powerpc/kernel: Use kprobe blacklist for asm functions

Rather than forcing the whole function into the ".kprobes.text" section,
just add the symbol's address to the kprobe blacklist.

This also lets us drop the three versions of the_KPROBE macro, in
exchange for just one version of _ASM_NOKPROBE_SYMBOL - which is a good
cleanup.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index d5d5b5e348f22c68dc4d88d3b9fcb0eb6e987229..cd39ac127786fd18e83177f940f854ccac7d35d3 100644 (file)
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -217,13 +217,6 @@ name: \
        addi r2,r2,(.TOC.-0b)@l; \
        .localentry name,.-name
 
-#define _KPROBE(name) \
-       .section ".kprobes.text","a"; \
-       .align 2 ; \
-       .type name,@function; \
-       .globl name; \
-name:
-
 #define DOTSYM(a)      a
 
 #else
@@ -247,20 +240,6 @@ GLUE(.,name):
 
 #define _GLOBAL_TOC(name) _GLOBAL(name)
 
-#define _KPROBE(name) \
-       .section ".kprobes.text","a"; \
-       .align 2 ; \
-       .globl name; \
-       .globl GLUE(.,name); \
-       .section ".opd","aw"; \
-name: \
-       .quad GLUE(.,name); \
-       .quad .TOC.@tocbase; \
-       .quad 0; \
-       .previous; \
-       .type GLUE(.,name),@function; \
-GLUE(.,name):
-
 #define DOTSYM(a)      GLUE(.,a)
 
 #endif
@@ -279,13 +258,22 @@ n:
 
 #define _GLOBAL_TOC(name) _GLOBAL(name)
 
-#define _KPROBE(n)     \
-       .section ".kprobes.text","a";   \
-       .globl  n;      \
-n:
-
 #endif
 
+/*
+ * __kprobes (the C annotation) puts the symbol into the .kprobes.text
+ * section, which gets emitted at the end of regular text.
+ *
+ * _ASM_NOKPROBE_SYMBOL and NOKPROBE_SYMBOL just adds the symbol to
+ * a blacklist. The former is for core kprobe functions/data, the
+ * latter is for those that incdentially must be excluded from probing
+ * and allows them to be linked at more optimal location within text.
+ */
+#define _ASM_NOKPROBE_SYMBOL(entry)                    \
+       .pushsection "_kprobe_blacklist","aw";          \
+       PPC_LONG (entry) ;                              \
+       .popsection
+
 #define FUNC_START(name)       _GLOBAL(name)
 #define FUNC_END(name)
 

diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index d9c912b6e632563a8a9865f63e195cd46b15dc06..03756ffdcd71063dd028d7d3825d89d70e47990c 100644 (file)
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -328,7 +328,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_UNIFIED_ID_CACHE)
  *
  * flush_icache_range(unsigned long start, unsigned long stop)
  */
-_KPROBE(flush_icache_range)
+_GLOBAL(flush_icache_range)
 BEGIN_FTR_SECTION
        PURGE_PREFETCHED_INS
        blr                             /* for 601, do nothing */
@@ -358,6 +358,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
        sync                            /* additional sync needed on g4 */
        isync
        blr
+_ASM_NOKPROBE_SYMBOL(flush_icache_range)
+
 /*
  * Flush a particular page from the data cache to RAM.
  * Note: this is necessary because the instruction cache does *not*

diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index cb195157b318e1fba91b045bf1f5697a3b8ebf40..5d7e583f1588c14d76944e0905436c8b70eaa343 100644 (file)
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -66,7 +66,7 @@ PPC64_CACHES:
  *   flush all bytes from start through stop-1 inclusive
  */
 
-_KPROBE(flush_icache_range)
+_GLOBAL(flush_icache_range)
 BEGIN_FTR_SECTION
        PURGE_PREFETCHED_INS
        blr
@@ -109,7 +109,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
        bdnz    2b
        isync
        blr
-       .previous .text
+_ASM_NOKPROBE_SYMBOL(flush_icache_range)
+
 /*
  * Like above, but only do the D-cache.
  *