linux-kernel - [tip: x86/irq] x86/kexec: Set_[gi]dt() -> native_[gi]dt_invalidate() in machine_kexec

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Date:   Tue, 25 May 2021 09:29:15 -0000
From:   "tip-bot2 for H. Peter Anvin (Intel)" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "H. Peter Anvin (Intel)" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/irq] x86/kexec: Set_[gi]dt() -> native_[gi]dt_invalidate()
 in machine_kexec_*.c

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

Commit-ID:     056c52f5e824c050c58fd27ea6d717cba32239c2
Gitweb:        https://git.kernel.org/tip/056c52f5e824c050c58fd27ea6d717cba32239c2
Author:        H. Peter Anvin (Intel) <hpa@...or.com>
AuthorDate:    Wed, 19 May 2021 14:21:52 -07:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 21 May 2021 12:36:45 +02:00

x86/kexec: Set_[gi]dt() -> native_[gi]dt_invalidate() in machine_kexec_*.c

These files contain private set_gdt() functions which are only used to
invalid the gdt; machine_kexec_64.c also contains a set_idt()
function to invalidate the idt.

phys_to_virt(0) *really* doesn't make any sense for creating an
invalid GDT. A NULL pointer (virtual 0) makes a lot more sense;
although neither will allow any actual memory reference, a NULL
pointer stands out more.

Replace these calls with native_[gi]dt_invalidate().

Signed-off-by: H. Peter Anvin (Intel) <hpa@...or.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/r/20210519212154.511983-7-hpa@zytor.com

---
 arch/x86/kernel/machine_kexec_32.c | 15 +------------
 arch/x86/kernel/machine_kexec_64.c | 33 +----------------------------
 2 files changed, 4 insertions(+), 44 deletions(-)

diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c
index 1e34fee..1b373d7 100644
--- a/arch/x86/kernel/machine_kexec_32.c
+++ b/arch/x86/kernel/machine_kexec_32.c
@@ -23,17 +23,6 @@
 #include <asm/set_memory.h>
 #include <asm/debugreg.h>
 
-static void set_gdt(void *newgdt, __u16 limit)
-{
-	struct desc_ptr curgdt;
-
-	/* ia32 supports unaligned loads & stores */
-	curgdt.size    = limit;
-	curgdt.address = (unsigned long)newgdt;
-
-	load_gdt(&curgdt);
-}
-
 static void load_segments(void)
 {
 #define __STR(X) #X
@@ -232,8 +221,8 @@ void machine_kexec(struct kimage *image)
 	 * The gdt & idt are now invalid.
 	 * If you want to load them you must set up your own idt & gdt.
 	 */
-	idt_invalidate();
-	set_gdt(phys_to_virt(0), 0);
+	native_idt_invalidate();
+	native_gdt_invalidate();
 
 	/* now call it */
 	image->start = relocate_kernel_ptr((unsigned long)image->head,
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index c078b0d..131f30f 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -256,35 +256,6 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 	return init_transition_pgtable(image, level4p);
 }
 
-static void set_idt(void *newidt, u16 limit)
-{
-	struct desc_ptr curidt;
-
-	/* x86-64 supports unaligned loads & stores */
-	curidt.size    = limit;
-	curidt.address = (unsigned long)newidt;
-
-	__asm__ __volatile__ (
-		"lidtq %0\n"
-		: : "m" (curidt)
-		);
-};
-
-
-static void set_gdt(void *newgdt, u16 limit)
-{
-	struct desc_ptr curgdt;
-
-	/* x86-64 supports unaligned loads & stores */
-	curgdt.size    = limit;
-	curgdt.address = (unsigned long)newgdt;
-
-	__asm__ __volatile__ (
-		"lgdtq %0\n"
-		: : "m" (curgdt)
-		);
-};
-
 static void load_segments(void)
 {
 	__asm__ __volatile__ (
@@ -379,8 +350,8 @@ void machine_kexec(struct kimage *image)
 	 * The gdt & idt are now invalid.
 	 * If you want to load them you must set up your own idt & gdt.
 	 */
-	set_gdt(phys_to_virt(0), 0);
-	set_idt(phys_to_virt(0), 0);
+	native_idt_invalidate();
+	native_gdt_invalidate();
 
 	/* now call it */
 	image->start = relocate_kernel((unsigned long)image->head,