linux-kernel - [tip:x86/platform] x86/platform: Control warm reset setup via legacy feature flag

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Date:   Sun, 14 Jan 2018 12:34:28 -0800
From:   tip-bot for Jan Kiszka <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     jan.kiszka@...mens.com, linux-kernel@...r.kernel.org,
        tglx@...utronix.de, hpa@...or.com, mingo@...nel.org
Subject: [tip:x86/platform] x86/platform: Control warm reset setup via
 legacy feature flag

Commit-ID:  e348caef8b4a161cc27bec8f7500b7e100370ef1
Gitweb:     https://git.kernel.org/tip/e348caef8b4a161cc27bec8f7500b7e100370ef1
Author:     Jan Kiszka <jan.kiszka@...mens.com>
AuthorDate: Mon, 27 Nov 2017 09:11:44 +0100
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Sun, 14 Jan 2018 21:11:53 +0100

x86/platform: Control warm reset setup via legacy feature flag

Allow to turn off the setup of BIOS-managed warm reset via a new flag in
x86_legacy_features. Besides the UV1, the upcoming jailhose guest support
needs this switched off.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: jailhouse-dev@...glegroups.com
Link: https://lkml.kernel.org/r/44376558129d70a2c1527959811371ef4b82e829.1511770314.git.jan.kiszka@siemens.com

---
 arch/x86/include/asm/x86_init.h    | 1 +
 arch/x86/kernel/apic/x2apic_uv_x.c | 1 +
 arch/x86/kernel/platform-quirks.c  | 1 +
 arch/x86/kernel/smpboot.c          | 4 ++--
 4 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index aa47475..fc2f082 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -212,6 +212,7 @@ enum x86_legacy_i8042_state {
 struct x86_legacy_features {
 	enum x86_legacy_i8042_state i8042;
 	int rtc;
+	int warm_reset;
 	int no_vga;
 	int reserve_bios_regions;
 	struct x86_legacy_devices devices;
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index e1b8e8b..6de35fc 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -316,6 +316,7 @@ static int __init uv_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 	} else if (!strcmp(oem_table_id, "UVH")) {
 		/* Only UV1 systems: */
 		uv_system_type = UV_NON_UNIQUE_APIC;
+		x86_platform.legacy.warm_reset = 0;
 		__this_cpu_write(x2apic_extra_bits, pnodeid << uvh_apicid.s.pnode_shift);
 		uv_set_apicid_hibit();
 		uv_apic = 1;
diff --git a/arch/x86/kernel/platform-quirks.c b/arch/x86/kernel/platform-quirks.c
index 39a5929..235fe60 100644
--- a/arch/x86/kernel/platform-quirks.c
+++ b/arch/x86/kernel/platform-quirks.c
@@ -9,6 +9,7 @@ void __init x86_early_init_platform_quirks(void)
 {
 	x86_platform.legacy.i8042 = X86_LEGACY_I8042_EXPECTED_PRESENT;
 	x86_platform.legacy.rtc = 1;
+	x86_platform.legacy.warm_reset = 1;
 	x86_platform.legacy.reserve_bios_regions = 0;
 	x86_platform.legacy.devices.pnpbios = 1;
 
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ed556d5..9adcae1 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -934,7 +934,7 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle,
 	 * the targeted processor.
 	 */
 
-	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
+	if (x86_platform.legacy.warm_reset) {
 
 		pr_debug("Setting warm reset code and vector.\n");
 
@@ -1006,7 +1006,7 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle,
 	/* mark "stuck" area as not stuck */
 	*trampoline_status = 0;
 
-	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
+	if (x86_platform.legacy.warm_reset) {
 		/*
 		 * Cleanup possible dangling ends...
 		 */