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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-20 19:22:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-20 19:22:15 -0800
commit1255f44017c02d14e3ad5b63cdf619a734d765a1 (patch)
treef5053f30a5b577826cc4a961b7d347fc3dea0a9e /arch/x86/include
parent4f7a4028d8b48d1dc6b51b0737087f5e3c16c336 (diff)
parentab234a260b1f625b26cbefa93ca365b0ae66df33 (diff)
downloadlinux-1255f44017c02d14e3ad5b63cdf619a734d765a1.tar.gz
Merge tag 'x86_paravirt_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 paravirt updates from Borislav Petkov: "Part one of a major conversion of the paravirt infrastructure to our kernel patching facilities and getting rid of the custom-grown ones" * tag 'x86_paravirt_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/pv: Rework arch_local_irq_restore() to not use popf x86/xen: Drop USERGS_SYSRET64 paravirt call x86/pv: Switch SWAPGS to ALTERNATIVE x86/xen: Use specific Xen pv interrupt entry for DF x86/xen: Use specific Xen pv interrupt entry for MCE
Diffstat (limited to 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/idtentry.h6
-rw-r--r--arch/x86/include/asm/irqflags.h46
-rw-r--r--arch/x86/include/asm/paravirt.h30
-rw-r--r--arch/x86/include/asm/paravirt_types.h17
4 files changed, 22 insertions, 77 deletions
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index f656aabd1545..41e2e2e1b439 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -585,6 +585,9 @@ DECLARE_IDTENTRY_MCE(X86_TRAP_MC, exc_machine_check);
#else
DECLARE_IDTENTRY_RAW(X86_TRAP_MC, exc_machine_check);
#endif
+#ifdef CONFIG_XEN_PV
+DECLARE_IDTENTRY_RAW(X86_TRAP_MC, xenpv_exc_machine_check);
+#endif
#endif
/* NMI */
@@ -605,6 +608,9 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_DB, xenpv_exc_debug);
/* #DF */
DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_double_fault);
+#ifdef CONFIG_XEN_PV
+DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF, xenpv_exc_double_fault);
+#endif
/* #VC */
#ifdef CONFIG_AMD_MEM_ENCRYPT
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 2dfc8d380dab..144d70ea4393 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -35,15 +35,6 @@ extern __always_inline unsigned long native_save_fl(void)
return flags;
}
-extern inline void native_restore_fl(unsigned long flags);
-extern inline void native_restore_fl(unsigned long flags)
-{
- asm volatile("push %0 ; popf"
- : /* no output */
- :"g" (flags)
- :"memory", "cc");
-}
-
static __always_inline void native_irq_disable(void)
{
asm volatile("cli": : :"memory");
@@ -79,11 +70,6 @@ static __always_inline unsigned long arch_local_save_flags(void)
return native_save_fl();
}
-static __always_inline void arch_local_irq_restore(unsigned long flags)
-{
- native_restore_fl(flags);
-}
-
static __always_inline void arch_local_irq_disable(void)
{
native_irq_disable();
@@ -131,25 +117,7 @@ static __always_inline unsigned long arch_local_irq_save(void)
#define SAVE_FLAGS(x) pushfq; popq %rax
#endif
-#define SWAPGS swapgs
-/*
- * Currently paravirt can't handle swapgs nicely when we
- * don't have a stack we can rely on (such as a user space
- * stack). So we either find a way around these or just fault
- * and emulate if a guest tries to call swapgs directly.
- *
- * Either way, this is a good way to document that we don't
- * have a reliable stack. x86_64 only.
- */
-#define SWAPGS_UNSAFE_STACK swapgs
-
#define INTERRUPT_RETURN jmp native_iret
-#define USERGS_SYSRET64 \
- swapgs; \
- sysretq;
-#define USERGS_SYSRET32 \
- swapgs; \
- sysretl
#else
#define INTERRUPT_RETURN iret
@@ -170,6 +138,20 @@ static __always_inline int arch_irqs_disabled(void)
return arch_irqs_disabled_flags(flags);
}
+
+static __always_inline void arch_local_irq_restore(unsigned long flags)
+{
+ if (!arch_irqs_disabled_flags(flags))
+ arch_local_irq_enable();
+}
+#else
+#ifdef CONFIG_X86_64
+#ifdef CONFIG_XEN_PV
+#define SWAPGS ALTERNATIVE "swapgs", "", X86_FEATURE_XENPV
+#else
+#define SWAPGS swapgs
+#endif
+#endif
#endif /* !__ASSEMBLY__ */
#endif
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f8dce11d2bc1..4abf110e2243 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -648,11 +648,6 @@ static inline notrace unsigned long arch_local_save_flags(void)
return PVOP_CALLEE0(unsigned long, irq.save_fl);
}
-static inline notrace void arch_local_irq_restore(unsigned long f)
-{
- PVOP_VCALLEE1(irq.restore_fl, f);
-}
-
static inline notrace void arch_local_irq_disable(void)
{
PVOP_VCALLEE0(irq.irq_disable);
@@ -776,31 +771,6 @@ extern void default_banner(void);
#ifdef CONFIG_X86_64
#ifdef CONFIG_PARAVIRT_XXL
-/*
- * If swapgs is used while the userspace stack is still current,
- * there's no way to call a pvop. The PV replacement *must* be
- * inlined, or the swapgs instruction must be trapped and emulated.
- */
-#define SWAPGS_UNSAFE_STACK \
- PARA_SITE(PARA_PATCH(PV_CPU_swapgs), swapgs)
-
-/*
- * Note: swapgs is very special, and in practise is either going to be
- * implemented with a single "swapgs" instruction or something very
- * special. Either way, we don't need to save any registers for
- * it.
- */
-#define SWAPGS \
- PARA_SITE(PARA_PATCH(PV_CPU_swapgs), \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_CPU_swapgs); \
- )
-
-#define USERGS_SYSRET64 \
- PARA_SITE(PARA_PATCH(PV_CPU_usergs_sysret64), \
- ANNOTATE_RETPOLINE_SAFE; \
- jmp PARA_INDIRECT(pv_ops+PV_CPU_usergs_sysret64);)
-
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(clobbers) \
PARA_SITE(PARA_PATCH(PV_IRQ_save_fl), \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index b6b02b7c19cc..de87087d3bde 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -156,20 +156,10 @@ struct pv_cpu_ops {
u64 (*read_pmc)(int counter);
- /*
- * Switch to usermode gs and return to 64-bit usermode using
- * sysret. Only used in 64-bit kernels to return to 64-bit
- * processes. Usermode register state, including %rsp, must
- * already be restored.
- */
- void (*usergs_sysret64)(void);
-
/* Normal iret. Jump to this with the standard iret stack
frame set up. */
void (*iret)(void);
- void (*swapgs)(void);
-
void (*start_context_switch)(struct task_struct *prev);
void (*end_context_switch)(struct task_struct *next);
#endif
@@ -178,16 +168,13 @@ struct pv_cpu_ops {
struct pv_irq_ops {
#ifdef CONFIG_PARAVIRT_XXL
/*
- * Get/set interrupt state. save_fl and restore_fl are only
- * expected to use X86_EFLAGS_IF; all other bits
- * returned from save_fl are undefined, and may be ignored by
- * restore_fl.
+ * Get/set interrupt state. save_fl is expected to use X86_EFLAGS_IF;
+ * all other bits returned from save_fl are undefined.
*
* NOTE: These functions callers expect the callee to preserve
* more registers than the standard C calling convention.
*/
struct paravirt_callee_save save_fl;
- struct paravirt_callee_save restore_fl;
struct paravirt_callee_save irq_disable;
struct paravirt_callee_save irq_enable;