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 somewhat ambiguous in a structure entirely about alternatives
already.
* "repl", being the same number of character as orig leads to slightly neater
code.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Stefano Stabellini <sstabell...@kernel.org>
CC: Julien Grall <jul...@xen.org>
CC: Volodymyr Babchuk <volodymyr_babc...@epam.com>
CC: Bertrand Marquis <bertrand.marq...@arm.com>
CC: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
CC: Ross Lagerwall <ross.lagerw...@citrix.com>
CC: Jan Beulich <jbeul...@suse.com>
CC: Roger Pau Monné <roger....@citrix.com>
CC: Wei Liu <w...@xen.org>
The other option is to make alt_instr an entirely common structure, but it's
already different between ARM and x86 and I'm not sure the result of doing
this would result in nicer code.
---
xen/arch/arm/alternative.c | 6 +++---
xen/arch/arm/include/asm/alternative.h | 12 ++++++------
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
index f00e3b9b3c11..7366af4ea646 100644
--- a/xen/arch/arm/alternative.c
+++ b/xen/arch/arm/alternative.c
@@ -44,7 +44,7 @@ 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;
/*
@@ -128,9 +128,9 @@ 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 1eb4b60fbb3e..d3210e82f9e5 100644
--- 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
--
2.30.2
