From mboxrd@z Thu Jan 1 00:00:00 1970 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 77D3A1292FF; Thu, 13 Jun 2024 12:24:17 +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=1718281457; cv=none; b=ir5rzg5C/5yCGuxcDUOGT3f1rJ/0J21/2WrIOTtCmHrDBsmkFY6M/DvuEou3vPGwwru5ImW3pz8Ie4dvj88CVpckuuT9dxbwjUMh8bflo0miih6lahM3gXfHPT8R1RDcVtEwN03t/icZCvPCnkPKBl0OumnkszZf4eTmktYC1aM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718281457; c=relaxed/simple; bh=D1ANCdK0p2QUUqSuFfeE0GBTmHqui7DEAu2aljf2ba0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NPKv+SBme0yzE1PIVE8jn4kNuMUMkG9NH0mc4LjWrPe6MX7YS5qACGr+3KOZV2XgroXtcXv1YQrIjel0rlgP7UJQPsqkx4r50C2td1rFRIjFrananBz++fBckzWoFXCq7qnjzBRLHS0GfOc+PPn745//Cm0XKfg65pRTlIjKbj8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rK5BXFjL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rK5BXFjL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4DDEC2BBFC; Thu, 13 Jun 2024 12:24:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718281457; bh=D1ANCdK0p2QUUqSuFfeE0GBTmHqui7DEAu2aljf2ba0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rK5BXFjL6etfTjnP/k2b5IQoP8wkTRMHjwVocUZpeRfm7ID9ACTXPMj6p/ZWpODRJ 1E0SCmLFNGs1/sea4ZDcvr+KMbdgkA2WbaDH6k2rwsd9MBWRqUEJUEllzxypCp0Z3K yeTlWZ3ZFjZTvv5v8JNYRBjFe1yhAuEyIIe0ky60= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christophe Leroy , Michael Ellerman , Sasha Levin Subject: [PATCH 5.10 260/317] powerpc/uaccess: Use asm goto for get_user when compiler supports it Date: Thu, 13 Jun 2024 13:34:38 +0200 Message-ID: <20240613113257.605251513@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113247.525431100@linuxfoundation.org> References: <20240613113247.525431100@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christophe Leroy [ Upstream commit 5cd29b1fd3e8f2b45fe6d011588d832417defe31 ] clang 11 and future GCC are supporting asm goto with outputs. Use it to implement get_user in order to get better generated code. Note that clang requires to set x in the default branch of __get_user_size_goto() otherwise is compliant about x not being initialised :puzzled: Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/403745b5aaa1b315bb4e8e46c1ba949e77eecec0.1615398265.git.christophe.leroy@csgroup.eu Stable-dep-of: 50934945d542 ("powerpc/uaccess: Use YZ asm constraint for ld") Signed-off-by: Sasha Levin --- arch/powerpc/include/asm/uaccess.h | 55 ++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 6b808bcdecd52..d4d59f57c42d9 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -243,6 +243,59 @@ extern long __get_user_bad(void); : "=r" (err) \ : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err)) +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT + +#define __get_user_asm_goto(x, addr, label, op) \ + asm_volatile_goto( \ + "1: "op"%U1%X1 %0, %1 # get_user\n" \ + EX_TABLE(1b, %l2) \ + : "=r" (x) \ + : "m"UPD_CONSTR (*addr) \ + : \ + : label) + +#ifdef __powerpc64__ +#define __get_user_asm2_goto(x, addr, label) \ + __get_user_asm_goto(x, addr, label, "ld") +#else /* __powerpc64__ */ +#define __get_user_asm2_goto(x, addr, label) \ + asm_volatile_goto( \ + "1: lwz%X1 %0, %1\n" \ + "2: lwz%X1 %L0, %L1\n" \ + EX_TABLE(1b, %l2) \ + EX_TABLE(2b, %l2) \ + : "=r" (x) \ + : "m" (*addr) \ + : \ + : label) +#endif /* __powerpc64__ */ + +#define __get_user_size_goto(x, ptr, size, label) \ +do { \ + BUILD_BUG_ON(size > sizeof(x)); \ + switch (size) { \ + case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break; \ + case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; \ + case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; \ + case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label); break; \ + default: x = 0; BUILD_BUG(); \ + } \ +} while (0) + +#define __get_user_size_allowed(x, ptr, size, retval) \ +do { \ + __label__ __gus_failed; \ + \ + __get_user_size_goto(x, ptr, size, __gus_failed); \ + retval = 0; \ + break; \ +__gus_failed: \ + x = 0; \ + retval = -EFAULT; \ +} while (0) + +#else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ + #define __get_user_asm(x, addr, err, op) \ __asm__ __volatile__( \ "1: "op"%U2%X2 %1, %2 # get_user\n" \ @@ -299,6 +352,8 @@ do { \ prevent_read_from_user(ptr, size); \ } while (0) +#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ + /* * This is a type: either unsigned long, if the argument fits into * that type, or otherwise unsigned long long. -- 2.43.0