[Xen-devel] [PATCH v2 04/20] alternatives: x86 rename and change parameters on ARM

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On x86 we squash 'apply_alternatives' in to
'alternative_instructions' (who was its sole user)
and 'apply_alternatives_nocheck' to 'apply_alternatives'.

On ARM we change the parameters for 'apply_alternatives'
to be of 'const struct alt_instr *' instead of void pointer and
size length.

We also add 'const' and make the arguments be on the
proper offset.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Jan Beulich <JBeulich@xxxxxxxx>

v1: First submission.
v2: Squash apply_alternatives(old) in alternative_instructions.
    Add const on x86.
---
 xen/arch/arm/alternative.c        |  4 ++--
 xen/arch/x86/alternative.c        | 29 ++++++++++++-----------------
 xen/common/livepatch.c            |  2 +-
 xen/include/asm-arm/alternative.h |  2 +-
 xen/include/asm-x86/alternative.h |  7 +++----
 5 files changed, 19 insertions(+), 25 deletions(-)

diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
index bf4101c..aba06db 100644
--- a/xen/arch/arm/alternative.c
+++ b/xen/arch/arm/alternative.c
@@ -200,11 +200,11 @@ void __init apply_alternatives_all(void)
     BUG_ON(ret);
 }
 
-int apply_alternatives(void *start, size_t length)
+int apply_alternatives(const struct alt_instr *start, const struct alt_instr 
*end)
 {
     const struct alt_region region = {
         .begin = start,
-        .end = start + length,
+        .end = end,
     };
 
     return __apply_alternatives(&region);
diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c
index fd8528e..6eaa10f 100644
--- a/xen/arch/x86/alternative.c
+++ b/xen/arch/x86/alternative.c
@@ -144,9 +144,10 @@ static void *init_or_livepatch text_poke(void *addr, const 
void *opcode, size_t
  * APs have less capabilities than the boot processor are not handled.
  * Tough. Make sure you disable such features by hand.
  */
-void init_or_livepatch apply_alternatives_nocheck(struct alt_instr *start, 
struct alt_instr *end)
+void init_or_livepatch apply_alternatives(const struct alt_instr *start,
+                                          const struct alt_instr *end)
 {
-    struct alt_instr *a;
+    const struct alt_instr *a;
     u8 *instr, *replacement;
     u8 insnbuf[MAX_PATCH_LEN];
 
@@ -187,24 +188,10 @@ void init_or_livepatch apply_alternatives_nocheck(struct 
alt_instr *start, struc
  * This routine is called with local interrupt disabled and used during
  * bootup.
  */
-void __init apply_alternatives(struct alt_instr *start, struct alt_instr *end)
-{
-    unsigned long cr0 = read_cr0();
-
-    ASSERT(!local_irq_is_enabled());
-
-    /* Disable WP to allow application of alternatives to read-only pages. */
-    write_cr0(cr0 & ~X86_CR0_WP);
-
-    apply_alternatives_nocheck(start, end);
-
-    /* Reinstate WP. */
-    write_cr0(cr0);
-}
-
 void __init alternative_instructions(void)
 {
     nmi_callback_t *saved_nmi_callback;
+    unsigned long cr0 = read_cr0();
 
     arch_init_ideal_nops();
 
@@ -225,7 +212,15 @@ void __init alternative_instructions(void)
      * expect a machine check to cause undue problems during to code
      * patching.
      */
+    ASSERT(!local_irq_is_enabled());
+
+    /* Disable WP to allow application of alternatives to read-only pages. */
+    write_cr0(cr0 & ~X86_CR0_WP);
+
     apply_alternatives(__alt_instructions, __alt_instructions_end);
 
+    /* Reinstate WP. */
+    write_cr0(cr0);
+
     set_nmi_callback(saved_nmi_callback);
 }
diff --git a/xen/common/livepatch.c b/xen/common/livepatch.c
index 774a51d..b771c7d 100644
--- a/xen/common/livepatch.c
+++ b/xen/common/livepatch.c
@@ -713,7 +713,7 @@ static int prepare_payload(struct payload *payload,
                 return -EINVAL;
             }
         }
-        apply_alternatives_nocheck(start, end);
+        apply_alternatives(start, end);
     }
 
     sec = livepatch_elf_sec_by_name(elf, ".ex_table");
diff --git a/xen/include/asm-arm/alternative.h 
b/xen/include/asm-arm/alternative.h
index f25d3a7..9f88fd9 100644
--- a/xen/include/asm-arm/alternative.h
+++ b/xen/include/asm-arm/alternative.h
@@ -27,7 +27,7 @@ struct alt_instr {
 #define ALT_REPL_PTR(a)                __ALT_PTR(a, alt_offset)
 
 void __init apply_alternatives_all(void);
-int apply_alternatives(void *start, size_t length);
+int apply_alternatives(const struct alt_instr *start, const struct alt_instr 
*end);
 
 #define ALTINSTR_ENTRY(feature)                                                
      \
        " .word 661b - .\n"                             /* label           */ \
diff --git a/xen/include/asm-x86/alternative.h 
b/xen/include/asm-x86/alternative.h
index de807c8..db4f08e 100644
--- a/xen/include/asm-x86/alternative.h
+++ b/xen/include/asm-x86/alternative.h
@@ -28,10 +28,9 @@ struct alt_instr {
 #define ALT_REPL_PTR(a)     __ALT_PTR(a, repl_offset)
 
 extern void add_nops(void *insns, unsigned int len);
-/* Similar to apply_alternatives except it can be run with IRQs enabled. */
-extern void apply_alternatives_nocheck(struct alt_instr *start,
-                                       struct alt_instr *end);
-extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
+/* Similar to alternative_instructions except it can be run with IRQs enabled. 
*/
+extern void apply_alternatives(const struct alt_instr *start,
+                               const struct alt_instr *end);
 extern void alternative_instructions(void);
 
 #define OLDINSTR(oldinstr)      "661:\n\t" oldinstr "\n662:\n"
-- 
2.4.11


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel