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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 03:22:47 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 03:22:47 +0000
commit31d3cc774e9124f10d3ed2ea144a6e232e93e822 (patch)
treede1ac8afc7248eec4b2fb60496b8e9273452d9f7 /arch/x86/entry/entry_64_compat.S
parentAdding upstream version 6.1.82. (diff)
downloadlinux-31d3cc774e9124f10d3ed2ea144a6e232e93e822.tar.xz
linux-31d3cc774e9124f10d3ed2ea144a6e232e93e822.zip
Adding upstream version 6.1.85.upstream/6.1.85
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/entry/entry_64_compat.S')
-rw-r--r--arch/x86/entry/entry_64_compat.S16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 4bcd009a2..b14b8cd85 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -92,6 +92,7 @@ SYM_INNER_LABEL(entry_SYSENTER_compat_after_hwframe, SYM_L_GLOBAL)
IBRS_ENTER
UNTRAIN_RET
+ CLEAR_BRANCH_HISTORY
/*
* SYSENTER doesn't filter flags, so we need to clear NT and AC
@@ -210,6 +211,7 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_after_hwframe, SYM_L_GLOBAL)
IBRS_ENTER
UNTRAIN_RET
+ CLEAR_BRANCH_HISTORY
movq %rsp, %rdi
call do_fast_syscall_32
@@ -278,3 +280,17 @@ SYM_INNER_LABEL(entry_SYSRETL_compat_end, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
int3
SYM_CODE_END(entry_SYSCALL_compat)
+
+/*
+ * int 0x80 is used by 32 bit mode as a system call entry. Normally idt entries
+ * point to C routines, however since this is a system call interface the branch
+ * history needs to be scrubbed to protect against BHI attacks, and that
+ * scrubbing needs to take place in assembly code prior to entering any C
+ * routines.
+ */
+SYM_CODE_START(int80_emulation)
+ ANNOTATE_NOENDBR
+ UNWIND_HINT_FUNC
+ CLEAR_BRANCH_HISTORY
+ jmp do_int80_emulation
+SYM_CODE_END(int80_emulation)