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Commit ad684dce authored by Jon Medhurst's avatar Jon Medhurst Committed by Russell King
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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: default avatarJon Medhurst <tixy@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 9cc6d9e5

arch/arm/kernel/kprobes-test.c

+9 −7
Original line number Diff line number Diff line
@@ -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;

arch/arm/kernel/kprobes-test.h

+4 −1
Original line number Diff line number Diff line
@@ -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"	\