Commit 39e54499 authored by Mark Brown's avatar Mark Brown Committed by Catalin Marinas
Browse files

arm64/signal: Include TPIDR2 in the signal context 



Add a new signal frame record for TPIDR2 using the same format as we
already use for ESR with different magic, a header with the value from the
register appended as the only data. If SME is supported then this record is
always included.

Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarSzabolcs Nagy <szabolcs.nagy@arm.com>
Link: https://lore.kernel.org/r/20221208-arm64-tpidr2-sig-v3-2-c77c6c8775f4@kernel.org


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 17d0c4a2

arch/arm64/include/uapi/asm/sigcontext.h

+8 −0
Original line number Diff line number Diff line
@@ -144,6 +144,14 @@ struct sve_context { 


#define SVE_SIG_FLAG_SM	0x1	/* Context describes streaming mode */



/* TPIDR2_EL0 context */

#define TPIDR2_MAGIC	0x54504902



struct tpidr2_context {

	struct _aarch64_ctx head;

	__u64 tpidr2;

};



#define ZA_MAGIC	0x54366345



struct za_context {

arch/arm64/kernel/signal.c

+59 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ struct rt_sigframe_user_layout { 
	unsigned long fpsimd_offset;

	unsigned long esr_offset;

	unsigned long sve_offset;

	unsigned long tpidr2_offset;

	unsigned long za_offset;

	unsigned long extra_offset;

	unsigned long end_offset;
@@ -220,6 +221,7 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx) 
struct user_ctxs {

	struct fpsimd_context __user *fpsimd;

	struct sve_context __user *sve;

	struct tpidr2_context __user *tpidr2;

	struct za_context __user *za;

};
@@ -361,6 +363,32 @@ extern int preserve_sve_context(void __user *ctx); 


#ifdef CONFIG_ARM64_SME



static int preserve_tpidr2_context(struct tpidr2_context __user *ctx)

{

	int err = 0;



	current->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0);



	__put_user_error(TPIDR2_MAGIC, &ctx->head.magic, err);

	__put_user_error(sizeof(*ctx), &ctx->head.size, err);

	__put_user_error(current->thread.tpidr2_el0, &ctx->tpidr2, err);



	return err;

}



static int restore_tpidr2_context(struct user_ctxs *user)

{

	u64 tpidr2_el0;

	int err = 0;



	/* Magic and size were validated deciding to call this function */

	__get_user_error(tpidr2_el0, &user->tpidr2->tpidr2, err);

	if (!err)

		current->thread.tpidr2_el0 = tpidr2_el0;



	return err;

}



static int preserve_za_context(struct za_context __user *ctx)

{

	int err = 0;
@@ -450,6 +478,8 @@ static int restore_za_context(struct user_ctxs *user) 
#else /* ! CONFIG_ARM64_SME */



/* Turn any non-optimised out attempts to use these into a link error: */

extern int preserve_tpidr2_context(void __user *ctx);

extern int restore_tpidr2_context(struct user_ctxs *user);

extern int preserve_za_context(void __user *ctx);

extern int restore_za_context(struct user_ctxs *user);
@@ -468,6 +498,7 @@ static int parse_user_sigframe(struct user_ctxs *user, 


	user->fpsimd = NULL;

	user->sve = NULL;

	user->tpidr2 = NULL;

	user->za = NULL;



	if (!IS_ALIGNED((unsigned long)base, 16))
@@ -534,6 +565,19 @@ static int parse_user_sigframe(struct user_ctxs *user, 
			user->sve = (struct sve_context __user *)head;

			break;



		case TPIDR2_MAGIC:

			if (!system_supports_sme())

				goto invalid;



			if (user->tpidr2)

				goto invalid;



			if (size != sizeof(*user->tpidr2))

				goto invalid;



			user->tpidr2 = (struct tpidr2_context __user *)head;

			break;



		case ZA_MAGIC:

			if (!system_supports_sme())

				goto invalid;
@@ -666,6 +710,9 @@ static int restore_sigframe(struct pt_regs *regs, 
			err = restore_fpsimd_context(user.fpsimd);

	}



	if (err == 0 && system_supports_sme() && user.tpidr2)

		err = restore_tpidr2_context(&user);



	if (err == 0 && system_supports_sme() && user.za)

		err = restore_za_context(&user);
@@ -760,6 +807,11 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, 
		else

			vl = task_get_sme_vl(current);



		err = sigframe_alloc(user, &user->tpidr2_offset,

				     sizeof(struct tpidr2_context));

		if (err)

			return err;



		if (thread_za_enabled(&current->thread))

			vq = sve_vq_from_vl(vl);
@@ -817,6 +869,13 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, 
		err |= preserve_sve_context(sve_ctx);

	}



	/* TPIDR2 if supported */

	if (system_supports_sme() && err == 0) {

		struct tpidr2_context __user *tpidr2_ctx =

			apply_user_offset(user, user->tpidr2_offset);

		err |= preserve_tpidr2_context(tpidr2_ctx);

	}



	/* ZA state if present */

	if (system_supports_sme() && err == 0 && user->za_offset) {

		struct za_context __user *za_ctx =