[PATCH v2 6/9] x86/kexec: set_[gi]dt() -> native_[gi]dt_invalidate() in machine_kexec_*.c

From: H. Peter Anvin
Date: Fri May 14 2021 - 21:44:49 EST


From: "H. Peter Anvin (Intel)" <hpa@xxxxxxxxx>

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@xxxxxxxxx>
---
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 1e34feebcd5d..1b373d79cedc 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 c078b0d3ab0e..131f30fdcfbd 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,
--
2.31.1