| Message ID | 20220301092431.1448419-1-thuth@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | tests/tcg/s390x: Fix the exrl-trt* tests with Clang | expand |
On 01.03.22 10:24, Thomas Huth wrote: > The exrl-trt* tests use two pre-initialized variables for the > results of the assembly code: > > uint64_t r1 = 0xffffffffffffffffull; > uint64_t r2 = 0xffffffffffffffffull; > > But then the assembly code copies over the full contents > of the register into the output variable, without taking > care of this pre-initialized values: > > " lgr %[r1],%%r1\n" > " lgr %[r2],%%r2\n" > > The code then finally compares the register contents to > a value that apparently depends on the pre-initialized values: > > if (r2 != 0xffffffffffffffaaull) { > write(1, "bad r2\n", 7); > return 1; > } > > This all works with GCC, since the 0xffffffffffffffff got into > the r2 register there by accident, but it fails completely with > Clang. > > Let's fix this by declaring the r1 and r2 variables as proper > register variables instead, so the pre-initialized values get > correctly passed into the inline assembly code. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > tests/tcg/s390x/exrl-trt.c | 8 +++----- > tests/tcg/s390x/exrl-trtr.c | 8 +++----- > 2 files changed, 6 insertions(+), 10 deletions(-) > > diff --git a/tests/tcg/s390x/exrl-trt.c b/tests/tcg/s390x/exrl-trt.c > index 16711a3181..451f777b9d 100644 > --- a/tests/tcg/s390x/exrl-trt.c > +++ b/tests/tcg/s390x/exrl-trt.c > @@ -5,8 +5,8 @@ int main(void) > { > char op1[] = "hello"; > char op2[256]; > - uint64_t r1 = 0xffffffffffffffffull; > - uint64_t r2 = 0xffffffffffffffffull; > + register uint64_t r1 asm("r1") = 0xffffffffffffffffull; > + register uint64_t r2 asm("r2") = 0xffffffffffffffffull; > uint64_t cc; > int i; > > @@ -21,8 +21,6 @@ int main(void) > " j 2f\n" > "1: trt 0(1,%[op1]),%[op2]\n" > "2: exrl %[op1_len],1b\n" > - " lgr %[r1],%%r1\n" > - " lgr %[r2],%%r2\n" > " ipm %[cc]\n" > : [r1] "+r" (r1), > [r2] "+r" (r2), > @@ -30,7 +28,7 @@ int main(void) > : [op1] "a" (&op1), > [op1_len] "a" (5), > [op2] "Q" (op2) > - : "r1", "r2", "cc"); > + : "cc"); > cc = (cc >> 28) & 3; > if (cc != 2) { > write(1, "bad cc\n", 7); > diff --git a/tests/tcg/s390x/exrl-trtr.c b/tests/tcg/s390x/exrl-trtr.c > index 5f30cda6bd..422f7f385a 100644 > --- a/tests/tcg/s390x/exrl-trtr.c > +++ b/tests/tcg/s390x/exrl-trtr.c > @@ -5,8 +5,8 @@ int main(void) > { > char op1[] = {0, 1, 2, 3}; > char op2[256]; > - uint64_t r1 = 0xffffffffffffffffull; > - uint64_t r2 = 0xffffffffffffffffull; > + register uint64_t r1 asm("r1") = 0xffffffffffffffffull; > + register uint64_t r2 asm("r2") = 0xffffffffffffffffull; > uint64_t cc; > int i; > > @@ -21,8 +21,6 @@ int main(void) > " j 2f\n" > "1: trtr 3(1,%[op1]),%[op2]\n" > "2: exrl %[op1_len],1b\n" > - " lgr %[r1],%%r1\n" > - " lgr %[r2],%%r2\n" > " ipm %[cc]\n" > : [r1] "+r" (r1), > [r2] "+r" (r2), > @@ -30,7 +28,7 @@ int main(void) > : [op1] "a" (&op1), > [op1_len] "a" (3), > [op2] "Q" (op2) > - : "r1", "r2", "cc"); > + : "cc"); > cc = (cc >> 28) & 3; > if (cc != 1) { > write(1, "bad cc\n", 7); Reviewed-by: David Hildenbrand <david@redhat.com>
On 2/28/22 23:24, Thomas Huth wrote: > The exrl-trt* tests use two pre-initialized variables for the > results of the assembly code: > > uint64_t r1 = 0xffffffffffffffffull; > uint64_t r2 = 0xffffffffffffffffull; > > But then the assembly code copies over the full contents > of the register into the output variable, without taking > care of this pre-initialized values: > > " lgr %[r1],%%r1\n" > " lgr %[r2],%%r2\n" > > The code then finally compares the register contents to > a value that apparently depends on the pre-initialized values: > > if (r2 != 0xffffffffffffffaaull) { > write(1, "bad r2\n", 7); > return 1; > } > > This all works with GCC, since the 0xffffffffffffffff got into > the r2 register there by accident, but it fails completely with > Clang. > > Let's fix this by declaring the r1 and r2 variables as proper > register variables instead, so the pre-initialized values get > correctly passed into the inline assembly code. > > Signed-off-by: Thomas Huth<thuth@redhat.com> > --- > tests/tcg/s390x/exrl-trt.c | 8 +++----- > tests/tcg/s390x/exrl-trtr.c | 8 +++----- > 2 files changed, 6 insertions(+), 10 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
diff --git a/tests/tcg/s390x/exrl-trt.c b/tests/tcg/s390x/exrl-trt.c index 16711a3181..451f777b9d 100644 --- a/tests/tcg/s390x/exrl-trt.c +++ b/tests/tcg/s390x/exrl-trt.c @@ -5,8 +5,8 @@ int main(void) { char op1[] = "hello"; char op2[256]; - uint64_t r1 = 0xffffffffffffffffull; - uint64_t r2 = 0xffffffffffffffffull; + register uint64_t r1 asm("r1") = 0xffffffffffffffffull; + register uint64_t r2 asm("r2") = 0xffffffffffffffffull; uint64_t cc; int i; @@ -21,8 +21,6 @@ int main(void) " j 2f\n" "1: trt 0(1,%[op1]),%[op2]\n" "2: exrl %[op1_len],1b\n" - " lgr %[r1],%%r1\n" - " lgr %[r2],%%r2\n" " ipm %[cc]\n" : [r1] "+r" (r1), [r2] "+r" (r2), @@ -30,7 +28,7 @@ int main(void) : [op1] "a" (&op1), [op1_len] "a" (5), [op2] "Q" (op2) - : "r1", "r2", "cc"); + : "cc"); cc = (cc >> 28) & 3; if (cc != 2) { write(1, "bad cc\n", 7); diff --git a/tests/tcg/s390x/exrl-trtr.c b/tests/tcg/s390x/exrl-trtr.c index 5f30cda6bd..422f7f385a 100644 --- a/tests/tcg/s390x/exrl-trtr.c +++ b/tests/tcg/s390x/exrl-trtr.c @@ -5,8 +5,8 @@ int main(void) { char op1[] = {0, 1, 2, 3}; char op2[256]; - uint64_t r1 = 0xffffffffffffffffull; - uint64_t r2 = 0xffffffffffffffffull; + register uint64_t r1 asm("r1") = 0xffffffffffffffffull; + register uint64_t r2 asm("r2") = 0xffffffffffffffffull; uint64_t cc; int i; @@ -21,8 +21,6 @@ int main(void) " j 2f\n" "1: trtr 3(1,%[op1]),%[op2]\n" "2: exrl %[op1_len],1b\n" - " lgr %[r1],%%r1\n" - " lgr %[r2],%%r2\n" " ipm %[cc]\n" : [r1] "+r" (r1), [r2] "+r" (r2), @@ -30,7 +28,7 @@ int main(void) : [op1] "a" (&op1), [op1_len] "a" (3), [op2] "Q" (op2) - : "r1", "r2", "cc"); + : "cc"); cc = (cc >> 28) & 3; if (cc != 1) { write(1, "bad cc\n", 7);
The exrl-trt* tests use two pre-initialized variables for the results of the assembly code: uint64_t r1 = 0xffffffffffffffffull; uint64_t r2 = 0xffffffffffffffffull; But then the assembly code copies over the full contents of the register into the output variable, without taking care of this pre-initialized values: " lgr %[r1],%%r1\n" " lgr %[r2],%%r2\n" The code then finally compares the register contents to a value that apparently depends on the pre-initialized values: if (r2 != 0xffffffffffffffaaull) { write(1, "bad r2\n", 7); return 1; } This all works with GCC, since the 0xffffffffffffffff got into the r2 register there by accident, but it fails completely with Clang. Let's fix this by declaring the r1 and r2 variables as proper register variables instead, so the pre-initialized values get correctly passed into the inline assembly code. Signed-off-by: Thomas Huth <thuth@redhat.com> --- tests/tcg/s390x/exrl-trt.c | 8 +++----- tests/tcg/s390x/exrl-trtr.c | 8 +++----- 2 files changed, 6 insertions(+), 10 deletions(-)