[tip: x86/entry] x86/entry: Convert NMI to IDTENTRY_NMI

From: tip-bot2 for Thomas Gleixner
Date: Tue May 19 2020 - 16:02:31 EST

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The following commit has been merged into the x86/entry branch of tip:

Commit-ID: b209b183b6db506737d2bf6c76a866fe954e513a
Gitweb: https://git.kernel.org/tip/b209b183b6db506737d2bf6c76a866fe954e513a
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 25 Feb 2020 23:33:25 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 19 May 2020 16:04:09 +02:00

x86/entry: Convert NMI to IDTENTRY_NMI

Convert #NMI to IDTENTRY_NMI:
- Implement the C entry point with DEFINE_IDTENTRY_NMI
- Fixup the XEN/PV code
- Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200505135314.609932306@xxxxxxxxxxxxx

---
arch/x86/entry/entry_32.S | 8 ++++----
arch/x86/entry/entry_64.S | 15 +++++++--------
arch/x86/include/asm/idtentry.h | 4 ++++
arch/x86/include/asm/traps.h | 3 ---
arch/x86/kernel/idt.c | 4 ++--
arch/x86/kernel/nmi.c | 4 +---
arch/x86/xen/enlighten_pv.c | 7 ++++++-
arch/x86/xen/xen-asm_64.S | 2 +-
8 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 4dd3d70..d4961ca 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1545,7 +1545,7 @@ SYM_CODE_END(double_fault)
* switched stacks. We handle both conditions by simply checking whether we
* interrupted kernel code running on the SYSENTER stack.
*/
-SYM_CODE_START(nmi)
+SYM_CODE_START(asm_exc_nmi)
ASM_CLAC

#ifdef CONFIG_X86_ESPFIX32
@@ -1574,7 +1574,7 @@ SYM_CODE_START(nmi)
jb .Lnmi_from_sysenter_stack

/* Not on SYSENTER stack. */
- call do_nmi
+ call exc_nmi
jmp .Lnmi_return

.Lnmi_from_sysenter_stack:
@@ -1584,7 +1584,7 @@ SYM_CODE_START(nmi)
*/
movl %esp, %ebx
movl PER_CPU_VAR(cpu_current_top_of_stack), %esp
- call do_nmi
+ call exc_nmi
movl %ebx, %esp

.Lnmi_return:
@@ -1638,7 +1638,7 @@ SYM_CODE_START(nmi)
lss (1+5+6)*4(%esp), %esp # back to espfix stack
jmp .Lirq_return
#endif
-SYM_CODE_END(nmi)
+SYM_CODE_END(asm_exc_nmi)

.pushsection .text, "ax"
SYM_CODE_START(rewind_stack_do_exit)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 5007b97..3d7f2cc 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1079,7 +1079,6 @@ idtentry_df X86_TRAP_DF double_fault do_double_fault

#ifdef CONFIG_XEN_PV
idtentry 512 /* dummy */ hypervisor_callback xen_do_hypervisor_callback has_error_code=0
-idtentry X86_TRAP_NMI xennmi do_nmi has_error_code=0
idtentry X86_TRAP_DB xendebug do_debug has_error_code=0
#endif

@@ -1414,7 +1413,7 @@ SYM_CODE_END(error_return)
* %r14: Used to save/restore the CR3 of the interrupted context
* when PAGE_TABLE_ISOLATION is in use. Do not clobber.
*/
-SYM_CODE_START(nmi)
+SYM_CODE_START(asm_exc_nmi)
UNWIND_HINT_IRET_REGS

/*
@@ -1499,7 +1498,7 @@ SYM_CODE_START(nmi)

movq %rsp, %rdi
movq $-1, %rsi
- call do_nmi
+ call exc_nmi

/*
* Return back to user mode. We must *not* do the normal exit
@@ -1556,7 +1555,7 @@ SYM_CODE_START(nmi)
* end_repeat_nmi, then we are a nested NMI. We must not
* modify the "iret" frame because it's being written by
* the outer NMI. That's okay; the outer NMI handler is
- * about to about to call do_nmi anyway, so we can just
+ * about to about to call exc_nmi() anyway, so we can just
* resume the outer NMI.
*/

@@ -1675,7 +1674,7 @@ repeat_nmi:
* RSP is pointing to "outermost RIP". gsbase is unknown, but, if
* we're repeating an NMI, gsbase has the same value that it had on
* the first iteration. paranoid_entry will load the kernel
- * gsbase if needed before we call do_nmi. "NMI executing"
+ * gsbase if needed before we call exc_nmi(). "NMI executing"
* is zero.
*/
movq $1, 10*8(%rsp) /* Set "NMI executing". */
@@ -1709,10 +1708,10 @@ end_repeat_nmi:
call paranoid_entry
UNWIND_HINT_REGS

- /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
+ /* paranoidentry exc_nmi(), 0; without TRACE_IRQS_OFF */
movq %rsp, %rdi
movq $-1, %rsi
- call do_nmi
+ call exc_nmi

/* Always restore stashed CR3 value (see paranoid_entry) */
RESTORE_CR3 scratch_reg=%r15 save_reg=%r14
@@ -1749,7 +1748,7 @@ nmi_restore:
* about espfix64 on the way back to kernel mode.
*/
iretq
-SYM_CODE_END(nmi)
+SYM_CODE_END(asm_exc_nmi)

#ifndef CONFIG_IA32_EMULATION
/*
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 2315eec..1f067e6 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -258,4 +258,8 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_BP, exc_int3);
DECLARE_IDTENTRY_MCE(X86_TRAP_MC, exc_machine_check);
#endif

+/* NMI */
+DECLARE_IDTENTRY_NMI(X86_TRAP_NMI, exc_nmi);
+DECLARE_IDTENTRY_XEN(X86_TRAP_NMI, nmi);
+
#endif
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 6096db9..57b83ae 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -12,7 +12,6 @@
#define dotraplinkage __visible

asmlinkage void debug(void);
-asmlinkage void nmi(void);
#ifdef CONFIG_X86_64
asmlinkage void double_fault(void);
#endif
@@ -20,14 +19,12 @@ asmlinkage void page_fault(void);
asmlinkage void async_page_fault(void);

#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
-asmlinkage void xen_xennmi(void);
asmlinkage void xen_xendebug(void);
asmlinkage void xen_double_fault(void);
asmlinkage void xen_page_fault(void);
#endif

dotraplinkage void do_debug(struct pt_regs *regs, long error_code);
-dotraplinkage void do_nmi(struct pt_regs *regs, long error_code);
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);

diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 6b93840..d3fecd8 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -74,7 +74,7 @@ static const __initconst struct idt_data early_idts[] = {
*/
static const __initconst struct idt_data def_idts[] = {
INTG(X86_TRAP_DE, asm_exc_divide_error),
- INTG(X86_TRAP_NMI, nmi),
+ INTG(X86_TRAP_NMI, asm_exc_nmi),
INTG(X86_TRAP_BR, asm_exc_bounds),
INTG(X86_TRAP_UD, asm_exc_invalid_op),
INTG(X86_TRAP_NM, asm_exc_device_not_available),
@@ -186,7 +186,7 @@ gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss;
*/
static const __initconst struct idt_data ist_idts[] = {
ISTG(X86_TRAP_DB, debug, IST_INDEX_DB),
- ISTG(X86_TRAP_NMI, nmi, IST_INDEX_NMI),
+ ISTG(X86_TRAP_NMI, asm_exc_nmi, IST_INDEX_NMI),
ISTG(X86_TRAP_DF, double_fault, IST_INDEX_DF),
#ifdef CONFIG_X86_MCE
ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 6407ea2..d55e448 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -507,8 +507,7 @@ static bool notrace is_debug_stack(unsigned long addr)
NOKPROBE_SYMBOL(is_debug_stack);
#endif

-dotraplinkage notrace void
-do_nmi(struct pt_regs *regs, long error_code)
+DEFINE_IDTENTRY_NMI(exc_nmi)
{
if (IS_ENABLED(CONFIG_SMP) && cpu_is_offline(smp_processor_id()))
return;
@@ -558,7 +557,6 @@ nmi_restart:
if (user_mode(regs))
mds_user_clear_cpu_buffers();
}
-NOKPROBE_SYMBOL(do_nmi);

void stop_nmi(void)
{
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index f116afe..c65aa4c 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -610,13 +610,18 @@ struct trap_array_entry {
.xen = xen_asm_##func, \
.ist_okay = ist_ok }

+#define TRAP_ENTRY_REDIR(func, xenfunc, ist_ok) { \
+ .orig = asm_##func, \
+ .xen = xen_asm_##xenfunc, \
+ .ist_okay = ist_ok }
+
static struct trap_array_entry trap_array[] = {
{ debug, xen_xendebug, true },
{ double_fault, xen_double_fault, true },
#ifdef CONFIG_X86_MCE
TRAP_ENTRY(exc_machine_check, true ),
#endif
- { nmi, xen_xennmi, true },
+ TRAP_ENTRY_REDIR(exc_nmi, exc_xennmi, 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 617ef3f..04fa01b 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -32,7 +32,7 @@ xen_pv_trap asm_exc_divide_error
xen_pv_trap debug
xen_pv_trap xendebug
xen_pv_trap asm_exc_int3
-xen_pv_trap xennmi
+xen_pv_trap asm_exc_xennmi
xen_pv_trap asm_exc_overflow
xen_pv_trap asm_exc_bounds
xen_pv_trap asm_exc_invalid_op

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