linux-kernel - [PATCH 4/4] xen/PVH: Remove reserved entry in PVH GDT

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Message-Id: <20180430162339.17143-5-boris.ostrovsky@oracle.com>
Date:   Mon, 30 Apr 2018 12:23:39 -0400
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:     jgross@...e.com, Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: [PATCH 4/4] xen/PVH: Remove reserved entry in PVH GDT

And without it we can't use _BOOT_XX macros any longer so define new ones.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
---
 arch/x86/xen/xen-pvh.S | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/x86/xen/xen-pvh.S b/arch/x86/xen/xen-pvh.S
index 4eed586..30dd067 100644
--- a/arch/x86/xen/xen-pvh.S
+++ b/arch/x86/xen/xen-pvh.S
@@ -54,7 +54,11 @@
  * charge of setting up it's own stack, GDT and IDT.
  */
 
-#define PVH_GDT_ENTRY_CANARY    4
+#define PVH_GDT_ENTRY_CS        1
+#define PVH_GDT_ENTRY_DS        2
+#define PVH_GDT_ENTRY_CANARY    3
+#define PVH_CS_SEL              (PVH_GDT_ENTRY_CS * 8)
+#define PVH_DS_SEL              (PVH_GDT_ENTRY_DS * 8)
 #define PVH_CANARY_SEL          (PVH_GDT_ENTRY_CANARY * 8)
 
 ENTRY(pvh_start_xen)
@@ -62,7 +66,7 @@ ENTRY(pvh_start_xen)
 
 	lgdt (_pa(gdt))
 
-	mov $(__BOOT_DS),%eax
+	mov $(PVH_DS_SEL),%eax
 	mov %eax,%ds
 	mov %eax,%es
 	mov %eax,%ss
@@ -99,7 +103,7 @@ ENTRY(pvh_start_xen)
 	mov %eax, %cr0
 
 	/* Jump to 64-bit mode. */
-	ljmp $__BOOT_CS, $_pa(1f)
+	ljmp $PVH_CS_SEL, $_pa(1f)
 
 	/* 64-bit entry point. */
 	.code64
@@ -122,13 +126,13 @@ ENTRY(pvh_start_xen)
 	or $(X86_CR0_PG | X86_CR0_PE), %eax
 	mov %eax, %cr0
 
-	ljmp $__BOOT_CS, $1f
+	ljmp $PVH_CS_SEL, $1f
 1:
 	call xen_prepare_pvh
 	mov $_pa(pvh_bootparams), %esi
 
 	/* startup_32 doesn't expect paging and PAE to be on. */
-	ljmp $__BOOT_CS, $_pa(2f)
+	ljmp $PVH_CS_SEL, $_pa(2f)
 2:
 	mov %cr0, %eax
 	and $~X86_CR0_PG, %eax
@@ -137,7 +141,7 @@ ENTRY(pvh_start_xen)
 	and $~X86_CR4_PAE, %eax
 	mov %eax, %cr4
 
-	ljmp $__BOOT_CS, $_pa(startup_32)
+	ljmp $PVH_CS_SEL, $_pa(startup_32)
 #endif
 END(pvh_start_xen)
 
@@ -149,13 +153,12 @@ gdt:
 	.word 0
 gdt_start:
 	.quad 0x0000000000000000            /* NULL descriptor */
-	.quad 0x0000000000000000            /* reserved */
 #ifdef CONFIG_X86_64
-	.quad 0x00af9a000000ffff            /* __BOOT_CS */
+	.quad 0x00af9a000000ffff            /* PVH_CS_SEL */
 #else
-	.quad 0x00cf9a000000ffff            /* __BOOT_CS */
+	.quad 0x00cf9a000000ffff            /* PVH_CS_SEL */
 #endif
-	.quad 0x00cf92000000ffff            /* __BOOT_DS */
+	.quad 0x00cf92000000ffff            /* PVH_DS_SEL */
 	.quad 0x0040900000000018            /* PVH_CANARY_SEL */
 gdt_end:
 
-- 
2.9.3