arm/alternatives: Rename alt_instr fields which are used in common code

Alternatives auditing for livepatches is currently broken.  To fix it, the
livepatch code needs to inspect more fields of alt_instr.

Rename ARM's fields to match x86's, because:

 * ARM already exposes alt_offset under the repl name via ALT_REPL_PTR().
 * "alt" is ambiguous in a structure entirely about alternatives already.
 * "repl", being the same width as orig leads to slightly neater code.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 418cf59c4e29451010d7efb3835b900690d19866)

diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
index f03cd943c636774cb1f14741b3c8fa9928c1b60e..ef98f374174ce11eb23a3b980c2eb5c9f61f6ddd 100644 (file)
--- a/xen/arch/arm/alternative.c
+++ b/xen/arch/arm/alternative.c
@@ -55,7 +55,7 @@ static bool branch_insn_requires_update(const struct alt_instr *alt,
         return true;
 
     replptr = (unsigned long)ALT_REPL_PTR(alt);
-    if ( pc >= replptr && pc <= (replptr + alt->alt_len) )
+    if ( pc >= replptr && pc <= (replptr + alt->repl_len) )
         return false;
 
     /*
@@ -139,9 +139,9 @@ static int __apply_alternatives(const struct alt_region *region,
             continue;
 
         if ( alt->cpufeature == ARM_CB_PATCH )
-            BUG_ON(alt->alt_len != 0);
+            BUG_ON(alt->repl_len != 0);
         else
-            BUG_ON(alt->alt_len != alt->orig_len);
+            BUG_ON(alt->repl_len != alt->orig_len);
 
         origptr = ALT_ORIG_PTR(alt);
         updptr = (void *)origptr + update_offset;

diff --git a/xen/arch/arm/include/asm/alternative.h b/xen/arch/arm/include/asm/alternative.h
index 1eb4b60fbb3ef92ffef0d4ccf63beab42cde26fc..d3210e82f9e50136a7defdfa1bc8a782afede710 100644 (file)
--- a/xen/arch/arm/include/asm/alternative.h
+++ b/xen/arch/arm/include/asm/alternative.h
@@ -13,16 +13,16 @@
 
 struct alt_instr {
        s32 orig_offset;        /* offset to original instruction */
-       s32 alt_offset;         /* offset to replacement instruction */
+       s32 repl_offset;        /* offset to replacement instruction */
        u16 cpufeature;         /* cpufeature bit set for replacement */
        u8  orig_len;           /* size of original instruction(s) */
-       u8  alt_len;            /* size of new instruction(s), <= orig_len */
+       u8  repl_len;           /* size of new instruction(s), <= orig_len */
 };
 
 /* Xen: helpers used by common code. */
 #define __ALT_PTR(a,f)         ((void *)&(a)->f + (a)->f)
 #define ALT_ORIG_PTR(a)                __ALT_PTR(a, orig_offset)
-#define ALT_REPL_PTR(a)                __ALT_PTR(a, alt_offset)
+#define ALT_REPL_PTR(a)                __ALT_PTR(a, repl_offset)
 
 typedef void (*alternative_cb_t)(const struct alt_instr *alt,
                                 const uint32_t *origptr, uint32_t *updptr,
@@ -90,12 +90,12 @@ int apply_alternatives(const struct alt_instr *start, const struct alt_instr *en
 #include <asm/asm_defns.h>
 #include <asm/macros.h>
 
-.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len
+.macro altinstruction_entry orig_offset repl_offset feature orig_len repl_len
        .word \orig_offset - .
-       .word \alt_offset - .
+       .word \repl_offset - .
        .hword \feature
        .byte \orig_len
-       .byte \alt_len
+       .byte \repl_len
 .endm
 
 .macro alternative_insn insn1, insn2, cap, enable = 1