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kselftest/arm64: Add a smoke test for ptracing hardware break/watch points

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There was a report that the hardware breakpoints and watch points weren't
reporting the debug architecture version as expected, they were reporting
a version of 0 which is not defined in the architecture.  This happens
when running in a KVM guest if the host has a debug architecture version
not supported by KVM, it in turn confuses GDB which rejects any debug
architecture version it does not know about.

Add a test that covers that situation and while we're at it reports the
debug architecture version and number of slots available to aid with
figuring out problems that may arise.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230414-arm64-test-hw-breakpoint-v2-1-90a19e3b1059@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Brown 2023-05-22 15:28:00 +01:00 committed by Catalin Marinas
parent 44c026a73b
commit cb5aa63794
1 changed files with 31 additions and 1 deletions
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32
tools/testing/selftests/arm64/abi/ptrace.c
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@ -20,7 +20,7 @@
#include "../../kselftest.h"
#define EXPECTED_TESTS 7
#define EXPECTED_TESTS 11
#define MAX_TPIDRS 2
@ -132,6 +132,34 @@ static void test_tpidr(pid_t child)
}
}
static void test_hw_debug(pid_t child, int type, const char *type_name)
{
struct user_hwdebug_state state;
struct iovec iov;
int slots, arch, ret;
iov.iov_len = sizeof(state);
iov.iov_base = &state;
/* Should be able to read the values */
ret = ptrace(PTRACE_GETREGSET, child, type, &iov);
ksft_test_result(ret == 0, "read_%s\n", type_name);
if (ret == 0) {
/* Low 8 bits is the number of slots, next 4 bits the arch */
slots = state.dbg_info & 0xff;
arch = (state.dbg_info >> 8) & 0xf;
ksft_print_msg("%s version %d with %d slots\n", type_name,
arch, slots);
/* Zero is not currently architecturally valid */
ksft_test_result(arch, "%s_arch_set\n", type_name);
} else {
ksft_test_result_skip("%s_arch_set\n");
}
}
static int do_child(void)
{
if (ptrace(PTRACE_TRACEME, -1, NULL, NULL))
@ -207,6 +235,8 @@ static int do_parent(pid_t child)
ksft_print_msg("Parent is %d, child is %d\n", getpid(), child);
test_tpidr(child);
test_hw_debug(child, NT_ARM_HW_WATCH, "NT_ARM_HW_WATCH");
test_hw_debug(child, NT_ARM_HW_BREAK, "NT_ARM_HW_BREAK");
ret = EXIT_SUCCESS;