selftests/powerpc/64: Test exception cases in copy_tofrom_user

This adds a set of test cases to test the behaviour of
copy_tofrom_user when exceptions are encountered accessing the
source or destination.  Currently, copy_tofrom_user does not always
copy as many bytes as possible when an exception occurs on a store
to the destination, and that is reflected in failures in these tests.

Based on a test program from Anton Blanchard.

[paulus@ozlabs.org - test all three paths, wrote commit description,
 made EX_TABLE create an exception table.]

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michael Ellerman 2018-08-03 20:13:05 +10:00
parent 98c45f51f7
commit 2679f63fe5
6 changed files with 188 additions and 21 deletions

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@ -8,3 +8,6 @@ memcpy_64_t1
memcpy_64_t2
memcpy_power7_t0
memcpy_power7_t1
copyuser_64_exc_t0
copyuser_64_exc_t1
copyuser_64_exc_t2

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@ -12,9 +12,10 @@ ASFLAGS = $(CFLAGS) -Wa,-mpower4
TEST_GEN_PROGS := copyuser_64_t0 copyuser_64_t1 copyuser_64_t2 \
copyuser_p7_t0 copyuser_p7_t1 \
memcpy_64_t0 memcpy_64_t1 memcpy_64_t2 \
memcpy_p7_t0 memcpy_p7_t1
memcpy_p7_t0 memcpy_p7_t1 \
copyuser_64_exc_t0 copyuser_64_exc_t1 copyuser_64_exc_t2
EXTRA_SOURCES := validate.c ../harness.c
EXTRA_SOURCES := validate.c ../harness.c stubs.S
include ../../lib.mk
@ -42,3 +43,10 @@ $(OUTPUT)/memcpy_p7_t%: memcpy_power7.S $(EXTRA_SOURCES)
-D COPY_LOOP=test_memcpy_power7 \
-D SELFTEST_CASE=$(subst memcpy_p7_t,,$(notdir $@)) \
-o $@ $^
$(OUTPUT)/copyuser_64_exc_t%: copyuser_64.S exc_validate.c ../harness.c \
copy_tofrom_user_reference.S stubs.S
$(CC) $(CPPFLAGS) $(CFLAGS) \
-D COPY_LOOP=test___copy_tofrom_user_base \
-D SELFTEST_CASE=$(subst copyuser_64_exc_t,,$(notdir $@)) \
-o $@ $^

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@ -1,4 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SELFTESTS_POWERPC_PPC_ASM_H
#define __SELFTESTS_POWERPC_PPC_ASM_H
#include <ppc-asm.h>
#define CONFIG_ALTIVEC
@ -26,25 +28,10 @@
#define PPC_MTOCRF(A, B) mtocrf A, B
#define EX_TABLE(x, y)
FUNC_START(enter_vmx_usercopy)
li r3,1
blr
FUNC_START(exit_vmx_usercopy)
li r3,0
blr
FUNC_START(enter_vmx_ops)
li r3,1
blr
FUNC_START(exit_vmx_ops)
blr
FUNC_START(__copy_tofrom_user_base)
blr
#define EX_TABLE(x, y) \
.section __ex_table,"a"; \
.8byte x, y; \
.previous
#define BEGIN_FTR_SECTION .if test_feature
#define FTR_SECTION_ELSE .else
@ -56,3 +43,5 @@ FUNC_START(__copy_tofrom_user_base)
/* Default to taking the first of any alternative feature sections */
test_feature = 1
#endif /* __SELFTESTS_POWERPC_PPC_ASM_H */

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@ -0,0 +1,24 @@
#include <asm/ppc_asm.h>
_GLOBAL(copy_tofrom_user_reference)
cmpdi r5,0
beq 4f
mtctr r5
1: lbz r6,0(r4)
2: stb r6,0(r3)
addi r3,r3,1
addi r4,r4,1
bdnz 1b
3: mfctr r3
blr
4: mr r3,r5
blr
.section __ex_table,"a"
.llong 1b,3b
.llong 2b,3b
.text

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@ -0,0 +1,124 @@
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/mman.h>
#include "utils.h"
extern char __start___ex_table[];
extern char __stop___ex_table[];
#if defined(__powerpc64__)
#define UCONTEXT_NIA(UC) (UC)->uc_mcontext.gp_regs[PT_NIP]
#elif defined(__powerpc__)
#define UCONTEXT_NIA(UC) (UC)->uc_mcontext.uc_regs->gregs[PT_NIP]
#else
#error implement UCONTEXT_NIA
#endif
static void segv_handler(int signr, siginfo_t *info, void *ptr)
{
ucontext_t *uc = (ucontext_t *)ptr;
unsigned long addr = (unsigned long)info->si_addr;
unsigned long *ip = &UCONTEXT_NIA(uc);
unsigned long *ex_p = (unsigned long *)__start___ex_table;
while (ex_p < (unsigned long *)__stop___ex_table) {
unsigned long insn, fixup;
insn = *ex_p++;
fixup = *ex_p++;
if (insn == *ip) {
*ip = fixup;
return;
}
}
printf("No exception table match for NIA %lx ADDR %lx\n", *ip, addr);
abort();
}
static void setup_segv_handler(void)
{
struct sigaction action;
memset(&action, 0, sizeof(action));
action.sa_sigaction = segv_handler;
action.sa_flags = SA_SIGINFO;
sigaction(SIGSEGV, &action, NULL);
}
unsigned long COPY_LOOP(void *to, const void *from, unsigned long size);
unsigned long test_copy_tofrom_user_reference(void *to, const void *from, unsigned long size);
static int total_passed;
static int total_failed;
static void do_one_test(char *dstp, char *srcp, unsigned long len)
{
unsigned long got, expected;
got = COPY_LOOP(dstp, srcp, len);
expected = test_copy_tofrom_user_reference(dstp, srcp, len);
if (got != expected) {
total_failed++;
printf("FAIL from=%p to=%p len=%ld returned %ld, expected %ld\n",
srcp, dstp, len, got, expected);
//abort();
} else
total_passed++;
}
//#define MAX_LEN 512
#define MAX_LEN 16
int test_copy_exception(void)
{
int page_size;
static char *p, *q;
unsigned long src, dst, len;
page_size = getpagesize();
p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (p == MAP_FAILED) {
perror("mmap");
exit(1);
}
memset(p, 0, page_size);
setup_segv_handler();
if (mprotect(p + page_size, page_size, PROT_NONE)) {
perror("mprotect");
exit(1);
}
q = p + page_size - MAX_LEN;
for (src = 0; src < MAX_LEN; src++) {
for (dst = 0; dst < MAX_LEN; dst++) {
for (len = 0; len < MAX_LEN+1; len++) {
// printf("from=%p to=%p len=%ld\n", q+dst, q+src, len);
do_one_test(q+dst, q+src, len);
}
}
}
printf("Totals:\n");
printf(" Pass: %d\n", total_passed);
printf(" Fail: %d\n", total_failed);
return 0;
}
int main(void)
{
return test_harness(test_copy_exception, str(COPY_LOOP));
}

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@ -0,0 +1,19 @@
#include <asm/ppc_asm.h>
FUNC_START(enter_vmx_usercopy)
li r3,1
blr
FUNC_START(exit_vmx_usercopy)
li r3,0
blr
FUNC_START(enter_vmx_ops)
li r3,1
blr
FUNC_START(exit_vmx_ops)
blr
FUNC_START(__copy_tofrom_user_base)
blr