From 2126994528a160f56fbaa6e5f0a2da9c0d628095 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 15 May 2014 13:22:29 +0200
Subject: smm: unify SMM handlers

The next patch will add shared code between the initial handler for
SMBASE relocation and the actual SMI handler.  Combine the code of
the two handlers for simplicity.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 src/fw/smm.c | 27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

(limited to 'src')

diff --git a/src/fw/smm.c b/src/fw/smm.c
index eccef88..f486c78 100644
--- a/src/fw/smm.c
+++ b/src/fw/smm.c
@@ -17,13 +17,17 @@
 #include "util.h" // smm_setup
 #include "x86.h" // wbinvd
 
-extern u8 smm_relocation_start, smm_relocation_end;
+extern u8 smm_code_start, smm_code_end;
+
 ASM32FLAT(
-    ".global smm_relocation_start, smm_relocation_end\n"
+    ".global smm_code_start, smm_code_end\n"
     "  .code16gcc\n"
+    "smm_code_start:\n"
+    "  mov %cs, %ax\n"
+    "  cmp $0xa000, %ax\n"
+    "  je smm_exit\n"
 
     /* code to relocate SMBASE to 0xa0000 */
-    "smm_relocation_start:\n"
     "  movl $" __stringify(BUILD_SMM_INIT_ADDR) " + 0x7efc, %ebx\n"
     "  addr32 movb (%ebx), %al\n"  /* revision ID to see if x86_64 or x86 */
     "  cmpb $0x64, %al\n"
@@ -39,16 +43,7 @@ ASM32FLAT(
     "  movb $0x00, %al\n"
     "  movw $" __stringify(PORT_SMI_STATUS) ", %dx\n"
     "  outb %al, %dx\n"
-    "  rsm\n"
-    "smm_relocation_end:\n"
-    "  .code32\n"
-    );
-
-extern u8 smm_code_start, smm_code_end;
-ASM32FLAT(
-    ".global smm_code_start, smm_code_end\n"
-    "  .code16gcc\n"
-    "smm_code_start:\n"
+    "smm_exit:\n"
     "  rsm\n"
     "smm_code_end:\n"
     "  .code32\n"
@@ -60,9 +55,9 @@ smm_save_and_copy(void)
     /* save original memory content */
     memcpy((void *)BUILD_SMM_ADDR, (void *)BUILD_SMM_INIT_ADDR, BUILD_SMM_SIZE);
 
-    /* copy the SMM relocation code */
-    memcpy((void *)BUILD_SMM_INIT_ADDR, &smm_relocation_start,
-           &smm_relocation_end - &smm_relocation_start);
+    /* copy the SMM code, which will relocate itself on the first execution */
+    memcpy((void *)BUILD_SMM_INIT_ADDR, &smm_code_start,
+           &smm_code_end - &smm_code_start);
 }
 
 static void
-- 
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