commit 62844c4415f50e01ab46fa8bedc127cc098aa77b
Author: Andrew Cooper <andrew.cooper3@citrix.com>
AuthorDate: Fri Dec 22 18:01:37 2023 +0000
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Tue Apr 9 16:45:01 2024 +0100
x86: Drop INDIRECT_JMP
Indirect JMPs which are not tailcalls can lead to an unwelcome form of
speculative type confusion, and we've removed the uses of INDIRECT_JMP to
compensate. Remove the temptation to reintroduce new instances.
This is part of XSA-456 / CVE-2024-2201.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 0b66d7ce3c0290eaad28bdafb35200052d012b14)
---
xen/arch/x86/include/asm/asm-defns.h | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/xen/arch/x86/include/asm/asm-defns.h b/xen/arch/x86/include/asm/asm-defns.h
index 9a7073ced5..d55dd3bbc3 100644
--- a/xen/arch/x86/include/asm/asm-defns.h
+++ b/xen/arch/x86/include/asm/asm-defns.h
@@ -29,10 +29,9 @@
BUG /* Shouldn't return */
.endm
-.macro INDIRECT_BRANCH insn:req arg:req
+.macro INDIRECT_CALL arg:req
/*
- * Create an indirect branch. insn is one of call/jmp, arg is a single
- * register.
+ * Create an indirect call. arg is a single register.
*
* With no compiler support, this degrades into a plain indirect call/jmp.
* With compiler support, dispatch to the correct __x86_indirect_thunk_*
@@ -42,7 +41,7 @@
$done = 0
.irp reg, ax, cx, dx, bx, bp, si, di, 8, 9, 10, 11, 12, 13, 14, 15
.ifeqs "\arg", "%r\reg"
- \insn __x86_indirect_thunk_r\reg
+ call __x86_indirect_thunk_r\reg
$done = 1
.exitm
.endif
@@ -53,19 +52,10 @@
.endif
.else
- \insn *\arg
+ call *\arg
.endif
.endm
-/* Convenience wrappers. */
-.macro INDIRECT_CALL arg:req
- INDIRECT_BRANCH call \arg
-.endm
-
-.macro INDIRECT_JMP arg:req
- INDIRECT_BRANCH jmp \arg
-.endm
-
#ifdef CONFIG_XEN_IBT
# define ENDBR64 endbr64
#else
--
generated by git-patchbot for /home/xen/git/xen.git#staging-4.18
Author: Andrew Cooper <andrew.cooper3@citrix.com>
AuthorDate: Fri Dec 22 18:01:37 2023 +0000
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Tue Apr 9 16:45:01 2024 +0100
x86: Drop INDIRECT_JMP
Indirect JMPs which are not tailcalls can lead to an unwelcome form of
speculative type confusion, and we've removed the uses of INDIRECT_JMP to
compensate. Remove the temptation to reintroduce new instances.
This is part of XSA-456 / CVE-2024-2201.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 0b66d7ce3c0290eaad28bdafb35200052d012b14)
---
xen/arch/x86/include/asm/asm-defns.h | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/xen/arch/x86/include/asm/asm-defns.h b/xen/arch/x86/include/asm/asm-defns.h
index 9a7073ced5..d55dd3bbc3 100644
--- a/xen/arch/x86/include/asm/asm-defns.h
+++ b/xen/arch/x86/include/asm/asm-defns.h
@@ -29,10 +29,9 @@
BUG /* Shouldn't return */
.endm
-.macro INDIRECT_BRANCH insn:req arg:req
+.macro INDIRECT_CALL arg:req
/*
- * Create an indirect branch. insn is one of call/jmp, arg is a single
- * register.
+ * Create an indirect call. arg is a single register.
*
* With no compiler support, this degrades into a plain indirect call/jmp.
* With compiler support, dispatch to the correct __x86_indirect_thunk_*
@@ -42,7 +41,7 @@
$done = 0
.irp reg, ax, cx, dx, bx, bp, si, di, 8, 9, 10, 11, 12, 13, 14, 15
.ifeqs "\arg", "%r\reg"
- \insn __x86_indirect_thunk_r\reg
+ call __x86_indirect_thunk_r\reg
$done = 1
.exitm
.endif
@@ -53,19 +52,10 @@
.endif
.else
- \insn *\arg
+ call *\arg
.endif
.endm
-/* Convenience wrappers. */
-.macro INDIRECT_CALL arg:req
- INDIRECT_BRANCH call \arg
-.endm
-
-.macro INDIRECT_JMP arg:req
- INDIRECT_BRANCH jmp \arg
-.endm
-
#ifdef CONFIG_XEN_IBT
# define ENDBR64 endbr64
#else
--
generated by git-patchbot for /home/xen/git/xen.git#staging-4.18