From nobody Sun Dec 14 11:18:48 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 40EBB31A044; Thu, 11 Dec 2025 17:21:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765473668; cv=none; b=A8r0RFmomTlQpAlTZc0TMu/KyR2ENKWOfPTI5PcgZaNuxEaKUixNhn8t6zLQe1HCR2O5gd7O5F4cOy3w7CfUa3INMtYEKHjhRZSQ7jznmsPLWlV5A9jOWx+DOtHi5C2nHZ3EBwRToT2iT7XvBovKw9HU3KfF+kcvAWQcidgmCCY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765473668; c=relaxed/simple; bh=+gp1fj5BfJ+eOhETz1HHOc8IlGQMg/lxBXkxOeE956E=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=B6B3Pz8ienK7jnA3LJ1Dvv1TczDucC4xar8vBVI/vYwIts36OO7nKEOp5wknxMaCa4ZmrDG6cO36H3FbclYp34BtT8T3fzkX0kTYns5IIMGL15Y4XYgv8s/PIQ8TeWN0xbD12SfyvanzezBhduezW3xvTEnLYG/mZ/sJFrzMRu8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Uaio8rQJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Uaio8rQJ" Received: by smtp.kernel.org (Postfix) with ESMTPS id 1D261C19424; Thu, 11 Dec 2025 17:21:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765473668; bh=+gp1fj5BfJ+eOhETz1HHOc8IlGQMg/lxBXkxOeE956E=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=Uaio8rQJfs9JUzxxYkIIxxSa4Y3HyNP1VVUAoqoaUMNgG39838c2RxQfocjxX4xpy Ue4/zBZbHunRwHhJZzcNd4vKFzdY7ZWwyQQOoHMW1u7XIMWc+UpFq4zYBrtWurmIQZ 80IVw6FLQniKqpOz9I6VaGWoY2SXc/mDABVo/lxMuDnP84UCs9RwvECBYxtgWFQkTG SPd7eLG/cIbiCXfOjtkksC388uY/f2LZuNY0FtcfpMeua2rvsthUmi1gfLW7akMR++ Rmdxv9pPjWCvJrffvwinkC75oUZq09FeHQLiJoDRRiSz/RTllB+kuYFowbSIiPtSzG IihTouaXKBM9A== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02DE5D41D6A; Thu, 11 Dec 2025 17:21:08 +0000 (UTC) From: Deepak Gupta via B4 Relay Date: Thu, 11 Dec 2025 09:20:49 -0800 Subject: [PATCH v26 16/28] riscv: signal: abstract header saving for setup_sigcontext Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251211-v5_user_cfi_series-v26-16-f0f419e81ac0@rivosinc.com> References: <20251211-v5_user_cfi_series-v26-0-f0f419e81ac0@rivosinc.com> In-Reply-To: <20251211-v5_user_cfi_series-v26-0-f0f419e81ac0@rivosinc.com> To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Lorenzo Stoakes , Paul Walmsley , Palmer Dabbelt , Albert Ou , Conor Dooley , Rob Herring , Krzysztof Kozlowski , Arnd Bergmann , Christian Brauner , Peter Zijlstra , Oleg Nesterov , Eric Biederman , Kees Cook , Jonathan Corbet , Shuah Khan , Jann Horn , Conor Dooley , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Andreas Hindborg , Alice Ryhl , Trevor Gross , Benno Lossin Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, alistair.francis@wdc.com, richard.henderson@linaro.org, jim.shu@sifive.com, andybnac@gmail.com, kito.cheng@sifive.com, charlie@rivosinc.com, atishp@rivosinc.com, evan@rivosinc.com, cleger@rivosinc.com, alexghiti@rivosinc.com, samitolvanen@google.com, broonie@kernel.org, rick.p.edgecombe@intel.com, rust-for-linux@vger.kernel.org, Andreas Korb , Valentin Haudiquet X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1765473664; l=5649; i=debug@rivosinc.com; s=20251023; h=from:subject:message-id; bh=vq/ZvBue8s/rWueDBtiDCI4RMH9wNgtCWdsULpDvACA=; b=fcGGbWdWOjwhlM1aPr7cTo15ZAkpZh5ksTo6RxYf/ozPDLogPKA0/qixkNHOzwqc2eI06QoT9 QzVjrJKhN+wAgNVdukixz5yWNzXCbjSIRbF1t0E0pOOraObB3IwZpPY X-Developer-Key: i=debug@rivosinc.com; a=ed25519; pk=O37GQv1thBhZToXyQKdecPDhtWVbEDRQ0RIndijvpjk= X-Endpoint-Received: by B4 Relay for debug@rivosinc.com/20251023 with auth_id=553 X-Original-From: Deepak Gupta Reply-To: debug@rivosinc.com From: Andy Chiu The function save_v_state() served two purposes. First, it saved extension context into the signal stack. Then, it constructed the extension header if there was no fault. The second part is independent of the extension itself. As a result, we can pull that part out, so future extensions may reuse it. This patch adds arch_ext_list and makes setup_sigcontext() go through all possible extensions' save() callback. The callback returns a positive value indicating the size of the successfully saved extension. Then the kernel proceeds to construct the header for that extension. The kernel skips an extension if it does not exist, or if the saving fails for some reasons. The error code is propagated out on the later case. This patch does not introduce any functional changes. Tested-by: Andreas Korb Tested-by: Valentin Haudiquet Signed-off-by: Andy Chiu --- arch/riscv/include/asm/vector.h | 3 ++ arch/riscv/kernel/signal.c | 62 +++++++++++++++++++++++++++----------= ---- 2 files changed, 44 insertions(+), 21 deletions(-) diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vecto= r.h index b61786d43c20..75d8bd417797 100644 --- a/arch/riscv/include/asm/vector.h +++ b/arch/riscv/include/asm/vector.h @@ -423,6 +423,9 @@ static inline bool riscv_v_vstate_ctrl_user_allowed(voi= d) { return false; } #define riscv_v_thread_free(tsk) do {} while (0) #define riscv_v_setup_ctx_cache() do {} while (0) #define riscv_v_thread_alloc(tsk) do {} while (0) +#define get_cpu_vector_context() do {} while (0) +#define put_cpu_vector_context() do {} while (0) +#define riscv_v_vstate_set_restore(task, regs) do {} while (0) =20 #endif /* CONFIG_RISCV_ISA_V */ =20 diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 08378fea3a11..a5e3d54fe54b 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -68,18 +68,19 @@ static long save_fp_state(struct pt_regs *regs, #define restore_fp_state(task, regs) (0) #endif =20 -#ifdef CONFIG_RISCV_ISA_V - -static long save_v_state(struct pt_regs *regs, void __user **sc_vec) +static long save_v_state(struct pt_regs *regs, void __user *sc_vec) { - struct __riscv_ctx_hdr __user *hdr; struct __sc_riscv_v_state __user *state; void __user *datap; long err; =20 - hdr =3D *sc_vec; - /* Place state to the user's signal context space after the hdr */ - state =3D (struct __sc_riscv_v_state __user *)(hdr + 1); + if (!IS_ENABLED(CONFIG_RISCV_ISA_V) || + !((has_vector() || has_xtheadvector()) && + riscv_v_vstate_query(regs))) + return 0; + + /* Place state to the user's signal context spac */ + state =3D (struct __sc_riscv_v_state __user *)sc_vec; /* Point datap right after the end of __sc_riscv_v_state */ datap =3D state + 1; =20 @@ -97,15 +98,11 @@ static long save_v_state(struct pt_regs *regs, void __u= ser **sc_vec) err |=3D __put_user((__force void *)datap, &state->v_state.datap); /* Copy the whole vector content to user space datap. */ err |=3D __copy_to_user(datap, current->thread.vstate.datap, riscv_v_vsiz= e); - /* Copy magic to the user space after saving all vector conetext */ - err |=3D __put_user(RISCV_V_MAGIC, &hdr->magic); - err |=3D __put_user(riscv_v_sc_size, &hdr->size); if (unlikely(err)) - return err; + return -EFAULT; =20 - /* Only progress the sv_vec if everything has done successfully */ - *sc_vec +=3D riscv_v_sc_size; - return 0; + /* Only return the size if everything has done successfully */ + return riscv_v_sc_size; } =20 /* @@ -142,10 +139,20 @@ static long __restore_v_state(struct pt_regs *regs, v= oid __user *sc_vec) */ return copy_from_user(current->thread.vstate.datap, datap, riscv_v_vsize); } -#else -#define save_v_state(task, regs) (0) -#define __restore_v_state(task, regs) (0) -#endif + +struct arch_ext_priv { + __u32 magic; + long (*save)(struct pt_regs *regs, void __user *sc_vec); +}; + +struct arch_ext_priv arch_ext_list[] =3D { + { + .magic =3D RISCV_V_MAGIC, + .save =3D &save_v_state, + }, +}; + +const size_t nr_arch_exts =3D ARRAY_SIZE(arch_ext_list); =20 static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) @@ -270,7 +277,8 @@ static long setup_sigcontext(struct rt_sigframe __user = *frame, { struct sigcontext __user *sc =3D &frame->uc.uc_mcontext; struct __riscv_ctx_hdr __user *sc_ext_ptr =3D &sc->sc_extdesc.hdr; - long err; + struct arch_ext_priv *arch_ext; + long err, i, ext_size; =20 /* sc_regs is structured the same as the start of pt_regs */ err =3D __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); @@ -278,8 +286,20 @@ static long setup_sigcontext(struct rt_sigframe __user= *frame, if (has_fpu()) err |=3D save_fp_state(regs, &sc->sc_fpregs); /* Save the vector state. */ - if ((has_vector() || has_xtheadvector()) && riscv_v_vstate_query(regs)) - err |=3D save_v_state(regs, (void __user **)&sc_ext_ptr); + for (i =3D 0; i < nr_arch_exts; i++) { + arch_ext =3D &arch_ext_list[i]; + if (!arch_ext->save) + continue; + + ext_size =3D arch_ext->save(regs, sc_ext_ptr + 1); + if (ext_size <=3D 0) { + err |=3D ext_size; + } else { + err |=3D __put_user(arch_ext->magic, &sc_ext_ptr->magic); + err |=3D __put_user(ext_size, &sc_ext_ptr->size); + sc_ext_ptr =3D (void *)sc_ext_ptr + ext_size; + } + } /* Write zero to fp-reserved space and check it on restore_sigcontext */ err |=3D __put_user(0, &sc->sc_extdesc.reserved); /* And put END __riscv_ctx_hdr at the end. */ --=20 2.43.0