[PATCH 5.18 08/61] x86/retpoline: Cleanup some #ifdefery

Greg Kroah-Hartman
2022-07-12T19:10:41Z

From: Peter Zijlstra <peterz@infradead.org>

commit 369ae6ffc41a3c1137cab697635a84d0cc7cdcea upstream.

On it's own not much of a cleanup but it prepares for more/similar
code.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/disabled-features.h | 9 ++++++++-
arch/x86/include/asm/nospec-branch.h | 7 +++----
arch/x86/net/bpf_jit_comp.c | 7 +++----
3 files changed, 14 insertions(+), 9 deletions(-)

--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -56,6 +56,13 @@
# define DISABLE_PTI (1 << (X86_FEATURE_PTI & 31))
#endif

+#ifdef CONFIG_RETPOLINE
+# define DISABLE_RETPOLINE 0
+#else
+# define DISABLE_RETPOLINE ((1 << (X86_FEATURE_RETPOLINE & 31)) | \
+ (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31)))
+#endif
+
#ifdef CONFIG_INTEL_IOMMU_SVM
# define DISABLE_ENQCMD 0
#else
@@ -82,7 +89,7 @@
#define DISABLED_MASK8 0
#define DISABLED_MASK9 (DISABLE_SMAP|DISABLE_SGX)
#define DISABLED_MASK10 0
-#define DISABLED_MASK11 0
+#define DISABLED_MASK11 (DISABLE_RETPOLINE)
#define DISABLED_MASK12 0
#define DISABLED_MASK13 0
#define DISABLED_MASK14 0
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -120,17 +120,16 @@
_ASM_PTR " 999b\n\t" \
".popsection\n\t"

-#ifdef CONFIG_RETPOLINE
-
typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE];
+extern retpoline_thunk_t __x86_indirect_thunk_array[];
+
+#ifdef CONFIG_RETPOLINE

#define GEN(reg) \
extern retpoline_thunk_t __x86_indirect_thunk_ ## reg;
#include <asm/GEN-for-each-reg.h>
#undef GEN

-extern retpoline_thunk_t __x86_indirect_thunk_array[];
-
#ifdef CONFIG_X86_64

/*
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -407,16 +407,15 @@ static void emit_indirect_jump(u8 **ppro
{
u8 *prog = *pprog;

-#ifdef CONFIG_RETPOLINE
if (cpu_feature_enabled(X86_FEATURE_RETPOLINE_LFENCE)) {
EMIT_LFENCE();
EMIT2(0xFF, 0xE0 + reg);
} else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) {
OPTIMIZER_HIDE_VAR(reg);
emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip);
- } else
-#endif
- EMIT2(0xFF, 0xE0 + reg);
+ } else {
+ EMIT2(0xFF, 0xE0 + reg);
+ }

*pprog = prog;
}