| Message ID | 1411743864.1529.36.camel@linaro1.home (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Sep 26, 2014 at 04:04:24PM +0100, Jon Medhurst (Tixy) wrote: > 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> > --- > > Russell, OK to add your 'reported-by' here (or should it be Olof)? I suspect it should be Olof - I'm just the middle man, spotting errors in Olof's build results... though it did help that it was my for-next branch which was being built.
On Fri, 2014-09-26 at 16:19 +0100, Russell King - ARM Linux wrote: > On Fri, Sep 26, 2014 at 04:04:24PM +0100, Jon Medhurst (Tixy) wrote: > > 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> > > --- > > > > Russell, OK to add your 'reported-by' here (or should it be Olof)? > > I suspect it should be Olof - I'm just the middle man, spotting errors > in Olof's build results... though it did help that it was my for-next > branch which was being built. I've added this patch to the patch tracker as 8179/1 I didn't add a Reported-by as I didn't receive a response from Olof and didn't want to add him without his say so; and I am assuming this matter isn't worth wasting peoples time chasing up...
On Tue, Sep 30, 2014 at 10:33:21AM +0100, Jon Medhurst (Tixy) wrote: > On Fri, 2014-09-26 at 16:19 +0100, Russell King - ARM Linux wrote: > > I suspect it should be Olof - I'm just the middle man, spotting errors > > in Olof's build results... though it did help that it was my for-next > > branch which was being built. > > I've added this patch to the patch tracker as 8179/1 > > I didn't add a Reported-by as I didn't receive a response from Olof and > didn't want to add him without his say so; and I am assuming this matter > isn't worth wasting peoples time chasing up... I concur. I'll apply it later today, thanks.
diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c index 08d7312..b206d77 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 eecc90a..4430990 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" \
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> --- Russell, OK to add your 'reported-by' here (or should it be Olof)? arch/arm/kernel/kprobes-test.c | 16 +++++++++------- arch/arm/kernel/kprobes-test.h | 5 ++++- 2 files changed, 13 insertions(+), 8 deletions(-)