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authorLinus Torvalds <torvalds@linux-foundation.org>2020-07-05 12:23:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-07-05 12:23:49 -0700
commit72674d480076067d627e708c0a062dd900438bd7 (patch)
tree8ae54e966f78e59d48f9edad7aa3362eb87c2a9c /arch
parentf23dbe18930ba992f5c8c7b31e80f40dd6716081 (diff)
parentcc801833a171163edb6385425349ba8903bd1b20 (diff)
Merge tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner: "A series of fixes for x86: - Reset MXCSR in kernel_fpu_begin() to prevent using a stale user space value. - Prevent writing MSR_TEST_CTRL on CPUs which are not explicitly whitelisted for split lock detection. Some CPUs which do not support it crash even when the MSR is written to 0 which is the default value. - Fix the XEN PV fallout of the entry code rework - Fix the 32bit fallout of the entry code rework - Add more selftests to ensure that these entry problems don't come back. - Disable 16 bit segments on XEN PV. It's not supported because XEN PV does not implement ESPFIX64" * tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/ldt: Disable 16-bit segments on Xen PV x86/entry/32: Fix #MC and #DB wiring on x86_32 x86/entry/xen: Route #DB correctly on Xen PV x86/entry, selftests: Further improve user entry sanity checks x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER selftests/x86: Consolidate and fix get/set_eflags() helpers selftests/x86/syscall_nt: Clear weird flags after each test selftests/x86/syscall_nt: Add more flag combinations x86/entry/64/compat: Fix Xen PV SYSENTER frame setup x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C x86/entry: Assert that syscalls are on the right stack x86/split_lock: Don't write MSR_TEST_CTRL on CPUs that aren't whitelisted x86/fpu: Reset MXCSR to default in kernel_fpu_begin()
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/entry/common.c49
-rw-r--r--arch/x86/entry/entry_32.S5
-rw-r--r--arch/x86/entry/entry_64_compat.S31
-rw-r--r--arch/x86/include/asm/fpu/internal.h5
-rw-r--r--arch/x86/include/asm/idtentry.h47
-rw-r--r--arch/x86/kernel/cpu/intel.c11
-rw-r--r--arch/x86/kernel/cpu/mce/core.c4
-rw-r--r--arch/x86/kernel/fpu/core.c6
-rw-r--r--arch/x86/kernel/ldt.c35
-rw-r--r--arch/x86/kernel/traps.c14
-rw-r--r--arch/x86/xen/enlighten_pv.c28
-rw-r--r--arch/x86/xen/xen-asm_64.S25
12 files changed, 196 insertions, 64 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index bd3f14175193..e83b3f14897c 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -45,6 +45,32 @@
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
+/* Check that the stack and regs on entry from user mode are sane. */
+static void check_user_regs(struct pt_regs *regs)
+{
+ if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) {
+ /*
+ * Make sure that the entry code gave us a sensible EFLAGS
+ * register. Native because we want to check the actual CPU
+ * state, not the interrupt state as imagined by Xen.
+ */
+ unsigned long flags = native_save_fl();
+ WARN_ON_ONCE(flags & (X86_EFLAGS_AC | X86_EFLAGS_DF |
+ X86_EFLAGS_NT));
+
+ /* We think we came from user mode. Make sure pt_regs agrees. */
+ WARN_ON_ONCE(!user_mode(regs));
+
+ /*
+ * All entries from user mode (except #DF) should be on the
+ * normal thread stack and should have user pt_regs in the
+ * correct location.
+ */
+ WARN_ON_ONCE(!on_thread_stack());
+ WARN_ON_ONCE(regs != task_pt_regs(current));
+ }
+}
+
#ifdef CONFIG_CONTEXT_TRACKING
/**
* enter_from_user_mode - Establish state when coming from user mode
@@ -127,9 +153,6 @@ static long syscall_trace_enter(struct pt_regs *regs)
unsigned long ret = 0;
u32 work;
- if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
- BUG_ON(regs != task_pt_regs(current));
-
work = READ_ONCE(ti->flags);
if (work & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU)) {
@@ -346,6 +369,8 @@ __visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs)
{
struct thread_info *ti;
+ check_user_regs(regs);
+
enter_from_user_mode();
instrumentation_begin();
@@ -409,6 +434,8 @@ static void do_syscall_32_irqs_on(struct pt_regs *regs)
/* Handles int $0x80 */
__visible noinstr void do_int80_syscall_32(struct pt_regs *regs)
{
+ check_user_regs(regs);
+
enter_from_user_mode();
instrumentation_begin();
@@ -460,6 +487,8 @@ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs)
vdso_image_32.sym_int80_landing_pad;
bool success;
+ check_user_regs(regs);
+
/*
* SYSENTER loses EIP, and even SYSCALL32 needs us to skip forward
* so that 'regs->ip -= 2' lands back on an int $0x80 instruction.
@@ -510,6 +539,18 @@ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs)
(regs->flags & (X86_EFLAGS_RF | X86_EFLAGS_TF | X86_EFLAGS_VM)) == 0;
#endif
}
+
+/* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */
+__visible noinstr long do_SYSENTER_32(struct pt_regs *regs)
+{
+ /* SYSENTER loses RSP, but the vDSO saved it in RBP. */
+ regs->sp = regs->bp;
+
+ /* SYSENTER clobbers EFLAGS.IF. Assume it was set in usermode. */
+ regs->flags |= X86_EFLAGS_IF;
+
+ return do_fast_syscall_32(regs);
+}
#endif
SYSCALL_DEFINE0(ni_syscall)
@@ -553,6 +594,7 @@ SYSCALL_DEFINE0(ni_syscall)
bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs)
{
if (user_mode(regs)) {
+ check_user_regs(regs);
enter_from_user_mode();
return false;
}
@@ -686,6 +728,7 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit)
*/
void noinstr idtentry_enter_user(struct pt_regs *regs)
{
+ check_user_regs(regs);
enter_from_user_mode();
}
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 024d7d276cd4..2d0bd5d5f032 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -933,9 +933,8 @@ SYM_FUNC_START(entry_SYSENTER_32)
.Lsysenter_past_esp:
pushl $__USER_DS /* pt_regs->ss */
- pushl %ebp /* pt_regs->sp (stashed in bp) */
+ pushl $0 /* pt_regs->sp (placeholder) */
pushfl /* pt_regs->flags (except IF = 0) */
- orl $X86_EFLAGS_IF, (%esp) /* Fix IF */
pushl $__USER_CS /* pt_regs->cs */
pushl $0 /* pt_regs->ip = 0 (placeholder) */
pushl %eax /* pt_regs->orig_ax */
@@ -965,7 +964,7 @@ SYM_FUNC_START(entry_SYSENTER_32)
.Lsysenter_flags_fixed:
movl %esp, %eax
- call do_fast_syscall_32
+ call do_SYSENTER_32
/* XEN PV guests always use IRET path */
ALTERNATIVE "testl %eax, %eax; jz .Lsyscall_32_done", \
"jmp .Lsyscall_32_done", X86_FEATURE_XENPV
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 0f974ae01e62..541fdaf64045 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -57,29 +57,30 @@ SYM_CODE_START(entry_SYSENTER_compat)
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
- /*
- * User tracing code (ptrace or signal handlers) might assume that
- * the saved RAX contains a 32-bit number when we're invoking a 32-bit
- * syscall. Just in case the high bits are nonzero, zero-extend
- * the syscall number. (This could almost certainly be deleted
- * with no ill effects.)
- */
- movl %eax, %eax
-
/* Construct struct pt_regs on stack */
pushq $__USER32_DS /* pt_regs->ss */
- pushq %rbp /* pt_regs->sp (stashed in bp) */
+ pushq $0 /* pt_regs->sp = 0 (placeholder) */
/*
* Push flags. This is nasty. First, interrupts are currently
- * off, but we need pt_regs->flags to have IF set. Second, even
- * if TF was set when SYSENTER started, it's clear by now. We fix
- * that later using TIF_SINGLESTEP.
+ * off, but we need pt_regs->flags to have IF set. Second, if TS
+ * was set in usermode, it's still set, and we're singlestepping
+ * through this code. do_SYSENTER_32() will fix up IF.
*/
pushfq /* pt_regs->flags (except IF = 0) */
- orl $X86_EFLAGS_IF, (%rsp) /* Fix saved flags */
pushq $__USER32_CS /* pt_regs->cs */
pushq $0 /* pt_regs->ip = 0 (placeholder) */
+SYM_INNER_LABEL(entry_SYSENTER_compat_after_hwframe, SYM_L_GLOBAL)
+
+ /*
+ * User tracing code (ptrace or signal handlers) might assume that
+ * the saved RAX contains a 32-bit number when we're invoking a 32-bit
+ * syscall. Just in case the high bits are nonzero, zero-extend
+ * the syscall number. (This could almost certainly be deleted
+ * with no ill effects.)
+ */
+ movl %eax, %eax
+
pushq %rax /* pt_regs->orig_ax */
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
@@ -135,7 +136,7 @@ SYM_CODE_START(entry_SYSENTER_compat)
.Lsysenter_flags_fixed:
movq %rsp, %rdi
- call do_fast_syscall_32
+ call do_SYSENTER_32
/* XEN PV guests always use IRET path */
ALTERNATIVE "testl %eax, %eax; jz swapgs_restore_regs_and_return_to_usermode", \
"jmp swapgs_restore_regs_and_return_to_usermode", X86_FEATURE_XENPV
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 42159f45bf9c..845e7481ab77 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -623,6 +623,11 @@ static inline void switch_fpu_finish(struct fpu *new_fpu)
* MXCSR and XCR definitions:
*/
+static inline void ldmxcsr(u32 mxcsr)
+{
+ asm volatile("ldmxcsr %0" :: "m" (mxcsr));
+}
+
extern unsigned int mxcsr_feature_mask;
#define XCR_XFEATURE_ENABLED_MASK 0x00000000
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index cf51c50eb356..eeac6dc2adaa 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -353,10 +353,6 @@ static __always_inline void __##func(struct pt_regs *regs)
#else /* CONFIG_X86_64 */
-/* Maps to a regular IDTENTRY on 32bit for now */
-# define DECLARE_IDTENTRY_IST DECLARE_IDTENTRY
-# define DEFINE_IDTENTRY_IST DEFINE_IDTENTRY
-
/**
* DECLARE_IDTENTRY_DF - Declare functions for double fault 32bit variant
* @vector: Vector number (ignored for C)
@@ -387,28 +383,18 @@ __visible noinstr void func(struct pt_regs *regs, \
#endif /* !CONFIG_X86_64 */
/* C-Code mapping */
+#define DECLARE_IDTENTRY_NMI DECLARE_IDTENTRY_RAW
+#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_RAW
+
+#ifdef CONFIG_X86_64
#define DECLARE_IDTENTRY_MCE DECLARE_IDTENTRY_IST
#define DEFINE_IDTENTRY_MCE DEFINE_IDTENTRY_IST
#define DEFINE_IDTENTRY_MCE_USER DEFINE_IDTENTRY_NOIST
-#define DECLARE_IDTENTRY_NMI DECLARE_IDTENTRY_RAW
-#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_RAW
-
#define DECLARE_IDTENTRY_DEBUG DECLARE_IDTENTRY_IST
#define DEFINE_IDTENTRY_DEBUG DEFINE_IDTENTRY_IST
#define DEFINE_IDTENTRY_DEBUG_USER DEFINE_IDTENTRY_NOIST
-
-/**
- * DECLARE_IDTENTRY_XEN - Declare functions for XEN redirect IDT entry points
- * @vector: Vector number (ignored for C)
- * @func: Function name of the entry point
- *
- * Used for xennmi and xendebug redirections. No DEFINE as this is all ASM
- * indirection magic.
- */
-#define DECLARE_IDTENTRY_XEN(vector, func) \
- asmlinkage void xen_asm_exc_xen##func(void); \
- asmlinkage void asm_exc_xen##func(void)
+#endif
#else /* !__ASSEMBLY__ */
@@ -455,9 +441,6 @@ __visible noinstr void func(struct pt_regs *regs, \
# define DECLARE_IDTENTRY_MCE(vector, func) \
DECLARE_IDTENTRY(vector, func)
-# define DECLARE_IDTENTRY_DEBUG(vector, func) \
- DECLARE_IDTENTRY(vector, func)
-
/* No ASM emitted for DF as this goes through a C shim */
# define DECLARE_IDTENTRY_DF(vector, func)
@@ -469,10 +452,6 @@ __visible noinstr void func(struct pt_regs *regs, \
/* No ASM code emitted for NMI */
#define DECLARE_IDTENTRY_NMI(vector, func)
-/* XEN NMI and DB wrapper */
-#define DECLARE_IDTENTRY_XEN(vector, func) \
- idtentry vector asm_exc_xen##func exc_##func has_error_code=0
-
/*
* ASM code to emit the common vector entry stubs where each stub is
* packed into 8 bytes.
@@ -565,16 +544,28 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_BP, exc_int3);
DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_PF, exc_page_fault);
#ifdef CONFIG_X86_MCE
+#ifdef CONFIG_X86_64
DECLARE_IDTENTRY_MCE(X86_TRAP_MC, exc_machine_check);
+#else
+DECLARE_IDTENTRY_RAW(X86_TRAP_MC, exc_machine_check);
+#endif
#endif
/* NMI */
DECLARE_IDTENTRY_NMI(X86_TRAP_NMI, exc_nmi);
-DECLARE_IDTENTRY_XEN(X86_TRAP_NMI, nmi);
+#ifdef CONFIG_XEN_PV
+DECLARE_IDTENTRY_RAW(X86_TRAP_NMI, xenpv_exc_nmi);
+#endif
/* #DB */
+#ifdef CONFIG_X86_64
DECLARE_IDTENTRY_DEBUG(X86_TRAP_DB, exc_debug);
-DECLARE_IDTENTRY_XEN(X86_TRAP_DB, debug);
+#else
+DECLARE_IDTENTRY_RAW(X86_TRAP_DB, exc_debug);
+#endif
+#ifdef CONFIG_XEN_PV
+DECLARE_IDTENTRY_RAW(X86_TRAP_DB, xenpv_exc_debug);
+#endif
/* #DF */
DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_double_fault);
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index c25a67a34bd3..0ab48f1cdf84 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -50,6 +50,13 @@ static enum split_lock_detect_state sld_state __ro_after_init = sld_off;
static u64 msr_test_ctrl_cache __ro_after_init;
/*
+ * With a name like MSR_TEST_CTL it should go without saying, but don't touch
+ * MSR_TEST_CTL unless the CPU is one of the whitelisted models. Writing it
+ * on CPUs that do not support SLD can cause fireworks, even when writing '0'.
+ */
+static bool cpu_model_supports_sld __ro_after_init;
+
+/*
* Processors which have self-snooping capability can handle conflicting
* memory type across CPUs by snooping its own cache. However, there exists
* CPU models in which having conflicting memory types still leads to
@@ -1071,7 +1078,8 @@ static void sld_update_msr(bool on)
static void split_lock_init(void)
{
- split_lock_verify_msr(sld_state != sld_off);
+ if (cpu_model_supports_sld)
+ split_lock_verify_msr(sld_state != sld_off);
}
static void split_lock_warn(unsigned long ip)
@@ -1177,5 +1185,6 @@ void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c)
return;
}
+ cpu_model_supports_sld = true;
split_lock_setup();
}
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index fbe89a92ff36..14e4b4d17ee5 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1901,6 +1901,8 @@ void (*machine_check_vector)(struct pt_regs *) = unexpected_machine_check;
static __always_inline void exc_machine_check_kernel(struct pt_regs *regs)
{
+ WARN_ON_ONCE(user_mode(regs));
+
/*
* Only required when from kernel mode. See
* mce_check_crashing_cpu() for details.
@@ -1954,7 +1956,7 @@ DEFINE_IDTENTRY_MCE_USER(exc_machine_check)
}
#else
/* 32bit unified entry point */
-DEFINE_IDTENTRY_MCE(exc_machine_check)
+DEFINE_IDTENTRY_RAW(exc_machine_check)
{
unsigned long dr7;
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 06c818967bb6..15247b96c6ea 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -101,6 +101,12 @@ void kernel_fpu_begin(void)
copy_fpregs_to_fpstate(&current->thread.fpu);
}
__cpu_invalidate_fpregs_state();
+
+ if (boot_cpu_has(X86_FEATURE_XMM))
+ ldmxcsr(MXCSR_DEFAULT);
+
+ if (boot_cpu_has(X86_FEATURE_FPU))
+ asm volatile ("fninit");
}
EXPORT_SYMBOL_GPL(kernel_fpu_begin);
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 8748321c4486..34e918ad34d4 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -29,6 +29,8 @@
#include <asm/mmu_context.h>
#include <asm/pgtable_areas.h>
+#include <xen/xen.h>
+
/* This is a multiple of PAGE_SIZE. */
#define LDT_SLOT_STRIDE (LDT_ENTRIES * LDT_ENTRY_SIZE)
@@ -543,6 +545,37 @@ static int read_default_ldt(void __user *ptr, unsigned long bytecount)
return bytecount;
}
+static bool allow_16bit_segments(void)
+{
+ if (!IS_ENABLED(CONFIG_X86_16BIT))
+ return false;
+
+#ifdef CONFIG_XEN_PV
+ /*
+ * Xen PV does not implement ESPFIX64, which means that 16-bit
+ * segments will not work correctly. Until either Xen PV implements
+ * ESPFIX64 and can signal this fact to the guest or unless someone
+ * provides compelling evidence that allowing broken 16-bit segments
+ * is worthwhile, disallow 16-bit segments under Xen PV.
+ */
+ if (xen_pv_domain()) {
+ static DEFINE_MUTEX(xen_warning);
+ static bool warned;
+
+ mutex_lock(&xen_warning);
+ if (!warned) {
+ pr_info("Warning: 16-bit segments do not work correctly in a Xen PV guest\n");
+ warned = true;
+ }
+ mutex_unlock(&xen_warning);
+
+ return false;
+ }
+#endif
+
+ return true;
+}
+
static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
{
struct mm_struct *mm = current->mm;
@@ -574,7 +607,7 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
/* The user wants to clear the entry. */
memset(&ldt, 0, sizeof(ldt));
} else {
- if (!IS_ENABLED(CONFIG_X86_16BIT) && !ldt_info.seg_32bit) {
+ if (!ldt_info.seg_32bit && !allow_16bit_segments()) {
error = -EINVAL;
goto out;
}
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index f58679e487f6..b038695f36c5 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -870,6 +870,12 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
trace_hardirqs_off_finish();
/*
+ * If something gets miswired and we end up here for a user mode
+ * #DB, we will malfunction.
+ */
+ WARN_ON_ONCE(user_mode(regs));
+
+ /*
* Catch SYSENTER with TF set and clear DR_STEP. If this hit a
* watchpoint at the same time then that will still be handled.
*/
@@ -887,6 +893,12 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
static __always_inline void exc_debug_user(struct pt_regs *regs,
unsigned long dr6)
{
+ /*
+ * If something gets miswired and we end up here for a kernel mode
+ * #DB, we will malfunction.
+ */
+ WARN_ON_ONCE(!user_mode(regs));
+
idtentry_enter_user(regs);
instrumentation_begin();
@@ -917,7 +929,7 @@ DEFINE_IDTENTRY_DEBUG_USER(exc_debug)
}
#else
/* 32 bit does not have separate entry points. */
-DEFINE_IDTENTRY_DEBUG(exc_debug)
+DEFINE_IDTENTRY_RAW(exc_debug)
{
unsigned long dr6, dr7;
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index acc49fa6a097..0d68948c82ad 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -598,6 +598,26 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
}
#ifdef CONFIG_X86_64
+void noist_exc_debug(struct pt_regs *regs);
+
+DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
+{
+ /* On Xen PV, NMI doesn't use IST. The C part is the sane as native. */
+ exc_nmi(regs);
+}
+
+DEFINE_IDTENTRY_RAW(xenpv_exc_debug)
+{
+ /*
+ * There's no IST on Xen PV, but we still need to dispatch
+ * to the correct handler.
+ */
+ if (user_mode(regs))
+ noist_exc_debug(regs);
+ else
+ exc_debug(regs);
+}
+
struct trap_array_entry {
void (*orig)(void);
void (*xen)(void);
@@ -609,18 +629,18 @@ struct trap_array_entry {
.xen = xen_asm_##func, \
.ist_okay = ist_ok }
-#define TRAP_ENTRY_REDIR(func, xenfunc, ist_ok) { \
+#define TRAP_ENTRY_REDIR(func, ist_ok) { \
.orig = asm_##func, \
- .xen = xen_asm_##xenfunc, \
+ .xen = xen_asm_xenpv_##func, \
.ist_okay = ist_ok }
static struct trap_array_entry trap_array[] = {
- TRAP_ENTRY_REDIR(exc_debug, exc_xendebug, true ),
+ TRAP_ENTRY_REDIR(exc_debug, true ),
TRAP_ENTRY(exc_double_fault, true ),
#ifdef CONFIG_X86_MCE
TRAP_ENTRY(exc_machine_check, true ),
#endif
- TRAP_ENTRY_REDIR(exc_nmi, exc_xennmi, true ),
+ TRAP_ENTRY_REDIR(exc_nmi, true ),
TRAP_ENTRY(exc_int3, false ),
TRAP_ENTRY(exc_overflow, false ),
#ifdef CONFIG_IA32_EMULATION
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 5d252aaeade8..aab1d99b2b48 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -29,10 +29,9 @@ _ASM_NOKPROBE(xen_\name)
.endm
xen_pv_trap asm_exc_divide_error
-xen_pv_trap asm_exc_debug
-xen_pv_trap asm_exc_xendebug
+xen_pv_trap asm_xenpv_exc_debug
xen_pv_trap asm_exc_int3
-xen_pv_trap asm_exc_xennmi
+xen_pv_trap asm_xenpv_exc_nmi
xen_pv_trap asm_exc_overflow
xen_pv_trap asm_exc_bounds
xen_pv_trap asm_exc_invalid_op
@@ -161,10 +160,22 @@ SYM_FUNC_END(xen_syscall32_target)
/* 32-bit compat sysenter target */
SYM_FUNC_START(xen_sysenter_target)
- mov 0*8(%rsp), %rcx
- mov 1*8(%rsp), %r11
- mov 5*8(%rsp), %rsp
- jmp entry_SYSENTER_compat
+ /*
+ * NB: Xen is polite and clears TF from EFLAGS for us. This means
+ * that we don't need to guard against single step exceptions here.
+ */
+ popq %rcx
+ popq %r11
+
+ /*
+ * Neither Xen nor the kernel really knows what the old SS and
+ * CS were. The kernel expects __USER32_DS and __USER32_CS, so
+ * report those values even though Xen will guess its own values.
+ */
+ movq $__USER32_DS, 4*8(%rsp)
+ movq $__USER32_CS, 1*8(%rsp)
+
+ jmp entry_SYSENTER_compat_after_hwframe
SYM_FUNC_END(xen_sysenter_target)
#else /* !CONFIG_IA32_EMULATION */