arm64: kernel: Add support for User Access Override

[deliverable/linux.git] / arch / arm64 / include / asm / alternative.h

diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h
index e4962f04201e295d933d33f7f39745a5f5e65f65..a9fc24ec1aa9ee5f19909dda3d0ea465f31365ec 100644 (file)
--- a/arch/arm64/include/asm/alternative.h
+++ b/arch/arm64/include/asm/alternative.h
@@ -1,6 +1,8 @@
 #ifndef __ASM_ALTERNATIVE_H
 #define __ASM_ALTERNATIVE_H
 
+#include <asm/cpufeature.h>
+
 #ifndef __ASSEMBLY__
 
 #include <linux/init.h>
@@ -63,6 +65,8 @@ void apply_alternatives(void *start, size_t length);
 
 #else
 
+#include <asm/assembler.h>
+
 .macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len
        .word \orig_offset - .
        .word \alt_offset - .
@@ -136,6 +140,74 @@ void apply_alternatives(void *start, size_t length);
        alternative_insn insn1, insn2, cap, IS_ENABLED(cfg)
 
 
+/*
+ * Generate the assembly for UAO alternatives with exception table entries.
+ * This is complicated as there is no post-increment or pair versions of the
+ * unprivileged instructions, and USER() only works for single instructions.
+ */
+#ifdef CONFIG_ARM64_UAO
+       .macro uao_ldp l, reg1, reg2, addr, post_inc
+               alternative_if_not ARM64_HAS_UAO
+8888:                  ldp     \reg1, \reg2, [\addr], \post_inc;
+8889:                  nop;
+                       nop;
+               alternative_else
+                       ldtr    \reg1, [\addr];
+                       ldtr    \reg2, [\addr, #8];
+                       add     \addr, \addr, \post_inc;
+               alternative_endif
+
+               .section __ex_table,"a";
+               .align  3;
+               .quad   8888b,\l;
+               .quad   8889b,\l;
+               .previous;
+       .endm
+
+       .macro uao_stp l, reg1, reg2, addr, post_inc
+               alternative_if_not ARM64_HAS_UAO
+8888:                  stp     \reg1, \reg2, [\addr], \post_inc;
+8889:                  nop;
+                       nop;
+               alternative_else
+                       sttr    \reg1, [\addr];
+                       sttr    \reg2, [\addr, #8];
+                       add     \addr, \addr, \post_inc;
+               alternative_endif
+
+               .section __ex_table,"a";
+               .align  3;
+               .quad   8888b,\l;
+               .quad   8889b,\l;
+               .previous
+       .endm
+
+       .macro uao_user_alternative l, inst, alt_inst, reg, addr, post_inc
+               alternative_if_not ARM64_HAS_UAO
+8888:                  \inst   \reg, [\addr], \post_inc;
+                       nop;
+               alternative_else
+                       \alt_inst       \reg, [\addr];
+                       add             \addr, \addr, \post_inc;
+               alternative_endif
+
+               .section __ex_table,"a";
+               .align  3;
+               .quad   8888b,\l;
+               .previous
+       .endm
+#else
+       .macro uao_ldp l, reg1, reg2, addr, post_inc
+               USER(\l, ldp \reg1, \reg2, [\addr], \post_inc)
+       .endm
+       .macro uao_stp l, reg1, reg2, addr, post_inc
+               USER(\l, stp \reg1, \reg2, [\addr], \post_inc)
+       .endm
+       .macro uao_user_alternative l, inst, alt_inst, reg, addr, post_inc
+               USER(\l, \inst \reg, [\addr], \post_inc)
+       .endm
+#endif
+
 #endif  /*  __ASSEMBLY__  */
 
 /*