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Date: Tue, 25 Feb 2020 23:33:32 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: x86@...nel.org, Steven Rostedt <rostedt@...dmis.org>,
Brian Gerst <brgerst@...il.com>,
Juergen Gross <jgross@...e.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Arnd Bergmann <arnd@...db.de>
Subject: [patch 11/16] x86/entry: Switch XEN/PV hypercall entry to IDTENTRY
Convert # to IDTENTRY:
- Implement the C entry point with DEFINE_IDTENTRY
- Emit the ASM stub with DECLARE_IDTENTRY
- Remove the ASM idtentry in 64bit
- Remove the open coded ASM entry code in 32bit
- Fixup the XEN/PV code
- Remove the old prototyoes
No functional change.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
arch/x86/entry/entry_32.S | 7 +++++--
arch/x86/entry/entry_64.S | 11 ++++-------
arch/x86/include/asm/idtentry.h | 13 +++++++++++++
arch/x86/xen/setup.c | 4 +++-
arch/x86/xen/smp_pv.c | 3 ++-
arch/x86/xen/xen-asm_32.S | 8 ++++----
arch/x86/xen/xen-asm_64.S | 2 +-
arch/x86/xen/xen-ops.h | 1 -
8 files changed, 32 insertions(+), 17 deletions(-)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1307,7 +1307,10 @@ SYM_CODE_END(native_iret)
#endif
#ifdef CONFIG_XEN_PV
-SYM_FUNC_START(xen_hypervisor_callback)
+/*
+ * See comment in entry_64.S for further explanation
+ */
+SYM_FUNC_START(exc_xen_hypervisor_callback)
/*
* Check to see if we got the event in the critical
* region in xen_iret_direct, after we've reenabled
@@ -1331,7 +1334,7 @@ SYM_FUNC_START(xen_hypervisor_callback)
call xen_maybe_preempt_hcall
#endif
jmp ret_from_intr
-SYM_FUNC_END(xen_hypervisor_callback)
+SYM_FUNC_END(exc_xen_hypervisor_callback)
/*
* Hypervisor uses this for application faults while it executes.
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1059,10 +1059,6 @@ idtentry X86_TRAP_PF page_fault do_pag
idtentry X86_TRAP_PF async_page_fault do_async_page_fault has_error_code=1
#endif
-#ifdef CONFIG_XEN_PV
-idtentry 512 /* dummy */ hypervisor_callback xen_do_hypervisor_callback has_error_code=0
-#endif
-
/*
* Reload gs selector with exception handling
* edi: new selector
@@ -1125,9 +1121,10 @@ SYM_FUNC_END(do_softirq_own_stack)
* So, on entry to the handler we detect whether we interrupted an
* existing activation in its critical region -- if so, we pop the current
* activation and restart the handler using the previous one.
+ *
+ * C calling convention: exc_xen_hypervisor_callback(struct *pt_regs)
*/
-/* do_hypervisor_callback(struct *pt_regs) */
-SYM_CODE_START_LOCAL(xen_do_hypervisor_callback)
+SYM_CODE_START_LOCAL(exc_xen_hypervisor_callback)
/*
* Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
@@ -1145,7 +1142,7 @@ SYM_CODE_START_LOCAL(xen_do_hypervisor_c
call xen_maybe_preempt_hcall
#endif
jmp error_exit
-SYM_CODE_END(xen_do_hypervisor_callback)
+SYM_CODE_END(exc_xen_hypervisor_callback)
/*
* Hypervisor uses this for application faults while it executes.
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -308,6 +308,13 @@ static __always_inline void __##func(str
#endif /* __ASSEMBLY__ */
+/*
+ * Dummy trap number so the low level ASM macro vector number checks do not
+ * match which results in emitting plain IDTENTRY stubs without bells and
+ * whistels.
+ */
+#define X86_TRAP_OTHER ~0uL
+
/* Simple exception entries: */
DECLARE_IDTENTRY(X86_TRAP_DE, exc_divide_error);
DECLARE_IDTENTRY(X86_TRAP_BP, exc_int3);
@@ -348,4 +355,10 @@ DECLARE_IDTENTRY_XEN(X86_TRAP_DB, debug)
DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_double_fault);
#endif
+#ifdef CONFIG_XEN_PV
+DECLARE_IDTENTRY(X6_TRAP_OTHER, exc_xen_hypervisor_callback);
+#endif
+
+#undef X86_TRAP_OTHER
+
#endif
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -20,6 +20,7 @@
#include <asm/setup.h>
#include <asm/acpi.h>
#include <asm/numa.h>
+#include <asm/idtentry.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
@@ -993,7 +994,8 @@ void __init xen_pvmmu_arch_setup(void)
HYPERVISOR_vm_assist(VMASST_CMD_enable,
VMASST_TYPE_pae_extended_cr3);
- if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
+ if (register_callback(CALLBACKTYPE_event,
+ asm_exc_xen_hypervisor_callback) ||
register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
BUG();
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -27,6 +27,7 @@
#include <asm/paravirt.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
+#include <asm/idtentry.h>
#include <asm/cpu.h>
#include <xen/interface/xen.h>
@@ -346,7 +347,7 @@ cpu_initialize_context(unsigned int cpu,
ctxt->gs_base_kernel = per_cpu_offset(cpu);
#endif
ctxt->event_callback_eip =
- (unsigned long)xen_hypervisor_callback;
+ (unsigned long)asm_exc_xen_hypervisor_callback;
ctxt->failsafe_callback_eip =
(unsigned long)xen_failsafe_callback;
per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
--- a/arch/x86/xen/xen-asm_32.S
+++ b/arch/x86/xen/xen-asm_32.S
@@ -93,7 +93,7 @@ SYM_CODE_START(xen_iret)
/*
* If there's something pending, mask events again so we can
- * jump back into xen_hypervisor_callback. Otherwise do not
+ * jump back into exc_xen_hypervisor_callback. Otherwise do not
* touch XEN_vcpu_info_mask.
*/
jne 1f
@@ -113,7 +113,7 @@ SYM_CODE_START(xen_iret)
* Events are masked, so jumping out of the critical region is
* OK.
*/
- je xen_hypervisor_callback
+ je asm_exc_xen_hypervisor_callback
1: iret
xen_iret_end_crit:
@@ -127,7 +127,7 @@ SYM_CODE_END(xen_iret)
.globl xen_iret_start_crit, xen_iret_end_crit
/*
- * This is called by xen_hypervisor_callback in entry_32.S when it sees
+ * This is called by exc_xen_hypervisor_callback in entry_32.S when it sees
* that the EIP at the time of interrupt was between
* xen_iret_start_crit and xen_iret_end_crit.
*
@@ -144,7 +144,7 @@ SYM_CODE_END(xen_iret)
* eflags }
* cs } nested exception info
* eip }
- * return address : (into xen_hypervisor_callback)
+ * return address : (into asm_exc_xen_hypervisor_callback)
*
* In order to deliver the nested exception properly, we need to discard the
* nested exception frame such that when we handle the exception, we do it
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -54,7 +54,7 @@ xen_pv_trap asm_exc_simd_coprocessor_err
#ifdef CONFIG_IA32_EMULATION
xen_pv_trap entry_INT80_compat
#endif
-xen_pv_trap hypervisor_callback
+xen_pv_trap asm_exc_xen_hypervisor_callback
__INIT
SYM_CODE_START(xen_early_idt_handler_array)
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -8,7 +8,6 @@
#include <xen/xen-ops.h>
/* These are code, but not functions. Defined in entry.S */
-extern const char xen_hypervisor_callback[];
extern const char xen_failsafe_callback[];
void xen_sysenter_target(void);
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