Re: [RFC PATCH for 4.15 16/22] rseq: selftests: arm: workaround gcc asm size guess
From: Shuah Khan
Date: Tue Nov 21 2017 - 10:39:53 EST
On 11/21/2017 07:18 AM, Mathieu Desnoyers wrote:
> Fixes assembler errors:
> /tmp/cceKwI9a.s: Assembler messages:
> /tmp/cceKwI9a.s:849: Error: co-processor offset out of range
>
> with gcc prior to gcc-7. This can trigger if multiple rseq inline asm
> are used within the same function.
>
> My best guess on the cause of this issue is that gcc has a hard
> time figuring out the actual size of the inline asm, and therefore
> does not compute the offsets at which literal values can be
> placed from the program counter accurately.
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
> CC: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
> CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> CC: Paul Turner <pjt@xxxxxxxxxx>
> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> CC: Andrew Hunter <ahh@xxxxxxxxxx>
> CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
> CC: Dave Watson <davejwatson@xxxxxx>
> CC: Chris Lameter <cl@xxxxxxxxx>
> CC: Ingo Molnar <mingo@xxxxxxxxxx>
> CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
> CC: Ben Maurer <bmaurer@xxxxxx>
> CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
> CC: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
> CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> CC: Russell King <linux@xxxxxxxxxxxxxxxx>
> CC: Catalin Marinas <catalin.marinas@xxxxxxx>
> CC: Will Deacon <will.deacon@xxxxxxx>
> CC: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
> CC: Boqun Feng <boqun.feng@xxxxxxxxx>
> CC: Florian Weimer <fweimer@xxxxxxxxxx>
> CC: Shuah Khan <shuah@xxxxxxxxxx>
> CC: linux-kselftest@xxxxxxxxxxxxxxx
> CC: linux-api@xxxxxxxxxxxxxxx
> ---
> tools/testing/selftests/rseq/rseq-arm.h | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/tools/testing/selftests/rseq/rseq-arm.h b/tools/testing/selftests/rseq/rseq-arm.h
> index 47953c0cef4f..6d3fda276f4d 100644
> --- a/tools/testing/selftests/rseq/rseq-arm.h
> +++ b/tools/testing/selftests/rseq/rseq-arm.h
> @@ -79,12 +79,15 @@ do { \
> teardown \
> "b %l[" __rseq_str(cmpfail_label) "]\n\t"
>
> +#define rseq_workaround_gcc_asm_size_guess() __asm__ __volatile__("")
> +
> static inline __attribute__((always_inline))
> int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv,
> int cpu)
> {
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
> @@ -115,11 +118,14 @@ int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv,
> RSEQ_INJECT_CLOBBER
> : abort, cmpfail
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> cmpfail:
> + rseq_workaround_gcc_asm_size_guess();
> return 1;
> }
>
> @@ -129,6 +135,7 @@ int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
> {
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
> @@ -164,11 +171,14 @@ int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
> RSEQ_INJECT_CLOBBER
> : abort, cmpfail
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> cmpfail:
> + rseq_workaround_gcc_asm_size_guess();
> return 1;
> }
>
> @@ -177,6 +187,7 @@ int rseq_addv(intptr_t *v, intptr_t count, int cpu)
> {
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
> @@ -203,8 +214,10 @@ int rseq_addv(intptr_t *v, intptr_t count, int cpu)
> RSEQ_INJECT_CLOBBER
> : abort
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> }
> @@ -216,6 +229,7 @@ int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
> {
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
> @@ -253,11 +267,14 @@ int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
> RSEQ_INJECT_CLOBBER
> : abort, cmpfail
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> cmpfail:
> + rseq_workaround_gcc_asm_size_guess();
> return 1;
> }
>
> @@ -268,6 +285,7 @@ int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
> {
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
> @@ -306,11 +324,14 @@ int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
> RSEQ_INJECT_CLOBBER
> : abort, cmpfail
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> cmpfail:
> + rseq_workaround_gcc_asm_size_guess();
> return 1;
> }
>
> @@ -321,6 +342,7 @@ int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
> {
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
> @@ -359,11 +381,14 @@ int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
> RSEQ_INJECT_CLOBBER
> : abort, cmpfail
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> cmpfail:
> + rseq_workaround_gcc_asm_size_guess();
> return 1;
> }
>
> @@ -376,6 +401,7 @@ int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
>
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> "str %[src], %[rseq_scratch0]\n\t"
> @@ -442,11 +468,14 @@ int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
> RSEQ_INJECT_CLOBBER
> : abort, cmpfail
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> cmpfail:
> + rseq_workaround_gcc_asm_size_guess();
> return 1;
> }
>
> @@ -459,6 +488,7 @@ int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
>
> RSEQ_INJECT_C(9)
>
> + rseq_workaround_gcc_asm_size_guess();
> __asm__ __volatile__ goto (
> RSEQ_ASM_DEFINE_TABLE(__rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)
> "str %[src], %[rseq_scratch0]\n\t"
> @@ -526,10 +556,13 @@ int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
> RSEQ_INJECT_CLOBBER
> : abort, cmpfail
> );
> + rseq_workaround_gcc_asm_size_guess();
> return 0;
> abort:
> + rseq_workaround_gcc_asm_size_guess();
> RSEQ_INJECT_FAILED
> return -1;
> cmpfail:
> + rseq_workaround_gcc_asm_size_guess();
> return 1;
> }
>
Looks fine to me. For this patch.
Acked-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
I have comments on other patches in this series.
thanks,
-- Shuah