ARM: 8179/1: kprobes-test: Fix compile error "bad immediate value for offset"

When compiling kprobes-test-arm.c the following error has been observed

/tmp/ccoT403o.s:21439: Error: bad immediate value for offset (4168)

This is caused by the compiler spilling it's literal pool too far away
from the site which is trying to reference it with a PC relative load.
This arises because the compiler is underestimating the size of the
inline assembler code present, which apparently it approximates as 4
bytes per line or instruction.

We fix this problem by moving the operations which generate more than
4 bytes out of the text section. Specifically, moving the .ascii
directives to the .rodata section.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 13 insertions, 8 deletions

diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c
index 08d731294bcd..b206d7790c77 100644
--- a/arch/arm/kernel/kprobes-test.c
+++ b/arch/arm/kernel/kprobes-test.c
@@ -110,10 +110,13 @@
  *
  *      @ TESTCASE_START
  *      bl      __kprobes_test_case_start
- *      @ start of inline data...
+ *      .pushsection .rodata
+ *      "10:
  *      .ascii "mov r0, r7"     @ text title for test case
  *      .byte   0
- *      .align  2, 0
+ *      .popsection
+ *      @ start of inline data...
+ *      .word   10b             @ pointer to title in .rodata section
  *
  *      @ TEST_ARG_REG
  *      .byte   ARG_TYPE_REG
@@ -971,7 +974,7 @@ void __naked __kprobes_test_case_start(void)
         __asm__ __volatile__ (
                 "stmdb  sp!, {r4-r11}                           \n\t"
                 "sub    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
-                "bic    r0, lr, #1  @ r0 = inline title string  \n\t"
+                "bic    r0, lr, #1  @ r0 = inline data          \n\t"
                 "mov    r1, sp                                  \n\t"
                 "bl     kprobes_test_case_start                 \n\t"
                 "bx     r0                                      \n\t"
@@ -1349,15 +1352,14 @@ static unsigned long next_instruction(unsigned long pc)
         return pc + 4;
 }
 
-static uintptr_t __used kprobes_test_case_start(const char *title, void *stack)
+static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
 {
         struct test_arg *args;
         struct test_arg_end *end_arg;
         unsigned long test_code;
 
-        args = (struct test_arg *)PTR_ALIGN(title + strlen(title) + 1, 4);
-
-        current_title = title;
+        current_title = *title++;
+        args = (struct test_arg *)title;
         current_args = args;
         current_stack = stack;
 
diff --git a/arch/arm/kernel/kprobes-test.h b/arch/arm/kernel/kprobes-test.h
index eecc90a0fd91..4430990e90e7 100644
--- a/arch/arm/kernel/kprobes-test.h
+++ b/arch/arm/kernel/kprobes-test.h
@@ -111,11 +111,14 @@ struct test_arg_end {
 #define TESTCASE_START(title)                                   \
         __asm__ __volatile__ (                                  \
         "bl     __kprobes_test_case_start               \n\t"   \
+        ".pushsection .rodata                           \n\t"   \
+        "10:                                            \n\t"   \
         /* don't use .asciz here as 'title' may be */           \
         /* multiple strings to be concatenated.  */             \
         ".ascii "#title"                                \n\t"   \
         ".byte  0                                       \n\t"   \
-        ".align 2, 0                                    \n\t"
+        ".popsection                                    \n\t"   \
+        ".word  10b                                     \n\t"
 
 #define TEST_ARG_REG(reg, val)                                  \
         ".byte  "__stringify(ARG_TYPE_REG)"             \n\t"   \