Merge branch 'for-next/spectre-bhb' into for-next/core

[platform/kernel/linux-starfive.git] / arch / arm64 / include / asm / assembler.h

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 8df4121..8c5a61a 100644 (file)
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -109,6 +109,13 @@
        .endm
 
 /*
+ * Clear Branch History instruction
+ */
+       .macro clearbhb
+       hint    #22
+       .endm
+
+/*
  * Speculation barrier
  */
        .macro  sb
@@ -845,4 +852,50 @@ alternative_endif
 
 #endif /* GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT */
 
+       .macro __mitigate_spectre_bhb_loop      tmp
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+alternative_cb  spectre_bhb_patch_loop_iter
+       mov     \tmp, #32               // Patched to correct the immediate
+alternative_cb_end
+.Lspectre_bhb_loop\@:
+       b       . + 4
+       subs    \tmp, \tmp, #1
+       b.ne    .Lspectre_bhb_loop\@
+       sb
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+       .endm
+
+       .macro mitigate_spectre_bhb_loop        tmp
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+alternative_cb spectre_bhb_patch_loop_mitigation_enable
+       b       .L_spectre_bhb_loop_done\@      // Patched to NOP
+alternative_cb_end
+       __mitigate_spectre_bhb_loop     \tmp
+.L_spectre_bhb_loop_done\@:
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+       .endm
+
+       /* Save/restores x0-x3 to the stack */
+       .macro __mitigate_spectre_bhb_fw
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+       stp     x0, x1, [sp, #-16]!
+       stp     x2, x3, [sp, #-16]!
+       mov     w0, #ARM_SMCCC_ARCH_WORKAROUND_3
+alternative_cb smccc_patch_fw_mitigation_conduit
+       nop                                     // Patched to SMC/HVC #0
+alternative_cb_end
+       ldp     x2, x3, [sp], #16
+       ldp     x0, x1, [sp], #16
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+       .endm
+
+       .macro mitigate_spectre_bhb_clear_insn
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+alternative_cb spectre_bhb_patch_clearbhb
+       /* Patched to NOP when not supported */
+       clearbhb
+       isb
+alternative_cb_end
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+       .endm
 #endif /* __ASM_ASSEMBLER_H */