tools/testing/selftests/powerpc/dexcr/dexcr.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/powerpc/dexcr/dexcr.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/powerpc/dexcr/dexcr.c
Extension
.c
Size
4133 bytes
Lines
173
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0+

#include <errno.h>
#include <setjmp.h>
#include <signal.h>
#include <sys/prctl.h>
#include <sys/types.h>
#include <sys/wait.h>

#include "dexcr.h"
#include "reg.h"
#include "utils.h"

static jmp_buf generic_signal_jump_buf;

static void generic_signal_handler(int signum, siginfo_t *info, void *context)
{
	longjmp(generic_signal_jump_buf, 0);
}

bool dexcr_exists(void)
{
	struct sigaction old;
	volatile bool exists;

	old = push_signal_handler(SIGILL, generic_signal_handler);
	if (setjmp(generic_signal_jump_buf))
		goto out;

	/*
	 * If the SPR is not recognised by the hardware it triggers
	 * a hypervisor emulation interrupt. If the kernel does not
	 * recognise/try to emulate it, we receive a SIGILL signal.
	 *
	 * If we do not receive a signal, assume we have the SPR or the
	 * kernel is trying to emulate it correctly.
	 */
	exists = false;
	mfspr(SPRN_DEXCR_RO);
	exists = true;

out:
	pop_signal_handler(SIGILL, old);
	return exists;
}

unsigned int pr_which_to_aspect(unsigned long which)
{
	switch (which) {
	case PR_PPC_DEXCR_SBHE:
		return DEXCR_PR_SBHE;
	case PR_PPC_DEXCR_IBRTPD:
		return DEXCR_PR_IBRTPD;
	case PR_PPC_DEXCR_SRAPD:
		return DEXCR_PR_SRAPD;
	case PR_PPC_DEXCR_NPHIE:
		return DEXCR_PR_NPHIE;
	default:
		FAIL_IF_EXIT_MSG(true, "unknown PR aspect");
	}
}

int pr_get_dexcr(unsigned long which)
{
	return prctl(PR_PPC_GET_DEXCR, which, 0UL, 0UL, 0UL);
}

int pr_set_dexcr(unsigned long which, unsigned long ctrl)
{
	return prctl(PR_PPC_SET_DEXCR, which, ctrl, 0UL, 0UL);
}

bool pr_dexcr_aspect_supported(unsigned long which)
{
	if (pr_get_dexcr(which) == -1)
		return errno == ENODEV;

	return true;
}

bool pr_dexcr_aspect_editable(unsigned long which)
{
	return pr_get_dexcr(which) & PR_PPC_DEXCR_CTRL_EDITABLE;
}

/*
 * Just test if a bad hashchk triggers a signal, without checking
 * for support or if the NPHIE aspect is enabled.
 */
bool hashchk_triggers(void)

Annotation

Implementation Notes