linux-kernel - [patch V4 04/37] x86/smpboot: Rename start_cpu0() to soft_restart

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Message-ID: <20230512205255.662319599@linutronix.de>
Date:   Fri, 12 May 2023 23:07:03 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, David Woodhouse <dwmw2@...radead.org>,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Brian Gerst <brgerst@...il.com>,
        Arjan van de Veen <arjan@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Paul McKenney <paulmck@...nel.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Sean Christopherson <seanjc@...gle.com>,
        Oleksandr Natalenko <oleksandr@...alenko.name>,
        Paul Menzel <pmenzel@...gen.mpg.de>,
        "Guilherme G. Piccoli" <gpiccoli@...lia.com>,
        Piotr Gorski <lucjan.lucjanov@...il.com>,
        Usama Arif <usama.arif@...edance.com>,
        Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        xen-devel@...ts.xenproject.org,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        linux-arm-kernel@...ts.infradead.org,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Guo Ren <guoren@...nel.org>,
        linux-csky@...r.kernel.org,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        linux-mips@...r.kernel.org,
        "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
        Helge Deller <deller@....de>, linux-parisc@...r.kernel.org,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        linux-riscv@...ts.infradead.org,
        Mark Rutland <mark.rutland@....com>,
        Sabin Rapan <sabrapan@...zon.com>,
        "Michael Kelley (LINUX)" <mikelley@...rosoft.com>,
        Ross Philipson <ross.philipson@...cle.com>
Subject: [patch V4 04/37] x86/smpboot: Rename start_cpu0() to soft_restart_cpu()

From: Thomas Gleixner <tglx@...utronix.de>

This is used in the SEV play_dead() implementation to re-online CPUs. But
that has nothing to do with CPU0.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Michael Kelley <mikelley@...rosoft.com>
---
 arch/x86/include/asm/cpu.h   |    2 +-
 arch/x86/kernel/callthunks.c |    2 +-
 arch/x86/kernel/head_32.S    |   10 +++++-----
 arch/x86/kernel/head_64.S    |   10 +++++-----
 arch/x86/kernel/sev.c        |    2 +-
 5 files changed, 13 insertions(+), 13 deletions(-)

--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -30,7 +30,7 @@ struct x86_cpu {
 #ifdef CONFIG_HOTPLUG_CPU
 extern int arch_register_cpu(int num);
 extern void arch_unregister_cpu(int);
-extern void start_cpu0(void);
+extern void soft_restart_cpu(void);
 #ifdef CONFIG_DEBUG_HOTPLUG_CPU0
 extern int _debug_hotplug_cpu(int cpu, int action);
 #endif
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -134,7 +134,7 @@ static bool skip_addr(void *dest)
 	if (dest == ret_from_fork)
 		return true;
 #ifdef CONFIG_HOTPLUG_CPU
-	if (dest == start_cpu0)
+	if (dest == soft_restart_cpu)
 		return true;
 #endif
 #ifdef CONFIG_FUNCTION_TRACER
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -140,16 +140,16 @@ SYM_CODE_END(startup_32)
 
 #ifdef CONFIG_HOTPLUG_CPU
 /*
- * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
- * up already except stack. We just set up stack here. Then call
- * start_secondary().
+ * Entry point for soft restart of a CPU. Invoked from xxx_play_dead() for
+ * restarting the boot CPU or for restarting SEV guest CPUs after CPU hot
+ * unplug. Everything is set up already except the stack.
  */
-SYM_FUNC_START(start_cpu0)
+SYM_FUNC_START(soft_restart_cpu)
 	movl initial_stack, %ecx
 	movl %ecx, %esp
 	call *(initial_code)
 1:	jmp 1b
-SYM_FUNC_END(start_cpu0)
+SYM_FUNC_END(soft_restart_cpu)
 #endif
 
 /*
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -377,11 +377,11 @@ SYM_CODE_END(secondary_startup_64)
 
 #ifdef CONFIG_HOTPLUG_CPU
 /*
- * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
- * up already except stack. We just set up stack here. Then call
- * start_secondary() via .Ljump_to_C_code.
+ * Entry point for soft restart of a CPU. Invoked from xxx_play_dead() for
+ * restarting the boot CPU or for restarting SEV guest CPUs after CPU hot
+ * unplug. Everything is set up already except the stack.
  */
-SYM_CODE_START(start_cpu0)
+SYM_CODE_START(soft_restart_cpu)
 	ANNOTATE_NOENDBR
 	UNWIND_HINT_END_OF_STACK
 
@@ -390,7 +390,7 @@ SYM_CODE_START(start_cpu0)
 	movq	TASK_threadsp(%rcx), %rsp
 
 	jmp	.Ljump_to_C_code
-SYM_CODE_END(start_cpu0)
+SYM_CODE_END(soft_restart_cpu)
 #endif
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1328,7 +1328,7 @@ static void sev_es_play_dead(void)
 	 * If we get here, the VCPU was woken up again. Jump to CPU
 	 * startup code to get it back online.
 	 */
-	start_cpu0();
+	soft_restart_cpu();
 }
 #else  /* CONFIG_HOTPLUG_CPU */
 #define sev_es_play_dead	native_play_dead