Merge tag 'x86-entry-2021-02-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 irq entry updates from Thomas Gleixner:
 "The irq stack switching was moved out of the ASM entry code in course
  of the entry code consolidation. It ended up being suboptimal in
  various ways.

  This reworks the X86 irq stack handling:

   - Make the stack switching inline so the stackpointer manipulation is
     not longer at an easy to find place.

   - Get rid of the unnecessary indirect call.

   - Avoid the double stack switching in interrupt return and reuse the
     interrupt stack for softirq handling.

   - A objtool fix for CONFIG_FRAME_POINTER=y builds where it got
     confused about the stack pointer manipulation"

* tag 'x86-entry-2021-02-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix stack-swizzle for FRAME_POINTER=y
  um: Enforce the usage of asm-generic/softirq_stack.h
  x86/softirq/64: Inline do_softirq_own_stack()
  softirq: Move do_softirq_own_stack() to generic asm header
  softirq: Move __ARCH_HAS_DO_SOFTIRQ to Kconfig
  x86: Select CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
  x86/softirq: Remove indirection in do_softirq_own_stack()
  x86/entry: Use run_sysvec_on_irqstack_cond() for XEN upcall
  x86/entry: Convert device interrupts to inline stack switching
  x86/entry: Convert system vectors to irq stack macro
  x86/irq: Provide macro for inlining irq stack switching
  x86/apic: Split out spurious handling code
  x86/irq/64: Adjust the per CPU irq stack pointer by 8
  x86/irq: Sanitize irq stack tracking
  x86/entry: Fix instrumentation annotation

arch/Kconfig

@@ -821,6 +821,12 @@ config HAVE_IRQ_EXIT_ON_IRQ_STACK
 	  This spares a stack switch and improves cache usage on softirq
 	  processing.
 
+config HAVE_SOFTIRQ_ON_OWN_STACK
+	bool
+	help
+	  Architecture provides a function to run __do_softirq() on a
+	  seperate stack.
+
 config PGTABLE_LEVELS
 	int
 	default 2

arch/parisc/Kconfig

@@ -63,6 +63,7 @@ config PARISC
 	select HAVE_FTRACE_MCOUNT_RECORD if HAVE_DYNAMIC_FTRACE
 	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
+	select HAVE_SOFTIRQ_ON_OWN_STACK if IRQSTACKS
 	select SET_FS
 
 	help

arch/parisc/include/asm/hardirq.h

@@ -12,10 +12,6 @@
 #include <linux/threads.h>
 #include <linux/irq.h>
 
-#ifdef CONFIG_IRQSTACKS
-#define __ARCH_HAS_DO_SOFTIRQ
-#endif
-
 typedef struct {
 	unsigned int __softirq_pending;
 	unsigned int kernel_stack_usage;

arch/parisc/kernel/irq.c

@@ -17,6 +17,7 @@
 #include <linux/types.h>
 #include <asm/io.h>
 
+#include <asm/softirq_stack.h>
 #include <asm/smp.h>
 #include <asm/ldcw.h>
 

arch/powerpc/Kconfig

@@ -235,6 +235,7 @@ config PPC
 	select MMU_GATHER_PAGE_SIZE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE		if PPC_BOOK3S_64 && CPU_LITTLE_ENDIAN
+	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_VIRT_CPU_ACCOUNTING
 	select HAVE_IRQ_TIME_ACCOUNTING

arch/powerpc/include/asm/irq.h

@@ -37,8 +37,6 @@ extern int distribute_irqs;
 
 struct pt_regs;
 
-#define __ARCH_HAS_DO_SOFTIRQ
-
 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
 /*
  * Per-cpu stacks for handling critical, debug and machine check

arch/powerpc/kernel/irq.c

@@ -66,6 +66,7 @@
 #include <asm/livepatch.h>
 #include <asm/asm-prototypes.h>
 #include <asm/hw_irq.h>
+#include <asm/softirq_stack.h>
 
 #ifdef CONFIG_PPC64
 #include <asm/paca.h>

arch/s390/Kconfig

@@ -184,6 +184,7 @@ config S390
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
+	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_VIRT_CPU_ACCOUNTING
 	select HAVE_VIRT_CPU_ACCOUNTING_IDLE

arch/s390/include/asm/hardirq.h

@@ -18,7 +18,6 @@
 #define or_softirq_pending(x)  (S390_lowcore.softirq_pending |= (x))
 
 #define __ARCH_IRQ_STAT
-#define __ARCH_HAS_DO_SOFTIRQ
 #define __ARCH_IRQ_EXIT_IRQS_DISABLED
 
 static inline void ack_bad_irq(unsigned int irq)

arch/s390/kernel/irq.c

@@ -28,6 +28,7 @@
 #include <asm/irq.h>
 #include <asm/hw_irq.h>
 #include <asm/stacktrace.h>
+#include <asm/softirq_stack.h>
 #include "entry.h"
 
 DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);

arch/sh/Kconfig

@@ -54,6 +54,7 @@ config SUPERH
 	select HAVE_PERF_EVENTS
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_UID16
+	select HAVE_SOFTIRQ_ON_OWN_STACK if IRQSTACKS
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select IRQ_FORCED_THREADING

arch/sh/include/asm/irq.h

@@ -51,7 +51,6 @@ asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs);
 #ifdef CONFIG_IRQSTACKS
 extern void irq_ctx_init(int cpu);
 extern void irq_ctx_exit(int cpu);
-# define __ARCH_HAS_DO_SOFTIRQ
 #else
 # define irq_ctx_init(cpu) do { } while (0)
 # define irq_ctx_exit(cpu) do { } while (0)

arch/sh/kernel/irq.c

@@ -20,6 +20,7 @@
 #include <linux/uaccess.h>
 #include <asm/thread_info.h>
 #include <cpu/mmu_context.h>
+#include <asm/softirq_stack.h>
 
 atomic_t irq_err_count;
 

arch/sparc/Kconfig

@@ -96,6 +96,7 @@ config SPARC64
 	select ARCH_HAS_PTE_SPECIAL
 	select PCI_DOMAINS if PCI
 	select ARCH_HAS_GIGANTIC_PAGE
+	select HAVE_SOFTIRQ_ON_OWN_STACK
 
 config ARCH_PROC_KCORE_TEXT
 	def_bool y

arch/sparc/include/asm/irq_64.h

@@ -93,7 +93,6 @@ void arch_trigger_cpumask_backtrace(const struct cpumask *mask,
 
 extern void *hardirq_stack[NR_CPUS];
 extern void *softirq_stack[NR_CPUS];
-#define __ARCH_HAS_DO_SOFTIRQ
 
 #define NO_IRQ		0xffffffff
 

arch/sparc/kernel/irq_64.c

@@ -42,6 +42,7 @@
 #include <asm/head.h>
 #include <asm/hypervisor.h>
 #include <asm/cacheflush.h>
+#include <asm/softirq_stack.h>
 
 #include "entry.h"
 #include "cpumap.h"

arch/um/include/asm/Kbuild

@@ -20,6 +20,7 @@ generic-y += param.h
 generic-y += pci.h
 generic-y += percpu.h
 generic-y += preempt.h
+generic-y += softirq_stack.h
 generic-y += switch_to.h
 generic-y += topology.h
 generic-y += trace_clock.h

arch/x86/Kconfig

@@ -191,6 +191,7 @@ config X86
 	select HAVE_HW_BREAKPOINT
 	select HAVE_IDE
 	select HAVE_IOREMAP_PROT
+	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
 	select HAVE_IRQ_TIME_ACCOUNTING
 	select HAVE_KERNEL_BZIP2
 	select HAVE_KERNEL_GZIP
@@ -223,6 +224,7 @@ config X86
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
 	select HAVE_FUNCTION_ARG_ACCESS_API
+	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
 	select HAVE_STACK_VALIDATION		if X86_64
 	select HAVE_STATIC_CALL

arch/x86/entry/common.c

@@ -249,30 +249,23 @@ static __always_inline bool get_and_clear_inhcall(void) { return false; }
 static __always_inline void restore_inhcall(bool inhcall) { }
 #endif
 
-static void __xen_pv_evtchn_do_upcall(void)
+static void __xen_pv_evtchn_do_upcall(struct pt_regs *regs)
 {
-	irq_enter_rcu();
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
 	inc_irq_stat(irq_hv_callback_count);
 
 	xen_hvm_evtchn_do_upcall();
 
-	irq_exit_rcu();
+	set_irq_regs(old_regs);
 }
 
 __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs)
 {
-	struct pt_regs *old_regs;
+	irqentry_state_t state = irqentry_enter(regs);
 	bool inhcall;
-	irqentry_state_t state;
 
-	state = irqentry_enter(regs);
-	old_regs = set_irq_regs(regs);
-
-	instrumentation_begin();
-	run_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs);
-	instrumentation_begin();
-
-	set_irq_regs(old_regs);
+	run_sysvec_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs);
 
 	inhcall = get_and_clear_inhcall();
 	if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) {

arch/x86/entry/entry_64.S

@@ -754,47 +754,6 @@ SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs)
 SYM_CODE_END(.Lbad_gs)
 	.previous
 
-/*
- * rdi: New stack pointer points to the top word of the stack
- * rsi: Function pointer
- * rdx: Function argument (can be NULL if none)
- */
-SYM_FUNC_START(asm_call_on_stack)
-SYM_INNER_LABEL(asm_call_sysvec_on_stack, SYM_L_GLOBAL)
-SYM_INNER_LABEL(asm_call_irq_on_stack, SYM_L_GLOBAL)
-	/*
-	 * Save the frame pointer unconditionally. This allows the ORC
-	 * unwinder to handle the stack switch.
-	 */
-	pushq		%rbp
-	mov		%rsp, %rbp
-
-	/*
-	 * The unwinder relies on the word at the top of the new stack
-	 * page linking back to the previous RSP.
-	 */
-	mov		%rsp, (%rdi)
-	mov		%rdi, %rsp
-	/* Move the argument to the right place */
-	mov		%rdx, %rdi
-
-1:
-	.pushsection .discard.instr_begin
-	.long 1b - .
-	.popsection
-
-	CALL_NOSPEC	rsi
-
-2:
-	.pushsection .discard.instr_end
-	.long 2b - .
-	.popsection
-
-	/* Restore the previous stack pointer from RBP. */
-	leaveq
-	ret
-SYM_FUNC_END(asm_call_on_stack)
-
 #ifdef CONFIG_XEN_PV
 /*
  * A note on the "critical region" in our callback handler.