x86/spec_ctrl: Hold SCF in %ebx across SPEC_CTRL_ENTRY_{PV,INTR}

... as we do in the exit paths too.  This will allow simplification to the
sub-blocks.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 9607aeb6602b8ed9962404de3f5f90170ffddb66)

diff --git a/xen/arch/x86/include/asm/spec_ctrl_asm.h b/xen/arch/x86/include/asm/spec_ctrl_asm.h
index aa8c5e3c33bdc86fea7df9bd38f6311d50287d1f..667ec7ffe05615f285e18b0575c6f397e4a4da3e 100644 (file)
--- a/xen/arch/x86/include/asm/spec_ctrl_asm.h
+++ b/xen/arch/x86/include/asm/spec_ctrl_asm.h
@@ -251,9 +251,11 @@
  */
 .macro SPEC_CTRL_ENTRY_FROM_PV
 /*
- * Requires %rsp=regs/cpuinfo, %rdx=0
- * Clobbers %rax, %rcx, %rdx
+ * Requires %rsp=regs/cpuinfo, %r14=stack_end, %rdx=0
+ * Clobbers %rax, %rbx, %rcx, %rdx
  */
+    movzbl STACK_CPUINFO_FIELD(scf)(%r14), %ebx
+
     ALTERNATIVE "", __stringify(DO_SPEC_CTRL_COND_IBPB maybexen=0),     \
         X86_FEATURE_IBPB_ENTRY_PV
 
@@ -277,8 +279,10 @@
 .macro SPEC_CTRL_ENTRY_FROM_INTR
 /*
  * Requires %rsp=regs, %r14=stack_end, %rdx=0
- * Clobbers %rax, %rcx, %rdx
+ * Clobbers %rax, %rbx, %rcx, %rdx
  */
+    movzbl STACK_CPUINFO_FIELD(scf)(%r14), %ebx
+
     testb $3, UREGS_cs(%rsp)
     jz .L\@_skip
 

diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S
index 98ea4f5a4a2bd846a75c4067253ba8d2df551ee7..3c544e9a14d6b899b3d80ea8f69e436d3a13078a 100644 (file)
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -20,7 +20,7 @@ ENTRY(entry_int82)
 
         GET_STACK_END(14)
 
-        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
+        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %r14=end, %rdx=0, Clob: abcd */
         /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
 
         sti

diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 405281fa2508f069c32dafac05acd9dca2cd7f39..1d7344117bdd89f8fdede56004ad3d8e924b9f5d 100644 (file)
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -268,7 +268,7 @@ ENTRY(lstar_enter)
 
         GET_STACK_END(14)
 
-        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
+        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %r14=end, %rdx=0, Clob: abcd */
         /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
 
         mov   STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
@@ -306,7 +306,7 @@ ENTRY(cstar_enter)
 
         GET_STACK_END(14)
 
-        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
+        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %r14=end, %rdx=0, Clob: abcd */
         /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
 
         mov   STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
@@ -348,7 +348,7 @@ GLOBAL(sysenter_eflags_saved)
 
         GET_STACK_END(14)
 
-        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
+        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %r14=end, %rdx=0, Clob: abcd */
         /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
 
         /* PUSHF above has saved EFLAGS.IF clear (the caller had it set). */
@@ -403,7 +403,7 @@ ENTRY(int80_direct_trap)
 
         GET_STACK_END(14)
 
-        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
+        SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %r14=end, %rdx=0, Clob: abcd */
         /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
 
         mov   STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
@@ -713,7 +713,7 @@ ENTRY(common_interrupt)
 
         GET_STACK_END(14)
 
-        SPEC_CTRL_ENTRY_FROM_INTR /* Req: %rsp=regs, %r14=end, %rdx=0, Clob: acd */
+        SPEC_CTRL_ENTRY_FROM_INTR /* Req: %rsp=regs, %r14=end, %rdx=0, Clob: abcd */
         /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
 
         mov   STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
@@ -747,7 +747,7 @@ GLOBAL(handle_exception)
 
         GET_STACK_END(14)
 
-        SPEC_CTRL_ENTRY_FROM_INTR /* Req: %rsp=regs, %r14=end, %rdx=0, Clob: acd */
+        SPEC_CTRL_ENTRY_FROM_INTR /* Req: %rsp=regs, %r14=end, %rdx=0, Clob: abcd */
         /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
 
         mov   STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx