irqs())
+ legacy_irq_data[virq] = NULL;
+#endif
if (data) {
free_cpumask_var(data->domain);
free_cpumask_var(data->old_domain);
@@ -318,11 +322,7 @@ static void x86_vector_free_irqs(struct irq_domain *domain,
apic_data = irq_data->chip_data;
irq_domain_reset_irq_data(irq_data);
raw_spin_unlock_irqrestore(&vector_lock, flags);
- free_apic_chip_data(apic_data);
-#ifdef CONFIG_X86_IO_APIC
- if (virq + i < nr_legacy_irqs())
- legacy_irq_data[virq + i] = NULL;
-#endif
+ free_apic_chip_data(virq + i, apic_data);
}
}
}
@@ -363,7 +363,7 @@ static int x86_vector_alloc_irqs(struct irq_domain *domain, unsigned int virq,
err = assign_irq_vector_policy(virq + i, node, data, info);
if (err) {
irq_data->chip_data = NULL;
- free_apic_chip_data(data);
+ free_apic_chip_data(virq + i, data);
goto error;
}
}
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index be644afab1bb..24d2a3ee743f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -44,6 +44,7 @@
#include <asm/debugreg.h>
#include <asm/kvm_para.h>
#include <asm/irq_remapping.h>
+#include <asm/microcode.h>
#include <asm/nospec-branch.h>
#include <asm/virtext.h>
@@ -4919,7 +4920,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
* being speculatively taken.
*/
if (svm->spec_ctrl)
- wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
+ native_wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
asm volatile (
"push %%" _ASM_BP "; \n\t"
@@ -5028,11 +5029,11 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
* If the L02 MSR bitmap does not intercept the MSR, then we need to
* save it.
*/
- if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))
- rdmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
+ if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)))
+ svm->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL);
if (svm->spec_ctrl)
- wrmsrl(MSR_IA32_SPEC_CTRL, 0);
+ native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
/* Eliminate branch target predictions from guest mode */
vmexit_fill_RSB();
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c51aaac953b4..0f3bb4632310 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -49,6 +49,7 @@
#include <asm/kexec.h>
#include <asm/apic.h>
#include <asm/irq_remapping.h>
+#include <asm/microcode.h>
#include <asm/nospec-branch.h>
#include "trace.h"
@@ -8906,7 +8907,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
* being speculatively taken.
*/
if (vmx->spec_ctrl)
- wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
+ native_wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
vmx->__launched = vmx->loaded_vmcs->launched;
asm(
@@ -9041,11 +9042,11 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
* If the L02 MSR bitmap does not intercept the MSR, then we need to
* save it.
*/
- if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))
- rdmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
+ if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)))
+ vmx->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL);
if (vmx->spec_ctrl)
- wrmsrl(MSR_IA32_SPEC_CTRL, 0);
+ native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
/* Eliminate branch target predictions from guest mode */
vmexit_fill_RSB();
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 578973ade71b..eac92e2d171b 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -10,6 +10,7 @@
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
+#include <asm/nospec-branch.h>
#include <asm/cache.h>
#include <asm/apic.h>
#include <asm/uv/uv.h>
@@ -29,6 +30,8 @@
* Implement flush IPI by CALL_FUNCTION_VECTOR, Alex Shi
*/
+atomic64_t last_mm_ctx_id = ATOMIC64_INIT(1);
+
struct flush_tlb_info {
struct mm_struct *flush_mm;
unsigned long flush_start;
@@ -104,6 +107,28 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
unsigned cpu = smp_processor_id();
if (likely(prev != next)) {
+ u64 last_ctx_id = this_cpu_read(cpu_tlbstate.last_ctx_id);
+
+ /*
+ * Avoid user/user BTB poisoning by flushing the branch
+ * predictor when switching between processes. This stops
+ * one process from doing Spectre-v2 attacks on another.
+ *
+ * As an optimization, flush indirect branches only when
+ * switching into processes that disable dumping. This
+ * protects high value processes like gpg, without having
+ * too high performance overhead. IBPB is *expensive*!
+ *
+ * This will not flush branches when switching into kernel
+ * threads. It will also not flush if we switch to idle
+ * thread and back to the same process. It will flush if we
+ * switch to a different non-dumpable process.
+ */
+ if (tsk && tsk->mm &&
+ tsk->mm->context.ctx_id != last_ctx_id &&
+ get_dumpable(tsk->mm) != SUID_DUMP_USER)
+ indirect_branch_prediction_barrier();
+
if (IS_ENABLED(CONFIG_VMAP_STACK)) {
/*
* If our current stack is in vmalloc space and isn't
@@ -118,6 +143,14 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
set_pgd(pgd, init_mm.pgd[stack_pgd_index]);
}
+ /*
+ * Record last user mm's context id, so we can avoid
+ * flushing branch buffer with IBPB if we switch back
+ * to the same user.
+ */
+ if (next != &init_mm)
+ this_cpu_write(cpu_tlbstate.last_ctx_id, next->context.ctx_id);
+
this_cpu_write(cpu_tlbstate.state, TLBSTATE_OK);
this_cpu_write(cpu_tlbstate.active_mm, next);
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 7840331d3056..1f7ed2ed6ff7 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -12,6 +12,7 @@
#include <linux/filter.h>
#include <linux/if_vlan.h>
#include <asm/cacheflush.h>
+#include <asm/nospec-branch.h>
#include <linux/bpf.h>
int bpf_jit_enable __read_mostly;
@@ -281,7 +282,7 @@ static void emit_bpf_tail_call(u8 **pprog)
EMIT2(0x89, 0xD2); /* mov edx, edx */
EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
offsetof(struct bpf_array, map.max_entries));
-#define OFFSET1 43 /* number of bytes to jump */
+#define OFFSET1 (41 + RETPOLINE_RAX_BPF_JIT_SIZE) /* number of bytes to jump */
EMIT2(X86_JBE, OFFSET1); /* jbe out */
label1 = cnt;
@@ -290,7 +291,7 @@ static void emit_bpf_tail_call(u8 **pprog)
*/
EMIT2_off32(0x8B, 0x85, -STACKSIZE + 36); /* mov eax, dword ptr [rbp - 516] */
EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
-#define OFFSET2 32
+#define OFFSET2 (30 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JA, OFFSET2); /* ja out */
label2 = cnt;
EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
@@ -304,7 +305,7 @@ static void emit_bpf_tail_call(u8 **pprog)
* goto out;
*/
EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
-#define OFFSET3 10
+#define OFFSET3 (8 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JE, OFFSET3); /* je out */
label3 = cnt;
@@ -317,7 +318,7 @@ static void emit_bpf_tail_call(u8 **pprog)
* rdi == ctx (1st arg)
* rax == prog->bpf_func + prologue_size
*/
- EMIT2(0xFF, 0xE0); /* jmp rax */
+ RETPOLINE_RAX_BPF_JIT();
/* out: */
BUILD_BUG_ON(cnt - label1 != OFFSET1);
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 28c04123b6dd..842ca3cab6b3 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -472,7 +472,7 @@ static int nmi_setup(void)
goto fail;
for_each_possible_cpu(cpu) {
- if (!cpu)
+ if (!IS_ENABLED(CONFIG_SMP) || !cpu)
continue;
memcpy(per_cpu(cpu_msrs, cpu).counters,
diff --git a/arch/x86/platform/intel-mid/intel-mid.c b/arch/x86/platform/intel-mid/intel-mid.c
index 7850128f0026..834783bc6752 100644
--- a/arch/x86/platform/intel-mid/intel-mid.c
+++ b/arch/x86/platform/intel-mid/intel-mid.c
@@ -79,7 +79,7 @@ static void intel_mid_power_off(void)
static void intel_mid_reboot(void)
{
- intel_scu_ipc_simple_command(IPCMSG_COLD_BOOT, 0);
+ intel_scu_ipc_simple_command(IPCMSG_COLD_RESET, 0);
}
static unsigned long __init intel_mid_calibrate_tsc(void)
diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 7f664c416faf..4ecd0de08557 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -1,11 +1,14 @@
#include <linux/types.h>
#include <linux/tick.h>
+#include <linux/percpu-defs.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/grant_table.h>
#include <xen/events.h>
+#include <asm/cpufeatures.h>
+#include <asm/msr-index.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>
#include <asm/fixmap.h>
@@ -68,6 +71,8 @@ static void xen_pv_post_suspend(int suspend_cancelled)
xen_mm_unpin_all();
}
+static DEFINE_PER_CPU(u64, spec_ctrl);
+
void xen_arch_pre_suspend(void)
{
if (xen_pv_domain())
@@ -84,6 +89,9 @@ void xen_arch_post_suspend(int cancelled)
static void xen_vcpu_notify_restore(void *data)
{
+ if (xen_pv_domain() && boot_cpu_has(X86_FEATURE_SPEC_CTRL))
+ wrmsrl(MSR_IA32_SPEC_CTRL, this_cpu_read(spec_ctrl));
+
/* Boot processor notified via generic timekeeping_resume() */
if (smp_processor_id() == 0)
return;
@@ -93,7 +101,15 @@ static void xen_vcpu_notify_restore(void *data)
static void xen_vcpu_notify_suspend(void *data)
{
+ u64 tmp;
+
tick_suspend_local();
+
+ if (xen_pv_domain() && boot_cpu_has(X86_FEATURE_SPEC_CTRL)) {
+ rdmsrl(MSR_IA32_SPEC_CTRL, tmp);
+ this_cpu_write(spec_ctrl, tmp);
+ wrmsrl(MSR_IA32_SPEC_CTRL, 0);
+ }
}
void xen_arch_resume(void)
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-02 17:38:32 +0000