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Message-Id: <20200428151725.31091-34-joro@8bytes.org>
Date: Tue, 28 Apr 2020 17:16:43 +0200
From: Joerg Roedel <joro@...tes.org>
To: x86@...nel.org
Cc: hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Hellstrom <thellstrom@...are.com>,
Jiri Slaby <jslaby@...e.cz>,
Dan Williams <dan.j.williams@...el.com>,
Tom Lendacky <thomas.lendacky@....com>,
Juergen Gross <jgross@...e.com>,
Kees Cook <keescook@...omium.org>,
David Rientjes <rientjes@...gle.com>,
Cfir Cohen <cfir@...gle.com>,
Erdem Aktas <erdemaktas@...gle.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mike Stunes <mstunes@...are.com>,
Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
virtualization@...ts.linux-foundation.org
Subject: [PATCH v3 33/75] x86/head/64: Load segment registers earlier
From: Joerg Roedel <jroedel@...e.de>
Make sure segments are properly set up before setting up an IDT and
doing anything that might cause a #VC exception. This is later needed
for early exception handling.
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
arch/x86/kernel/head_64.S | 52 +++++++++++++++++++--------------------
1 file changed, 26 insertions(+), 26 deletions(-)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 20a9df062088..b5ff38bb32f2 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -168,6 +168,32 @@ SYM_CODE_START(secondary_startup_64)
movq %rax, boot_gdt_base(%rip)
lgdt boot_gdt_descr(%rip)
+ /* set up data segments */
+ xorl %eax,%eax
+ movl %eax,%ds
+ movl %eax,%ss
+ movl %eax,%es
+
+ /*
+ * We don't really need to load %fs or %gs, but load them anyway
+ * to kill any stale realmode selectors. This allows execution
+ * under VT hardware.
+ */
+ movl %eax,%fs
+ movl %eax,%gs
+
+ /* Set up %gs.
+ *
+ * The base of %gs always points to fixed_percpu_data. If the
+ * stack protector canary is enabled, it is located at %gs:40.
+ * Note that, on SMP, the boot cpu uses init data section until
+ * the per cpu areas are set up.
+ */
+ movl $MSR_GS_BASE,%ecx
+ movl initial_gs(%rip),%eax
+ movl initial_gs+4(%rip),%edx
+ wrmsr
+
/* Check if nx is implemented */
movl $0x80000001, %eax
cpuid
@@ -203,32 +229,6 @@ SYM_CODE_START(secondary_startup_64)
*/
lgdt early_gdt_descr(%rip)
- /* set up data segments */
- xorl %eax,%eax
- movl %eax,%ds
- movl %eax,%ss
- movl %eax,%es
-
- /*
- * We don't really need to load %fs or %gs, but load them anyway
- * to kill any stale realmode selectors. This allows execution
- * under VT hardware.
- */
- movl %eax,%fs
- movl %eax,%gs
-
- /* Set up %gs.
- *
- * The base of %gs always points to fixed_percpu_data. If the
- * stack protector canary is enabled, it is located at %gs:40.
- * Note that, on SMP, the boot cpu uses init data section until
- * the per cpu areas are set up.
- */
- movl $MSR_GS_BASE,%ecx
- movl initial_gs(%rip),%eax
- movl initial_gs+4(%rip),%edx
- wrmsr
-
/* rsi is pointer to real mode structure with interesting info.
pass it to C */
movq %rsi, %rdi
--
2.17.1
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