Commit 9160f7e9 authored by Joey Gouly's avatar Joey Gouly Committed by Will Deacon
Browse files

arm64: add POE signal support 



Add PKEY support to signals, by saving and restoring POR_EL0 from the stackframe.

Signed-off-by: default avatarJoey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
Acked-by: default avatarSzabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20240822151113.1479789-20-joey.gouly@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 7f955be9

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

+7 −0
Original line number Diff line number Diff line
@@ -98,6 +98,13 @@ struct esr_context { 
	__u64 esr;

};



#define POE_MAGIC	0x504f4530



struct poe_context {

	struct _aarch64_ctx head;

	__u64 por_el0;

};



/*

 * extra_context: describes extra space in the signal frame for

 * additional structures that don't fit in sigcontext.__reserved[].

arch/arm64/kernel/signal.c

+62 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ struct rt_sigframe_user_layout { 
	unsigned long za_offset;

	unsigned long zt_offset;

	unsigned long fpmr_offset;

	unsigned long poe_offset;

	unsigned long extra_offset;

	unsigned long end_offset;

};
@@ -185,6 +186,8 @@ struct user_ctxs { 
	u32 zt_size;

	struct fpmr_context __user *fpmr;

	u32 fpmr_size;

	struct poe_context __user *poe;

	u32 poe_size;

};



static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
@@ -258,6 +261,32 @@ static int restore_fpmr_context(struct user_ctxs *user) 
	return err;

}



static int preserve_poe_context(struct poe_context __user *ctx)

{

	int err = 0;



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

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

	__put_user_error(read_sysreg_s(SYS_POR_EL0), &ctx->por_el0, err);



	return err;

}



static int restore_poe_context(struct user_ctxs *user)

{

	u64 por_el0;

	int err = 0;



	if (user->poe_size != sizeof(*user->poe))

		return -EINVAL;



	__get_user_error(por_el0, &(user->poe->por_el0), err);

	if (!err)

		write_sysreg_s(por_el0, SYS_POR_EL0);



	return err;

}



#ifdef CONFIG_ARM64_SVE



static int preserve_sve_context(struct sve_context __user *ctx)
@@ -621,6 +650,7 @@ static int parse_user_sigframe(struct user_ctxs *user, 
	user->za = NULL;

	user->zt = NULL;

	user->fpmr = NULL;

	user->poe = NULL;



	if (!IS_ALIGNED((unsigned long)base, 16))

		goto invalid;
@@ -671,6 +701,17 @@ static int parse_user_sigframe(struct user_ctxs *user, 
			/* ignore */

			break;



		case POE_MAGIC:

			if (!system_supports_poe())

				goto invalid;



			if (user->poe)

				goto invalid;



			user->poe = (struct poe_context __user *)head;

			user->poe_size = size;

			break;



		case SVE_MAGIC:

			if (!system_supports_sve() && !system_supports_sme())

				goto invalid;
@@ -857,6 +898,9 @@ static int restore_sigframe(struct pt_regs *regs, 
	if (err == 0 && system_supports_sme2() && user.zt)

		err = restore_zt_context(&user);



	if (err == 0 && system_supports_poe() && user.poe)

		err = restore_poe_context(&user);



	return err;

}
@@ -980,6 +1024,13 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, 
			return err;

	}



	if (system_supports_poe()) {

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

				     sizeof(struct poe_context));

		if (err)

			return err;

	}



	return sigframe_alloc_end(user);

}
@@ -1042,6 +1093,14 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, 
		err |= preserve_fpmr_context(fpmr_ctx);

	}



	if (system_supports_poe() && err == 0 && user->poe_offset) {

		struct poe_context __user *poe_ctx =

			apply_user_offset(user, user->poe_offset);



		err |= preserve_poe_context(poe_ctx);

	}





	/* ZA state if present */

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

		struct za_context __user *za_ctx =
@@ -1178,6 +1237,9 @@ static void setup_return(struct pt_regs *regs, struct k_sigaction *ka, 
		sme_smstop();

	}



	if (system_supports_poe())

		write_sysreg_s(POR_EL0_INIT, SYS_POR_EL0);



	if (ka->sa.sa_flags & SA_RESTORER)

		sigtramp = ka->sa.sa_restorer;

	else